Boolean cutting of an array

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PeterSprQ
Posts: 16
Joined: Wed Feb 22, 2017 3:12 pm
Location: Reading, UK

Boolean cutting of an array

Post by PeterSprQ »

Hello.

I am new to FreeCAD since two days ago, so you may think I have not really persevered with trying to solve the problem for myself. Not so: I have tried various workarounds, and read posts on the forum (lensman, NormandC, etc.), watched numerous YouTube tutorials by bram de vries, Learn FreeCAD, and others ...

Objective:
To model a tube sheet for a shell & tube heat exchanger.

Method:
1) Create two concentric solid cylinders (the tube sheet) and fuse them. 2) Create a single 'bar' through the tube sheet which, when cut, will be a tube hole (I have ensured that the bar overhangs the tube sheet on both faces to facilitate the cut). 3) Create 5x [draft/arrays] of the bar so that I have 7 tube rows of a total 95 bars (tube holes) for the first tube pass. 4 Used [part/mirror] to create a symmetrical second pass. See attached PDF.

Problem:
I cannot now seem to cut many more than a few of the bars from the tube sheet (see PDF). The faces go black/yellow and I often lose visibility of the (fused) tube sheet.

Work-arounds:
I have tried several. As well as [part/mirror] I have used [draft/mirror]. I have tried drawing each tube in manually (too tedious, with 190 tube holes in total). I have failed to find a way to explode the arrays.

Hope someone can help.

Many thanks for your support

PQ
For FreeCAD forum.pdf
(158.31 KiB) Downloaded 48 times

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.16.6706 (Git)
Build type: Release
Branch: releases/FreeCAD-0-16
Hash: f86a4e411ff7848dea98d7242f43b7774bee8fa0
Python version: 2.7.8
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 6.8.0.oce-0.17
Attachments
tube sheet backup.FCStd
(59.46 KiB) Downloaded 36 times
chrisb
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Re: Boolean cutting of an array

Post by chrisb »

PeterSprQ wrote: For FreeCAD forum.pdf
You can upload images directly to this forum. It is much easier to read the post.
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
chrisb
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Re: Boolean cutting of an array

Post by chrisb »

When I do a Part->CheckGeometry of Tube Row 7 evrything is ok. Checking the array made of it I get loads of BopAlgo Self intersect errors.
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chrisb
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Re: Boolean cutting of an array

Post by chrisb »

I found the reason: you have in Y direction 2 tubes which overlap. You shoud enter 1 there.

I changed the sequence of operations to minimize the number of mirrors: first make a union of all tubes, then mirror once.
Attachments
tube sheet backup_cb.FCStd
(122.92 KiB) Downloaded 30 times
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Gustav180
Posts: 74
Joined: Mon Jun 29, 2015 6:45 pm
Location: Sweden

Re: Boolean cutting of an array

Post by Gustav180 »

Hello chrisb.

I think I have found the problem. You have copies in the arrays. If you zoom up the image, you can see doubble circles on some tubes. Mark e.g. Array004 and Array004. In the combo view - Data tab - Draft - Number Y is the value 2. That means there is 2 copies closed to each other. You can change this to 1 and click in an other raw for a OK. This will remove the copy. Do so for all Arrays that have this value.

Then you can Fusion all Arrays and Array Mirror to one part called Tubes. You can fusion Raised face and Gasket face to one part called Face and then make a cut. I send my file back.
Attachments
tube sheet -2.FCStd
(111.23 KiB) Downloaded 37 times
PeterSprQ
Posts: 16
Joined: Wed Feb 22, 2017 3:12 pm
Location: Reading, UK

Re: Boolean cutting of an array

Post by PeterSprQ »

Bingo! Thank you very much chrisb and Gutav180. I guess it was sloppy draughting by myself.
chrisb
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Joined: Tue Mar 17, 2015 9:14 am

Re: Boolean cutting of an array

Post by chrisb »

PeterSprQ wrote:Bingo! Thank you very much chrisb and Gutav180. I guess it was sloppy draughting by myself.
You are welcome, glad to help.
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