Sweep - Deformation of profile

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Lars
Posts: 19
Joined: Sat May 05, 2018 10:39 am

Sweep - Deformation of profile

Postby Lars » Sun Jun 14, 2020 10:17 am

Dear Fellow FreeCAD users,
We are preparing the design of a tube coil applying the sweep feature of FreeCAD but face a challenge, maintaining the profile shape when sweeping along the center line of the part, and we would be so grateful for your contribution for overcoming this problem.

1. Original design (attached image Tube Coil 01)
We prepared this part applying the helix functionality for generating a center line followed by the sweep feature of the part design workbench. Works great. Unfortunately, the processing equipment for manufacturing this part can handle only bends with constant radius.

2. Modified design (attached image Tube Coil 02)
In order to accommodate limitations of the processing equipment, the center line of the part was discretized applying the curves workbench, and disctances between points were modified to bends with constant radius or straight lines.
Upon sweeping the tube profile along the new center line, the shape of the tube can not be maintained but slowly becomes deformated along the sweep edge.


Q: Obliged to design the coil with a center line consisting of 1) straight lines or 2) arcs with constant radius, how could we successfully avoid the deformation when sweeping?




SIncerely
Lars

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.4 (GitTag)
Build type: Release
Branch: releases/FreeCAD-0-18
Hash: 980bf9060e28555fecd9e3462f68ca74007b70f8
Python version: 3.6.6
Qt version: 5.6.2
Coin version: 4.0.0a
OCC version: 7.3.0
Locale: English/UnitedKingdom (en_GB)
Attachments
A25 Separator LTHW coil ver01cd.FCStd
(399.41 KiB) Downloaded 23 times
Tube coil 02.jpg
Tube coil 02.jpg (140.56 KiB) Viewed 886 times
Tube coil 01.jpg
Tube coil 01.jpg (162.07 KiB) Viewed 886 times
Best regards

Lars
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hammax
Posts: 1261
Joined: Thu Jan 19, 2017 5:03 pm
Location: Ammersee

Re: Sweep - Deformation of profile

Postby hammax » Sun Jun 14, 2020 12:07 pm

... bending the pipe with controllable rollers instead of a die.

Separator.PNG
Separator.PNG (69.78 KiB) Viewed 866 times
Attachments
A25 Sep_LTHW_2.FCStd
(147.37 KiB) Downloaded 20 times
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GlouGlou
Posts: 2757
Joined: Sun Apr 05, 2015 9:02 am
Location: La Rochelle, France

Re: Sweep - Deformation of profile

Postby GlouGlou » Sun Jun 14, 2020 4:37 pm

Right Corner option for the sweep seems get some troubles. Because a very close coplanearity issue with paths? :roll:
Some thoughts?
Attachments
RightCornerIssue.FCStd
(53.86 KiB) Downloaded 14 times
Capture.JPG
Capture.JPG (32.9 KiB) Viewed 832 times
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hammax
Posts: 1261
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Location: Ammersee

Re: Sweep - Deformation of profile

Postby hammax » Mon Jun 15, 2020 6:47 am

Hey Lars,
I tried to model your pipe helix in a regular manner => constant bend radius and straight run after each other.
Done by intersection of a loft and helix sweep - only to understand the principle of bending sequence.
Making up the pipe sweep my PC and/or FC.18.4 are really gasping.
Some minutes of calculation and 18MB file size.

Separator_2.PNG
Separator_2.PNG (118.03 KiB) Viewed 782 times
mario52
Posts: 3311
Joined: Wed May 16, 2012 2:13 pm

Re: Sweep - Deformation of profile

Postby mario52 » Mon Jun 15, 2020 8:46 am

hi

converted in unique bspline


25_mono.png
25_mono.png (40.57 KiB) Viewed 762 times

(only the wire the file with sweep 2.63 mega and 10 minutes for create)
25_mono.FCStd
(155 KiB) Downloaded 18 times
mario
Maybe you need a special feature, go into Macros_recipes and Code_snippets, Topological_data_scripting, Dialog creation. My macros on Gist.github.
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hammax
Posts: 1261
Joined: Thu Jan 19, 2017 5:03 pm
Location: Ammersee

Re: Sweep - Deformation of profile

Postby hammax » Mon Jun 15, 2020 11:01 am

... the helix body has without in- and outlet a total length of about 7,55m.
Making a cylindrical helix with minimum diameter gives some 24 rounds.
This helix can be subdivided to 4 "symmetrical" parts and get defined markers.
Bending to greater radii afterwards could easily be done and gives this hour glass form?
Question: what's the use of this apparatus?
Heat exchanger fluid-fluid or fluid-gas?

Separator_3.PNG
Separator_3.PNG (18.89 KiB) Viewed 735 times
Last edited by hammax on Mon Jun 15, 2020 4:47 pm, edited 1 time in total.
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papyblaise
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Location: France

Re: Sweep - Deformation of profile

Postby papyblaise » Mon Jun 15, 2020 12:31 pm

Hi
simply part whith conical helix > miror > clone
and do addpipe whith
Attachments
bed spring.FCStd
(867.98 KiB) Downloaded 11 times
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papyblaise
Posts: 2913
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Re: Sweep - Deformation of profile

Postby papyblaise » Mon Jun 15, 2020 12:32 pm

Hi
simply part whith conical helix > miror > clone
and do addpipe whith
Attachments
bed spring.PNG
bed spring.PNG (103.91 KiB) Viewed 706 times
bed spring.FCStd
(867.98 KiB) Downloaded 14 times
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hammax
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Location: Ammersee

Re: Sweep - Deformation of profile

Postby hammax » Tue Jun 16, 2020 9:04 am

... another answer/solution to the starting question.
Sometimes the shape has a high angular resolution value and gets splintered/incomplete.
Insert smaller resolution values.

Separator_6.PNG
Separator_6.PNG (205.08 KiB) Viewed 634 times
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hammax
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Re: Sweep - Deformation of profile

Postby hammax » Wed Jun 17, 2020 3:16 pm

... a really interesting task, to build a helical pipe with a controlled contour - more than cylindrical or conical.
The icon of the Section tool in PartWB only promises a cut with a plane - but it can apparently do more.
Here a helix done as a sweep with an edge, is cut with a rotation profile and produces a space curve.
Using this space curve as a sweep path delivers long calculation times => maybe a too complex dataset.
But using Discretized_Edge to reduce the dataset (36 points per round) from CurvesWB
and making an Approximation_Curve out of them, reduces the data volume apparently about 1/10.
Now the modelling is an easy going.

Separator_7.PNG
Separator_7.PNG (97.84 KiB) Viewed 585 times
A25 Sep_LTHW_6.FCStd
FC.18.4
(403.35 KiB) Downloaded 18 times

..oh and I found the trick to reduce the data overflow in the Section feature
check Approximation to true!

Separator_8.PNG
Separator_8.PNG (92.7 KiB) Viewed 538 times
A25 Sep_LTHW_8.FCStd
(106.19 KiB) Downloaded 16 times