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Russell Ludwick
11-19-2010, 12:23 AM
Hi Creekers,

I wanted to ask everyone if they could give me some starting points for cutting.

I recently got my cutting table and I have nowhere to begin as far as how fast to run my laser for different materials. For reference I have a 30W laser

I am looking to cut acrylic and wood in various thicknesses, mainly 1/16, 1/8, 3/16 and 1/4. Can someone give me some ballpark speeds and tips for cutting?

Rodne Gold
11-19-2010, 12:47 AM
Various lasers of the same power cut at different speeds and power levels and all materials cut differently too - especially wood. Start off with your mnfgrs recommendations and do trial runs to see what works well for you. Generally work at 100% power for cutting and vary speeds , you would most likely have to start at something like 5% speed for 1/8th acrylic and work slower for thicker stuff and woods. There is no exact recipe.

What I can tell you is that you should not try cut stuff in multiple passes as this may work , but will have some issues with edge quality - typically with acrylic - you will have melt damage and with woods charring might be the problem.

When a laser vector cuts , it does so by "treppaning" , it drills a series of holes that overlap to cut. A laser also works by thermally shocking materials and vaporising them , not "burning" , if you bear those 2 facts in mind , you can gain some understanding of how materials will react to the laser - what you really don't want to do is have large heat affected zones , ie transfer heat into material adjacent to the cut which will not do you any favours.

So spacing of these holes and whether you want or dont want heat are factors - for example you dont want closely overlapping holes or heat when doing wood as it chars the edge , you might want a bit of the opposite when doing acrylic as it will promote some edge melting and a nice polished look. When cutting you MUST use air assist - it blows away melt and vapour and stops fires.

Good luck with your trial and error journey :)

Mike Null
11-19-2010, 8:15 AM
I disagree with Rodney about multiple pass cutting. I frequently use it to keep down flaming and charring.

Your Trotec has a faster speed than almost all other machines so the settings others may give you will probably not work.

Since all machines vary you'll have to find your own settings to be really efficient. Be prepared to cut at speeds well under 10% using full power.

If you have air assist use it for cutting as well.

Chris Mahoney
11-19-2010, 9:50 AM
Here's a link on the lasers website that has some tips on cutting different materials.
http://www.trotec.net/_en-US/041+Laser+Cutting.htm

Gary Sheriff
11-20-2010, 11:38 PM
Russell,
For .25” acrylic - try:

100% power
.2% speed
1000 hz
Focus into the material almost halfway (you can program -0.1 into the Z Offset column in the Material Settings and this will be done automatically) All you do is focus on the top of the material and press start.

For thinner material increase speed slightly. If you are over .4% speed, then increase the Hz to perhaps 1100 or 1200. Think of the Hz function as a strobe light. Each time the strobe light flashes it makes a dot (or fires the laser). You need to connect the dots. As you increase speed, and don't compensate for with higher Hz (frequency) then you will leave materal in between the dots. There are many theories for cutting, but I like to cut at lower Frequencies because peak energy is higher and therefore better for piercing a material.

Good luck!
Gary

Martin Boekers
11-21-2010, 9:43 AM
On wood vary the freq (lower the better to cut down on charring) when you get
some basic cutting down. Air assist is a must!