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Turbo Talk => General Discussion => Topic started by: cmsrobert1 on December 15, 2009, 01:43:30 PM

Title: tube bend problems
Post by: cmsrobert1 on December 15, 2009, 01:43:30 PM
Hi,
Ia m trying to bend a pipe Ø27mm outside, 2.3mm wall thickness into a U shape. The sides are to be 350mm long and the inner radius 200mm. I have tried using the tube bend function but I can not get the sides an even length or the curve equal on both sides. I can cheat and use a torus etc but I would like to know how to do it properly with tube bend. Any advice would be most welcome.

Regards
Rob
Title: Re: tube bend problems
Post by: Henry Hubich on December 15, 2009, 02:30:47 PM
Hi,
Ia m trying to bend a pipe Ø27mm outside, 2.3mm wall thickness into a U shape. The sides are to be 350mm long and the inner radius 200mm. I have tried using the tube bend function but I can not get the sides an even length or the curve equal on both sides. I can cheat and use a torus etc but I would like to know how to do it properly with tube bend. Any advice would be most welcome.

Regards
Rob
IMHO, Rob, the "proper" technique is whatever yields the desired result without a whole lot of work. I'd probably Sweep a pair of concentric circles along a Polyline path.

Henry H


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Title: Re: tube bend problems
Post by: Robert on December 16, 2009, 12:11:31 PM
It sounds like the center point at which the bend is supposed to be made is not correct. That would account for both problems.
Title: Re: tube bend problems
Post by: John R on December 16, 2009, 02:16:39 PM
re: I have tried using the tube bend function but I can not get the sides an even length or the curve equal on both sides.

I think there is a BUG in the Tube Bend tool.

Using the Torus is a good workaround. Create the Torus, reduce its Rotation Angle, Shell the ends simultaneously, then use the Quick Pull tool to pull out the ends.

Title: Re: tube bend problems
Post by: John R on December 18, 2009, 12:00:02 AM
re: .... but I would like to know how to do it properly with tube bend.

Try these settings in the picture. Set the bend to start 350mm from the end, instead of the middle of the tube/cylinder.

Henry said it could be done, but it took me quite a while to figure out the correct numbers.

Edit: You may need to change the Azimuth to something like 270 and then back to 90.



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Title: Re: tube bend problems
Post by: Robert on December 18, 2009, 06:20:33 PM
Nice job! But a person shouldn't have to go to all that trouble. It's indicates there's a problem with the tube bend procedure. Maybe it should be reported to Imsidesign.
Title: Re: tube bend problems
Post by: Orion20036 on December 18, 2009, 06:45:08 PM
Nice job! But a person shouldn't have to go to all that trouble. It's indicates there's a problem with the tube bend procedure. Maybe it should be reported to Imsidesign.

I don't see  a major problem here Robert, a simple calculation is not untoward as long as that calculation is in the example files or help file  (diameter of bend * pi) /2 equals the length of curved section in your example. In your case 350 mm of straight + length of curved section + 350mm of straight.  I do get your point of bending exactly in the centre , but it is six of one and half a dozen of the other. Some pipe benders bend in the middle and some pipe benders bend from the end of the straight section in real life. Saying that both options would be an advantage !!.

Mike Geraghty.
Title: Re: tube bend problems
Post by: Orion20036 on December 18, 2009, 06:51:28 PM
For any curved section length of any number of degrees of bend, (((radius of bend * 2) * pi) /360) * number of degrees of bend = curved section length. Taking into account of course the stretch in the material, which is not necessary for a drawing unless your are providing the actual overall pipe length prior to bending.
Title: Re: tube bend problems
Post by: Henry Hubich on December 18, 2009, 07:08:05 PM
Nice job! But a person shouldn't have to go to all that trouble. It's indicates there's a problem with the tube bend procedure. Maybe it should be reported to Imsidesign.

I don't see a problem, or a lot of trouble. Open the Tube Bend tool; click on the tube to be bent; TAB to the Radius field and type a number (it's the inside bend radius); TAB to the Angle field and type a number (bend angle in degrees); TAB to the Neutral depth field and type a number (it should show the outer radius by default; I'd leave it alone unless the bend radius is quite small, in which case the calculated length would not be identical to the centerline length); TAB to the Axial distance field and type a number (distance from the end at which the bend starts); TAB to the Azimuth angle field and type a number (orientation of the bend; you may need to experiment with this). Hit Enter and verify that the phantom bend looks OK; click the Finish flag if it does. Seems to me that this set of parameters is both necessary and sufficient to define the bend.

You can drag with the mouse to set Axial distance and Azimuth angle if you prefer. See attached screenshot.

Henry H

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Title: Re: tube bend problems
Post by: AndyCAD on January 29, 2010, 02:38:57 AM
Does anyone know if you can edit a cylinder bent using 'tube bend' ?. I have a cylinder bent in two places and I want to change the azmith of one of the bends.
Title: Re: tube bend problems
Post by: wd on January 29, 2010, 08:04:37 AM
Does anyone know if you can edit a cylinder bent using 'tube bend' ?. I have a cylinder bent in two places and I want to change the azmith of one of the bends.

Henry is the expert at these kind of things might want to email him directly.
Title: Re: tube bend problems
Post by: Henry Hubich on January 29, 2010, 09:00:03 AM
Does anyone know if you can edit a cylinder bent using 'tube bend' ?. I have a cylinder bent in two places and I want to change the azmith of one of the bends.

You can do that, if "Create editing history" had been enabled before making the bends. Select the tube; open the Selection Info palette; click on one of the "Tube Bend" entries in the palette's upper window (whereupon the corresponding bend in the drawing will turn blue); expand the "Part" listing in the lower window; highlight the Value in the Azimuth window; type a new number; press Enter.

If "Create editing history" had not been enabled, you can simply slice the tube, rotate one end, and 3D-Add the pieces back together. This might even be easier than fiddling with Selection Info.

Henry H
Title: Re: tube bend problems
Post by: John R on January 29, 2010, 12:43:17 PM
re: you can simply slice the tube, rotate one end, and 3D-Add the pieces back together.

Another option would be to slice and delete the bent section, then use the Quick Pull tool to pull the tube out to the old length and Bend again.
Title: Re: tube bend problems
Post by: AndyCAD on January 29, 2010, 03:29:01 PM
Many thanks guys for your help, I'm so glad I found this forum. I have TurboCAD 14 and the reference manual for it but it's not really detailed enough.

Henry, I tried the create edit history option first but from what I can see it only works on original 3D objects you have created and not ones that are copied from the original (unless I am missing something). You see I have a number of bent cylinders in my drawing which are all copied from the original one and repositioned. It is one of the copied ones that I was trying to modify. In the selection info top pane all the cylinders are listed as ACIS solids but there is only one tube bend and that is for the original cylinder. I thought of modifying the original, copying it, and then changing it back, but that would mean having to reposition the copy. Instead I tried your second option which was to slice it, rotate it, and add back, which worked well. John, thanks for your suggestion too, thats looks to be another good option.

Do you know if it is possible to use the selection info palette to edit copied 3D objects?

Regards Andrew

Title: Re: tube bend problems
Post by: John R on January 29, 2010, 04:14:42 PM
re: ...that looks to be another good option.

It would be if you had V16. In V14 you can use the Imprint tool. Place 2D circles on the inside & outside of the sliced face, then use the Imprint tool to pull the outside & inside parts up to the original height, then re-bend.

As far as I can tell, copies have all the Part Tree info. This is using the "Make Copy" feature from the Local Menu. If using one of the copy tools , such as Array or Radial, then you lose the Part Tree info.
Title: Re: tube bend problems
Post by: AndyCAD on January 31, 2010, 01:28:29 AM
Thanks John, very helpful. I tried doing some copies with 'Make Copy' and sure enough the part tree info is there and editing each object is no problem. I had used 'Linear Copy' and as you say the part tree info is not there with each copied object, and they are listed as ACIS solids. Strange why this should be the case though. I can't find any reference to it in my V14 manual.
Regards Andrew
Title: Re: tube bend problems
Post by: John R on January 31, 2010, 02:06:23 AM
re: missing Part Tree info

It may be "As Designed" to not include Part Tree in those Copy tools. The Part Tree adds a lot of extra info and the copies don't need all that extra baggage. They probably figure you can edit the source object and run the Copy process again.
Title: Re: tube bend problems
Post by: Jeffin90620 on January 31, 2010, 09:54:15 AM
I tried doing some copies with 'Make Copy' and sure enough the part tree info is there and editing each object is no problem. I had used 'Linear Copy' and as you say the part tree info is not there with each copied object... Strange why this should be the case though.

Not so strange to me.  It indicates that, if you changed the original object, all the Linearly Copied objects would update, too.

However, I am not seeing what the rest of you are seeing.  I created a box and cylinder, then did a Linear Copy of both (upper left to lower right).  After that, the Selection Info window clearly shows that each copy has its own history (I changed the width of two of the boxes, with the second change highlighted).

I am using V15.2, if that provides any useful information.

Jeff


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Title: Re: tube bend problems
Post by: John R on January 31, 2010, 11:13:50 AM
re: I am not seeing what the rest of you are seeing.

You missed it by a hair. Add or subtract your objects, then Linear Copy. The copies do not contain Part Tree information of the Boolean operations.

Array Copy shown below.

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Title: Re: tube bend problems
Post by: AndyCAD on February 01, 2010, 10:39:51 PM
Thanks Jeff and John for your help looking into this.

Jeff I did some linear copies of a box and cylinder like you did and yes you are right about being able to alter their dimensions. They come up in the selection info box as boxes and cylinders. However if you do a tube bend on a cylinder, which creates a tube bend and cylinder under a part tree in the selection info pane, you will find that a linear copy creates ACIS solids which cannot be edited. I also tried changing the dimensions of the original object and it doesn't automatically change the dimensions of the linear copies. Maybe V15.2 has that feature.

It would be very useful to be able to edit linear (or other copy entity) copies and I'm just wondering if we are missing something. Maybe there is a box we haven't ticked somewhere. The drawing I am doing has a fairly large number of reinforcing bars all based on a bent cylinder. It was easy to draw one then copy a whole pile of them in one go using linear copy, and then I thought I could tweak and modify each one. Its a case of creating lots of different objects built on a common base. There must be someway to do it.
Title: Re: tube bend problems
Post by: John R on February 01, 2010, 10:59:07 PM
Duh, it just dawned on me; would a Block work here? You edit the Block and all the copies update. If you're doing individual edits, you will still have the same problem, no Part Tree and Blocks wouldn't help here.
Title: Re: tube bend problems
Post by: Henry Hubich on February 02, 2010, 09:41:14 AM

It would be very useful to be able to edit linear (or other copy entity) copies and I'm just wondering if we are missing something. Maybe there is a box we haven't ticked somewhere. The drawing I am doing has a fairly large number of reinforcing bars all based on a bent cylinder. It was easy to draw one then copy a whole pile of them in one go using linear copy, and then I thought I could tweak and modify each one. Its a case of creating lots of different objects built on a common base. There must be someway to do it.

Easy. Just make the bent tube a Block before linear-copying. Edit the Block using the Selection Info palette and all copies will reflect the change.

Henry H

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Title: Re: tube bend problems
Post by: AndyCAD on February 07, 2010, 02:09:18 AM
Thanks Henry but I don't want all the copies to reflect the change. I need to be able to modify each one differently. That is the problem you see. However your suggestion is still an excellent idea for when I want to change them all equally.
Title: Re: tube bend problems
Post by: Jeffin90620 on February 07, 2010, 09:56:59 AM
If you want all the units to be basically the same, start with a Block.  After placement, you can Explode any individual objects you want to change.  While they won't have the Editing History, you can still modify them, or use them as reference templates when creating a new object.

Jeff
Title: Re: tube bend problems
Post by: AndyCAD on February 17, 2010, 12:50:37 PM
Thanks Jeff, that is a good suggestion. I ended up modifying the shape of the object (a bent tube to represent a reinforcing bar) that I was trying to replicate so that tweaking each one was easier. I was originally wanting to be able to adjust the azmith angle of one of two bends in the tube. I appreciate everyones help on this. I am now on another problem which I may start a thread on shortly.