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Soldering components 0201. Nervous, please move away from the screens

Good day, Habr!



I want to share the experience of soldering boards. I will also touch on the installation of very small components with size 0201.

Background


I previously had an article on a similar topic, “Manual installation of complex boards on components 0402, 0603, QFN, LQFP and THT” . I briefly showed how you can solder rather complex boards, with a large number of components, using tweezers and a hairdryer. Until recently, I never developed a board with a passive 0201, but everything happens for the first time.

Sizes


To begin with, let's determine the sizes of passive components. We will only talk about resistors and capacitors, since they are usually the most on the boards and it is most difficult to install them manually.

In my projects, I increasingly began to switch to 0402, as this allows for a denser layout and leave space on the upper layers for polygons and conductors.


Fig. 1. Resistors 0603, 0402 and 0201.

I photographed three tapes (Fig. 1.) with different types of resistors so that they can be visually compared.

Metric dimensions of Yageo resistors:

  • 0603 - 1.6x0.8mm;
  • 0402 - 1.0x0.5mm;
  • 0201 - 0.6x0.3mm.

As you can see, the differences are significant.

Tools


For more than ten years of developing boards and soldering my layouts, I began to pay more attention to tools. They do not have to be many, but they must be “suitable”. I did not post photos, who are interested, you can google. The information is not given for advertising, but to understand which tool you can use.

Tweezers. For the first three years, I used ProsKit 1pk-101t tweezers. Then I installed components 1206, 0805 and 0603. After that, for five years I used “VETUS ESD-10”, installing them also 0402 components. It is slightly softer than the first and the same in size. Over the past few years, I have had two identical goothelp gt-11ESDs. This is a narrow, elongated, soft specimen and is bred by only 8mm (it is on the cover photo for the article). Only to them I was able to normally capture 0201. In addition to this set of tweezers (I kept them all), I use “goot TS-13”, wide, to capture large components (microcircuit, inductance, etc.). There were various intermediates, but they are not worthy of attention.

I have had one soldering station for seven years now, I don’t even remember what it was before. Lukey 852D +.

Solder paste "SolderPlus 7020199 62NCLR-A". Flux "FluxPlus 7019074 6-412-A". I mix them about 1: 1 and apply the resulting mixture to the pads of the components with a syringe.

Arrangement of components on board


With the tool sorted out. Now a little about Altium and how it will help us in the arrangement. I use my component library and partially talked about the necessary fields in my other article, “Developing a module on iMX8. Features of trace transfer. ” . So, if all the necessary fields for the components are present, then the task is simplified. Right-click on the component and select the Find Similar Objects menu item.


Fig. 2. Search for components on the board

In the window that appears, set the filters by layer, face value and footprint. Click OK and see that all the necessary components are highlighted. Now we know their location on the board. It’s important to switch to the silkscreen layer (the + and - buttons on the keyboard) to see the component labels, it will be even easier.


Fig. 3. Selected Components

After that, you can begin to arrange the components. I usually put the side first (if the board is double-sided), on which there are large connectors. After I solder the whole side, you can turn the board over and not be afraid that the components will move when the second side is sealed (you can use grips for the boards). At first I set the passive 0201 and 0402, then 0603 and inductance. After that, you can put QFN and everything else.


Fig. 4. Sealing components (a)


Fig. 5. Sealing the components (b)

After all the components are arranged, I solder them with a hairdryer at a time, aligning them in parallel.

I install BGA after everything else is already soldered and the board is washed away from the flux. Washing in an ultrasonic bath with either alcohol or a washing liquid.


Fig. 6. Installed 0603, 0402 and 0201

On the board it can be seen that the installation density is low. If you try, you could fit 0402 instead of 0201, but in some places on the board it would be difficult and, most likely, to the detriment of the trace. This is, so to speak, a test of the pen, in order to understand how laborious it is and whether it is worth using such sizes in the future.

Conclusion


I will not argue that this method is the simplest. Manual soldering is relevant only on prototypes, when it comes to serial production. Several times we soldered the mock-ups at the production site and once faced with the fact that the wrong values ​​of the resistors 0402 were soldered (they are not marked). They searched for the problem for several days, since there were more than 2000 components on the board and the malfunctions of the product were not regular. In this case, you first start looking for a problem in circuitry and tracing and do not suspect that the problem is completely different. The probability of an error during manual soldering (in this way) is minimal, since a group of components is installed immediately and even if I make a mistake with setting one value, the error will be found when I put another. I will say more, there have never been errors in the alignment with manual soldering.Debugged production at the plant, of course, will not make mistakes, but when soldering a prototype, it is very important to know that all components are in place, otherwise you can spend much more time searching for a nonexistent problem.

If you need any more nuances - ask!

Thank you and see you soon!

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