Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: method13 on June 22, 2006, 11:07:54 AM
-
Hi,
I am having a problem with my cnc macnine, I bought a macnine from K2cnc and I am trying to tune it so I can machine faster with out missing steps. I have no problems cutting at 40 to 50 in/min but if I go any faster it messes up and looses its place. Other problems I have been having is when it goes from G1 to G0 it looses it place more often. For example I was finishing a sign and profiling out the outside shape and it was at last pass I was about .5 deep and it was to rapid up to Z+.5 and it only made it about .05 up from the bottom and it took off to X0Y0 right through my finished part.doh!
When I bought the machine I was under the impression that it could cut at feeds of 120 in/min, I don't want to talk bad about the guys from k2 because they have been really helpful in the past but I though it might be worth asking a question in a forum that is dedicated to helping people with these problems.
I am new to all of this and am not familiar with the terminology so who ever replies to this post must have a lot patience with me and be very descriptive. :P
Also,
I would like to try Mach 3 but I haven't even got my machine running right with Mach 2 so mabe I can try that at a later time, unless we can try to fix my problems using Mach 3.
Thanks,
Greg
method13
-
Try lowering your acceleration by 1/2 and se if that helps. Also, what drives are you using, what motors, what size power supply, what leadscrews... will all help. What size machine, too.
-
Mach3 has less phase jitter than mach2... So you should get better speed out of mach3 :)
-
Hi,
Here are the details of my machine:
-Superstep Nema 23, 276 oz/in 2.8a 1.1ohm 1.8 degree stepper on all three axis.
-KERK Brand Anti-Backlash Nuts, 0.1 pitch lead screws.
-Direct drive coupling /w 2000 full steps/in, Made of 6061 Aluminum and Delran.
-4 linear ball bearings on each axes,Harden precision shafts.
-Stepper Controller Standard 3 Axis,Servo Motors with feedback encoders.
Gecko Drives - Wired for Step/Dir signals from Printer/Parallel Port -
Fully enclosed control box and pre wired for Parallel Interface
110 watts power supply. 24VDC unregulated (~30V) 8 Amps.
5 watt power input wire from 1 computer USB port.
Power Cord - Fuse - E-Stop.
Is there more you can tell me with this info?
I plan on downloading Mach 3 and giving it a try.
Thanks,
Greg
-
This is a picture of the mistake that I was talking about
-
Method13,
I've posted a XML file for the K2 39X25 here:
http://machsupport.com/forum/index.php?board=7.0
I've also made a screen set that will work very well with the K2CNC and Mach 3
http://machsupport.com/forum/index.php?topic=602.0
One of my machines that I have is the K2 39X25 same set up as you. I'm getting around 150-200 IPM with 0.002 accuracy. Let me know if the setup file gives you these speeds.
-
looks like your setup is a little diffrent from mine. Did you upgrade to the "Hi-Tolerance Ball screws of .001 backlash tolerance"
Footprint with the motors 54" x 30" x 26"
Travel or Cutting dimension:
X-39" Y-24.5" Z-5"
Pulley
Ratio is 2:1 on X and Y
Pulley made of Aluminum
Frame Features:
Structure is CNC machined 6061 aluminum and extrusions
6061 Billet Machined Aluminum
X and Y Axis uses 20mm THK style linear rails/blocks (4 Blocks for X and 2 for Y)
Z Axis Details:
5" Travel comes with Linear Rigid Rails and Hi-Tolerance Ball screw of .001 Tolerance
Servo Controller Details:
3 to 4 Servo Motors with feedback encoders.
Geckodrive G320 servo controller
Wired for Step/Dir signals from Printer/Parallel Port
Fully enclosed control box and prewired for Parallel Interface
110 (std.) or 220 (request) watts power supply. 24VDC unregulated (~30V) 8 Amps.
5 watt power input wire from 1 computer USB port.
Linear Motion of X and Y Axis:
Rigid Rails
Hi-Tolerance Ball screws of .001 backlash tolerance available( bearing house has a plastic dust cover )
Ballscrews .001" backlas tolerance.
305 oz/in Servo.
2:1 Pulley ratio.
-
Sounds like you have a smaller servo system... 30V is not a very high voltage for a servo system, did you make the drive system or did it come with the router?
-
He mentioned steppers, then said servos. Which is it? Servos shouldn't miss steps, the drives should fault and stop.
-
Hi,
Sorry I was cutting and pasting from their website, they are steppers not servos. I bought the drive system, I went with a cheaper system to keep the cost down. I have a KT-2514 with the regular lead screw it says it max feed is 150 ipm. My upgrades include the high torque steppers and 5" in the Z instead of the regular 3".
Another question I have is how well does the thread cutting program work in Mach2/3, I haven't tried the wizard can you make any thread? or just the known ones?
Regards,
Greg
-
You can threadmill any thread you like :)
Did you lower the accel and see what the effect is?
-
I'll give it a try tomorrow but I'll run a program in the air just in case. How much should I drop it by?
Here is a pic of my machine I am roughing a pocket it aluminum, using a 1/2 carbide endmill.
thanks,
Greg
-
half the accel as a test..
Thanks
-
So far so good I am cutting aluminum and am running my feeds slower because lack of rigidity, but it is switching back and forth from G0 to G1 with out any problems. I set the acceleration to just over half of what it was, what should I do now? Keep running test programs gradually moving up the acceleration till it makes a mistake and then back it off a bit?
Thanks,
Greg
-
That's generally how it's done. Gradually increase it until it misses steps, than back off 15-20% for a safety margin.
-
What about the velocity? Can that be increased? Or just try to find a good balance?
Thanks,
Greg
-
You should be able to take up the velocity with the Accel down...
Hope that helps
Brian