Drafting of Complex Pipes
Drafting of Complex Pipes
(OP)
I am trying to dimention pipes that are to be bent on a CNC bender and have troubles getting the true angle of the bend. To get the true angle you need both legs of the bend on the plane of the paper. If the pipe has multiple complex bends then is is very dificult to get both legs on the plane. From the 3d software I can create a plane using the centerline vectors of the bend and then place a view using the created plane. But I am finding this method to have a lot of resistance from the checker because I cannot explane the orientation of the view from the standard views. Is there a drafting standard for this type of problem, can I place a view that has no easy tracability to the standard 3 views? What is the preferd method of drafing compex pipe/tube shapes?





RE: Drafting of Complex Pipes
Chris
SolidWorks/PDMWorks 08 1.1
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog
RE: Drafting of Complex Pipes
RE: Drafting of Complex Pipes
While it may take much thought, properly defining view orientation is important if the part is to be defined on paper. It may take three or four projections to get a single view to dimension, and many drawing sheets to completely define the part.
Think what drafters went through when descriptive geometry was the only way to accomplish this and count your blessings.
I realize that this isn't what you wanted, but have patience and think it out.
Believe it if you need it or leave it if you dare. - Robert Hunter
RE: Drafting of Complex Pipes
This would not be of use to anyone programming a tube bender, but our radii were too short to bend anyway, and it worked okay for inspection.
Mike Halloran
Pembroke Pines, FL, USA
RE: Drafting of Complex Pipes
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You need a table to indicate the bends.
Chris
SolidWorks/PDMWorks 08 1.1
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog
RE: Drafting of Complex Pipes
Tube Forming Processes
Gregory Miller
ISBN 087263633X
Its hard to use strictly XYZ coordinates with working with compound bends in a tube. You will need a table that defines starting angles, ending angles, CW/CCW rotation in degrees, etc. You drawing will have many auxiliary views to get the straight tube length for inspection. You finished drawing should look similar to fig 1-7 of the above book.
The work around consists of multiple Go/No Go checking fixtures.
"Art without engineering is dreaming; Engineering without art is calculating."
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RE: Drafting of Complex Pipes
RE: Drafting of Complex Pipes
Mike Halloran
Pembroke Pines, FL, USA
RE: Drafting of Complex Pipes
"Art without engineering is dreaming; Engineering without art is calculating."
Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of Eng-Tips Forums?
RE: Drafting of Complex Pipes
RE: Drafting of Complex Pipes
If you care to look at the the standard (ANSI/ASME Y14.3-2003) for Multiview and Sectional View Drawings, I only have a copy of Y14.3-1975[affirmed 1980] and unless it has changed, which I doubt, use of auxiliary views from standard view to first aux then to second aux is defined to show true shape and relationship of features that are not parallel to any of the principal planes of projection is defined. In the days before CAD, I have even prepared (board) and witnessed on roll size formats (H,J & K) chained auxiliary views. Where starting from the standard projection plane of the most important view (defining datum)there was a first aux then second then third. I have even witnessed fourth. I do realize, as I'm sure all here do, this corresponds to lots of work.
However, I believe that for this type of product/industry, the best way to depict and define is this method as opposed to the ambiguous non-standard "shotcuts" evolving, mostly because of the time required to do it correctly and unambiguously in a standard that all understand.
My suggestion is select the most important section/interface end then be consistent in depicting and specifying with respect to (w.r.t.) it. There is also the option of using partial relevant only views in the auxiliary view to save real estate if you choose.
RE: Drafting of Complex Pipes
I my piping detailing days (spools and ISO's on the board) we did single line representation, and showed compound bends by two adjacent views, 90° apart and dimensioned the bend (say) 42°H in one view and 17°V in the other view.
RE: Drafting of Complex Pipes
RE: Drafting of Complex Pipes
With this call out a fabricator can manufacture any elbow required. The only other thing is I would try to take the accuracy any tighter then 0.5 Deg.s, that is about how accurate a fabricator can get. The only coordinates or dimension you will need is for the contractor to use this fabricated piece. Good Luck!
RE: Drafting of Complex Pipes
Believe it if you need it or leave it if you dare. - Robert Hunter
RE: Drafting of Complex Pipes
RE: Drafting of Complex Pipes
Believe it if you need it or leave it if you dare. - Robert Hunter
RE: Drafting of Complex Pipes
Thanks for all of your help and sugestions, it has been very insightfull.
RE: Drafting of Complex Pipes
It is the only way I know of how to do it.
Thanks!
Chris
SolidWorks/PDMWorks 08 1.1
AutoCAD 06
ctopher's home (updated 10-07-07)
ctopher's blog
RE: Drafting of Complex Pipes
"Art without engineering is dreaming; Engineering without art is calculating."
Have you read FAQ731-376: Eng-Tips.com Forum Policies to make the best use of Eng-Tips Forums?