How to solder SMD at home even better-Part two

This is continuing of part one. The following advice is for how to solder SMD parts with improved technology.

Soldering Oven isolation

As an isolation material, their glass insulation can be used. In this case, glass insulation was packed in aluminum foil:

soldering oven

Inspected improvement in heating speed:

  • 0.95% without isolation;
  • 1.50% with isolation only inside oven;
  • 1.72% full isolation.

Preparing the mask for applying solder paste

Using the mask for applying solder paster may improve solder quality, and the board may look more professional.

small stencils

As mask material is a plastic plate of 0.2mm used. Mask also can be etched as a usual circuit board.

If circuit design is made using Eagle CAD software, then make a mask go to Tools->DRC->Masks. In the field, CREAM chooses minimum 0, maximum10mil. In the field %, values can be corrected.

pcb cad

In order to expose negative of SMD plates in Eagle select layer tCream:

pcb gerber
  • File->CAM Processor;
  • Select layer Dimensions and tcream;
  • Select in Devices option PS_INVERTED;
  • make sure that Scale is equal to 1;
  • File: name.ps
  • Process Job;
  • File name.ps should be placed in the working directory of the project;
  • Set GSView or another environment for reading .ps files;
  • Open the name.ps file and print it.

It is most convenient to etch the mask plate as a usual circuit board. For this special brass plate may be used, which has both sides covered with a photo-resistive coating. Peal one protective film another leave as it is. This way, you can etch through-hole, not all plates.

pcb and stencils

Next stage is putting cream on

First of all, fix the mask to the board so that mask area matches SMD solder areas:

fixing stencils

apply cream smoothly by using a strip:

applying soldering paste

Hold the strip at the angle of 45 degrees so the paste distributes evenly:

stencils

Take the mask off the circuit board. Try to remove it vertically so that the solder nicely stays on the board.

smt paste applied

Then put SMD components on the mask by slightly pressing them down. Make sure SMD parts are well centered.

soldered smd board

Put the board into the oven, as discussed earlier. And it would help if you got a nice circuit board:

soldered smd board

Soldered SMD board looks more beautiful and smooth

soldered smd

Few problems may occur while soldering with soldering paste in the oven—one of the short circuit between SMD legs. Don’t panic. Just apply enough flux and use solder remover. Next time make mask holes smaller when designing Eagle.

Sometimes solder paste may dry out without soldering parts. This means that oven heats too slowly. One os solutions may be to shorten drying time.

Sources: www.radiokot.ru, https://cxem.net, https://wiki.jelectronique.com.

4 Comments:

  1. Nice job. The pictures show the process quite well.

  2. Patrick Morrison

    I don’t understand how you were able to make your solder mask? How did you create the plate with all the proper openings on it?

  3. I have the same question as Patrick.
    Can you please explain better that point?

  4. the solder mask (openings) is already created for you in eagle by default ….you just have to deselect all your normal layers and then enable the tcream layer (short for top cream) or bcream (bottom) to suit.

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