Laser Cutting Accuracy

[2jack]

What is the general accuracy expected from laser cutting metals from 1/8 inch to 1 inch in thickness. If anyone has specs from particular machines I would be greatfull as I am in the process of looking for one to buy.
Thanks

 

[SERVOCAM]

It depends on how fast you want to go, what shape your cutting, and how precise your XY stages are and how well your laser control the spot size.

I have worked on applications were cutting a failry complex part with a lot of corners and curves, moving 125lbs around, and ding the process in 30 seconds and holding 0.0005 on the ball screw stages. Some don't need that some need better.

I have worked on some where we have a 1 um spot size and using air bearing stages where accuracy is down 0.2 um on the system.

Basically, we can get it as accurate as you want, it comes down to how much $ you want to spend.

Give us an idea of what you want to cut (shape), how fast, how heavy...etc. and maybe others reading this can help.

I work with several companies that build Laser systems out of my stages & controls.
Cameron Anderson - Sales & Applications Engineer
Aerotech, Inc. -

http://www.aerotech.com

"Dedicated to the Science of Motion"

 

[JayMaechtlen]

Accuracy is more than precise positioning. It depends on process control as well- the kerf width must be consistant, as variations will show up as variations in feature size/part dimension. In greater thinkness there can be some taper or variation of kerf from top to bottom.
"Process control" includes material composition and surface finish!
Accuracy also depends on working area required- easier to build a small ultra-precise machine than a large one.
Are you looking for a standard unit like an Amada or Trumph, or some kind of custom?





Jay Maechtlen

 

[2jack]

Standard machines such as a trumph, bystronic, mazak, mitsubishi, or cincinnati is what i am looking at currently. General fab work I am looking at requires +-0.005" or better some of the work I have jobbed out to local vendors has been outside of +-0.005" for hole locations vs profile outer edge which has given me fixture problems due to tolerance buildup. The variation of kerf you mentioned could have been part of the problems I was experiencing for both hole location and outer perimeter. I was just wondering if some of the standard machines on the market are "tighter" than others. As an engineer I know that accuracy is sometimes difficult to quantify - but need to know if certain standard machines are better accuracy than others.
Thanks

 

[JayMaechtlen]

I really don't know which machines are more accurate than others. I would start with published accuracy, and maybe discuss your previous problems with those who sell the machines that were used.
One other thing in laser processing- heat. The blank heats up during the cutting process, and it expands. depending on geometry, that can affect accuracy and reletive positioning of holes and other features. Even if the program is "perfect", this can affect the final result. Further, if you change process parameters (more power and cut faster, etc.) it may change the amount of heat absorbed and hence the amount of expansion. So the part accuracy can change even if the machine is perfect!

cheers
Jay Jay Maechtlen

 

[stan4419]

What are the size parts that you want to cut? This will determine the size and speed of your system.
Major suppliers of sheet metal cutters include:
Trumpf - 860-255-6055
Mazak - 847-252-4500
Amada - 714-739-2111
NTC - 248-478-4104
Schuler - 734-207-7200
Whitney - 815-964-6771
Cincinnati - 513-367-7100
Alabama Laser - 256-358-9055

 

[abnrml1]

I do Prototype Automotive parts. We like to shoot for
.025 MM on Holes and cutouts at a Feedrate of 1500-2000 MM a min.
and .05 MM on Trim at 2000-6000 MM a min.

 

[JayMaechtlen]

that sounds reasonable for materials of .01 - .25 inch or so, except that overall dimension may vary according to process heat and cutting sequence, etc. (especially, think overall dimensional % change as function of heat absorbed by material). For thicker materials, I would be pleasently surprised to get that kind of accuracy.
Of course, the laser nozzle and beam can be positioned very accurately, but see previous comments regarding accuracy of thicker materials.
regards
Jay (formerly of Amada) Jay Maechtlen