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Fred Ball
05-09-2012, 5:16 PM
Hi everyone, another servo motor burnt out - this is the fourth or fifth I've replaced. Can't seem to get them to last 6 -8 months, mostly on the Y Axis. The laser is an Epilog 25W Mini, approx. 6 yrs old and the motor started giving me problems about a year and a half ago, this is the only problem I've had with this machine. Anyone have an issue such as this or any comments or solutions. Thanks

Ralph Boumenot
05-09-2012, 6:23 PM
Check the both the y and z axis to make sure that there isn't any binding or hard spots. Sounds like the servo is drawing too much current trying to move.

Mark Sipes
05-09-2012, 6:26 PM
If it was the x-axis I could understand a higher wearout rate. But the y-axis? I have never replaced the y-motor..... 3 - x motors . and 6-8 months between failures. There is more going on than normal wear and tear.

Duncan Crawford
05-09-2012, 7:35 PM
Hi everyone, another servo motor burnt out - this is the fourth or fifth I've replaced. Can't seem to get them to last 6 -8 months, mostly on the Y Axis. The laser is an Epilog 25W Mini, approx. 6 yrs old and the motor started giving me problems about a year and a half ago, this is the only problem I've had with this machine. Anyone have an issue such as this or any comments or solutions. Thanks

Fred,

I'm on my fourth Y axis motor on my 2010-ish Mini-18. The original had an encoder electronics failure after about five months. The second lasted about three months, before the Y dimensions became erratic, sometimes compressed. Turns out that one had floating-around debris on the encoder disk, what appeared to be a small bit of white plastic, as what might be peeled off the connector when the wiring harness pins were inserted. I believe Epilog buys the encoders, wiring harnesses and motors from third parties, then assembles-- so that failure looked to be an 'oops' problem at the factory. I kept that motor after cleaning the encoder-- tested it, and it's apparently OK-- at least as an emergency spare. The third motor had an actual wiring failure, after about a month-- the white wire on the encoder connector broke clean off, as for a bad crimp. The failure symptoms were interesting-- when the laser powered up one morning, I heard a muted "clank" at the Y zero position. Midway through a longish job, 'Y-axis disabled' appeared on the control panel. Thinking I might have another encoder or possibly a dirty belt issue, I removed the motor, cleaned all the drive splines with a brass wire brush, and reinstalled. When I then powered up the machine, the whole bar assembly headed towards the front/control panel end of the machine at *full* speed, stopping with a hard thud and 'Y disabled.' Given the problem had gotten worse after my cleaning, I removed the motor and took a hard look at the encoder assembly-- found a clear break-away of the white wire. Not a nice thing for a servo motor. Given I had a job to finish, I soldered a bit of 26 ga solid wire into the connector pin, then soldered the white lead to that and quite carefully reinstalled everything. Worked fine, and has continued to work. That said, I did get a replacement motor (warranty) and I'm anticipating that it will be installed sooner rather than later.

So, for advice (apart from no. 1, calling Epilog tech support :-) I'd suggest making sure the spring that tensions the Y motor is set in it's proper position, then the holder locked into that position with no additional tension. Before that, ensure that the various spines which drive the timing belts are thoroughly clean, e.g., brass wire brush and IPA. Perhaps take a peek under the encoder cap of the last failed motor-- give it the sniff test for fried parts, check for muck on the encoder disk. If things are fried (e.g., routine failure mode for you) then you might have a binding issue somewhere that drives up the motor current (e.g., you might see a shuddering of the mirror as it moves along the Y axis while vector cutting at speed). Be sure you've done any necessary rail cleaning/lubes for your machine. Another thing is to ensure that the wiring bundle for the Y motor is properly dressed back into it's recess, or at least well back out of the way of the work table when that moves for focus or work insertion. On my 'repaired' motor, I've added a bit of hotmelt glue (where it can't melt insulation :-) and a bit o' duct tape to provide some additional strain relief to the encoder connector wiring harness-- not good to have any of it swing in the breeze (or be hit by table). Speaking of 'breeze,' the Y motor on my Mini-18 isn't directly in the exhaust airstream-- the encoder cap is back a bit to the right side from the door vents-- and these motors get driven hard (electrically). While the Y axis might be the slowest moving one in the machine, it's driven to either move or stop so cooling is important. YMMV on that one, folks and techs will debate heating issues. Finally, the factory tech support guys might have thoughts on potential motherboard component failures/age-related issues. (Be sure you're running the latest firmware version for your machine as well.) Boards do get updated now and then, might be time <shudder> for a new one. As an old system engineering guy I quite like the Epilog mechanical packaging, but I'm not all that convinced that the motherboard in mine has totally robust current limiting designs for the various axis and/or sensors. I think there have been other opinions on that here in the forum, not too long ago. Whatever, good luck, and do give the factory a call.

duncan

Dan Hintz
05-10-2012, 6:28 AM
Consider replacing the motor driver circuit (hopefully it's a separate card, like on the ULS).

Frank Corker
05-10-2012, 6:34 AM
Seems way more than excessive, perhaps the belts are being overtightened or angle of alignment is out.

Fred Ball
05-11-2012, 7:13 PM
Thanks everyone for the input. Contacted Epilog tech support and a new motor is on the way but they're also stumped as to why this is happening and they did mention the motherboard, but I still think there is another problem elsewhere. When the new motor arrives, will give the machine another thorough cleaning and lubrication. Thanks again.