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Bed Heater External wire length for zip tie at calibration
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Description

The OHAI states we need to zip tie the heat bed wires all together (see calibration OHAI step 4) but the heater wires seem to be coming too long after the heat shrink.


See how much longer they are than in the OHAI picture:

We cannot reach the zip tie around all wires as pictured unless we push the purple wires back through the heat shrink, causing the braid to pop out on the other side. On the other hand, if we move the heat shrink part out of the y cable mount the wires flop around all loosely in the mount.
Is there a spec for this length? Can we have something standardized in regards to how long this is or where the zip tie goes?

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Event Timeline

paulette created this task.Aug 5 2019, 1:53 PM
paulette changed the edit policy from "All Users" to "LulzBot Hardware Products (Project)".Aug 5 2019, 1:57 PM
kent added a comment.Aug 5 2019, 2:01 PM

If you look at the spec sheet it has different spacing for the heat shrink on either side (10mm vs 5mm). Is it possible this one is installed with a flipped orientation? Otherwise, it might just be out of spec in which case it will probably need red tagged and reworked.

It seems to be almost all of them. It is measuring about 30-35mm from the heat shrink to the connector. Red tagging these for rework would stop production, as we have so few Control Box Chassis right now. It is possible to put the zip tie on the other side of the connector for now, if the main reason for it is to keep the wires from dragging while the Y axis is in motion. Would that be an acceptable work around until these get fixed before they are sent to us?

kent added a subscriber: adam.Aug 5 2019, 2:32 PM

@guadalupe @draubach Are these made in house? Can you make sure any of these we have are correct before sending to Mountain?

@guadalupe please review this ticket so that we can see if we can help with this issue.

@kent comparing the documentation you posted with the one we have in Electro-Mech, there is a difference in spacing for the side opposite of the 10 mm spacing. Ours is calling for 15 mm from end of heat shrink and the one you shared is only calling for 5 mm of heat shrink coming off of the side opposite the 10 mm spacing. So we have not been measuring these out completely due to old documentation. We can definitely make this change and add this to all current wires we have made

Talking with @kent today, we may need to have the drawing revised to specify where the heat shrink needs to be in relation to the connector.

west added a comment.EditedAug 6 2019, 9:11 AM

west added a comment.Aug 6 2019, 9:14 AM

Would this alleviate the issue?

logan added a comment.Aug 6 2019, 9:19 AM

@west as you photographed would not allow the zip tie that goes around those wires per T7987, see last photo of step 4 here: https://ohai.lulzbot.com/project/calibration-taz-workhorse/taz-workhorse/

west added a comment.Aug 6 2019, 9:21 AM

I didnt photograph, i took the image from the beginning of the post. The one with the issue. The image above says we can move the bed heater back so the front zip tie doent capture the heatshrink tubing only the back would

logan added a comment.Aug 6 2019, 9:26 AM

Ah I see what you're saying. @paulette can you try that and see if you can still get the last zip tie on without stressing wires?

west added a comment.Aug 6 2019, 9:29 AM

@logan can you measure the braided loom on some of the harnesses that are being set aside?

I tried this and it still doesn't move it enough to capture all the wires in the zip tie.

west added a comment.Aug 6 2019, 9:42 AM

@paulette thanks for trying that

logan added a comment.Aug 6 2019, 9:44 AM

@west they all look the same as far as I can tell. We haven't removed any yet, but I can. Can you measure some of what they have over there?

west added a comment.Aug 6 2019, 9:46 AM

I have one from pilot that measures 400mm, the drawing calls out for 430mm

logan added a comment.Aug 6 2019, 9:49 AM

One of the ones I pulled is 425mm

west added a comment.Aug 6 2019, 9:49 AM

can you post a picture of that one?

logan added a comment.Aug 6 2019, 10:12 AM

After re-securing it as described above, here is a 425mm and a 430mm:


west added a comment.Aug 6 2019, 10:14 AM

@logan can you get a picture of the full cable by itself?

west added a comment.Aug 6 2019, 10:44 AM

@guadalupe brought something to my attention that could be contributing to this. The harnesses can be made to the drawing and everything measures out, but when the harness gets bent (installed and ran) the heatshrink and loom slip down the wires exposing more wire than when originally assembled

logan added a comment.Aug 6 2019, 10:54 AM

@west Yeah that's pretty much whats happening, essentially what I'm doing is stretching the loom some and pushing the wires back so the end of the connectors reach the same point.

west added a comment.Aug 6 2019, 10:54 AM

Is that working out?

west added a comment.Aug 6 2019, 10:55 AM

The images of the assembly you did look promising

logan added a comment.Aug 6 2019, 11:02 AM

It seems to be working out, but may not be ideal. It would be best from our perspective to lengthen the loom by 10mm or more so that they can be tied like the OHAI shows

logan added a comment.Aug 6 2019, 11:08 AM

How much do you think we should lengthen it by? 15mm to be safe?

west added a comment.Aug 6 2019, 11:10 AM

15mm sounds good

logan moved this task from Report Issues Here to Change Order on the Redgum board.Aug 6 2019, 11:22 AM

For now we will have to rework what we have, any where the loom is shorter than 420-425mm should probably be rejected.
CO T9425

@logan So if it's 420-425mm, it's usable?

And we have some of these from CCX. Will CCX rework the ones they sent us, or will we need to rework them like with what happened with the EL-HR0160s a few weeks back?

logan added a subscriber: sherylb.Aug 6 2019, 11:50 AM

@draubach Lets go ahead and say anything over 425mm is usable.
Your second question would be best answered by supply chain but a bit more info would be helpful; Are the ones you have from CCX out of spec? How many?

heat shrink is not placed to current documentation rev

@draubach Myself and @david.hall have agreed that the incoming EL-HR0174 from CCX with short loom should be reworked. Please save all removed lengths of loom to be repurposed for shorter lengths, for example the lengths used on the Pro tool head.