Y-Motor heat causes table rise

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d.herrendoerfer
Posts: 4
Joined: Sun Jan 26, 2014 9:28 pm

Y-Motor heat causes table rise

Post by d.herrendoerfer »

I've observed that the Y stepper gets very little ventilation, and the v3 parts
are subject to heat extension.
After a print of about two hours duration the Table is about 1.2mm higher than
after cooling down for about an hour.
It appears the moulded parts extend quite a bit when they get warm, and the
stepper gets close to 60 degrees celsius.

*EDIT: The 1.2mm are measured on the left side of the table, opposite the mount.

:wq
Dirk

andrewsi
Posts: 130
Joined: Mon Dec 23, 2013 1:26 am

Post by andrewsi »

I agree that the Y stepper gets much warmer than the others in the 3.0 design but I haven't seen anything like a 1.2mm rise in the bed height. The extruder would be dragging horribly through the print by the end if that was the case, and I routinely do objects that take well over 2 hours and things are still running nicely from beginning to end. I do make sure, however, to do bed leveling with the heat on, as there is definitely expansion that takes place between room temperature and the active bed temp that would have a very negative effect if leveled while cold.

A few things you could look at:
1) You could adjust down the Y current trimpot. Higher current = higher heat, so you could do some tweaking to ensure that you're using the minimum necessary current to keep it running reliably without missing steps but at the same time not generating unnecessary additional heat. The 3.0 manual for trimpot settings is not exactly "precise." :-)
2) Are you certain that the threaded studs in the bottom of the heated bed are not screwed all the way into their inserts such that they are touching the top plate from the inside? The assembly instructions warn against this: I suspect this is to keep them isolated from the hot part of the bed and therefore conducting heat from the bed down into the arm and other mechanical portions of the y-carriage.
__________________________________________
Andy Silverman, Technogeek in Seattle
Felix Tec4 Single-head

d.herrendoerfer
Posts: 4
Joined: Sun Jan 26, 2014 9:28 pm

Post by d.herrendoerfer »

Thanks for the answer,

I compared the steppers to some of the Japan motor co. ones that I have lying around and observed that those have an air-duct at the top.
Likewise I made a small spacer for the Y-stepper that allows some air to pass by, effectively
cooling the stepper to about the same level as the X-stepper. (~35C)
That solved most of my problems, also I moved the printer to a slightly warmer location, so
the before-and-after effects are not as big.

:wq
Dirk

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