Sheet Metal Workbench

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DenysKovalenko
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Re: Sheet Metal Workbench

Post by DenysKovalenko »

papyblaise wrote: Tue Nov 30, 2021 4:37 pm I do not know if the protocol which was used to create the original is compatible with that of Sheetmetal, nor if a STEP can become a compatible Sheetmetal object
I see that all the angles are not bent with the same k factor: the hinges are at mid-thickness and without gap, also for the cut of the fenetre which cuts half of the radius
Thanks for reply, is there any way to know is STEP file compatible with Sheetmetal?
chrisb
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Re: Sheet Metal Workbench

Post by chrisb »

DenysKovalenko wrote: Thu Dec 02, 2021 11:57 am Thanks for reply, is there any way to know is STEP file compatible with Sheetmetal?
I think so. Did you try and encounter problems?
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-alex-
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Re: Sheet Metal Workbench

Post by -alex- »

DenysKovalenko wrote: Thu Dec 02, 2021 11:57 am
Thanks for reply, is there any way to know is STEP file compatible with Sheetmetal?
I'm not sure to get what you mean.
You can try to unfold the imported step file like you have done, if it fails to unfold that mean there is some issue.
In your part there is several bad shapes. You have to clean up corners, add gaps in ends of bends.
Then suppress chamfers of countersunk holes: sharp edges with no thickness run into a fail.
Then... the part is quite complex, you could have to select the most appropriate starting face to unfold.
My side I almost succeed to unfold it, but it's quite difficult, some bugs occur about a couple of bends.
Maybe OCC version matters as well.
I will report if I success.

Edit: It works to unfold, as said above, by cleaning up corners and edges. However removing chamfers of countersunk holes was a bit tricky, because of irregular splitting of circular edges: the step file is the culprit on this point, a native FC part would not fail this way.
Edit2: typo
sheet_metal_casing.png
sheet_metal_casing.png (108.04 KiB) Viewed 2492 times
sheetmetal_casing.FCStd
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Last edited by -alex- on Mon Dec 06, 2021 10:45 am, edited 2 times in total.
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papyblaise
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Re: Sheet Metal Workbench

Post by papyblaise »

I managed to reconstruct the 3 main faces
it is not easy
I degraded the original STEP into a multitude of faces that I copy / paste into a new file, I reconstructed PADs, joined together by spokes according to the SheetMetal compatible protocol
and luky men, it works
it remains to reconstruct the other edges, it will be child's play
it is necessary to check the lengths and widths, the original folding protocol is not the same it is possible that there are variations
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coffret electronique.FCStd
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coffret electronique.PNG
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mfraz74
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Re: Sheet Metal Workbench

Post by mfraz74 »

Trying to unfold this drawing from a tutorial in the latest issue of Hack Space magazine in FreeCAD 0.20.
Screenshot_20211220_134251.png
Screenshot_20211220_134251.png (41.59 KiB) Viewed 2323 times
I get the error:
09:43:23 Engineering mode is enabled.
09:44:51 Material found: 0.40ansi
09:44:51 This is a Manual K-factor{'kfactor': 0.4, 'standard': 'ansi'}
09:44:53 Manual K-factor is being used: 0.40 (ansi)
09:44:53 exception at line 2865('list indices must be integers or slices, not NoneType',)
09:44:53 ('list indices must be integers or slices, not NoneType',)
09:44:53 Traceback (most recent call last):
09:44:53 File "/home/mfraser/.local/share/FreeCAD/Mod/sheetmetal/SheetMetalUnfolder.py", line 2865, in accept
s, foldComp, norm, thename, err_cd, fSel, obN = getUnfold(k_factor_lookup)
09:44:53 File "/home/mfraser/.local/share/FreeCAD/Mod/sheetmetal/SheetMetalUnfolder.py", line 2173, in getUnfold
TheTree.Bend_analysis(f_number, None) # traverses the shape and builds the tree-structure
09:44:53 File "/home/mfraser/.local/share/FreeCAD/Mod/sheetmetal/SheetMetalUnfolder.py", line 1328, in Bend_analysis
self.Bend_analysis(child_info[0], t_node, child_info[1])
09:44:53 File "/home/mfraser/.local/share/FreeCAD/Mod/sheetmetal/SheetMetalUnfolder.py", line 1328, in Bend_analysis
self.Bend_analysis(child_info[0], t_node, child_info[1])
09:44:53 File "/home/mfraser/.local/share/FreeCAD/Mod/sheetmetal/SheetMetalUnfolder.py", line 1319, in Bend_analysis
t_node = self.make_new_face_node(face_idx, parent_node, parent_edge, wires_edge_lists)
09:44:53 File "/home/mfraser/.local/share/FreeCAD/Mod/sheetmetal/SheetMetalUnfolder.py", line 1102, in make_new_face_node
oppVertIndexes = range(len(self.__Shape.Faces[newNode.c_face_idx].Vertexes))
09:44:53 TypeError: list indices must be integers or slices, not NoneType
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SheetMetal 1.FCStd
(285.51 KiB) Downloaded 45 times
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Shalmeneser
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Re: Sheet Metal Workbench

Post by Shalmeneser »

mfraz74 wrote: Mon Dec 20, 2021 1:46 pm Trying to unfold this drawing from a tutorial in the latest issue of Hack Space magazine in FreeCAD 0.20.
IMHO, try not to fold near the round line.
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Capture du 2021-12-20 18-43-08.png
Capture du 2021-12-20 18-43-08.png (4.71 KiB) Viewed 2283 times
Capture du 2021-12-20 18-40-58.png
Capture du 2021-12-20 18-40-58.png (9.48 KiB) Viewed 2283 times
SheetMetal 1_SHALM.FCStd
(100.51 KiB) Downloaded 29 times
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shaise
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Re: Sheet Metal Workbench

Post by shaise »

mfraz74 wrote: Mon Dec 20, 2021 1:46 pm Trying to unfold this drawing from a tutorial in the latest issue of Hack Space magazine in FreeCAD 0.20.
The Fold001 creates an illegal shape for sheet metal:
Fold_issue.jpg
Fold_issue.jpg (14.22 KiB) Viewed 2241 times
You need to change fold001 "Position" property from "Forward" to "Backward"
unfold_fix.jpg
unfold_fix.jpg (22.9 KiB) Viewed 2241 times
this should fix the problematic fold:
unfold_fixed.jpg
unfold_fixed.jpg (14.37 KiB) Viewed 2241 times
shai
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mfraz74
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Re: Sheet Metal Workbench

Post by mfraz74 »

shaise wrote: Tue Dec 21, 2021 8:15 am
mfraz74 wrote: Mon Dec 20, 2021 1:46 pm Trying to unfold this drawing from a tutorial in the latest issue of Hack Space magazine in FreeCAD 0.20.
The Fold001 creates an illegal shape for sheet metal:
Fold_issue.jpg

You need to change fold001 "Position" property from "Forward" to "Backward"
unfold_fix.jpg

this should fix the problematic fold:
unfold_fixed.jpg

shai
Thanks Shai,
That's fixed it.

Mark.
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Re: Sheet Metal Workbench

Post by Whistler »

Morning All,

in order to be able to draw more complex folded parts in our company faster and to be able to punch on our Trumpf TruPunch, I have been working with Sheet Metal. A super tool simple and fast. Only unfortunately the unfoldet parts are too big even if I set the K-factor to 0. The Trumpf drawing program has a very rudimentary bending wizard that can calculate the unfoldet length of a bend part to fit. When I compare the lengths, the Sheet Metal part is about 3.8mm too long per bend.

We have a TruBend press brake where the unfoldet sheet metal is upset and not stretched like a swing bending machine.

I have now rummaged through many many forum posts but unfortunately nowhere found anything to enter a negative K-factor or somehow otherwise to get the unfoldet length smaller. Or is there another way?

Greetings Sebastian
Attachments
SheetMetalTruTops.jpg
SheetMetalTruTops.jpg (102.95 KiB) Viewed 1993 times
Laptop Buerotischregal-1.FCStd
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Vincent B
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Re: Sheet Metal Workbench

Post by Vincent B »

About SketchOnSheet:
What about to make the pad instead the pocket? Sometimes it's better to design the shape instead the holes.
Could be easy to add this option, isn't it?
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Capture.JPG
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