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Hello,
These are old pics, I use metal cutting carbide cutters now. I would like to speed up the machine, currently using 400 oz in stepper motors with 5 start 1/2"-10 lead screws.
It runs at 90 IPM because I'm finding that the lead screws tend to whip any faster than that. Not sure why that is, one whips the other doesn't. Short list - move the motors and screws to the outside of the cutting bed, perhaps expand the X axis thru using new brackets up to 24" of full travel. The machine has 42" of Y travel right now. Servos or track system might be possible for drive? Need to go way faster. Thanks for any suggestions.
Shawn
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For examples of the type of work I've been doing on this machine with Rhino 3D
Signs by Shawn – CNC cut 3D signs for personal and commercial
If one is whipping, and one is not, it's either bent, or not perfectly aligned. But you really should be using larger screws for an axis that long.
Larger acme screws would be much less efficient, so ballscrews, or rack and pinion would be the best option. Probably 2010 or 2010 ballscrews?
Whatare the specs on your motors, and what drives are you using? What power supply voltage? If you can get the screw to stop whipping, you should be able to get 300-400 ipm out of the current screws, with the right motor-drive-PS combination.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
Looks like the wiring could do with some cleaning up a little!
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
I am using Gecko G540 and pretty sure with a 48v supply. 400 oz in motors originally from Xylotex, and they are able to provide good speed. I am having trouble lining up the screws over that distance, will try again, been using trial and error. Would rack and pinion be ordered through McMaster?
Yes the wiring does need cleaning up that pic is old and it's worse now but I bought some cable carriers off Amazon of course busy work work and there are few opportunities to work on the machine.
Last year I was running for a little while at 300 IPM but observing noticed the steppers would occasionally bind. So I guess the way to know they are working is to run longer term repeat ability tests with a dial indicator.
Are they binding or locking up due to being over-driven?
Al.
CNC, Mechatronics Integration and Custom Machine Design
“Logic will get you from A to B. Imagination will take you everywhere.”
Albert E.
Over driven? One of the problems I've noticed is wood on the screws when cutting increases resistance in the delrin nuts. I will do some tests today/tomorrow.
binding I would guess.
Last edited by justCNCit; 12-24-2017 at 04:51 PM.
I am using g540 at 32 volts,1/2"-10 5start acme rod, 381oz steppers, cnc router parts rails that I made, 50"X50", I can also only get around 90 ipm in rapids, it is due to whipping of the acme screw, resonance also plays a big part in it, when I hit around the mid point is where I have all the problems, the screws are whipping on both sides and as it compress the wave on the side you traveling to you will hear the vibration pitch increasing and it will stall the machine. I just don't think we will be able to get more out of it with this setup. I am switching to 20mm supported rails, I think it will help a little.
I'm using a Xylotex @ 24V, with 1/2-8 2 start screws, and 250 oz motors. I can get 190 ion on my 40 inch Y axis, and 150 ion on my 48 inch X axis. Only the X screws whip, due to the length.
You should be able to go twice as fast as me.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)
I thought Xylotex had serious mid band resonance issues? I still have the old xylotex, not sure what to do with it. ger your screws are a lot different than Mike and I. You would have different harmonics and vibrations no?
Ger21
What kind of linea rails are you using?
A lot of guys here made dampers for the steppers, though it's a lot easier to implement if your stepper has dual shafts. I used a pretty coarse leadscrew (1/2"-8, 8 start, 1" lead) so my machine operated below that speed (around 400rpm or so) but I used the dampers anyway since it seemed to smooth movement.
Gerry
UCCNC 2017 Screenset
[URL]http://www.thecncwoodworker.com/2017.html[/URL]
Mach3 2010 Screenset
[URL]http://www.thecncwoodworker.com/2010.html[/URL]
JointCAM - CNC Dovetails & Box Joints
[URL]http://www.g-forcecnc.com/jointcam.html[/URL]
(Note: The opinions expressed in this post are my own and are not necessarily those of CNCzone and its management)