Re: [rp-ml] sla250

From: Markus Hitter <>
Date: Thu, 8 Aug 2013 13:53:32 +0200

Am 08.08.2013 um 11:42 schrieb VRT BV:

> We have a SLA250/50 machine. The elevator stops moving during the
> build and
> this is at random layer heights.
> So we can not use the machine as sometimes it builds ok but most of
> the
> builds it starts and than stops completely.
> Does anyone has a solution for this?

As there is no diagnosis, we can't give a solution, obviously.

Three issues to investigate come to mind:

- Does the machine completely stop, like no wiper moving, no laser
moving, essentially nothing more happening? Then it might be an issue
with the controller PC or its attached electronics, which stops
working as soon as it gets warm. Checking all the electrical
connections might help.

- Oxidised electrical connections of the stepper motor - more likely,
as it's in this outgassing build chamber. This would reduce the
stepper motors available torque, leading to dropouts. Check the
connector right next to the motor, going through the backplane, clean
it and put some battery terminal grease in before reconnecting.
Battery terminal grease helps greatly to reduce existing and prohibit
new oxydisation.

- Mechanical issues of high friction on the Z stage drive, like
clogged ball bearings. Not so easy to detect without disassembling
the Z stage, but you can listen for an uneven sound while the Z stage
searches its endstop at machine initialisation and/or turn the knob
on top of the stepper motor while its turned off to detect strong
going areas. To solve such issues, putting oil on the Z drive rods
might help, worst case you have to disassemble the Z drive and clean
or replace the ball bearings.

Also make sure the debris at the bottom of the vat didn't pile up
high enough to disturb the elevator.

Hope that gives you sufficient ideas on where to search,


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Dipl. Ing. (FH) Markus Hitter
Received on Thu Aug 08 2013 - 14:34:00 EEST

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