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use flanged hex head M5x10s for Z lower to frame
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Description

These fasteners:
https://www.mcmaster.com/98093A310
With this tool:
https://www.mcmaster.com/5163a24

The flanged hex head fasteners work well here.
A few small printed part changes would make it perfect:

  1. recess for screw washer needs to be wider since the flange of the bolt is wider than a washer
  2. the top rear fastener needs more clearance for the wrench

We can also get an 8mm crow's foot for a torque wrench and actually (for the first time) be able to torque these fasteners to the spec and check them :-O

Event Timeline

logan created this task.Jun 25 2019, 12:24 PM
logan created this object with edit policy "LulzBot Hardware Products (Project)".

T5787 is the same concern, but for Quiver and will require a change order to implement there.

adam added subscribers: jperry, adam.Jun 25 2019, 2:39 PM

@jperry can you get a quote for these bolts from our typical hardware supplier?

Attached is the quote from Hardware Specialty. These parts went down to $0.09 from $0.1059.

logan triaged this task as High priority.Jun 26 2019, 12:48 PM

@adam @west @Steven can we move forward on this one? I feel this is too much of an improvement to this situation to not implement for production, if so we need to get this moving. If you need my help making model changes please let me know. I have submitted a COR T8316 for this issue that is in common with Quiver.

adam added a comment.Jun 26 2019, 1:10 PM

My caution here is that this requires change on a common printed part with Pro so we either need to create a new part or we need to run the change order concurrently.

Adam and Dani,
Please proceed with T8316, so Logan can execute.
thank you,
christian

adam added a comment.Jun 26 2019, 1:16 PM

@jperry can you create a part number for these flanged hex head bolts?

Logan,
How do you propose to handle the change to the common part? Concurrent change? Coordinate change in production with new fasteners and tools? End Pro production one day with old part, fasteners and tools, and roll the changes in on next day?

i personally would rather see a change in the assembly flow to address this issue rather than a change in hardware

i think we can assemble the z lower, upper, and x end with z belt and z idler attached, just leave the z motor off. This assembly can go on the shelf held together with a large rubber band or two. then the assembly goes on the frame, with no z motor attached you will have access to the mounting screws to torque them properly, then the z motors go on and the z idlers get fastened down.

logan added a comment.Jun 26 2019, 1:42 PM

@tutley That would only solve the concern of cosmetic damage to the motor, and not the issue of proper access causing tool wear, cross-threaded and/or stripped fasteners. We have tried the suggested method and it simply isn't feasible for manufacturing. I have been instructed to proceed with this hardware change.

@cmerot I think it would be best to end Pro production one day with old part, fasteners and tools, and roll the changes in on next day so that nothing gets mixed up. This will allow us to define a serial number where this change begins and ensure all parts, tools and instructions are in place and ready to go.

it would actually solve the problem for proper access. You can get at the fasteners much straighter with the motor not attached. This is the exact same as what we have done for all of Taz5 and Taz6

logan added a comment.Jun 26 2019, 1:50 PM

This is the exact same as what we have done for all of Taz5 and Taz6

Exactly why we are proceeding with this change. It is time to improve and solve this issue.

@logan do you mean the instruction is to move forward with the immediate change in production or the change order?

@logan never mind, I see there is already a change order. I'm assuming it has been made clear to technical support on how they will need to support this change considering we do not provide a tool for a hex head?

logan added a subscriber: TyTh.EditedJun 26 2019, 2:03 PM

@Steven I will get with @TyTh to ensure they are aware. Tools for 8mm hex are by no means difficult to source and as is we do not provide all necessary tools should someone decide to completely disassemble the printer. For example P2 Phillips drivers are required to completely remove the control box, which you have to do to even reach the z lower fasteners with the ball tip hex key. I think any of our customers undertaking such repairs and/or adjustments would appreciate the more robust fastener drive system.
Production is stoked on it.
If this is of sufficient concern then we source and add a cheap 8mm wrench to the tool kit.

@logan i am not fully convinced that this is an improvement. you will still end up with cross threaded bolts/screws as it still happens even with direct access to any fastener. This only introduces yet another required tool and another fastener to keep stocked.
And yes hex drivers wear out but that happens with hex cap screws regardless.
Currently you can work on any part of the frame assembly with 1 driver. A few months ago we were consolidating all the hardware, specifically for manufacturability and RMA purposes.
Also this introduces an expensive new tool to add to the tool bag.

@logan i think if we do roll forward with this then we will need to include the 8mm wrench

logan added a comment.EditedJun 26 2019, 2:13 PM

@tutley Thank you for the feedback

@adam what do you think about adding an 8mm wrench to the tool kit? Is it necessary given that we already do not provide every tool they could possibly need?

@jperry What is the absolute cheapest 8mm wrench we can get? They don't need the ratcheting kind like we will use in production.

TyTh added a comment.Jun 26 2019, 2:19 PM

I can't find anything about customers needing to remove this in the last year or so (from RMAs at least), and I know personally that z-axis motor issues are extremely rare.
Whatever works for production works for me, I have no special feelings one way or the other

karrad added a subscriber: karrad.Jun 26 2019, 2:45 PM

As this is such a rare piece to replace, we will not need to include the tool to install/repair this in the tool kit.

adam added a comment.Jun 26 2019, 2:46 PM

@TyTh do we ever ask customers to mess with the frame of the printer? If not, I don't think we need to include this.
I feel that the tool kit is the minimum necessary to operate and maintain the printer as well as allowing a robust ability to assist TSR with diagnosing issues. We don't include crimping tools, crimp removal tools, or electronics test equipment because we expect the customers to send the machine back when it gets to that point. I feel like a frame issue requiring access to these screws would be the same thing - an issue serious enough to warrant sending the machine back.

TyTh added a comment.Jun 26 2019, 2:52 PM

@adam
We have not had to since the TAZ service bulletin about the frames.

logan moved this task from Report Issues Here to Beta on the Redgum board.Jun 27 2019, 8:42 AM

Getting tooling together for torquing these fasteners.
I have ordered an 8mm crowsfoot adapter and one of these torque wrenches set to 8in*lbs: https://www.mcmaster.com/7151a811
With this tool though, the assembler would have to remove the adapter and place it back in the forward position after reaching 8in-lbs.
Unfortunately I couldn't find any click type ratcheting torque wrenches that would go that low, at least from McMaster, I found this one at grainger: https://www.grainger.com/product/WESTWARD-1-4-Fixed-Electronic-Torque-6PAE8
Checking the torque on these fasteners may be something we do during frame QA.

Since we've never been able to properly torque fasteners at this location we decided to do a little test to ensure the plastic parts would hold up under 8in*lbs torque before ordering a tool.
I designed a test piece with the same dimensions as the mounting fastener holes on Z-lowers v2.5 and that could be printed in the same axis while allowing us to torque the fasteners. @EricNugent printed it in the cluster using the same profile being used for redgum/quiver z-lowers.
There are 5 fasteners for each test piece, I was able to torque them all to 8in*lbs without any issue.

Pushed slices and removed old versions in 825aaa537da5

logan added a comment.Jun 28 2019, 9:01 AM

These worked beautifully, installed in a complete frame assembly and squared with no issue.
Gcodes and correct models are in place.
So as soon as BOMs are changed and pushed this is ready for review/merge.

logan reassigned this task from west to adam.Jun 28 2019, 9:01 AM

I created part (HD-BT0250: M5 x 0.8mm Thread, 10mm Long Flanged Hex Head Screw) for the Hex Head Screw. Let me know if you need anything else.

logan added a comment.Jun 28 2019, 9:32 AM

@jperry could you create a TL-HD part number for the 8mm ratcheting wrench also? We'll need to order these for production

@logan Just to confirm this is the wrench you are referring to? https://www.mcmaster.com/5163a24

I ordered from McMaster knowing they'd get here the fastest. If the home depot one you linked above (https://www.homedepot.com/p/URREA-8mm-12-Point-Combination-Chrome-Wrench-1208M/202797562) is equivalent in quality we can go that route since it is cheaper. I don't know how the quality would match up though.

I created TL-HD0573: 8mm, Ratcheting Combination Wrench

adam added a comment.Jun 28 2019, 10:49 AM

@logan these are replacing 8x HD-BT0073s on AS-PR0165?

@adam Yes but also 8x HD-WA0040 because they are flanged we wont need the washers. So in total:
From AS-PR0165
Remove 8x HD-BT0073
Remove 8x HD-WA0040
Add 8x HD-BT0250 Flanged Hex Head M5x10

adam added a comment.Jun 28 2019, 12:00 PM

thanks - on it

adam reassigned this task from adam to Steven.Jun 28 2019, 12:38 PM

OCA BOM updated and pushed to branch. Please merge to master and change column to OHAI for updates.

adam moved this task from Beta to Needs Review on the Redgum board.Jun 28 2019, 12:38 PM
logan added a comment.Jul 2 2019, 1:27 PM

Drop test passed, full report:

Steven reassigned this task from Steven to logan.Jul 5 2019, 7:29 AM

@logan this is merged into master. I'm not sure if there is anything left to do on your end so I'm leaving this open and assigning back to you. Feel free to close if there is nothing else.

logan moved this task from Needs Review to OHAI Content on the Redgum board.Jul 5 2019, 8:08 AM