How to countersink a screw head in acrylic with 40watts?

[Larry Bratton]

I have need to countersink a screw head into an acrylic part I am making. My assumption is that it is a raster operation followed by a vector operation to cut out the hole for the screw. What would a speed/power combination be for the raster? Normal raster for my 40watt Epilog is 100s/55p for engraving at 300dpi. Please give me the benefit of your wisdom and experience. I need to do this tomorrow. Thanks in advance.

[Curt Stallings]

I would create a circle then use the fountain fill to make the circle increasingly darker as it goes to the center of the circle. You might have to go over it a couple of times. I've been meaning to play with chamfering in acrylic, but haven't yet.

Curt

[Bill Cunningham]

I think your going to end up taking a piece of scrap, and trying different speed/power combinations on some small black circles, and see how deep they go with what speed/setting then write it down.. You write it down so that six months from now when your no longer getting the same results, you can get a rough idea of how much power your machine may have lost over time as the tube gets older..(see!! this gives you something 'expensive' to worry about :) )What works on one laser will probably not work on another..

[Stephen Beckham]

Larry - this may be way out there - but how about taking a normal countersink bit and getting the right chamfer on the hole first at a depth really close to your target.

Then using the laser again in Raster mode going over the hole with solid black like your rastering a circle... That should remove all the surface scratches from the bit and keep the same shape as the hole?!?!

Just guessing :confused:

[Joe Pelonio]

I did one of those today, rastered then vector cut the hole. Then went back and rastered some more. I had used the contour function to make concentric circles, black on the inside, then 80%...and so on, but it took 3 passes to get deep enough. Would have been faster to just do the hole and hit it with a countersink bit.

[Frank Corker]

Normal countersunk bit. Smooth it out with wet and dry and if you have it, apply heat and flame polish it

[Larry Bratton]

Fellas, this is on a laser cut part that I hope to do a lot of. May be quicker to just set up a drill press to do the countersink as has been suggested. I'll try a couple of experiments with some different power settings though and see what happens. I'll post it if I figure it out.