Small laser cutter for few mils mylar only.

[Otatiaro]

Hello,

I'm doing a lot of electronic prototypes these days, and had a CNC mill few years ago.

I will have prototypes with too fined pitch to apply the solder paste without a stencil.

They cost a lot (50 to 60$ inclusing shipping to France) so I was wondering if I can make myself a stencil cutter CNC machine.

Here are the awaited specs :

- Low cost
- High precision (0.05mm to 0.1mm)
- Small dimensions (working area 100x160mm should be more than enough)
- ONLY to cut mylar sheets a few mils thick, hence very low power laser

I will do the control electronics and PC software myself (2 functions, import gerber file, and cut it), but I'm a total noobie concerning laser stuff.

Do you think it is feasible ?
Any hint ?

Regards,
Thomas.

[epilotdk]

I tried cutting stencils on the laser from a number of different plastics but the results were not good. The heat would cause the edges to curl slighty - enough to make applying the solder paste a problem. My solution was to photo etch the stencils instead. The setup is very cheap and works well. I used resistcoated brass, laser printed artwork and a UV facial solarium bought on Ebay for the exposure. About 1/100 the cost of buying a laser and does the job well.

[Tweakie]

Hi Thomas,

Small CO2 lasers 25watt upwards are fine for cutting Mylar solder paste stencils although Kapton would probably be a better material to use.
Cost may be a problem though, as I would expect a starting price upwards of 2000 euro.
The best bet may be to try and locate a forum member near you who already has a laser.

Tweakie.

[fullspeceng]

We cut stencils all the time with our lasers out of laser transparency.

Kapton does not work as well as mylar. Several people have recommended Kapton without trying it. Our first hand experience indicates it is inferior to laser transparency.

You need to raster the image. Vector cutting doesn't work well to produce nice even holes.

We can easily raster cut holes for .5mm pitch devices with our CO2 lasers. We rastered all the stencils for our RetinaEngrave prototypes and hand assembled them under a microscope.

I would say .1mm holes are beyond the normal diffraction limit of CO2.

Full Spectrum Engineering

[cnc-newb]

just for pcb stencil cutting - 3-5mil mylar/kapton, how much power is needed and what spectrum is the best? just need a very small (tabletop) unit as much stuff i do is very small and use components down to 0402 and small llc components - .5mm or possibly smaller pitch.

[bpoulin]

I don't know the requirements for the material. But you can check out this, if it would work it would be a lot cheaper than a laser setup. You can get a decent vinyl cutter for <$500USD and some vinyl stencil material.Vinyl Masking

[cnc-newb]

We cut stencils all the time with our lasers out of laser transparency.

Kapton does not work as well as mylar. Several people have recommended Kapton without trying it. Our first hand experience indicates it is inferior to laser transparency.

You need to raster the image. Vector cutting doesn't work well to produce nice even holes.

We can easily raster cut holes for .5mm pitch devices with our CO2 lasers. We rastered all the stencils for our RetinaEngrave prototypes and hand assembled them under a microscope.

I would say .1mm holes are beyond the normal diffraction limit of CO2.

Full Spectrum Engineering

when you say laser transparency, are you referring to the transparencies for laser printers or something else?