Benbox Laser Machines/CO2 Lasers/3D Printers

General Category => Engraving => Topic started by: mattm58 on October 11, 2018, 01:42:13 PM

Title: Questions for those of you who do acrylic
Post by: mattm58 on October 11, 2018, 01:42:13 PM
I've searched and read everything I can here on acrylics.  From what I gather:

- Either burn the back side if it has transfer tape/brown paper backing (and reverse image)
or
- Place acrylic on black paper and focus on paper (no need to reverse)

- Burn full power
- Feed rate I've seen various posts, ranging from 30 - 150mm/s depending on the laser wattage.


My question to you guys, is that feed rate correct?  If so, a burn very big will take forever!  I loaded a simple image last night, about 6" square, raster, and at a speed of 30 it said 17 hours to burn!

What feed rate do you guys that have a 2.5w laser burn acrylic at?

Thanks!
Title: Re: Questions for those of you who do acrylic
Post by: ThothLoki on October 11, 2018, 03:04:06 PM
do a test piece at 100, 300, 500 and 700 and see what looks better. That is what i did with glass

you can also get some acrylic black paint (cheap stuff from walmart for $0.50/bottle) and put that on as the resist. It should wash off with hot water when you are done.
Title: Re: Questions for those of you who do acrylic
Post by: ggallant571 on October 11, 2018, 07:47:29 PM
The speed units used on most diode laser machines with grbl firmware is mm/min. 30 would be 1800mm/min, 150mm/sec would be quite fast!!

I do 4 x 4 inch slate at 900mm/min and they take about 30 minutes depending on the pattern.

You could raise the non-cutting speed and it might help.
Title: Re: Questions for those of you who do acrylic
Post by: Zax on October 12, 2018, 04:10:48 AM
30 sounds OK for cutting (maybe a bit slow even for that), but I would use 400~800 for engraving.
Title: Re: Questions for those of you who do acrylic
Post by: nottingham82 on October 12, 2018, 09:21:27 PM
with acrylic, the slower you go, the wider the curf.  Therefore the less dimensionally accurate your part will be.  The faster, the thinner the curf but the more passes you will need.  But the speeds you read for 30-150 are cutting speeds.

If you are doing a raster engraving you can go much faster.  If you are trying to do a cut, you would not want a raster file.  It needs to be a vector file or you will waste a week of sundays trying to get 1 cut finished.