🎩 👨🏿‍⚕️ 👨‍👩‍👧‍👧 Simulation model of the process of processing material by cutting on a CNC lathe 👨🏾 👏🏾 💅🏾

Introduction

The methodology for the development of simulation models and simulators in various technical disciplines is mainly focused on reducing the level of abstraction of educational material. Along with the theoretical teaching material, visual simulation of a particular technological process or operation allows the student to more fully master the taught material with the maximum approximation to natural conditions. In this case, simulation models and simulators can only be considered as an auxiliary tool in the educational process. The main purpose of this category of educational resources is a basic (initial) familiarization with the principles of operation of complex technical facilities in the absence of the possibility of using real industrial equipment,or in order to preliminary increase the competence of the student before undergoing practical training.

Of particular relevance is the methodology of combining educational tasks with engineering and applied tasks in a single toolbox that meets the current level of development of technology and industry as a whole. Here we are talking about the integrated implementation of computer-aided design (CAD / CAM) functions and the principles of simulation-numerical simulation of technological processes.

The main trend in introducing simulation training models into engineering education practice is to achieve maximum interactivity. A prerequisite here is the ability to perform “erroneous” actions by students and adequate response of the simulation model to these actions in order to achieve the required level of understanding of the educational material for students. The higher the degree of freedom of the simulated object (device or machine), the greater the effect of real interaction is achieved in the learning process.

The purpose and objectives of the project

The aim of the presented project is to develop an educational and methodological software product (simulation model or simulator), intended for the basic familiarization of novice engineering specialists with the principles of programming the operations of turning parts using a standard G / M code.

Fields of application of the software product primarily cover the educational process using computer technology in the form of laboratory classes for students in computer classes, distance learning, as well as demonstration support of lecture material in the group of training areas and specialties (OKSO) “Metallurgy, mechanical engineering and material processing”. The flexible functionality and mobility of the software product also allows it to be used as an application tool for verification and preliminary testing of control programs for material turning operations on numerically controlled machines (CNC) using Fanuc program code (code system A).

The functionality of the simulator should provide the following tasks:

G/M ;
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The technical advantage of the simulator under development is its relatively low resource consumption and multi-platform support, allowing you to use this software product on various computing devices, including interactive whiteboards, smartphones, tablet and desktop computers, which, in turn, increases the flexibility and mobility of the educational process, corresponding to the modern level of information education.

Modeling object

The basis of the three-dimensional simulation model is the TS1625FZ lathe manufactured by the Tver machine-tool plant of StankoMashKompleks JSC with a horizontal bed and a classic assembly of units, equipped with a CNC system, an eight-position turret, a three-jaw turning cartridge, a tailstock, a lubricant-coolant supply system and other units. Material processing is performed in two coordinates in the horizontal plane of the machine. The main technical characteristics of the equipment prototype are presented in table 1.

The simulator simulates a set of cutting tools (prefabricated turning tools and drills), including 185 items. The types of replaceable cutting inserts used for turning tools are presented in table 2.

Also in the model, cutters with special thread-cutting plates and drills are used. Figure 1 shows a geometric model of a precast turning tool.

Figure 1 - Geometrical model of a precast turning tool and designation of the main characteristics of a removable cutting insert: the main angle in terms of φ1, the auxiliary angle in terms of φ2, the diameter of the inscribed circle D, the radius of rounding at the vertex R

A brief description of the method of geometric modeling of the formation of parts during turning

In the project under consideration, a simplified model of shaping the workpiece is used, based on the assumption that the axial symmetry of the part is constant throughout the entire turning process [1, 2]. This model excludes the possibility of constructing helical surfaces, and threaded elements of parts are depicted conditionally - by sections of concentric ribbing. Basic calculations using this technique are formalized by the geometric problem of intersecting two flat closed loops in the working plane of the machine — the contour of the workpiece and the contour of the cutting tool. Based on the shape-forming contour, which is a logical difference at the intersection of two source contours,a three-dimensional surface of the simulated part is formed by uniformly turning the forming contour around the main axis of the machine (axis of rotation of the workpiece). The applied method makes it possible to simulate the shaping of a part such as a body of revolution in real time at relatively low computational costs.

The initial stage of the algorithm is the formation of many points Wi of the contour of the workpiece (Fig. 2.a). In the initial state (before the start of the processing process), the part contour includes four points, while the longitudinal section of the part is represented by a rectangle. In subsequent iterations of the algorithm, the initial contour of the part is the previously calculated shape-forming contour. The contour is described counterclockwise.

At the second stage of the algorithm, the contour of the cutting insert of the turning tool is formed taking into account its geometric characteristics - overall dimensions, the main angle in plan and the radius of rounding at the apex. The contour of the insert is described by points Cj in the opposite direction with respect to the contour of the part (clockwise).

Figure 2- To the task of calculating the shape-forming contour of the workpiece: the
intersection of the original contours of the part and the cutting insert (a); obtaining the shape-forming contour of the part as the logical difference of the source contours (b)

The third stage of the algorithm is to determine the set of intersection points Ik of the source contours. In this case, the found intersection points are indexed in accordance with how much closer they lie to the starting point of the part’s contour, and are included in the generalized set of points of both contours in the indexing order. The coordinates of the intersection points are determined for two segments belonging to two different contours (Fig. 3).

Figure 3 - Towards determining the coordinates of the intersection point of two segments

For the segments P1 – P2 and P3 – P4 belonging to two intersecting straight lines L1 and L2, it follows:

The x, y coordinates of the intersection point of the lines L1 and L2 are determined by the matrix equation:

therefore: The

points of the generalized set belonging to the contour of the cutting insert are outside the intervals between the points intersections are excluded from the generalized set of points of both contours. Thus, the final set of points Fn is formed that describe the shape-forming contour of the part (Fig. 2.b). The resulting contour is described in the same direction as the original contour of the part.

The considered algorithm is a simplified version of the Weiler – Azerton cut-off algorithm [3]. A number of simplifications of the algorithm is due to the geometrical features of the problem being solved, namely: a constant condition for the convexity of the cutting insert contour, conditions for detecting collisions of inoperative elements of the cutter (holder) with the workpiece, the condition for excluding the completely cut-off part of the part from the computational process when modeling the operation segments, etc.

Due to the fact that the shaping of the part is carried out during the movement of the cutting tool, at each iteration of the algorithm, a discrete change in the coordinates of the points of the contour of the cutting insert relative to the contour of the workpiece occurs. The step of discreteness in this case is due to a given parameter of the movement of the cutting tool (the value of the working feed) and the iteration time of the simulation cycle. In this case, the step of discreteness of movement of the tool (δ) may exceed the linear dimensions of the overlapping area of the contours of the cutting insert and the workpiece (Fig. 4.a), which leads to the appearance of artifacts (“uncut” sections) of the forming contour of the part (Fig. 4.b )

Figure 4 - The problem of discreteness of computing intersections of contours

One solution to the described problem is the Jarvis method, which consists in constructing a minimal convex hull around the set of vertices of the contours of the cutting insert in the current and previous discrete states (Fig. 5).

Figure 5 - Construction of the minimum convex hull around the contours of the cutting insert in two successive discrete states

In this case, the intersection of the contour of the workpiece with the contour of the minimum convex shell is calculated, which provides the required overlap area in the gaps between the discrete states of the cutting tool. When constructing a minimal convex hull, the condition of invariance of the circumvention of its contour is especially important. The minimum convex hull can cover several discrete states of the cutting insert, provided that the direction of the working feed of the cutter does not change in these states (the cutter moves along a straight path).

In the project under consideration, an alternative method of eliminating artifacts of the formative contour is used, based on the Ramer – Douglas – Peker generalization algorithm [4, 5], which is widely used in topography and cartography problems. The main goal of the recursive generalization procedure is to reduce the number of vertices of the polyline based on a given threshold value of the distance between the vertices. The initial condition for the algorithm to work is to select the most distant point with respect to the starting point of the polyline of the contour. In subsequent iterations of the algorithm, the distances between the intermediate points of the polyline are determined and compared with the threshold value. The connection of points in the approximating polyline is carried out provided that the distance between them exceeds a predetermined threshold value (Fig. 6).

Figure 6- Iterations of the Ramer-Douglas-Pecker generalization algorithm using an example of an arbitrary broken line.

Technically, the procedure for approximating the shape-forming contour of a part is combined with the initial stage of the general modeling algorithm, at which many vertices of the initial contour of the workpiece are formed.

The formation of the three-dimensional surface of the simulated part is carried out by calculating the coordinates of the points in the circles of the cross sections of the part along the length of the shape-forming contour, followed by combining these points into triangular facets (between sections). The length of the radius vector Ri of each point of the forming contour is calculated as the distance from this point to the main axis of the machine (Fig. 7).

Figure 7- Polygonal model of a part such as a body of revolution in a section (partition of polygons into triangular facets not shown)

The order of traversal of vertices when assembling a three-dimensional frame is strictly defined. Each polygon of a three-dimensional surface is divided into 2 triangular facets, uniting 4 vertices (Fig. 8). The radial smoothness of the formed three-dimensional surface depends on a given number of segments (circle sectors) in the section of the simulated part. The procedure for assembling a three-dimensional wireframe also calculates the normal vectors at each vertex (Fig. 9) and the texture coordinates of UV. According to the calculated texture coordinates, the surface of the part is drawn with an overlaid image of the metal texture, which in turn increases the realistic perception of the simulated process.

Thus, the final three-dimensional model of the workpiece allows you to visualize the results of material removal by the cutter in real-time dynamics with the required degree of realism.

Figure 8 - The facet skeleton of the three-dimensional model of the workpiece, inscribed in the overall cylinder of the original workpiece

Figure 9 - Normal vectors at the vertices of the facet model of the workpiece

The principles of simulation of numerical program control of the process of turning material

The list of basic functions of program control of the machine

As a linguistic basis for programming the basic technological operations during material turning, GM codes of the Fanuc numerical control system were selected:

G00 / G01 - linear interpolation at accelerated / working feed;
G02 / G03 - circular interpolation clockwise / counterclockwise;
G04 - time delay;
G20 / G21 - data entry in inches / millimeters;
G32 / G34 - threading with constant / variable pitch in one pass;
G50 - setting the maximum spindle speed;
G53 – G59 - switching between working coordinate systems No. 1–6;
G70 – G76 - main turning cycles;
G80 – G83- hole machining cycles;
G90 - the cycle of the main turning of the outer / inner diameter;
G92 - constant-pitch threading cycle;
G94 - cycle of the main external / internal end turning;
G96 / G97 - constant cutting / rotation speed of the spindle;
G98 / G99 - feed rate [mm / min] / feed rate [mm / rev];
M00 / M01 - soft stop with confirmation;
M02 / M30 - completion of the control program;
M03 / M04 - start spindle rotation clockwise / counterclockwise;
M05 - spindle rotation stop;
M07 – M09 - turning on / off the coolant supply;
M38 / M39- opening / closing of automatic doors;
M97 – M99 - call and end of internal / external routines.

The structure and format of the control program code

The control program code is represented as a sequence of lines (frames). The simulator allows you to develop and execute control programs up to 999 frames (taking into account the first uneditable line containing the number of the control program). Each frame consists of a sequence of words, which is a combination of an alphabetic address and a numerical parameter. No spaces are allowed between the address and the parameter. The typing of the control program is carried out in alphanumeric characters using a monospace font. Some special characters are allowed. Any group of characters that cannot be parsed should be enclosed in parentheses or written after the characters “;” or "/". This information is considered a comment on the code and is not analyzed during the simulation.The addresses of the preparatory (G) and auxiliary (M) functions are programmed with integer parameters defining the numbers of these functions. Numerical positioning parameters (after addresses X, Z, U, W, I, K, R, etc.) can be specified in fractional or integer values. The minus sign is allowed here.

After starting the simulation process, the control program code is automatically checked for compliance with the format. In case of errors, the corresponding messages are displayed.

Brief description of control program parsing algorithm

Syntactic analysis (parsing) of the control program (UE) code and simulation of its execution are carried out according to the standard algorithm [6], the block diagram of which is shown in Figure 10.

Figure 10 - Block diagram of the UE parsing algorithm

In accordance with the block diagram shown in Figure 10 the parsing scheme of the control program begins with the formation of a list of frames. For each frame, a list of words is generated. A word is a data structure — a command that includes a letter address and a numeric parameter. Teams are conditionally classified as modal and positional.

Modal commands change the status of the simulation model of the machine, and determine its current state - the mode of movement of the tool (moving at accelerated or working feed, type of interpolation), spindle rotation mode, position of automatic doors, condition of the cooling system, etc. In turn, positional commands directly determine the parameters of movements - the coordinates of the end points, the parameters of the arcs during circular interpolation, etc.

According to the obtained motion parameters, the coordinates of the cutting tool, the rotation angles of the rotating elements of the machine, the position of the automatic doors, etc. are interpolated. Thus, a frame-by-frame simulation of the control program occurs. When the last frame is reached, the simulation process ends.

Implementation of turning tool movement control

By analogy with a real CNC system, the movement of the cutting tool is programmed by linear and circular interpolation methods. Linear interpolation is the main type of movement when machining on a CNC lathe. With linear interpolation, the tool moves along a straight path with the known coordinates of its beginning and end (Fig. 11).

Figure 11 - Trajectory of the tool during linear interpolation

When the calculated point C moves from point A to point B along a straight line section with a constant feed rate, both coordinates are linearly interpolated in time. By designating the start time of the movement as tA and the end time as tB, the current coordinates of point C corresponding to the current time tC can be determined by linear interpolation formulas:

The final travel time is defined as:

where tS is the time spent on a straight travel at a constant feed rate F (mm / min):

Linear interpolation at rapid feed is programmed with the modal function G00 (this function is active in the initial state of the CNC system). Linear interpolation at the feed rate is programmed with the modal function G01. After these functions, the coordinates of the end point of the straight section of the path are set. The current position of the tool is always taken as the starting point. The set feedrate for rapid traverse is ignored. The coordinates of the end point can be specified in absolute values (X, Z), that is, relative to zero of the working coordinate system, or in relative (incremental) values (U, W), that is, relative to the starting point of a rectilinear trajectory. If one of the coordinates is omitted, movement along its axis is not carried out.

Circular interpolation is used to grind curved surfaces, the shape of which is described by an arc of a circle of a certain radius. Two arc programming methods are used. The first method is to set the coordinates of the center of the arc and the end point, while the radius of the arc is calculated automatically. The second method involves specifying the radius of the arc and the coordinates of the end point, while the coordinates of the center of the arc are automatically calculated. Clockwise circular interpolation is specified using function G02, and counterclockwise circular interpolation is specified by function G03, respectively.

Consider one of the cases of circular interpolation counterclockwise with the center of the arc (Fig. 12.a). When the calculated point C moves from point A to point B along an arc with a constant feed rate, both coordinates can also be interpolated in time. The trajectory of motion is determined by the position of the end point B and the position of the center of the arc O in incremental coordinates (i, k) relative to the starting point A. The

angular position of the radius vectors OA, OB and OC is described by the trigonometric angles φA, φB and φC, respectively.

Figure 12 - The tool path during circular interpolation counterclockwise with the task: the center of the arc (a); arc radius (b)

By designating the start time of the movement as tA and the end time as tB, the angle φC corresponding to the current time tC can be determined by the linear interpolation formula:

where φA, φB are the trigonometric angles of the radius vectors of the starting and ending points of the arc:

Note: when calculating trigonometric the angles of the extreme points of the arc, it is necessary to take into account situations in which the arc tangent function takes singular values.

The Cartesian coordinates of point C are defined as:

where

The final time of displacement is determined by expression (6). In this case, the time tS spent on moving along the arc at a constant feed rate F (mm / min) can be determined using the expression for the length of the arc:

The incremental coordinates of the center of the arc are programmed with addresses I and K in the directions of the X and Z axes, respectively. When programming circular interpolation with an indication of the center of the arc, it is necessary that the radius vectors of the start and end points of the arc have the same length.

Circular interpolation is always performed on the feedrate.

The second method for programming an arc is to specify the radius of the arc circle. In this case, two cases of setting the radius are allowed - with a positive or negative value. If the radius value is positive, the arc angle is less than 180 degrees. Otherwise, the angle of the arc is more than 180 degrees (Fig. 12.b). When defining an arc with a radius, the TNC automatically determines the position of the center of the arc (O + or O– depending on the sign of the radius). In this method of specifying the arc, the condition must be met: the radius modulus cannot be less than half the length of the chord (AB) of the arc.

Figure 13 shows an example of the formation of a curved surface when programming circular interpolation counterclockwise.

Figure 13 - The formation of a curved surface when programming circular interpolation counterclockwise

Implementation of functions of work with coordinate systems

The presented simulation model includes several coordinate systems (Fig. 14). The main and invariable coordinate system is the coordinate system of the machine with the origin corresponding to the machine zero point M, geometrically coinciding with the point of intersection of the end plane of the spindle and its axis of rotation.

Figure 14 - The basic coordinate system of the simulation model The

second important coordinate system is the reference coordinate system with the origin corresponding to the reference point R or the point of tool change. In this coordinate system, the basic movements of the moving parts of the machine are calculated, and collisions of the tool with the structural elements of the machine are determined when modeling possible emergency situations.

The programming of the turning process is carried out in the working coordinate system. The simulator provides 6 independent working coordinate systems with zero points W1–6. The initial settings for the position of these zeros are set by the user in the parameters of the simulation model and are designated as zero corrections.

The directions of the axes in each coordinate system are the same. The longitudinal axis Z is always directed from the turning chuck towards the tailstock of the machine. The transverse axis X (or the axis of the diameters) is directed towards the caliper (towards yourself with a front view to the machine). The Y axis is the normal to the work plane ZX and is directed vertically upward. Movements in the direction of the Y axis in the considered model of the machine are not carried out.

Switching between working coordinate systems is carried out programmatically using the corresponding functions G54 – G59 (for coordinate systems with zero points W1 – W6, respectively). The zero coordinates W1–6 are calculated in the machine coordinate system relative to machine zero M. The syntax of the functions G54 – G59 suggests two possible ways to use them. In the first version, the functions are set without specifying the X and Z coordinates. In this case, the position of the selected working coordinate system is determined by the predefined zero corrections. In this case, the functions G54 – G59 can be programmed separately in an individual block or in one block with other commands. The second option for using the G54 – G59 functions involves the programmed displacement of the axes of the selected working coordinate system relative to a predefined zero W1.In this case, the X and Z axis offsets are programmed immediately after the function in the same block (for example, “G54 X30.5 Z15”). Figure 15 shows the position of the first coordinate origin after programmatically shifting the axes to a point [X = 10, Z = –20] relative to the initial zero position W1 specified in the zero corrector settings block.

Figure 15 - Illustration of the software offset of the axes of the working coordinate system No. 1

Programming with respect to machine zero is carried out using function G53. This function is not modal, and is executed in the block in which it is programmed. The function temporarily cancels the modal functions of the G54-G59. In this case, all movements are counted in the coordinate system of the machine with the beginning at point M, and the active zero corrector is temporarily canceled. The G53 function must be programmed whenever it is necessary to indicate the coordinates relating to machine zero. The syntax of the function does not imply the presence of parameters after the word G53. The function is programmed in any block that has path control commands (for example, “G53 G00 X0 Z120”). Figure 16 shows the position of the origin of the working coordinate system during the operation of function G53.

Figure 16 - Illustration of the position of the origin of the working coordinate system during the operation of function G53

Implementation of basic turning and hole machining cycles

The implemented control program parsing algorithm allows simulating the execution of turning and drilling cycles of the Fanuc system. When each cycle is performed, a so-called buffer list of frames is created in the memory of the computing device, including intermediate tool movements when a programmed part contour is received. Turning cycles are defined by one or two consecutive initiating frames, in which the main parameters of the cycle are prescribed - roughing and finishing allowances, cutting depth during roughing with the cutter, the number of roughing passes with the cutting, the amount of cutting back, parameters of the processing mode, etc. The part contour is programmed by a sequence of frames with the required numbering of the first and last frame.

The stock removal cycle parallel to the Z axis is initiated by function G71. The parameters of the cycle are programmed in two consecutive blocks in the format: where in the first block: U is the processing depth for rough passes (programming mode in radii), R is the distance of the cutter retraction after the end of each pass; in the second frame: P is the sequence number of the first description frame of the processed circuit; Q is the serial number of the last frame of the description of the machined contour, U is the size and direction of removal of the finishing allowance along the X axis (programming mode in diameters), W is the value and direction of removal of the final allowance along the Z axis, F is the feed rate for roughing cutters, S - spindle speed or cutting speed during finishing.

G71 U_ R_
G71 P_ Q_ U_ W_ F_ S_

Figure 17 shows the tool paths during the G71 turning cycle. The green lines show the movements of the cutter on the working feed, the purple lines show the accelerated feed. As can be seen from the figure, the processed circuit may include curved sections programmed by the method of circular interpolation.

Figure 17 - Trajectories of the cutting tool during the G71 turning cycle and a code fragment of the control program

The allowance removal cycle parallel to the X axis is initiated by the G72 function. The programming principle of this cycle is similar to the G71 cycle. The execution of rough passes by the cutter is carried out in the direction of the X axis of the working coordinate system. The loop parameters are programmed in two consecutive blocks in the format:

G72 W_ R_
G72 P_ Q_ U_ W_ F_ S_

where in the first frame: W is the working depth for rough passes, R is the distance of the cutter retraction after the end of each pass; in the second frame: P - serial number of the first description frame of the machined contour, Q - serial number of the last description frame of the machined contour, U - size and direction of removal of the finishing allowance along the X axis (programming mode in diameters), W - size and direction of removal of the final allowance along the Z, F axis is the feed rate for rough passes with a cutter, S is the spindle speed or cutting speed during finishing.

Figure 18 shows the tool paths during the G72 turning cycle.

Figure 18 - Trajectories of the cutting tool during the execution of the turning cycle G72 and a code fragment of the control program

The stock removal cycle parallel to the specified contour is initiated by function G73. The loop parameters are programmed in two consecutive blocks in the format:

G73 U_ W_ R_
G73 P_ Q_ U_ W_ F_ S_

where in the first frame: U is the size and direction of removal of the total allowance along the X axis (programming mode in radii), W is the value and direction of removal of the total allowance along the Z axis, R is the number of consecutive passes when removing the rough allowance, including a half-pass; in the second frame: P is the sequence number of the first description frame of the processed circuit; Q - serial number of the last description frame of the processed circuit; U is the value and direction of removal of the finishing allowance along the X axis (programming mode in diameters), W is the value and direction of removal of the final allowance along the Z axis, F is the feed rate for rough cuts, S is the spindle speed or cutting speed during finishing .

Figure 19 shows the tool paths during the G73 turning cycle.

Figure 19 - Trajectories of the cutting tool during the G73 turning cycle and a code fragment of the control program

The final stock removal cycle is initiated by the G70 function. The parameters of the cycle are programmed in one

G70 P_ Q_ F_ S_

block in the format: where P is the sequence number of the first description frame of the machined contour, Q is the sequence number of the last description frame of the machined contour, F is the feedrate during finishing, S is the spindle speed or cutting speed during finishing.

The G70 Finishing Cycle complements Cycles G71, G72, and G73. It allows you to finish the contour after applying the cycles of rough turning. Using the G70 cycle as an independent cycle is impractical.

Programming the machining of the outer / inner and end grooves is carried out using special cycles G74 and G75.

End grooving / rebound cycle initiated by function G74. The parameters of the cycle are programmed in two consecutive blocks in the format: where in the first block: R is the distance to which the cutting tool is retracted after completing the grooving step; in the second frame: X (U) - coordinate of the end point on the X axis, Z (W) - coordinate of the end point on the Z axis, P - step of the groove on the X axis in microns, Q - step of the groove on the Z axis in microns, F - feed rate.

G74 R_
G74 X(U)_ Z(W)_ P_ Q_ F_

Figure 20 shows the tool paths during the grooving cycle of the end grooves G74. When performing this cycle, the tool after each working pass is retracted by the specified rebound value in order to remove chips from the machined groove. The G74 cycle can also be used when programming the end hole drilling operation.

Figure 20 - Trajectories of the cutting tool during the execution of the grooving cycle of the end grooves G74 and a code fragment of the control program

The groove cycle of the external / internal grooves with a rebound is initiated by the G75 function. The principle of using the G75 cycle is similar to the G74 cycle. The groove groove is carried out in the direction of the X axis. The set value of the groove pitch along the Z axis allows grooving with overlapping. After each working pass, the tool is retracted by a predetermined rebound value. The parameters of the cycle are programmed in two consecutive blocks in the format: where in the first block: R is the distance to which the tool is retracted after the completion of the grooving step; in the second frame: X (U) - coordinate of the end point on the X axis, Z (W) - coordinate of the end point on the Z axis, P - step of the groove on the X axis in microns, Q - step of the groove on the Z axis in microns, F - feed rate.

G75 R_
G75 X(U)_ Z(W)_ P_ Q_ F_

Figure 21 shows the tool paths during the grooving cycle of the outer groove G75.

Figure 21 - Trajectories of the cutting tool during the grooving cycle of the external / internal grooves G75 and a code fragment of the control program.

For processing threaded joints, a multi-pass threading cycle initiated by the G76 function is implemented. The loop parameters are programmed in two consecutive blocks in the format:

G76 Pxxyyzz Q_ R_
G76 X(U)_ Z(W)_ R_ P_ Q_ F_

where in the first frame: xx is the two-digit number of screw passes with a thread-cutting tool; yy is a two-digit number that defines the size of the chamfer, zz is a two-digit number that determines the angle of the cutting edge of the cutting tool, Q is the minimum depth of threading in microns (programming mode in radii), R is the depth of cut during the final pass; in the second block: X (U) - coordinate of the end point of threading on the X axis, Z (W) - coordinate of the end point of threading on the Z axis, R - amount of movement along the X axis when cutting tapered thread (not programmed when cutting cylindrical thread ), P is the height of the thread in microns, Q is the depth of threading for the first pass in microns, F is the thread pitch along the Z axis.

Figure 22 shows the tool paths during a multi-pass cylindrical thread G76 cycle. Blue lines indicate the movement of the thread-cutting tool on the working feed.

Figure 22 - Trajectories of the cutting tool during a multi-pass thread cutting cycle G76 and a code fragment of the control program

Cycle G76 also allows you to program the processing of tapered threads (Fig. 23).

Figure 23 - Trajectories of the cutting tool during a multi-pass taper thread G76 and a code fragment of the control program

When programming the machining of threaded joints, an alternative constant-pitch threading cycle initiated by the G92 function can be used. The cycle parameters are programmed in one block in the format:

G92 X(U)_ Z(W)_ R_ F_

where X (U) is the coordinate of the end point of thread cutting along the X axis, Z (W) is the coordinate of the end point of thread cutting along the Z axis, R is the amount of movement along the X axis when cutting tapered thread (not is programmed when cutting cylindrical threads), F is the thread pitch along the Z axis.

Each working pass with a thread-cutting tool is programmed as a separate block, which goes in the general sequence of frames after the G92 cycle initialization block. In this case, only the X coordinate is specified, that is, the diameter value at which the calculated point of the cutter is located on the current working pass.

Figure 24 shows the tool paths during a taper cycle with a constant pitch of G92.

Figure 24 - Trajectories of the cutting tool during the threading cycle with a constant pitch G92 and a code fragment of the control program

To program the grooving of long cylindrical or conical sections of the part, the main turning / outside diameter turning cycle initiated by the G90 function is used. The structure of the cycle is similar to the threading cycle G92. Before the start of the cycle, the cutter is displayed at the starting point. The cycle parameters are programmed in one block in the format:

G90 X(U)_ Z(W)_ R_ F_

where X (U) is the coordinate of the end point along the X axis, Z (W) is the coordinate of the end point along the Z axis, R is the change in the radius of the base of the cone, F is the feedrate.

Each working pass with the cutter is programmed by a separate block, which goes in the general sequence of frames after the G90 cycle initialization block. In this case, only the X coordinate can be specified, that is, the diameter value at which the calculated point of the cutter is located on the current working pass. Also in the frames of the description of the working passages, the Z coordinate can also be set in case it is necessary to process the stepped part of the part. Figure 25 shows the tool paths during the main turning cycle of the outer / inner diameter G90.

Figure 25 - Trajectories of the cutting tool during the cycle of the main turning of the outer / inner diameter G90 and a code fragment of the control program

The machining of the end surfaces of parts can be programmed using the main external / internal end turning cycle initiated by the G94 function. The parameters of the cycle are programmed in one block in the format:

G94 X(U)_ Z(W)_ R_ F_

where X (U) is the coordinate of the end point along the X axis, Z (W) is the coordinate of the end point along the Z axis, R is the change in the radius of the base of the cone, F is the feedrate.

By analogy with the G90 cycle, the cutter passes are programmed in separate blocks after the G94 cycle initialization block. In this case, for each passage, the coordinates Z and / or X can be set, as well as the parameter R, which determines the change in the radius of the base of the cone. Figure 26 shows the tool paths during the main external / internal end turning cycle G94.

Figure 26- Trajectories of the cutting tool during the main external / internal end turning cycle G94 and a code fragment of the control program The

simulation model also allows you to program end hole drilling operations using constant cycles: simple single-pass drilling, single-pass drilling with holding at the bottom of the hole and multi-pass (intermittent ) drilling (Fig. 27).

The simple one-pass drilling cycle is initiated by the G81 function, and has the frame format:

G81 X(U)_ Z(W)_ R_ F_

where X (U) is the coordinate of the end point along the X axis, Z (W) is the coordinate of the end point along the Z axis, R is the absolute coordinate of the tool retraction plane along the Z, F axis - feed rate.

The single-pass drilling cycle with a shutter speed at the bottom of the hole is initiated by the G82 function and has the frame format:

G82 X(U)_ Z(W)_ R_ P_ F_

where X (U) is the coordinate of the end point along the X axis, Z (W) is the coordinate of the end point along the Z axis, R is the absolute coordinate of the tool retraction plane along axis Z, P - holding time at the bottom of the hole in milliseconds, F - feed rate.

The intermittent drilling cycle is initiated by the G83 function, and has the frame format:

G83 X(U)_ Z(W)_ R_ P_ Q_ F_

where X (U) is the coordinate of the end point along the X axis, Z (W) is the coordinate of the end point along the Z axis, R is the absolute coordinate of the tool retraction plane along the Z axis, P - the exposure time at the bottom of the hole in milliseconds, Q is the drilling step along the Z axis in microns, F is the feed rate.

The cancellation of the continuous hole machining cycle is carried out by function G80.

Figure 27 - Drill paths during intermittent drilling cycle G83 and a code fragment of the control program

Implementation of general functions of numerical control

Spindle rotation is started clockwise by the modal function M03, and counterclockwise by the function M04, respectively. Spindle rotation is stopped using function M05. Functions M03 – M04 give the command to start the spindle rotation, but do not determine the rotation speed parameters. For this purpose, the main motion function S is used with the rotation speed (or cutting speed) indicated. In this case, the spindle speed is set by address S, after which the number of revolutions per minute is indicated (if the modal function G97 is active). In the event that processing occurs at a constant cutting speed (modal function G96 is active), the number following the address S indicates the cutting speed in m / min. In this case, the actual spindle speed is determined by the calculation based on the expression:

where V is the specified cutting speed m / min, d is the current processing diameter, m, π = 3.14159.

The movement of the machine supports is carried out at working and accelerated feeds. Material processing by cutting is carried out at a working feed. The feedrate is set by the feedrate F in two ways. Using the modal function G98, a mode is set in which the feedrate is set in mm / min. The second programming mode of the feed quantity is carried out using the modal function G99. The feed rate is set in mm / rev. Function G99 is active in the initial state of the CNC system. When cutting a thread with address F, a constant thread pitch or the initial pitch in case of a thread with a variable (increasing or decreasing) pitch is programmed.

Tool function T is used to select and switch the position of a turret equipped with a cutting tool. The function is programmed in the format "T0A0B", where A is the number of the target position of the turret, B is the number of the corrector for the radius of the tool. In the process of switching the position of the turret, the tool returns to the reference point, where the tool disc of the turret is rotated over the shortest distance.

The simulation model implements the ability to use internal and external routines. Internal routines are placed in the main program code after the program termination functions M02 or M30. The call of the internal subprogram is carried out by function M97 in the format:

M97 P_ L_

where P is the frame number of the start of the internal subprogram, L is the number of calls to the internal subprogram.

External subprograms are autonomous texts with their own headings and frame numbering. The simulation model supports five external control programs in one session. The call of external subprograms is carried out by function M98 in the format:

M98 Pxxyyyy

where xx is the number of calls of the external subprogram; yyyy is the number of the external routine (for example, 0005).

The completion of the internal and external routines with the subsequent return to the main program is carried out using function M99.

Other auxiliary functions of the CNC system include: functions to stop the execution of the control program M00 / M01, functions to complete the control program M02 / M30, functions to turn on / off the supply of cutting fluid MZ / M08 / M09, and functions to open / close automatic doors M38 / M39. These functions can be programmed both in separate blocks, and in conjunction with other commands. After performing the functions M02 and M30, the simulation process ends - the tool is taken to the referencing point, the spindle rotation is stopped, the peripheral devices are turned off.

Description of CNC Turning Simulator

General product description

The CNC turning simulator is implemented in the form of a multi-platform graphical application . Type of target computing device and supported platform: IBM-compatible personal computer running Microsoft Windows and Linux operating systems, Apple Macintosh personal computer running MacOS operating system, mobile devices based on Android and iOS operating systems. Additionally, the program can be run in a web browser environment with support for HTML5 technology and hardware support for 3D graphics (WebGL technology). The graphic component of the software uses the OpenGL 2.0 component base. The graphical user interface of the program is implemented in Russian and English.

Minimum system requirements for a computing device:

CPU clock speed: 1.6 GHz;
RAM capacity: 1 GB;
video memory capacity: 512 MB;
screen resolution: 1024 × 768 (for desktop computers);
support for OpenGL version 2.0;
standard keyboard and computer mouse with scroll wheel (for desktop computers);
sound reproduction means (speakers, audio speakers or headphones).

When working with web versions of the application, it is recommended to use the MicrosoftEdge web browser, which is part of the Windows 10 operating system.

User Data Format

During the installation of the software product in the standard "Documents" directory of the operating system, the root directory of the simulator projects is created, which includes a number of subdirectories with examples of control programs. For example, in the Microsoft Windows 10 operating system, the Documents directory is located at: C: \ Users \ Current User \ Documents. Creating, renaming and deleting files and subdirectories should be done using the standard file manager of the operating system.

Simulator project files have the extension * .csdata. For optimization purposes, byte input / output of data is performed, therefore, opening a project file in an external text editor is not possible. The byte structure of the file is presented in table 3.

GUI Structure

The simulator runs in full-screen graphics mode. The sizes of the structural elements of the graphical interface adaptively vary depending on the format (aspect ratio) of the screen. Thus, the execution of the program is possible on screens with different aspect ratios, both close to 1.0 (resolution 1024x768, 1280x1024, etc.), and 2.0 (resolution 1920x1080, 2160x1080, etc.).

Interaction with elements of the graphical interface is carried out using a standard computer mouse (when working on a desktop computer) or by sensory interaction with the screen (when working on an interactive whiteboard, tablet or smartphone).

The main screen of the program is represented by a three-dimensional scene, the main object of which is a graphic polygonal model of a lathe placed in a conditional spatial environment (Fig. 28).

Figure 28 - View of the main screen of the program

Throughout the entire session with the program, a navigation bar is displayed on the right side of the screen. The first (top to bottom) button on the panel is designed to open the program termination dialog. The program shutdown dialog displays warning information about a possible data loss if the current project has not been saved to a file. Closing the dialog screen is also carried out by repeated pressing the corresponding button on the navigation panel. The second button of the navigation panel brings up the dialog screen of the built-in file manager (Fig. 29). The elements of this dialog screen are three vertically arranged buttons: “New Project”, “Open Project” and “Save Project”. The first (top to bottom) function button resets all parameters of the current project to the default values.This action is accompanied by an additional confirmation dialog. The second button displays the elements of the file system in the most traditional representation (Fig. 30).

Figure 29 - Dialog screen of the built-in file manager The

list of directories is presented in the left part of the file open dialog. The root directory is created in the system during the installation of the program. Directories located above the root hierarchy are not accessed through the built-in file manager.

Figure 30 - The dialog box for opening a project file

The right side of the dialog box for opening a file shows a list of files in the current active directory. Files are filtered by extension corresponding to the type of program files (files with a different extension are not displayed in the list).

Navigation in the directory structure is carried out by a single mouse click (or a single click on the touch screen) on the directory name in the list. Return to the upper hierarchical level is carried out by clicking on the upper empty line with the corresponding icon (Fig. 31).

Figure 31 - Image of the return line to the top level of directories.

The file is selected by a similar single click on the file name in the right list. The name of the selected file is displayed in bright green (Fig. 32).

Figure 32 - Highlighting the name in color when selecting a file.

Directory and file lists are equipped with vertical and horizontal scrollbars, allowing you to place any number of list items in a fixed-size field.

The third button on the file manager dialog screen displays a file save dialog, similar to the open dialog, but equipped with a text box for entering the file name (Fig. 33).

Figure 33 - Dialog screen for saving a project file

The text field located at the top of the screen is intended for keyboard input of the file name. If you work on a device without a physical keyboard, you are supposed to use a virtual keyboard, which is a component of the operating system or a stand-alone background application. Enter the file name without extension. When entering text in a field, only text and numeric characters are supported. The maximum length of the input text is 128 characters. If you want to overwrite an existing project file, you must select it in the list of files. In this case, the actual name of the selected file will be displayed in the file name field.

Confirmation (or cancellation) of the action in the dialog screens for opening and saving files is carried out using the corresponding buttons located in the lower right corner of the screen.

The third button of the navigation panel brings up the dialog box for setting the workpiece parameters (Fig. 34).

Figure 34 - Dialog screen for setting blank parameters

The main elements of the blank settings screen are the dimensional reference field and the blank parameters panel. The dimensional reference field shows the working area of the lathe with a top view. The conditional drawing shows the main moving parts of the machine: a three-jaw chuck, turret and tailstock (for long workpieces). Using the appropriate buttons to increase / decrease the numerical values of the first four parameters (on the right panel), the basic dimensions of the workpiece and its departure from the chuck are set (table 4).

Parameters L1 and L2 are the fixed dimensions of the three-jaw chuck, which are set aside from the machine zero point indicated by the letter M. Parameter L3 represents the actual overhang of the workpiece and depends on the parameters L, D and L4 set by the user.

The group of ten parameters located in the lower part of the right panel is intended for changing the values of the machine zero corrections or, in other words, for positioning the zeros W2–6 of five additional working coordinate systems, switching between which is carried out programmatically using the corresponding functions G55 – G59. The coordinates of the zeros of additional coordinate systems are counted from the point of machine zero. The main working coordinate system with zero W1 is always positioned on the right end of the workpiece, fixed in the chuck, taking into account the allowance for primary face machining L5. The working coordinate systems and their zeros are shown in the drawing with colored axes and corresponding icons (Fig. 35).

Figure 35 - Fragment of a drawing of the dimensional reference of the workpiece

Along with the workpiece, a turret with a tool installed in it is shown in the field of the dimensional reference drawing. If the turret is equipped with an axial tool, the drawing simultaneously shows a drill with a nominal longitudinal reach of Zm and a cutter for external machining with a nominal lateral reach of Xm (Fig. 36.a). When using tools only for external machining, the axial tool is not shown in the drawing (Fig. 36.b).

Figure 36 - Various configuration options for the turret when using an axial tool (a) and without using an axial tool (b)

The reference position of the turret is determined in such a way that a theoretical tool with nominal overhangs Zm and Xm has safe longitudinal Z 'and transverse X' indents from the lower right corner of the workpiece contour in plan. The safety margins Z 'and X' are not adjustable and are 30 mm.

When setting the dimensions of the workpiece, the compliance with the conditions for preloading long workpieces by the rear center is automatically controlled. So, if the offset value L3 exceeds 3 diameters of the workpiece, the tailstock quill with the back center installed in it is displayed in the drawing field. When changing the setting of the part after the first machining, the machine is not readjusted with respect to the workpiece binding and the zeros of the working coordinate systems.

The fourth button of the navigation panel brings up the dialog box for setting tool parameters (Fig. 37). On the left side of the screen is a list (catalog) of tools, including 185 names of various tools for external and internal processing of parts. Each item in the list begins with an interactive tool icon that outlines the shape of the plate and the recommended directions for the feeds. To the right of the tool icon are a serial number and a short text description of the tool, including its geometric characteristics and the type of turning in which it is recommended to use this tool. The tool list has a vertical scroll bar.

On the right side of the tool parameter settings screen, a row of square cells with serial numbers from 1 to 8 is located at the top, which corresponds to the positions of the turret.

Figure 37 - Dialog screen for setting tool parameters

To set the tool in the desired position of the turret, you must hover over the icon with the image of the tool in the list, then press the left mouse button and hold it pressed, move the icon to a free cell in the upper right part of the screen, and then release the mouse button. If the tool moves to an already occupied position, it will be automatically returned to the catalog. When working on a device with a touch screen, the movement of tool icons is carried out in a similar way by continuously touching the screen with moving around the screen.

The installed tool is returned to the catalog by a similar movement of the icon. In this case, it is enough to move the icon of the returned tool to any area of the tool list field.

To rearrange an already installed tool from one position to another (free or occupied by another tool), it is enough to move the icon within the position block of the turret. If at the same time the cell into which the tool moves is already occupied by another tool, these tools will be swapped.

Below the block of positions of the turret head is a drawing of the dimensional reference of the tool, showing the model of the tool and equipment in plan, the actual values of the longitudinal and transverse flights, as well as the geometric diagram of the tool insert in the plan.

The position of the zero point of the tool, indicated by the corresponding icon, cannot be changed, and corresponds to the center of the hole in the plane of the front surface of the turret.

Departures of the tool can be changed depending on the type of tool using the buttons for increasing / decreasing the offset value located in the lower right part of the dimension reference drawing field (Figure 38). For external tools, the lateral offset along the X axis changes to a smaller side, and for axial tools, the longitudinal offset along the Z axis changes to a greater or lesser side.

Setting tool departures is one of the stages of setting up the machine. Shortening the outreach of axial tools by deepening them into the cavity of technological equipment (and, accordingly, the turret) allows you to expand the boundaries of the working space of the machine when machining the outer surface near the cartridge, provided that both the axial tools and the tools for external processing are fixed in the turret.

Switching between tools installed in the turret is carried out using the corresponding left / right buttons located in the upper right corner of the dimensional drawing drawing field. The main geometric parameters of the tool are displayed at the bottom of the drawing.

Figure 38 - Drawing view of the dimensional reference of the tool The

axial tool is not used in case of preloading the workpiece by the rear center. Moreover, if the turret is pre-equipped with an axial tool, and the dimensions of the workpiece are changed in the second place, as a result of which the rear center is involved, the axial tool automatically returns to the catalog. In order to avoid this situation, the turret must be completed after dimensional adjustment of the workpiece.

The fifth button of the navigation panel displays on the main screen of the simulator a built-in text editor of control programs (Fig. 39). The text editor has in the upper part a panel of functional buttons necessary for working with the machine control program code. The main part of the text editor is occupied by a text field equipped with vertical and horizontal scrollbars. The button for showing / hiding the virtual keyboard is located in the lower right part of the editor.

Figure 39 - View of the main screen of the simulator with an open editor of control programs

Typing in a text field can be carried out using both physical and virtual keyboards (Fig. 40).

Figure 40 - Virtual keyboard for typing in the code editor

Basic text editing operations in the code editor are similar to text editing operations in the standard Notepad text editor of the Microsoft Windows operating system. The editor allows you to carry out standard text editing operations, including transferring data through the system clipboard (copy, cut, and paste fragments of text). Selecting text fragments is carried out in three ways, including operations with the cursor keys of the physical keyboard (with the Shift key pressed), mouse buttons, and touch interaction with the screen (using the special Select Start button on the virtual keyboard).

The panel of functional buttons of a text editor includes 8 buttons (Fig. 41), the activity status of which depends on the current state of the simulation process, as well as the presence of the selected text fragment.

Figure 41 - Functional buttons panel of the code editor

If not a single fragment is selected in the text of the control program, the Copy button (1) has an additional inscription “ALL”. This means that when you click on this button all the text of the control program will be copied to the clipboard. Otherwise (if there is a selected fragment of text), only the selected text is copied to the clipboard. The “Cut” button (2) is activated when there is a selected fragment of text. When you click on this button, a standard copy operation is performed with the subsequent removal of the selected fragment from the text. The Paste button (3) is activated when there is text in the clipboard. The insert is in the position of the flickering cursor (carriage). If a fragment is selected in the text, this text fragment is replaced.The “Delete” button (4) is designed to instantly delete all the text of the control program with confirmation. The Start, Pause, Stop buttons (5-7) are used to control the simulation process. To start the execution of the control program, you must click on the "Start" button. During the simulation, editing the control program is not available. Button "Directory of used codes" (8) is intended to display on the screen a list of used G / M codes with a brief description of their format.Button "Directory of used codes" (8) is intended to display on the screen a list of used G / M codes with a brief description of their format.Button "Directory of used codes" (8) is intended to display on the screen a list of used G / M codes with a brief description of their format.

Below the functional buttons panel of the text editor of control programs, there are 5 interactive tabs with the names of control programs of the current project. Using these tabs, switching between control programs is carried out. When the simulation process starts, the current open control program is executed.

On the left side of the main screen of the simulator there are additional function buttons (Fig. 42) that are responsible for various program settings.

Figure 42 - Additional functional buttons of the main screen of the program

The “About program” button (1) displays on the screen information about the current version of the program, contact information of the developer, as well as licensed information. The “Switch language” button (2) is used to switch the language settings of the graphical interface of the program. Depending on the current language, the image on the button changes. By default, after installation, the program runs in English. The “Turn on / off sound” button (3) is used to turn on / off the sound accompaniment of the simulation process. The button "Switching the graphics mode" (4) is used to switch the display mode of the 3D model of the machine and the environment. In this case, two display modes are available - the high-poly mode (enabled by default) and the low-poly mode, designed to hide minor graphic elements.In the low-poly mode, the geometric model of the machine is significantly simplified and is shown in monochromatic translucent blocks. In this mode, graphic textures are not displayed, there is no imitation of the environment, cutting fluid and chips. The low-poly mode is used if it is necessary to concentrate the user's attention on the contour of the workpiece and the tool paths. Depending on the current graphic mode, the image on the button changes. The “Turn on / off 2D geometry” button (5) is used to turn on / off two-dimensional geometric constructions in the three-dimensional space of the simulator. 2D geometry refers to graphic elements such as coordinate axes, zero point icons, and the contours of the workpiece and tool.When processing internal surfaces of a part (drilling and boring), displaying a 2D contour of a part to the fullest extent contributes to visual control of the processing of internal surfaces. The “On / Off tool trajectories” button (6) is used to enable / disable the function of displaying tool paths and drills in the cutting plane. The calculation of the trajectory of movement of each tool installed in the turret is carried out from the moment the simulation is launched until its completion. Trajectories are shown by solid colored lines.The “On / Off tool trajectories” button (6) is used to enable / disable the function of displaying tool paths and drills in the cutting plane. The calculation of the trajectory of movement of each tool installed in the turret is carried out from the moment the simulation is launched until its completion. Trajectories are shown by solid colored lines.The “On / Off tool trajectories” button (6) is used to enable / disable the function of displaying tool paths and drills in the cutting plane. The calculation of the trajectory of movement of each tool installed in the turret is carried out from the moment the simulation is launched until its completion. Trajectories are shown by solid colored lines.

Also on the main screen of the program additional textual information is displayed: the number of the current setting of the part, the current simulation time, the coordinates of the calculated point of the cutter, the parameters of the high-speed processing mode. If the text editor of control programs is closed during the simulation, the buttons for controlling the simulation process “Start”, “Pause”, “Stop” and the line of the currently executed frame are displayed at the top of the main screen (Fig. 43).

Figure 43 - Additional elements of the main screen of the program during the simulation with a closed text editor

After machining the part from the first installation, an additional button for changing the installation is displayed on the left side of the main screen (Fig. 44.a). After changing the setup from the first to the second contour of the part, it is mirrored relative to the center of mass of the initial workpiece in the direction of the Z axis, and the screen displays three additional buttons for longitudinal displacement of the part (Fig. 44.b). Pressing the button 1 leads to a discrete longitudinal displacement of the part to the left (towards the machine zero point). Pressing button 2 displaces the part to the right. Button 3 is used to reset the specified displacements of the part. It should be borne in mind that the workpiece is not re-referenced (the location of the zero offsets is saved from the previous setting).

Figure 44 - Additional buttons for setting the part setting

Recalling the workpiece parameters dialog box after machining the part from the first setting initiates the dialog for confirming the reset of part contour changes.

In the lower part of the main screen of the program, the system information about the resources is displayed in small print: the current value of the frame frequency (Frame Per Second), the amount of video memory used in megabytes, the number of polygonal facets displayed on the screen at a time, the number of drawings loaded in the memory, the number of graphic sprites used and time renderings of one full-screen frame in seconds.

In the lower left corner of the main screen there is a button for switching the virtual camera mode (Fig. 45). The button shows the number of the target (next) camera mode to which the screen will be switched. In total, 5 camera operation modes are provided.

Figure 45 - The button for switching the virtual camera mode in various display options

The virtual camera mode No. 1 is controllable. In this case, the camera moves in a spherical coordinate system around the focus point (Fig. 46). The camera’s focus point can be moved in the vertical frontal plane of the model’s space. In addition, the camera can distance itself from the focus point to an arbitrary distance limited by the dimensions of the space.

The main manipulations with the camera in mode No. 1 are carried out using a computer mouse (touch control is described below). At the same time, pressing and holding the left mouse button with the accompanying movement of the mouse moves the focus point of the camera in the frontal plane of space. Pressing and holding the right mouse button with the associated mouse movement rotates the camera relative to the focus point. The rotation angles (azimuth and elevation) of the camera are limited by the dimensions of the model space. Changing the camera distance is carried out by rotating the scroll wheel in the forward and reverse directions.

Figure 46 - Camera control diagram in mode No. 1

To the right of the camera mode switching button (in mode No. 1), the button for disabling camera control with the mouse is displayed (Fig. 47.a).

Figure 47 - Button for switching the virtual camera mode in various display options

When disabling camera control with the mouse, a group of switch buttons (Fig. 47.b) is displayed at the bottom of the main screen to perform touch control of the camera in mode No. 1. Button 1 activates the operation of shifting the focus point of the camera, button 2 - the operation of rotating the camera relative to the focus point, and button 3 - the operation of changing the distance from the camera to the focus point, respectively. The manipulations themselves are carried out by interacting with the touch screen.

Camera modes No. 2-5 are designed to position the camera at a fixed-angle point. Mode No. 2 positions the camera above the top of the current instrument (top view). Perspective camera distortions are disabled in this mode (orthogonal projection is used). In mode No. 3, the camera operates in isometry. Modes No. 4 and No. 5 fix the camera at two additional points of view.

All program settings, including camera position, are saved when shutting down.

The simulator does not simulate specific CNC system software. The control panel of the machine is represented by a conditional display on which the main technological information is displayed during the simulation (Fig. 48). The current coordinates of the cutter’s calculated point along the X and Z axes are presented in the upper left part of the display. These are the coordinates of the programmable point lying on the tool path at the current time. In the initial state, these values are presented in millimeters. When programmatically changing the measurement system, the coordinates (as well as the feed value) are displayed in inches. Units are displayed to the right of the numerical coordinates themselves. All lateral movements are programmed for the diameter of the workpiece. Therefore, the coordinate axes X and Z have different scales.

The current technological parameters are displayed (in yellow) on the bottom left of the display: spindle speed S (rpm), feedrate F (mm / min) and current turret position number T.

There are 6 cells in the bottom right of the display for display active modal functions of the CNC system. From left to right, the following functions are displayed in the cells: spindle rotation direction M03 / M04, coolant system operation M07 – M09, current working coordinate system G53 – G59, work feed type G98 / G99 and interpolation type G00 – G03.

Figure 48 - Appearance of the display of the control system of the simulation model of the machine

Project Development Prospects

The immediate prospects for the development of the presented project include a number of tasks.

Task No. 1: expanding the functionality of the software product in terms of turning technology, including: automated preparation of a calculation and technological map of the processed product, a system for controlling product sizes at all stages of the process simulation, compatibility of control program formats, and support for standards of existing CAD / CAM packages .

Task No. 2: realization of the possibility of user configuration of the simulated machine, including: selection of the type of layout of the main components of the machine, selection and change of types of technological equipment and tools, simulation of the stages of setting up the machine for specific technological operations.

Task No. 3: expanding the functionality in terms of numerical control of the machine, including: support for additional CNC systems, simulating the control panel interface of specific CNC systems, implementing macro programming capabilities and dialog programming of technological operations.

Task No. 4: implementation of a physical and mathematical model of the turning process taking into account the properties of materials, and building on its basis a component of an expert system that engages in a dialogue with the user in the form of recommendations and corrective prompts.

Task No. 5: modification of the forming algorithm of the part, which makes it possible to simulate milling operations using the appropriate drive tool.

Along with the listed main tasks, it is necessary to introduce a number of optimizations into the general functionality of the software product.

Conclusions and Conclusions

To date, the achieved results for the project fully comply with the goals and objectives set at the beginning of the work. The software product has been tested in the educational process on the basis of several educational organizations, including Maikop State Technological University, ANO "UTsDPO CityMasterov-NN" and Central University of Queensland (CQUniversity, Australia). Mobile versions of the application are being tested among private users through the GooglePlay and AppStore platforms . The expansion of functionality in terms of the implementation of the promising tasks described above will improve the performance indicators of the software product and increase its competitiveness in general.

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3. Abramova O. F. - Comparative analysis of algorithms for removing invisible lines and surfaces working in image space / O.F. Abramova, N.S. Nikonova // NovaInfo. Technical science. 2015. No. 38-1.

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Simulation model of the process of processing material by cutting on a CNC lathe