Page MenuHomeAleph Objects Inc

z-top prone to warping at the thin feature
Closed, ResolvedPublic

Description

The z tops are tending to warp on the ends, I think we could modify the geometry somehow to mitigate this.

Event Timeline

kent created this task.Nov 16 2018, 1:07 PM
kent triaged this task as Normal priority.
kent changed the edit policy from "All Users" to "LulzBot Hardware Products (Project)".Nov 16 2018, 1:21 PM

Chop it off?
Do those fasteners contribute to the rigidity of the frame?
I think there's enough securing the printed part to the top plate that we could eliminate these four fasteners without losing anything
@tutley @west

west added a comment.Nov 19 2018, 2:16 PM

@logan what is securing the printed part to the top plate that isnt the 4x M3x10

@logan @west to clarify what is actually warping, the outside fasteners that screw into the t-slot extrusion. The part is angled to fit on a mini bed and as a result those features are at the coldest part of the bed.

logan added a comment.Nov 19 2018, 2:20 PM

@west I was referring to eliminating the M5x10s securing the printed part to the extrusions, do you think the 4 M3x10s are sufficient?

logan added a comment.Nov 19 2018, 2:21 PM

That would look off though because the sheet metal hangs over, probably not kosher

logan added a comment.Nov 21 2018, 8:35 AM

The file in the above commit eliminates the M5x10 fastener and has two tabs that extend into the slot of the extrusion.
@EricNugent did you have many issues with warping on the test parts you printed?

From the small sample that I had (3 prints) I saw an improvement on lifting. The areas that lifted were much less severe with the helpers in place. I think a combination of slice adjustments and those features will resolve my issues

west added a comment.Nov 21 2018, 8:43 AM

We could still have the screw holes while adding a 2mm tab to help. Im worried if we dont have the fasteners that the part may float out from the extrusion and look bad

logan added a comment.Nov 21 2018, 8:44 AM

I thought about that but would it interfere with the t-nut?

west added a comment.Nov 21 2018, 8:45 AM

the t nut sits just over 2mm from the surface

logan added a comment.Nov 21 2018, 8:48 AM

Always worth a try i suppose.
Eliminating the fastener is preferred; I don't think it will cause any cosmetic issues that would be more concerning than a part that doesn't mate nicely with the top plate because of persistent warp. It really cleans up the look of the Z-tops.

logan added a comment.Nov 21 2018, 8:49 AM

Plus an additional drop in BOM cost

west added a comment.Nov 21 2018, 8:52 AM

@EricNugent have you tried a higher bed temp with lower fan speed?

@west Yep. Thanks for the advice though. It is roughly 20% of prints right now, and the same issues we typically see with thin wall parts with ABS. The z-lowers suffer from the same issue commonly.

Steven added a subscriber: Steven.Nov 21 2018, 3:13 PM

@EricNugent would printing these on the TAZ eliminate the rate of failure from warping?

Standard print profile works great

logan added a comment.Nov 21 2018, 3:31 PM

@tutley the standard print profiles for ABS have entirely too much fan for that to be true.
Even with fan off it is difficult to prevent warp depending on part geometry.

west added a comment.Nov 21 2018, 3:39 PM

Something we could do to help with warp is completely remove the two "prongs sticking out of the front. Those are there just to match the sheet metal, it isnt necessary at all

@Steven I am sure a higher passing rate would happen off of TAZ machines; however, part of the reason for the part change was to open the opportunity to print it on mini which is the majority of cluster. The primary reason I see lift is usually due to the corners getting neglected when sanding in cluster, which makes sense, the majority of parts have their critical geometries in the center of the bed while printing.

@tutley I built the profile off of the standard, yes it does work well initially on a machine that is watched. Sending to 10 machines blind in cluster gives varied results. It is less than 30% of prints where the lift is bad enough to fail the part, I am sure with enough time we can work out some settings to find the 'Goldilocks' solution.

There have been some adjustments made to some prototype parts which remove the need for M2 inserts and screws as well as the M4 fasteners. I have only printed a handful so far and the results are better, less complex geometry around those areas helps keep the temperature more consistent while printing. Due to the vertical print orientation of the M4 holes on those 'prongs' we see the tool-head retract and travel over those areas more than if it was a solid wall, with how hot the enclosures get combined with the heat of the tool-head and bed it makes sense that less geometry will give more consistent results due to the more uniform cooling that is happening.

logan added a comment.Thu, Jan 3, 3:09 PM

@west I know it has been a while but I wanted to get this back on your radar before betas. Do you still think we could get rid of those fasteners and that portion of the printed part?

kent closed this task as Resolved.Wed, Jan 9, 2:59 PM

Ok we have installed these on 4 machines now and they are working as expected.

$ git diff master
diff --git a/production_docs/BOM.csv b/production_docs/BOM.csv
index 24e19f7..7f0d964 100644
--- a/production_docs/BOM.csv
+++ b/production_docs/BOM.csv
@@ -52,7 +52,7 @@ HD-BT0039,"Metric Class 12.9 Socket Head Cap Screw, Alloy Steel, M3 Thread, 12MM
 HD-BT0041,"Metric Class 12.9 Socket Head Cap Screw Alloy Steel, M3 Thread, 25mm Length, 0.50mm Pitch",PCE,2,Y
 HD-BT0042,"Metric Class 12.9 Socket Head Cap Screw, Alloy Steel, M3 Thread, 30MM Length, 0.50MM Pitch",PCE,3,Y
 HD-BT0049,"Metric Class 12.9 Socket Head Cap Screw, Alloy Steel, M5 thread, 14MM length, 0.80MM pitch",PCE,2,Y
-HD-BT0073,"Class 10.9 Stl Button Head Socket Cap Screw M5 Size, 10 Mm Length, .8 Mm Pitch",PCE,102,Y
+HD-BT0073,"Class 10.9 Stl Button Head Socket Cap Screw M5 Size, 10 Mm Length, .8 Mm Pitch",PCE,98,Y
 HD-BT0082,"Metric 18-8 SS Flat Head Socket Cap Screw M3 Size, 16mm Length, .50mm Pitch",PCE,4,Y
 HD-BT0104,"M3 x 8 Bolt, BHCS, SST",PCE,16,Y
 HD-BT0107,"Metric Class 12.9 Socket Head Cap Screw Alloy Steel, Black, M2 Thread, 10mm Length, 0.4mm Pitch",PCE,4,Y
@@ -122,7 +122,7 @@ HD-WA0012,"Steel Flat Washer, DIN 125 zinc-plated class 4,M2 screw sz, 5mm OD, .
 HD-WA0027,"Metric 18-8 Stainless Steel Internal-Tooth Lock Washer, M3 Screw Size, 6MM OD, .4MM Min Thick",PCE,2,Y
 HD-WA0035,"Metric 18-8 Stainless Steel External Serrated Lock Washer, M3 Screw Size, 6mm OD, 0.4mm min Thick",PCE,4,Y
 HD-WA0038,"Black-Oxide 18-8 Steel Flat Washer, M3 Screw Size, 3.2mm ID, 7.0mm OD",PCE,110,Y
-HD-WA0040,"Black-Oxide 18-8 Stainless Steel Flat Washer, M5 Screw Size, 5.3mm ID, 10.0mm OD",PCE,104,Y
+HD-WA0040,"Black-Oxide 18-8 Stainless Steel Flat Washer, M5 Screw Size, 5.3mm ID, 10.0mm OD",PCE,100,Y
 PC-BD0111,Dual_Interface PCBA Rev. D,,,
 PC-BD0114,USB_Reader_Rev_C PCBA,PCE,1,
 PC-BD0113,Archim2.2b PCBA,PCE,1,
diff --git a/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.2.fcstd b/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.2.fcstd
deleted file mode 100644
index 201f46c..0000000
Binary files a/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.2.fcstd and /dev/null differ
diff --git a/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.2.stl b/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.2.stl
deleted file mode 100644
index bed1a60..0000000
Binary files a/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.2.stl and /dev/null differ
diff --git a/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.3.fcstd b/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.3.fcstd
new file mode 100644
index 0000000..304f7a0
Binary files /dev/null and b/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.3.fcstd differ
diff --git a/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.3.stl b/production_parts/printed_parts/z_upper_left/Z_upper_leftv3.3.stl
new file mode 100644
index 0000000..c4b1810