Hi Guys, I just bought a second hand 408 and I'm noticing now it's not accurate. Approx 1mm in x axis and1.5 in y axis. So a 200x200 square becomes 201x201.5. I can cheat this a bit with the cutter but the circles are very bad. Has flats sections on top and bottom and fatter on the sides. It is rendering the machine useless at the moment and technical support here in Ireland is limited. So, would appreciate any help and if there is a guy out there who services these machines I would happily pay to have a chat and try and fix this issue.
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Gerber Sabre 408 not accurate
- Thread starter alcodes
- Start date
Adam.Foster
New Member
Check the X and Y lead screws. They should be all black, if you see silver they need to be replaced. Also try cutting in the back right of the table vs front left and see if you notice a difference. Front left usually gets the most use and is worn the most, back right is typically less.
HomerSimpson
New Member
What happens when you command a move in just the X, say travel 4 feet, then come back 4 feet. Does it end up at the exact same spot, if not, how far off is it? Then do the same in the Y axis.
The problem may be electrical. Are you sure your drive electronics are properly grounded?
The problem may be electrical. Are you sure your drive electronics are properly grounded?
All things points to the lead screws I think. I'd have a go fitting them myself if I could get them? Any idea where to buy them? People have also mentioned encoders and electrics for the issue however looking at these screws I should probably replace them because they will be probably need replacing soon anyway. Where to get them guys??
HomerSimpson
New Member
When trying to determine root cause, you always want to start with the easiest things first. By replacing the lead screws, you are starting with the hardest. Do the repeatability study first. You should be able to monitor the encoder positions with this machine and determine if there is an error (anything other than zero), when going out and back to zero. If there is, it is very likely to be a grounding issue. Get a solid copper rod (6 to 8 feet long), drive it in the ground, and connect a large wire from it to the ground for your drive electronics. Also look on youtube for videos of people showing how to go through the entire machine to determine if everything is grounded properly.
Ok I will do this, now that you mention this the machine would occasionally trip the fuse board with the RCD (Not sure how fuse boards are wired overseas but in Ireland we have an RCD which only trips when there is an earth leak) I just got the electrician out to remove the RCD. However there could be a larger issue here, would only trip when the spindle would start - it would move around from the control panel no problem and trip as soon as the spindle would start. Sounds totally unrelated though???
johnnysigns
New Member
If it were tripping from the motion drives I'd think you should definitely look more at the leadscrews, but since it's spindle based I'm not sure. We wore our lead screw coating almost completely off our old Gerber 408 all three Axis', but we did lubricate each screw daily with Lami-lube to delay the lead screw replacement. https://www.woodworkerexpress.com/laminate-lubricants-lami-lube-10-5oz.html Last time we did the screws it was a lot of money. I feel like it was closer to $4000 in parts domestically in the US for X and Y axis replacements.
Have you checked the slide bearings as well? I've also got a lot of the OEM repair guides if you need. I can upload them if you want to message me.
Have you checked the slide bearings as well? I've also got a lot of the OEM repair guides if you need. I can upload them if you want to message me.