Cables behind the x-motor are sometimes dragging on the frame
Closed, ResolvedPublic

Description

We noticed a few of the hibiscus machines have the igus cables just barely dragging on the inside of the left side frame.

kent created this task.Dec 20 2017, 12:29 PM
logan added a subscriber: logan.

This was a problem with Gladiola at the start as well.
The solution, in addition to a modification made to the part to allow more space for the wires, was to specify the manner in which they are Zip-tied to the X-End Motor assembly.
https://ohai.lulzbot.com/media/uploads/IMG_5605circle.JPG.600x0_q85.jpg
In the above linked picture you can see the current configuration.
On hibiscus however I've found that 3 cables in the front top zip-tie and 2 in the lower front zip tie tends to lay flatter against the plastic part and gives plenty of clearance.
There is also a printed jig that lays over the left side for the assembler building the sub-assembly to check before it gets installed in a frame. I recommend reworking that to fit Hibiscus someday when we are done changing the printed parts.
Tagged OHAI-content, we can refer back to this when we get past alphas.

MikeR added a subscriber: MikeR.Dec 20 2017, 1:04 PM

@kent , this is prolly a manufacturing mistake. If you do not secure the cables behind the z-axis properly the cables will drag along the frame. This happens sometimes in gladiola so we made a jig to make sure the cables have clearance.

west closed this task as Wontfix.Dec 27 2017, 11:49 AM
west claimed this task.
alexei edited projects, added Ohai-kit; removed OHAI-content.Jan 12 2018, 8:13 AM
logan moved this task from Report Issues Here to OHAI Content on the Mini-Hibiscus board.
kent reopened this task as Open.Feb 7 2018, 11:04 AM

We are still seeing this issue.

@mike where can I find that jig?

logan added a comment.Feb 7 2018, 11:10 AM


Here is the jig known as Claerence

west added a comment.Feb 7 2018, 11:11 AM

@kent i'm not seeing this issue

logan added a comment.Feb 7 2018, 11:16 AM

@kent Try arranging them as I described in my previous comment. From the pictures, that cable was set up similar to how the Gladiola OHAI kit shows. I have not found this to allow the same clearance on Hibiscus. @west Can you attach a photo of your arrangement there? Is it 3 top 2 bottom in the front Zip ties or vise versa?

kent triaged this task as Normal priority.Feb 20 2018, 11:28 AM
logan added a comment.Mar 7 2018, 10:30 AM

@west @kent Please review Z-Axis left OHAI and close as resolved if deemed sufficient; I haven't had any issues with cables dragging following those instructions.

kent closed this task as Resolved.Mar 19 2018, 8:47 AM

Step 5 here: https://ohai.lulzbot.com/project/z-axis-left-assembly-hibiscus/hibiscus-beta/ should be everything we need to keep the cables from dragging on the frame. Setting as resolved for now.

kent reopened this task as Open.May 3 2018, 7:53 AM
kent added a subscriber: tomc.

@tomc is seeing this in some production builds.

@kent i talked with @AOJAS a little about this yesterday. He has been seeing some left plates that are coming in bowed inwards. When we ran into this issue with Gladiolas we put a 3mm spec on the max acceptable amount it could be bent inwards to help prevent the cables from rubbing. Hibiscus has more clearance between the x motor and the left plate than gladiola does, so generally we should see a lot less of this issue on hibiscus. I think if the cabling is done correctly on the x motor, and the left plate is within the 3mm spec we shouldnt see any issues. Have we confirmed that the machines experiencing this issue meet the sheet metal spec and the cabling is routed properly?

logan added a comment.May 3 2018, 8:29 AM

@tutley @kent
The machines I saw on the line tagged for this issue are tied several different ways, some correct according to the OHAI, some tied in Gladiola fashion. The frames do appear to be out of spec though. I am personally not (yet) convinced that they will still rub if they are tied correctly and the sheet metal is within spec.

Feedback from assemblers indicates that the cables are being tied flat but end up moving around or otherwise end up rubbing when the Z-axis left is installed to the machine and have asked if any sort of guide or clip could be made to clip onto the top of the large cable chain to help hold the wires away from the frame. The cables do tend to move and settle as the Z-Axis moves up and down.

tutley added a comment.May 3 2018, 8:42 AM

@logan i agree that if the cables are tied properly and the sheet metal is in spec we should see no issues, or minimal issues at best. I have previously considered adding a zip tie to the large cable chain where it attaches to the x motor to hold the cables
a bit more out of the way, but i feel that this should not be necessary. I'm definitely open to giving it a shot though

logan added a comment.May 3 2018, 9:30 AM

@tutley I'm thinking if we find one tied correctly with a frame that is in spec and still rubbing we'll have a good unit to test solutions on. Would you like me to bring that machine to you if/when we find it?

@logan yea that sounds good!

tomc added a comment.May 3 2018, 11:41 AM

@kent @tutley I am not completely convinced that this (frame bowing) is totally the problem. Though we have found some extreme cases, some of the issue is how the cables for the extruder cable are being affixed to the left z-end. I have talked with one of the z-end builders and the frame assembler about this going forward. Wolff (frames) will be looking at this aspect burring the build process. We may want to include this inspection step on the OHAI kit for final frame assembly going forward. As I find more info on this i will be sure to report it here.

tomc added a comment.May 3 2018, 12:57 PM

@kent Another thing to note, all left side z-ends were built without using the clearance gauge to confirm that the wires would pass along the inside of the frame without rubbing. Two things, the OHAI does not call out this gauge and the one we do have does not fit very well. We may need to add the gauge step back into the OHAI and revisit the gauge to ensure that it properly fits onto the part.

AOJAS added a comment.EditedMay 3 2018, 1:40 PM

Our current corrective action in regard to the Weiser PP-FP0055 is to have units be straightened out before going on the line. Due to the differences in dimensional averages from Rapid and Weiser, it is difficult to ask for corrective action from the suppliers, but I will try to apply some pressure on them by providing them additional feedback on the perimeter values of their lefts, rights, bottoms, and tops, when the opportunity arises. I would like to see more of their units fall closer to the stated dimension, and less towards the extremes of the tolerance. The lead time on any positive outcome from this feedback could be months, or it could be indefinite(they may not take any action). Currently I haven't found any outside of spec for flatness on the Left side, but it may help alleviate production issues to have them straightened. I have trained Chris, Shane, and Luke on how to do this prior to stocking them out. This is not a fix-all unfortunately.

@AOJAS Thank you for looking into that.
@david.hall and myself looked at this and were able to determine a cable routing that gives us a lot more room on the sheet metal. I have applied this change to the OHAI kit for Z-Axis Left Sub-Assembly in steps 5 & 9. Step 9 describes a process which makes the Clearance jig unnecessary. Step 5 describes the new cable routing. In summary, the cables towards the front are tied the same (3 on top, 2 on bottom), before applying the zip-tie that goes near the X-pulley, the X-Motor cable gets passed underneath the 3 extruder cables. This keeps it from riding up (and outwards) on the X-Motor mounting flange. The Z-Max Endstop lead must also be tied to where it rests in front of the X-Motor mount flange, this keeps extra length there from rubbing the frame.
@tomc @bowman @ZachV We need to get one of the updated Z-Axis left sub-assemblies onto a frame as soon as possible. If this could also be installed on a frame with an inward bowing left plate to see how we stack up that would be beneficial as well to know whether or not these plates will continue to need corrected before being stocked on the line going forward. This will also tell us if using the table will be a good enough clearance check.

tutley added a comment.May 4 2018, 7:27 AM

@logan are we going to apply this change to the machines that have been built already? It seems we can pretty easily do this without tearing them back apart.

logan added a comment.May 4 2018, 7:31 AM

@tutley Unfortunately we cant apply this change to a completed machine; the X-Motor cable & ground have to be disconnected in order to be passed behind the 3 extruder cables. We are applying this change to any Z-Axis Left sub-assemblies that are not installed in machines, and any machines that exhibit rubbing. @bowman approved that they don't need to rework a machine if the cables weren't rubbing and I think @kent was present for that decision as well.

tutley added a comment.May 4 2018, 7:33 AM

@logan sounds good to me! Can we close this one as resolved?

logan added a comment.May 4 2018, 7:36 AM

@tutley Not quite yet, I am waiting to get a few of the updated assemblies on frames, including those with a slight inward bow, to ensure no corrective action is needed for inventory. There was discussion about needing to match up the stock of frame pieces at assembly to all have the same supplier due to fitment issues, I am hoping with the extra room we've gained that this wont be necessary.

tutley added a comment.May 4 2018, 7:50 AM

@logan ok no worries. Let me know what you find out

logan closed this task as Resolved.May 7 2018, 7:49 AM

I've seen this installed on several frames now, definitely gives us more room.