I've had several failures over the last 7 years of various electronic parts in my DIY cnc conversion of my bridgeport styled enco knee mill. I've gone thru 3 servo drives and 3 breakout boards and 4 proximity switches all just sorta out of the blue where its running fine and then its not. Its pretty annoying and getting sorta pricey at $280 a servo driver and 150 a breakout board. What is the typical experience of electronics reliability in diy cnc ?
reliability of electronics in cnc conversions
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dnalot
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I am using stepper motors (size 34) but I have been using my DIY CNC for over 22 years now and haven't replaced anything.. It gets extensive use and I have had to replace spindle bearings twice.
Mark T
I was thinking mine is over built with 1kw servos and the matching drivers , and I'm running it maybe once or twice a week. Ive got spike arrestors on every thing that you can. and a couple 5" cooling fans with filters blowing thru the box. so I'm guessing heat isn't the problem.
Like Mark T, my DIY CNC machines have given me years of trouble free service, and also like Mark's CNC, both my lathe and Mill use steppers, not servos, and certainly not even close to a Kilowatt.
My first guess would be that your spike arrestors are not doing their job. The second place I would look for problems: did you use shielded cables to your motors and your proximity switches and properly ground the shields? Finally, are the motor power wires bundled in with wires to the proximity switches? Tightly bundled wire cables make for a pleasing appearance but unless your wires are very well shielded the cable will act as a transformer and those kilowatt pulses driving your motors will induce current to flow in all the other wires in the cable.
Obviously, I haven't seen your machine, so these are just some guesses in the dark.
Good luck troubleshooting.
My first guess would be that your spike arrestors are not doing their job. The second place I would look for problems: did you use shielded cables to your motors and your proximity switches and properly ground the shields? Finally, are the motor power wires bundled in with wires to the proximity switches? Tightly bundled wire cables make for a pleasing appearance but unless your wires are very well shielded the cable will act as a transformer and those kilowatt pulses driving your motors will induce current to flow in all the other wires in the cable.
Obviously, I haven't seen your machine, so these are just some guesses in the dark.
Good luck troubleshooting.
I'm guessing you purchased an entire "Kit" to upgrade your manual Mill to CNC ?
Try doing a Google search for your specific kit and include the word "problems"; try finding out if others are having the same issues as you; if the early failures you're having are a common problem for your specific Kit, then it's likely someone else has already identified the specific problem and found a fix. Another helpful resource is the CNC Zone forums; good chance you'll find at least one person using the exact same kit you have.
If the internet has no answers:
Have you checked the DC power supply voltage to insure it's not too high. If the power supply for the motors is adjustable, then try lowering the voltage a bit; your Mill won't be as fast with the lower voltage, but the electronics should last a lot longer.
Again, good luck troubleshooting.
Try doing a Google search for your specific kit and include the word "problems"; try finding out if others are having the same issues as you; if the early failures you're having are a common problem for your specific Kit, then it's likely someone else has already identified the specific problem and found a fix. Another helpful resource is the CNC Zone forums; good chance you'll find at least one person using the exact same kit you have.
If the internet has no answers:
Have you checked the DC power supply voltage to insure it's not too high. If the power supply for the motors is adjustable, then try lowering the voltage a bit; your Mill won't be as fast with the lower voltage, but the electronics should last a lot longer.
Again, good luck troubleshooting.
Don't know if this will help but in my experience alot of electronic problems are caused by poor grounding. Missing grounds or poor connections can cause problems. Also see that the shields are connected to a good ground point at the source end (control panel) and isolated at the field end (motor).
Gut feel is that it's a thermal issue, otherwise as a general rule, I keep conductors that feed switching devices (relays, contactor's, solenoids and especially SCR speed controls) separated from any analog or sensitive signal (encoder) paths. Optically isolate whenever feasible. Shielded cables should be bonded to the devices at each end, providing shielding and more importantly keeping the ground potential the same at both ends. Try connecting a voltmeter or scope between the ground pins of different boxes in the system to see if a potential problem exists. In large systems with multiple cabinets, we often connected plated (not the white painted) backplanes with 000 welding cable to provide a stable common ground. And you may have done everything right, it could be just bad luck.
I'm not sure there is a commercial conversion kit. you an get appropriate sized hiwin balls screws but like the block that holds the two ball nuts had to be completely fabricated, the z quill axis was pretty much the same. the electrics are the 220 volt ac servos and and drivers and breakout board all from the same manufacture. and following their wiring diagrams there's a smooth stepper in there but those are pretty universal . I've got a couple 6 inch muffins blowing up thru it if any thing maybe a little overboard .
Recommend you Google your various components to see if others are having similar issues.
Again, go over to the CNC Zone forums, do a search for your components to see if others are having the same issues.
Finally, now that we know your electrics operate on 220 vac, IF you purchased the electrics from China there's a chance the system was designed to run on 50 Hz (as that is what China uses) instead of the US standard 60 Hz. In most cases, running a 50Hz motor at 60Hz isn't harmful, but the motor will get hotter.
Same with my KX3, no problems with electrics but they do cost more than a manual mill and a bunch of cheap components
nealeb
Well-Known Member
My CNC router is home-built although using fairly standard components. I have had one toroidal transformer fail, and several inductive proximity switches fail. However, I did buy a cheap box of switches from eBay when I built the machine. One was the wrong type (having two wires rather than three was a bit of a give-away) and one was faulty. Should have flashed up a warning then, but a couple have since failed in service. My CNC mill is a Wabeco (German-built) but with the electronics and servo motors installed by a US company (MDA Precision). The Clearpath servos seem to do a fine job but the control box was based around Mach3 and an Ethernet SmoothStepper which gave a number of problems. I suspect that this was software rather than hardware-related but given that Mach3 has been unsupported for years and the ESS does not have a good reputation for support, I scrapped the lot and replaced it with a UC300ETH and the UCCNC control software, all from one company and in current production/support. No problems found with that to date.
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