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Keith Colson
06-20-2014, 2:15 AM
I searched the web last night and found almost no positive answers to "can you cut phenolic with a laser cutter" So today I tried it. The answer is "yes you can" and it cuts really easily for my purposes.

I got some 1.6mm FR2 known as Paxolin, Tufnol or Phenolic. It was copper clad in parts. I have taken a few pictures on my microscope. The best settings I found on my 60 watt laser are 100% power with 30% speed. I could make it cut through the copper but not well and it charred a lot. It's quite easy just to pop out the engraved copper anyway.

Here are the pictures. I cut holes from 0.5mm to 1.0mm

Top view
291604

Bottom view
291605

measured 1mm hole came out at 1.225mm
291606
The 0.5mm hole came out at 0.725mm

It looks like I can now cut and drill my home PCB's on the laser cutter. I just need to get a good registration method in place. Another fun afternoon with the toys!

Cheers
Keith

Keith Colson
06-20-2014, 3:45 AM
I was thinking if I could get the laser to burn the middle of the hole after the circle is cut it would probably clear it out to a certain degree. So a couple of questions.

1) How do I draw a dot in Corel?
2) How do I tell the laser to burn the dot? e.g. hold there for a small amount of time with the laser on.

or a work around would be welcome too.

Cheers
Keith

Dee Gallo
06-20-2014, 9:16 AM
Keith,

To make the circle engrave in the center, just add a black fill to your circle shape. The laser will automatically engrave any shape that is filled and cut any line that is hairline... assuming you set up the print driver to do both raster (engrave) and vector (cut). Use a slow speed and high power plus 400-600 dpi. I do not have a 60w laser, but you should be able to look in your manual for settings used for wood for example to get a starting point.

You might have to do several passes to get all the way through (re-focussing in between). But if you cut several times, will it just go through without burning the centers out? Try that first. Maybe someone with a 60w will have a better answer for you.

Good luck, dee

Scott Shepherd
06-20-2014, 11:13 AM
The 0.5mm hole came out at 7.25mm



That's a pretty big difference ;)

Jerome Stanek
06-20-2014, 12:45 PM
That's a pretty big difference ;)

depends on whether he measures the hole or the piece that is left. If I draw a square say 10mm X 10mm the piece comes out at 10mm but the hole is closer to 12mm

Scott Shepherd
06-20-2014, 1:25 PM
depends on whether he measures the hole or the piece that is left. If I draw a square say 10mm X 10mm the piece comes out at 10mm but the hole is closer to 12mm

I don't think it matters that much. He said it was a .5mm hole, which is about .020" of an inch. 7.75mm is .305" of an inch. So he was cutting just over a 1/64" hole and measured at just under 5/16"? I think he meant .725mm. I was just kidding him about it, not serious.

Keith Colson
06-21-2014, 12:17 AM
I solved my problem in burning a spot. I just drew a circle inside the circle, so for a 1mm hole I did this

1mm circle on the green layer 100% power, 30% speed, that cut the hole but not the copper.
0.7mm circle on the black layer !00% power, 4% speed, that cut right through the copper.

While it did work the holes got a bit more charred and slightly oval on the horizontal axis. The copper around it also looked a bit bubbly from the heat. Nice to know it does work but its probably better just to chemical etch the copper part.

Jerome the "measured picture" has a graticule if you zoom in. The graticule is calibrated to 25 micros per graduation or 1mm per 40 grads. And I did measure the hole and not the waste core. Basally if I want a 1mm hole I would cut a circle about 230 microns smaller = 0.77mm. This accounts for the laser beam thickness.

Cheers
Keith

Ian Johnson
06-23-2014, 10:18 AM
If you find a way to etch the copper first, then register and drill the holes I would be interested in hearing about it. Doing it with the laser would save me a lot of time. I've read about using the laser to etch the mask before acid etching the copper, but it doesn't seem to be much easier than toner transfer.

Keith Colson
06-25-2014, 5:29 AM
Hi Ian

As soon as I get some phenolic I will give it a go. I don't have any blank copper clad in hand but will by end of week.

I am prolly going to laser drill and engrave the top side of the board first, then paint the back and burn the paint off. Doing this method does not appear to save time (least the way I am doing it) The Corel Draw object manager is terribly painful to work with.To do the a board you need to separate the pads, tracks and drill layers. I see there are some marco's I can add on for this which I must do if I plan to rinse and repeat. I have one board all ready to go though.

Laser layers are

Registration layer (for 2 pins to locate the board when flipped)
Cut/Drill layer
Components silk screen layer
Copper etch layer
Soldermask layer - which I will try if I get ambitious.

If it all works out I will do a post with pictures etc. I am finding this a lot of fun, (glad I have time up my sleeve), I learn t a lot about using Corel this week,especially with the object manager.

Cheers
Keith

Corel draw tip of the day. Hold down CTRL and click/edit individual segments of a combined/grouped object (without un-grouping). You already knew that didn't you.