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Drawing for AO-Hex heaterblock is missing dimensions and tolerances
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Description

The drawing for the hexagon heaterblock used on the TAZ 6 is missing dimensions and tolerances.

Event Timeline

kent created this task.Nov 6 2018, 5:16 PM
kent triaged this task as Normal priority.
kent created this object with edit policy "LulzBot Hardware Products (Project)".
kent added a comment.Nov 6 2018, 5:23 PM

@jessica I created a drawing to help with second sourcing this block. We will want to have it reviewed before sending it to anyone. I've attached the current version of the drawing here.

kent added a subscriber: kforrest.Nov 6 2018, 5:26 PM
tutley added a comment.Nov 7 2018, 7:50 AM

@kent here is some initial feedback on this drawing.
i think in the notes instead of "remove all burrs and shavings", and "no additional finishes or coatings" this should be changed to "break all edges" and "parts must be clean, free of oil and debris" for consistency across all our drawings
This drawing is missing a call out for the location of the thermistor slot. The heater cartridge hole diameter and location is not fully called out. There is no call out for the chamfer just a note that it cannot exceed a 6.4mm diameter on the surface. The 6.4mm hole that gets tapped is called out too large. if they drill to 6.4mm then try and tap it with m6 threads there will be basically no threads. the recommended drill size for an m6 tap is 5.2mm.

@samantha is also looking at this drawing and will likely have more feedback

I have left a redlined printout for @kent. Let me know when updates are ready for a second round of redlines, or if there are any questions.

AOJAS added a comment.EditedNov 7 2018, 10:37 AM

Some feedback on the chamfer dimension:
I've been rejecting chamfers over 6.64mm, so I think 6.4mm chamfer size limit in the drawing would work well. Specifying it well under 6.64(the highest diameter we know works with the Reprap nozzles) will make inspection much quicker and keep fallout to a minimum. Due to the size variance in Reprap nozzles, 6.4mm as a chamfer diameter limit will hopefully eliminate all nozzle leaks going forward.

Thanks for the quick turnaround on this spec sheet.


Justin Stamper

kent added a comment.Nov 7 2018, 1:59 PM

Ok, I've made some changes, please take a look again.

kent added a comment.Nov 7 2018, 2:44 PM

changes made based on redline, please check it again @samantha thanks!

tutley added a comment.Nov 7 2018, 2:50 PM

@kent the only thing i see that i think should be corrected now is that the tolerances are pretty loose. you will likely want to move most everything to 2 decimal places and probably some of it to 3 places

kent added a comment.Nov 7 2018, 3:22 PM

Ok I tightened most everything up. Please check it.

@kent The notes are numbered 1,2,4

kent added a comment.EditedNov 7 2018, 3:33 PM

Ok, re-numbered and fixed the tolerance on the heater cartridge hole. Only thing I'm a little uneasy about is that we might be over-specifying the hole for the thermistor on the top view because we call out the radius and the position of the edge but I think they might be specifying different things.

west added a comment.Nov 7 2018, 3:37 PM

should there be a depth specified for the M3 set screw hole?

kent added a comment.Nov 7 2018, 3:53 PM

Ok, I added a depth callout to that hole @west

tutley added a comment.Nov 8 2018, 7:22 AM

@kent im not sure what the tolerance is on the diameter of the heater cartridge, but i think the tolerance you specify on the heater cartridge hole is too tight at 4 places

kent added a comment.Nov 8 2018, 8:13 AM

Ok, I updated the tolerance @tutley

tutley added a comment.Nov 8 2018, 8:21 AM

@kent this latest change allows the minimum diameter of the heater cartridge hole to be 6mm which is the nominal diameter of the heater cartridge. The heater cartridge will have some tolerance as well, and could be greater than 6mm in diameter. On E3d's drawing for the cartridge they have it called out as 6.00 but there is no tolerance block or reference for ISO so I'm not sure what the tolerance is on those. We will just want to make sure that the largest diameter heaters we get will still fit in the block.

kent added a comment.Nov 8 2018, 9:07 AM

@tutley that's why I put it at four places in the rev before last. I haven't taken a huge sample or done any control chart for it, but based on a hand full of measurements of the heater cartridges, the average is 5.95mm with some as low as 5.9mm and some as high as 6.00mm so I think the +/-.1mm on the 6.1mm dimension should fit the large majority of the heater cartridges.

kent added a comment.Nov 8 2018, 9:14 AM

https://devel.lulzbot.com/hot_ends/ao-hexagon/lulzbot_edition_hexagon_hotend-0.5mm/PP-MP0114_modified-PP-MP0134.jpg

fwiw, the previous version of this drawing (which I am unable to locate the source for) specs the hole at 6.10 which means holes in the range from 6.85 to 6.35 would be acceptable, even though we know they are not.

tutley added a comment.Nov 8 2018, 9:55 AM

@kent sounds good. I think we should verify the tolerance on the heaters with E3d

@kent the depth callout on the hole should go at the end of the line of the callout it is to be applied to. so, it should come after "thread" here. Since it is at the end of everything it could be interpreted to apply to the chamfer as well. Since the angle of the chamfer is not specified, this would then mean its a very steeply angled chamfer of that depth that comes to the specified diameter. Also, you should probably specify the angle of the chamfers.

kent added a comment.Nov 8 2018, 4:44 PM

ok, I put the depth callout and added the angles.

kent added a comment.Nov 14 2018, 7:39 AM

@samantha any other feedback on this drawing? I think we addressed everything.

@kent get a proper rev letter on there and its good to go

kent closed this task as Resolved.Nov 14 2018, 10:37 AM

ok @jessica the drawing for the hexagon heaterblock can be found here http://devel.lulzbot.com/TAZ/Olive/production_parts/machined_parts/lulzbot_edition_hexagon_hotend-0.5mm/ao-hex_heater-block_revA.pdf

It might take a minute to sync.

Thank you all so much for getting this done so quickly!!

jessica reopened this task as Open.Nov 26 2018, 8:17 AM
jessica raised the priority of this task from Normal to High.

Both PMM and Quattro need a STP file. I am not seeing one, am I missing it?

I generated a .step and added it to the ticket branch, which has been sent along to PMM (who emailed me directly looking for it.)

@kent It would seem the title on the drawing is also incorrect. Lists PP-FP0134 and should be PP-MP0134.

kent closed this task as Resolved.Nov 26 2018, 4:34 PM

I updated the drawing number.