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DEK 265LT Rising Table Position Error

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#43989

DEK 265LT Rising Table Position Error | 16 September, 2006

I'm hoping that someone may be able to shed some light on this error we've been getting on our DEK 265LT printer. Several months ago we began getting a "Rising table position error" after the operator would open the hood to load paste or after changing a screen. The machine would have to be rebooted and usually the problem would resolve itself. Sometimes, however, it would not and would require several reboots. We replaced the rising table brake as we could see the table would actually drop about 10 mm and thought the brake was malfunctioning. It continued after changing the brake. We believe now it is not the brake because the brake engages correctly when a soft estop is activated such as lifting the head (besides the fact that we replaced the brake a second time, just to be sure). It is only when a hard estop is activated that it appears the brake engages just a touch too slowly and the table drops a bit. DEK tech support came out and discarded the possibility that it was a worn rising table ball screw as the brake would engage for a soft estop at all the locations it would fail to engage on with the hard estop. The technician spent the entire day changing out cards, servo drivers, relays and connectors inside that machine itself and also with a second identical DEK on a different line without being able to find what was causing the delay in engaging the brake. He ended up modifying the sensor flag so that it would not drop into the limit sensor and error out and we were able to run for two days. This morning the machine had errored out again with that same error and the table will not move from where it is near to the home position but not actually at it. Any ideas, thoughts or suggestions would be greatly appreciated (well, other than to buy a new machine :) )

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#43991

DEK 265LT Rising Table Position Error | 16 September, 2006

I don't believe that the logic used in discarding the rising table ballscrew is valid, as this is in fact probably what your problem is. My guess is this occurs with a hardware e-stop or a cover opening, but not with a headlift or a soft e-stop. Is this correct?

There are still 2 possibilities, the only way to narrow it down is to do the easy one first. The easy one (which your tech may have already tried) being to swap the PNOZ 9 e-stop relay. As you have a 2nd machine with which to work that is the easier way to go, you can do it by swapping some wires on the supposed bad relay but don't want you to blow anything. If this doesn't fix, I'd give >95% possibility to the ballscrew... which is no ones favorite to replace.

As far as the table situation now. I'm guessing that you have verified that the motor has power and the brake is not engaged. Does it still give a position error? or does it give a "comms error" or "following error" when homing is attempted (presumably in diagnostics)? Sorry, need more info to diagnose this one.

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#43992

DEK 265LT Rising Table Position Error | 16 September, 2006

yes we already swapped the relays and they worked fine on the second machine. How would we verify it is the ballscrew if that is a possibility?

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#43993

DEK 265LT Rising Table Position Error | 16 September, 2006

You are as close as you can be to verified... my 95% being an understatement... In a world (and a machine) where there are no absolutes... it's as good as it gets.

I can't offer absolutes... without going over things that I might consider obvious but you and or FSE missed. And/ or looking at it myself.

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#44024

DEK 265LT Rising Table Position Error | 19 September, 2006

It has been a while since I worked on one of this machine. I recall having a similar problem where a timer was the root cause of my problem. There is a break timer in the back of the machine, it may not be staying latched. Swaped this device and keep us posted.

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#44028

DEK 265LT Rising Table Position Error | 19 September, 2006

I think you may be remembering wrong. Timer circuit will normally cause table drop when system power is re-applied, not when it is removed.

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#44037

DEK 265LT Rising Table Position Error | 19 September, 2006

Have you tried changing the motor?

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