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reduce LCD assembly free play to alleviate cosmetic concerns
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Description

Because of so much free play in the assembly:
the LCD can be crooked in its frame very slightly
the frame can be crooked in the chassis
and the bezel can slide around in all 4 directions and expose metal wherever you like

Suggested fixes:
Enlarge beveled edge of bezel to more closely match sheet metal - currently there is a gap all around
Reduce hole size for standoffs in LCD frame - current hole sizing allows the screen to be moved laterally or rotated slightly

These fixes should help ensure the LCD is installed correctly the first time where no reliable checks are present, reduce the frequency of rework required in the event it is deemed crooked, and improve cosmetics for the bezel.
When changing the bezel, the edge that is the top while the part is being printed could stand to be wider to match the sheet metal. On alpha slices, many bezels the very thin top layer would peel off, leaving a white rough edge exposed.

Event Timeline

logan created this task.Jan 10 2019, 11:35 AM
logan triaged this task as Normal priority.
logan created this object with edit policy "LulzBot Hardware Products (Project)".
logan added a subscriber: anolen.

@logan

Suggested fixes:
Enlarge beveled edge of bezel to more closely match sheet metal - currently there is a gap all around
Reduce hole size for standoffs in LCD frame - current hole sizing allows the screen to be moved laterally or rotated slightly

There is a +/- 0.75mm tolerance on the LCD cutout size as well as the standoff locations. This is why the holes are oversized and why the bezel has a small gap on some machines.
We may be able to adjust the printed parts a bit, however they need to be able to work with all of the variance we get in sheet metal

logan added a comment.Jan 10 2019, 1:22 PM

Correction; all alphas had a gap around the bezel, not some, so I think there is certainly room for improvement here. If the tolerance is 0.75mm then the bezel doesn't need to be >1.78mm smaller than the cutout.
Looking forward to the solution, thanks! :)

@logan it would need to be 1.5mm smaller
i dont think .28mm will be noticeable enough to warrant this change

logan added a comment.Jan 10 2019, 2:18 PM

In the models it is sized at 1.23mm smaller horizontally. And unfortunately that wasn't gathered as a critical dimension for SPC for the chassis
I'm not sure what needs to be done here, but in my opinion, no change would poorly affect cosmetic appearance of part of the printer I spend a lot of time looking at while operating the machine. This will also cause variance across all machines, and is not very ergonomic to adjust in assembly after the USB reader and Archim connector are installed.

Can we add a feature to the top of the holes on the LCD frame that would locate the bezel to the frame?
Alternatively, we leave the cover off until after FW is flashed and have individual assemblers eyeball it.

oliver added a subscriber: oliver.Jan 10 2019, 2:31 PM

@logan If we go by the critical dimensions of other cut outs, they have all been well within tolerances. A first article report will need to be generated on the new chassis cases from PMM and during that time we can also gather some more critical dimensions if not redo the critical dimensions due to having a different supplier and revision.

We may want to also extend some of the critical dimensions to the printed bezel as well. We could get a better idea of the fit between both of the parts.

Steven added a subscriber: Steven.Jan 15 2019, 10:06 AM

@west @tutley it appears this is left outstanding.

west added a subscriber: EricNugent.EditedJan 22 2019, 7:46 AM

@MikeR how did installation go?

west added a subscriber: MikeR.Jan 22 2019, 8:57 AM

@west no issues on Quiver 7 when installing

Steven closed this task as Resolved.Jan 22 2019, 10:14 AM
Steven claimed this task.

This looks good and is now merged into master.