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Y-axis assembly jig
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Description

The Y-axis is slightly different so we will need a new y-axis assembly jig

Event Timeline

kent created this task.Sep 12 2018, 2:49 PM
kent triaged this task as Normal priority.
logan claimed this task.Oct 2 2018, 10:56 AM
logan added subscribers: west, logan.

@west Is there a FreeCAD assembly of the Y-Axis with most current hardware? I'd like to start working on this jig if possible

west added a comment.Oct 2 2018, 11:00 AM

I will get one updated

west added a comment.Oct 2 2018, 11:08 AM

@logan taz-quiver/Production_parts/TAZ7_assembly/Assemblies/Y_bed_assembly.fcstd

logan added a comment.EditedOct 19 2018, 3:02 PM

@kent @west Please review the assembly below and let me know if it needs something more or could be improved in some way

nickp changed the edit policy from "All Users" to "LulzBot Hardware Products (Project)".Oct 25 2018, 12:02 PM
kent added a comment.Nov 9 2018, 8:22 AM

@logan I think it would be good to have features that hold the x-motor in place during tightening of the mounting screws. The holes in the plate are over sized a little and we want to minimize the variance of the position of the pulley. The idler isn't as critical since the position is more determined by the position of the tensioner's threaded hole.

logan added a comment.Nov 9 2018, 8:48 AM

@kent I think because the motor is double shear mounted, the position of the pulley will be most affected by the position of the top bearing, which should be consistent. The jig is intended to be used before installing the Y-Axis motor

logan added a comment.Nov 9 2018, 10:55 AM

I know now that you're referring to the Y-Motor Mount printed part's relation to the Y-End Plate
Based on the size of the holes vs the size of the fasteners, we have about 0.8mm of available variance in that placement.
Is that enough to worry about? What would be the affect on print quality?

logan added a comment.EditedNov 9 2018, 12:04 PM

Alternatively, we could leave it loose at sub-assembly and tighten it during Y-Axis Assembly:

logan added a subscriber: tutley.Nov 9 2018, 2:30 PM

@west @tutley would you be opposed to incorporating a feature like this to the Y-Motor mount? This way that tapered hole in the printed part can be used with a jig that has a locating dowel on it, to ensure consistent placement.


What do you think?

Steven added a subscriber: Steven.Nov 21 2018, 3:07 PM

@west @tutley any feedback on this?

@logan i dont think the small amount of variance will really matter much but if you want to do this i am not opposed. I do have 1 question about this though, how are you locating the plate to the y ends? the plate could be shifted a little as well

logan added a comment.Nov 21 2018, 3:27 PM

@tutley I think I can incorporate that into the axis assembly jig, I will make a branch for this ticket and get a new one pushed on Monday.

@tutley I added two little posts to line up the end plate. Could you take a look at the assembly in the above commit when you have a moment?
I am concerned with how close I have placed the smooth rods to the jig, might have to print a few to find the happy medium as far as material expansion is concerned.

@logan i think it looks good other than the little bit of interference between the printed part and the rods that you are already aware of

west added a comment.EditedNov 26 2018, 1:42 PM

Why are we positioning the motor mount relative to the Y end plate based on one hole? The part could be up to 1.5mm off if we locate it on that hole. And aligning it with that hole wont position the belt to be straight since the belt mount holes have a +- 0.75 alone +- the tolerance stack. It seems like we are adding an extra step and complexity for not much result, while removing adjustment to make up for the stack

west added a comment.Nov 26 2018, 1:45 PM

With the Y assembly jig, I see where you are going with it but I think it would be better to position the extrusions and base everything off of that, the extrusions should set the position of everything
@kent what are your thoughts

logan added a comment.Nov 26 2018, 2:07 PM

@west

Why are we positioning the motor mount relative to the Y end plate based on one hole? The part could be up to 1.5mm off if we locate it on that hole. And aligning it with that hole wont position the belt to be straight since the belt mount holes have a +- 0.75 alone +- the tolerance stack. It seems like we are adding an extra step and complexity for not much result

@kent suggested that we should make a fixture for placing the Y-Motor Mount on the Y-End Plate. I just couldn't think of another way to constrain the part as requested. How do you figure we could be off by 1.5mm? The example pictured was to illustrate the concept. The idea was to have the hole tapered and sized to a dowel pin that would fit through the threaded hole in the end plate.

With the Y assembly jig, I see where you are going with it but I think it would be better to position the extrusions and base everything off of that, the extrusions should set the position of everything

Is there a good reason to do it any differently than TAZ 6? The goal of this jig was to accomplish the same task as the similar jig currently in use for TAZ 6.
Are you thinking just a spacer jig between the two extrusions? Then the issue of locating the end plates would require yet another part to that.

Is it possible that we're over-thinking this?
Is there an issue with the current method of assembly that we're not addressing, or are we purely theorizing on how tight these tolerances need to be? Because a lot of the free play we're trying to constrain here is not being controlled on TAZ 6. We are really just making sure the extrusions are flat, the rods evenly spaced, and the Y-Ends are level (the plate rests on the printed jig). We're not controlling whether or not the Y-Ends are centered in relation to the extrusions, or the position of the Y-Idler/Motor mounts in relation to the end plate. Has this caused any known issues? What issues could this potentially cause for TAZ 7?

logan added a comment.Nov 26 2018, 2:08 PM

edit: I see where 1.5mm came from; tolerances of the hole placement. Disregard that question

logan added a comment.Nov 26 2018, 2:11 PM

https://ohai.lulzbot.com/project/new-taz-6-y-axis-assembly/taz-6/
We dont square the plate in relation to the axis either as far as I can tell. I can't see why it would be necessary though.

west added a comment.Nov 26 2018, 2:16 PM

It looks like for TAZ 6 we use the extrusions as a base and fasten the Y end plate to that https://ohai.lulzbot.com/project/new-taz-6-y-axis-assembly/taz-6/

logan added a comment.Nov 26 2018, 2:18 PM

While holding the rods in against the jig, and pushing down on the Y-End plate, yes.
I can add material to hold the spacing between the extrusions more similar to the current jig if that would suffice. That is the only difference.
At that rate I might just redraw the current jig in new part design and modify any needed dimensions.

logan added a comment.Nov 27 2018, 9:03 AM

@tutley @kent @west
Please review the assembly in the above commit, I would like to come to a decision on this.

kent added a comment.Nov 27 2018, 12:08 PM

I don't see any major issues with the existing design, let's print one out and test it.

logan added a comment.Nov 27 2018, 1:00 PM

printing now in ABS

logan added a subscriber: kforrest.Dec 4 2018, 2:22 PM

@kforrest How did this jig work out while you were building Y-Axis?

@logan the Y-axis jig was warped a little causing one of the Y-corners to get stuck when inserting the part. Aside from that, the jig worked perfectly. I was able to build a complete assembly slightly under 20min. :)

@kforrest we'll try the next set out of PLA and see if the behavior is better dimensionally

logan reassigned this task from logan to kent.Jan 25 2019, 12:53 PM
logan moved this task from Alpha Sprint (2019/01/04) to Needs Review on the Quiver board.

We'll print the next set out of PLA, but I think it is best to keep a slightly tighter fit and let the jig wear in a bit.
In short, I think this is good to review/merge, confirmed working through alpha and is photographed for OHAI.

kent added a comment.Jan 28 2019, 12:30 PM

Looks good @logan this is merged in with d1027c1ecece6c64b619e614d397e9b60e60c722.

$ git diff master --summary 
 create mode 100644 production_parts/jigs/tooling/y-axis_assembly_jig/y-axis-assembly_withjig.fcstd
 create mode 100644 production_parts/jigs/tooling/y-axis_assembly_jig/y-axis_assemblyjig_v2.fcstd
 create mode 100644 production_parts/jigs/tooling/y-axis_assembly_jig/y-axis_assemblyjig_v2.stl
kent closed this task as Resolved.Jan 28 2019, 12:30 PM
logan claimed this task.Feb 7 2019, 2:12 PM
logan reopened this task as Open.
logan moved this task from Needs Review to Beta Sprint (2019/01/28) on the Quiver board.

Getting a closer look at this today after printing one in PLA, I noticed some damage to the Y Corner printed parts from forcing them into the jig. I think it will be best to open those sections up a bit.

logan reassigned this task from logan to kent.

Widened the holes, got one printed in PLA and tested, I am happier with the fit now.

kent closed this task as Resolved.Mar 6 2019, 4:34 PM

Ok these changes are merged in.