Un-bending (Straighten) capability for rod, tube or pipe.

andrew_troup · November 2015

In addition to the ability to un-fold (flatten, or 'develop') sheetmetal, it would be great if the same tools (or tools with a similar interface) were able to un-bend (straighten, or 'develop') rod or pipe or tube, applying a suitable k-factor (neutral axis offset) or bend allowance.

First, it goes without saying, we need a robust and easily used 3D sketch capability, but it is always beneficial to consider future use cases when designing present capability.

The key difference from a user perspective is that bend angles for rod and tube are multiaxial, so the un-bent drawing will need a second figure for the orientation (sometimes called "Phase") of each bend's plane, in the unbent condition, relative to a common datum plane.

_Ðave_ · November 2015

+1 @andrew_troup Actually that is quite a nice concept.

brucebartlett · November 2015

+1 yes please

chrisjh777 · November 2015

+1

viru · November 2015

+1

shashank_aarya · November 2015

+1
I feel that nice approach to have this in Onshape would be to add this functionality in transform option where we should able to give various references for bending such as axis, line etc.

brucebartlett · November 2015

I have alway wanted something like this in SolidWorks, currently I do this with 2 configurations, 1 of an extrude for the cut length, the second of a sweep around a path for the finished shape both using a common profile sketch and some hand cals to work out the extrude cut length.

Maybe this could also be incorporated with a simple flatten tool and could be use for many different application's where parts are formed from flat material or bar stock.

Do any other MCAD programs have this functionality?

shashank_aarya · November 2015

@brucebartlett There is similar functionality in Creo where we can use two configurations for single part. e.g. we can make one helical spring of normal length as one configuration. When the spring is being assembled, depending on assembly requirement it can be converted to compressed state by making it flexible. This is second configuration

matthew_menard · November 2015

This is something that I too would like. As @brucebartlett said, even Solidworks is lacking in this feature. "Phases" for 3D bent objects would make it extremely powerful too. My current work around is also using configurations for bent and straight geometry. I will usually sum the dimensions of the straight lengths and chord lengths of the bends to get the unbent length. As I think of it, is there a way to dimension the chord length of an arc, as shown below?

Image: https://us.v-cdn.net/5022071/uploads/editor/i5/xicatq52dua6.png

Workflow in Solidworks is to enter the dimension tool, click the endpoints of the arc and then the arc itself. Just tried something similar in OS and it didn't work. Thanks for any info, sorry if this is possible and I just don't know.

michael3424 · November 2015

+1 - this would be handy for a little home project, bending some electrical conduit.

andrew_troup · November 2015

@matthew_menard

matthew_menard said:

..................
.................

My current work around is also using configurations for bent and straight geometry. I will usually sum the dimensions of the straight lengths and chord lengths of the bends to get the unbent length.
.................

That only gets you part way there, if you use the sweep path:
the arc length (which I think you are calling chord length?) of the path will not give an accurate developed length for that bend, because each arc radius needs to be relocated to the neutral axis.

In other words, each arc radius needs to be adjusted to account for the fact that outer fibres stretch more than inner fibres compress (oversimplifying madly).
In sheet metal terms, the k factor.

matthew_menard said:
.................
is there a way to dimension the chord length of an arc, as shown below?

Workflow in Solidworks is to enter the dimension tool, click the endpoints of the arc and then the arc itself. Just tried something similar in OS and it didn't work. ......

Similar but subtly different: Activate dimension tool, click each arc endpoint, then HOVER over the arc until you get the preview of arc length. Click to accept WHILE the preview is active.

Here's how the preview looks:

I seem to recall that "chord length" is measured as the crow flies, in other words, it IS what you were getting, between endpoints ..... but i could have that wrong

matthew_menard · November 2015

Again, you're right and I'm confusing my terminology... It is arc length, not sure why I ran with chord, as you are correct that would be the straight line between endpoints. Thanks a lot though for trucking though all that wrongness, the arc length workflow in OS is something I didn't know about before.

Also, the crude sum of the central plane is an "eh, good enough" way of getting the rough length of the handful of bent pins we use. They are only .010-.015 in diameter, and tolerances are fairly loose so accounting for what is really happening in the bending operations isn't necessary.

I'm done confusing terminology for the day. Thank you very much again though for the arc length workflow.

phil_erdley628 · July 2016

+1 These capabilities are critical to making shop ready prints!

mattseibert · December 2016

+1 Agreed that this would be an incredibly helpful feature to add. In a lot of ways I feel Solidworks Flex feature could be much better... OnShape could one-up

john_mcclary · May 2017

+1

brucebartlett · May 2017

How cool would it be to have a tube bending fly out similar to the sheet metal one? If you have a bent tube, rod, pipe, add an unfold feature and get the part in the straight form with bend lines and table. It's a real pain using Configurations to do this in other MCAD.

I would be also good to get cut lengths for free-form wires, cables and hoses, but this may come more into the area of a routing module.

Josiah_Harthcock · March 2019

Please!

+1

brucebartlett · March 2019

Is there an improvement request we can vote? this would be a nice feature to have, one that I have always dreamed of.

PMG · August 2019

+1 Extremely relevant to the possibilities this product brings. Is there somewhere we can vote for this addition?

wout_theelen541 · September 2023

brucebartlett said:

Is there an improvement request we can vote? this would be a nice feature to have, one that I have always dreamed of.

https://forum.onshape.com/discussion/21906/unbending-straigten-capability-for-rod-tube-or-pipe/p1?new=1

glen_dewsbury · September 2023

@wout_theelen541
I've been using the frame tool for developed lengths.
Doesn't get us any closer to 3D sketching though!
https://cad.onshape.com/documents/8176bf42ef782f8303d3ee92/w/9a054da62eb5b27426d906a3/e/6f421a07d7207af52cd737e9

Image: https://us.v-cdn.net/5022071/uploads/editor/8o/r4p9ankh7wlc.png

vincent_bl · March 18

glen_dewsbury said:

@wout_theelen541
I've been using the frame tool for developed lengths.
Doesn't get us any closer to 3D sketching though!
https://cad.onshape.com/documents/8176bf42ef782f8303d3ee92/w/9a054da62eb5b27426d906a3/e/6f421a07d7207af52cd737e9

Is it normal that the measure length isn't the same?

Image: https://us.v-cdn.net/5022071/uploads/editor/bj/ax7ss8rgta8s.jpg

glen_dewsbury · March 18

Hmm. I get the same sort of difference from measured to cut list. Haven't been too concerned since the fabricator I'm working with trims to finished size after bending. They also do their own work up for fabrication and use my lengths for quick quoting only. I'm trying to remember a discussion about this topic from a while back but not having any luck. All the tubing that I work with is bent such that neutral axis should be lined up with sketch lengths with neutral axis at 0.5.

Maybe a question for OS support?

Image: https://us.v-cdn.net/5022071/uploads/editor/yi/b6jcta13c784.png

eric_pesty · March 18

I'm pretty sure I remember a discussion about this around the time the frame tools were released... I think it's intentional to be on the "safe side" of the length calculation, which I think is very difficult to get "right" over the entire range of materials / profile / path shapes...

jnewth_onshape · March 18

@eric_pesty You remember correctly.
@glen_dewsbury More information here: https://forum.onshape.com/discussion/comment/86014#Comment_86014

glen_dewsbury · March 18

Thanks Josh. Previous comment reminder very helpful.

Un-bending (Straighten) capability for rod, tube or pipe.

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