Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Flipz01 on August 14, 2007, 04:21:27 PM

Title: Acceleration
Post by: Flipz01 on August 14, 2007, 04:21:27 PM
If I understand correctly, Mach is capable of about 1/3 g acceleration.

Just wondering if the increased speeds to 100k SPS increases the accel that is possible?

Anybody know about this?
Title: Re: Acceleration
Post by: Whacko on August 15, 2007, 05:10:01 PM
I believe this is a relative question. Acceleration does not depend so much on Mach3 as it does on your hardware. The pulse engine on a slower computer is recommended at 25khz. If you have a strong enough stepper drive for instance, with a big pinion on a rack and a strong enough amplifier, and a theoretical 10 mm travel per step, you can imagine what the acceleration would be like if your speed up ramp is 0 milliseconds. It's all fiction really, and theory I suppose, but it could explain the possibilities.

Whacko for real
Title: Re: Acceleration
Post by: Flipz01 on August 16, 2007, 08:47:15 AM
There's nothing theoretical about acceleration.  It requires lots of power (our systems are servo and can be increased in size/power to accomodate higher accel rates), and also the ability of the computer/program to handle the accel/decel in a controlled fashion.

Such things have practical limits and I'm trying to find out what they are.

Why do I want/need higher acceleration?  For the ability to do small arcs and circles at feedrates around 400 IPM.  Think about what it takes to throw around a 1,000 lb. bridge in a controlled fashion making a 1/8" hole at 400 IPM - a hole that ends up being nearly perfectly round.  The higher the acceleration your system can handle confortably, the faster you can cut a controlled circle.

This is not a trivial task!
Title: Re: Acceleration
Post by: Whacko on August 16, 2007, 01:18:27 PM
What I'm saying is that the facility is there in Mach3 for zero accel parameter. I am an OEM manufacturer of flatbed machines and I get a comfortable 20 meters (+-780 IPM) per minute cutting speed, even higher, but that is over the usable range. But the acceleration settings will be needed to avoid overshoot. I have very short accel times because the machines are built from aluminium and is dual drive on the rail axis. So the lighter, the better for obvious reasons. You can feel comfartable that Mach3 will not be the inhibiting factor in your machines performance.

Title: Re: Acceleration
Post by: banditpowdercoat on August 16, 2007, 04:04:08 PM
I can not see the software being the limiting factor.  The drive's power to the weight it has to move will determine the max G accelleration/decelleration you will be able to acheave.  Like anything, as weight is increased, or Acceleration rate is increased, more power is needed to acheave.   Imagine your 1000Lb Gantry with 1HP Servo drive. it would accelerate, but not very fast.  Now, but 100HP worth of drive on it, it will accelerate alot quicker
Title: Re: Acceleration
Post by: Whacko on August 16, 2007, 06:26:49 PM

For real
Title: Re: Acceleration
Post by: jimpinder on August 17, 2007, 11:02:41 AM
I suppose , in theory, we could reach the moon !!!
Title: Re: Acceleration
Post by: Flipz01 on August 19, 2007, 10:24:49 AM
OK - now imagine a high speed machine using linear motors capable of 1,600 lbs. continuous force and peaking at about 4,000 lbs. of force pushing a crossbridge that weighs about 650 lbs.  This machine will easily run at 2g acceleration rates.

I have to decide soon whether to commit to Mach3 to run this or use my current CNC.  What I'm using now will do this, but I'm trying to move to Mach, and this may be the next project for us.

I get that, in theory, Mach can do this.  I'm hoping to get feedback from somebody who has actually tried something similar, and to know if they had any problems with the accel/decel, corner rounding, arc tolerences, etc.
Title: Re: Acceleration
Post by: MOTU on August 28, 2007, 11:13:58 AM
Inquiring minds want to know.  We're also consdering whether to try Mach3 on a 1G linear motor machine and have the same concerns - how will Mach3 perform in regards to square corners, small round holes, etc.
Title: Re: Acceleration
Post by: Whacko on September 03, 2007, 03:33:44 PM
Very good, trust me, you can go for it!