CNC Plasma Speeds
- HammerLight
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17 May 2015 07:41 #58770
by HammerLight
CNC Plasma Speeds was created by HammerLight
Hi, I have built a CNC routing machine using LinuxCNC so I am fairly familiar with it. I am starting construction of my CNC plasma cytter now. Probably use a 40-60 Amp cut head for less than 1/2" material.
The more I read the more I see people talking about CNC plasma machines running 500-1500 IPM. No way I can hand cut that fast so I doubt the small plasma cut head I plan to use will be able to either. When I look on youtube I see many machines that seem to run about as fast as my CNC router does 50-100ipm and the cuts look nice. 500+ IPM sounds kind of scary but I have read several comments from folks that seem sane that say you should build a CNC plasma machion planning for those high speeds or you will get wide kerfs, ragged cuts etc.
Can someone who has built a CNC plasma using a small (<75Amp) cutter please chime in?
How fast do you typically run?
Are you getting issues when you amp down and run thinner stuff at < 100 IPM speeds?
Thanks
Jeff
The more I read the more I see people talking about CNC plasma machines running 500-1500 IPM. No way I can hand cut that fast so I doubt the small plasma cut head I plan to use will be able to either. When I look on youtube I see many machines that seem to run about as fast as my CNC router does 50-100ipm and the cuts look nice. 500+ IPM sounds kind of scary but I have read several comments from folks that seem sane that say you should build a CNC plasma machion planning for those high speeds or you will get wide kerfs, ragged cuts etc.
Can someone who has built a CNC plasma using a small (<75Amp) cutter please chime in?
How fast do you typically run?
Are you getting issues when you amp down and run thinner stuff at < 100 IPM speeds?
Thanks
Jeff
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17 May 2015 19:47 - 17 May 2015 19:48 #58787
by BigJohnT
Replied by BigJohnT on topic CNC Plasma Speeds
I built a plasma table and the speed depends on the thickness of material. Your plasma manual should have charts. I used a Hypertherm 1250 and after very short time added the machine torch. I have a floating head for the torch with a touch off switch built in so I can find the top of the material. I used the Mesa THCAD card to send the tip voltage to LinuxCNC. The machine is Nema 23 triple stack (IIRC) driven with 63v power supply and used Gecko 203v drives with Mesa 5i25 + 7i76.
Looking at the cut charts for my Hypertherm 1250 speeds range from 9 ipm for 1" ss with the 80 amp nozzle to 638 ipm maximum speed on 26ga mild steel with the 40 amp nozzle. I cut 16ga to 11ga normally with an occasional 3/8" or 1/2" piece tossed in. So my typical speeds range from 100 ipm to 150 ipm for the thinner stuff.
My plasma machine is here:
gnipsel.com/shop/plasma/plasma.xhtml
I did not start out with the finished product as seen in this video of my first cuts.
I must stress it is more important to do your math correctly when choosing drive components so you can get some really good acceleration and speed for a plasma.
Last but not least you need to be running LinuxCNC 2.7 for a plasma. The new trajectory planner is awesome.
JT
Looking at the cut charts for my Hypertherm 1250 speeds range from 9 ipm for 1" ss with the 80 amp nozzle to 638 ipm maximum speed on 26ga mild steel with the 40 amp nozzle. I cut 16ga to 11ga normally with an occasional 3/8" or 1/2" piece tossed in. So my typical speeds range from 100 ipm to 150 ipm for the thinner stuff.
My plasma machine is here:
gnipsel.com/shop/plasma/plasma.xhtml
I did not start out with the finished product as seen in this video of my first cuts.
I must stress it is more important to do your math correctly when choosing drive components so you can get some really good acceleration and speed for a plasma.
Last but not least you need to be running LinuxCNC 2.7 for a plasma. The new trajectory planner is awesome.
JT
Last edit: 17 May 2015 19:48 by BigJohnT.
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17 May 2015 19:53 #58788
by BigJohnT
Replied by BigJohnT on topic CNC Plasma Speeds
Just to give you an idea this is the X axis ini entries for velocity and acceleration. You can see my MAX_ACCELERATION is quite a bit higher than the MAX_VELOCITY of 7 ips (420 ipm). This is because of the lots of tiny lines and arcs that most plasma CAM programs put out and you want to maintain speed at direction changes as best as possible.
[AXIS_0]
# X Axis
TYPE = LINEAR
MAX_VELOCITY = 7
MAX_ACCELERATION = 125
STEPGEN_MAXACCEL = 150
BACKLASH = 0.000
SCALE = 3180Please Log in or Create an account to join the conversation.
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