Who Says Solder Paste Stencils Have To Be CNC Cut? | Hackaday

Imagine you have a surface mount kit and you want to use solder paste and reflow soldering to make a mold, but it does not come with a soldering template. That is what [Honghong Lu] faced, she rose to challenge

. This is not a big toolkit,

, But her homemade mold can still effectively complete the work.

So, how to create a solder template from household waste? In the video we put under the rest area, she starts with the packaging and then cuts out a PET sheet from it. Its thickness is 0.24mm, which is an ideal choice. Then, she placed it on the PCB and marked all the pads with a marker, and then cut or drilled holes for the pads. Then the bottom surface is sanded to remove the protruding chips, and the template can be used in the normal way. She proved this by kneading the solder paste, manually placing the parts and reflowing the solder onto the hot plate.

Obviously, this is most suitable for a small number of large components, and we will never use it to replace a thousand tiny 0201 discrete device laser cutting molds. But this is not the point. It is an interesting technique for those less complicated circuit boards, and it can be tried by anyone who is curious about stencil printing and reflow soldering and does not have a stencil cutting project. . For that, we like it.

Making your own templates does not have to include this fairly basic method. they can

, Or

.

Love the low budget method!

If you happen to have a cutter and transparent printable paper, you can also use them. Even if I run 1000 pcb on a piece of paper, they still work for me. (A few years ago, there was an article about this technique here.

Even the editor, I can do 3D printing. If you are careful, its production speed is fast, the printing speed is fast, enough to support dozens of boards, and it costs almost no money. Even if there are only a few 1206 seconds, I would not bother to cut anything by hand

Great idea, please tell me, Sla? What is the thickness of the final mold? And layer height in use?

There are various tutorials on 3D printing solder templates on YT.

very good, thank you

You don’t have to go too far to find some good examples:

Can you do that with 0603 or smaller and 0.5mm fine pitch?

neat. I kind of imagined someone sitting there, and when I saw the title for the first time, I cut it open with a Xacto knife.

The effect of the exercise was amazing. I would love to see some cheap plastic CNC milling cutters with precision milling cutters to accomplish this task.

I think round holes are very effective for certain components because they have the lowest ratio of circumference (= resistance) to area. The solder paste will still flow.

However, it would be troublesome to redraw the PCB with a marker. Why not simply print the template on paper and use it as a template (on top or bottom of PET), or, if available, print it on overhead paper (if these things still exist)

Print on overhead film and drill holes. that is really good.

I forgot to add:

Round holes may be suitable for resistances as low as 0201 or even smaller.

But I do think you may have trouble with ICs such as QFNs with many leads and small pitches. For circular holes, you may not have enough solder before starting to overlap.

In this case, two overlapping small holes may be better, or use a small drill bit, then insert the drill bit into the hole and drag the sheet out slightly to form a rectangle

For many years, I have been using a polyester film stencil cutting machine to perform graphtec procedures with Gerber.

It is only suitable for any circuit board of various sizes.

I want to know if polyester film is suitable.

You can get thick plates with a thickness of 7 million. These plates can be cut well with a CO2 laser for use in paint stencils. But can they also use solder paste? It does not seem far-fetched.

I don’t know the behavior of military-spec polyester film sheets. However, buying ordinary 100µm polyester film as an overhead transparent film works well. Maybe I can optimize the cutting parameters more to reduce the burrs of partially molten materials. Kapton would have been better, but I didn't have it, and the thing I didn't have was time (waiting to order an orderly business template). Therefore, I took the CO2 laser cutting machine to my local hackerspace and took a spare FR4 PCB to scrape most of the cutting burrs.

0.5mm fine pitch IC requires some manual rework after reflow, but this method is much faster than manual soldering.

I have been using plastic film (usually a transparent window wrapped in cardboard) for surface-mounted parts masks. I have never been a loser. Before welding, I also use a thicker plastic mask to place parts on the board, and smd and tremor are usually not mixed together well.

We used it because it was convenient and fast from 2005 to 2008, before laser cutting templates were very cheap in China. In most cases, we use a thickness of 0.1mm~0.15mm, because we use them to print designs for PCB review, and also make a sfor test bench thicker in MFC. It is beneficial to 0603 components and larger than it.

At those times I only used a sheet of plain paper and a laser cutting machine, and only made 1-5 boards.

It can hold several boards. Many different thicknesses of paper can be ordered, and it is easy to obtain, and the dirt is cheap. (Typical 80 g/m² paper is a bit "thick", but for 0603 packaging and similarly sized equipment, it works fine.)

My weapon of choice for the template mold is Kapton film on Epilog Legend 75W laser. The combination of grating through the film and edge cleaning using vector lines can make the holes very small and precise, making QFN and BGA garage installations very reliable.

Please be kind and respectful to help make the comment section great. (

)

The site uses Akismet to reduce spam.

By using our website and services, you expressly agree to our placement of performance, functionality and advertising cookies.