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| Z axis - very loud when moving slowly http://www-.luthiersforum.com/forum/viewtopic.php?f=10106&t=42521 |
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| Author: | AlexanderJamesGuitar [ Thu Jan 23, 2014 12:54 pm ] |
| Post subject: | Z axis - very loud when moving slowly |
Hey everyone. I have an old Isel CNC router. The X and Y axis sound great when jogging them slow and at max IPM. The Z axis sounds horrible jogging slow and fine at max IPM. I tried calibrating the Z axis. The max IPM was 100.00 before. I now have it set at 120.00 IPM (same as my X and Y). The Z axis now sounds much better (but not as good as X and Y). Is it fine to have made this adjustment? The CNC was given to me, so I am not sure if it was ever professionally setup. I know the Z axis has the same Isel stepper motors as the X and Y axis. Any advice or reccomendations would be greatly appreciated. |
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| Author: | Andy Birko [ Thu Jan 23, 2014 2:48 pm ] |
| Post subject: | Re: Z axis - very loud when moving slowly |
It sounds like it could be a resonance issue. I use a Gecko G540 and it has a trim pot feature that you use to get rid of exactly what you're talking about. In the case of the Gecko, it has something to do with the micro stepping. What you do is jog it along really slowly and simply turn the pot back and forth until noise is at its lowest. Perhaps your drives have something similar? |
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| Author: | RandK [ Thu Jan 23, 2014 10:38 pm ] |
| Post subject: | Re: Z axis - very loud when moving slowly |
Has it always done this or is it a recent development ? Unless you have changed something with the controller/drives etc as Andy suggests it might be good to check off the mechanical stuff first. Is it still cutting properly ? Does the Z axis move smoothly without power ? I don't know how your machine is set up, if it has a counterbalancer or a brake to hold it steady. How long since you clean/lubed it. I have an older Techno servo machine, parts of it are Isel and some made by Techno out of Isel parts like the rails and screws. Getting access to the rails & ballscrew on Z involves considerable disassembly of the enclosed axis assy but perhaps yours is different. Since it is enclosed it doesn't get very dirty but can still get dry from use/age. There may be some useful information on the docs.technorouters.com site on machine maintenance or in their wiki. There are several Isel Automation sites which I've looked at in the past, now very much rearranged that you can search if you've got the time. |
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| Author: | AlexanderJamesGuitar [ Fri Jan 24, 2014 11:57 am ] |
| Post subject: | Re: Z axis - very loud when moving slowly |
The Z axis has always made this noise. Up until recently it really started to get to me and I said "that noise can't be good". The machine has to be about 20 years old...minimum. It still cuts great. I have never cleaned and lubed it. I have only had it for about 2 years. I am pretty sure it was never taken care of before either way. The only accessible axis would be the X axis ball screw. I have no clue how you would properly clean and lube it. What should be used on ball screws? To get at the Y and Z axis it looks like there would be considerable disessembly. I did tighten up all the screws and stuff to try and eliminate any frame resonance etc. When I hand turn the z axis it sounds alright but there is a noticeable noise within the same interval every couple of turns. It is also the same when jogging the Z axis down with power. There will be normal movement noise and then a vibration or rubbing noise every couple of IPM (always at the same interval). Thoughts? |
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| Author: | RandK [ Fri Jan 24, 2014 3:35 pm ] |
| Post subject: | Re: Z axis - very loud when moving slowly |
Is the noise a clicking kind of thing ? I'm thinking ballnut needs lubrication or has a stuck ball bearing / contamination. It's a good thing that it still cuts properly. Don't know how closely the mechanical assemblies of your machine resemble the later ones but take a look at the lubrication instructions in this file: http://www.docs.technorouters.com/image ... e_2010.pdf They list the lubricants in the document. I have their kit which is Tellus 23 oil and Alvania 2 grease which are Shell products. I'm sure you can find something suitable locally but I wouldn't use regular lithium grease and 3-1 oil type stuff. On my Z axis, I can take the bottom endplate off, and using a mirror, light, and acid brush or cotton-ball CA'ed to a stick (giant homemade q-tip) get some oil on the rails and grease on the ball screw. It's not fun or precise and I can't get to the top like that but it helps. Clean off everything possible with a rag and then lube the bottom and run it up and down to spread as far to the top as possible. I only do my Z perhaps once a year and disassemble to get at everything every few years depending on use. My bottom endplate does not hold the ballscrew bearing, it is one smooth aluminum plate and nothing bad will happen if I remove it, with respect to the internal mechanism. If your is different and seems to hold the ballscrew bearing then you'll have to decide whether to proceed or take it apart to get to everything. |
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