Sheet Metal - The missing step (for me!)

peter_cuthbert

Hi Folks

I am a new Onshape user having moved on from Alibre Atom.  I was so pleased to see that you have sheet metal functions since I am in the middle of a sheet metal project.  Having watched a couple of videos in adding flanges in which it looked so easy I thought I would have a go. So this is what I did, but the system would not let me select an edge:

1. Draw a rectangle for the door plate.

2. Thicken it up to 0.9mm, the size of the proposed metal.

3. Highlight the rectangle

4. Select Sheet Metal Model from the dropdown list

5. Select flange

6. Click on edge to be flanged

7. Edge does not highlight.  Error message that sheet metal model 1 did not re-generate properly.

The part drawn as a 2D isometric should be shown in the picture below.  The 'wings' at the lower sides of the door are hinge bar mounts.  The vertical length of the triangle is 143mm which I see that I have not dimensioned. The door handle would be in the middle of the top on the curve.

Your advice would be most welcome.

Regards

Pete

martin_kopplow

@peter_cuthbertIt looks like the model you attempt calls for a flange added directly to a flange (or bend), which does not work. There just has to be a straight length between flanges. That makes abloute sense when it comes to manufacturability, anyway. It works, when you set the flange lenght to 1mm longer than the radius is.

https://cad.onshape.com/documents/920c65251b0d8fc9627e4b15/w/79e556df62f710cbc5455249/e/2139db3ec1630b2b837da4c9?renderMode=0&uiState=655c905ad894656739a6e593

martin_kopplow

Hi @peter_cuthbert , I just looked into your file, and I believe you are just making it more complicated than it is. With sheet metal, I'd always avoid sharp angled pointy parts and rather go for the beefy shapes. Keep in mind that while bending, the bending bench's jaw needs a certain width contact area, to hold the part down, which usually fails on pointy parts. It appears you are trying to attach the heavier sheet hinges to the thin sheet door: Wouldn't it make sense to make the flanges on the hinges, where the bend would be much sturdier, and leave the door as a straight sheet in that region? I can imagine this would make the whole assembly process much more stable. Also, you'd avoid the nick in the door.

https://cad.onshape.com/documents/123fe7fc1df36f9181e790ad/w/6c9557249373bea768d0b209/e/91fc8e0a9204f2066464a97d?renderMode=0&uiState=6560caace9702508f59d4531

dirk_van_der_vaart

I,m a bit late on this on.
In my opinion these simple construction,s are easy done in One single Part studio, all part,s related to each other and perfectly editable.

https://cad.onshape.com/documents/54d97e027be00435d8cb3131/w/c535d447bec8dd0e3d549898/e/5bba3faa5fb9f3c6eb629360

peter_cuthbert

Hi Dirk and Glen

Many thanks for your contributions.  Your versions of the boiler casing are so good.  I will have to 'reverse engineer' your steps to see how it is done.  Thanks too for the link.  I will chase that up this morning.

Sorry to hear that you have been under the weather with Covid Glen. Hope that you get on top of it soon.  It certainly seems to knock some people for six so I am appreciative of your taking the trouble to respond to my questions. Indeed I am very grateful to everybody who contributes to these Forums as so many pieces of software seem impenetratable to the newbie.  It also amazes me that folk are willing to contribute possibly at the end of a long working day. You are all 'Stars' in my book.

Best wishes

Pete

eric_pesty

The easiest would probably be to use the "extrude" method for this shape.

Something like this (not to scale...):
https://cad.onshape.com/documents/d82feafe295a0de50d9f8fc9/w/f365a52750336cf7e75de52c/e/33560aee52a50b49f4353b48?renderMode=0&rightPanel=sheetMetalPanel&uiState=655bd8d641c7e17edcf6fb0c

nick_papageorge073

eric_pesty said:

The easiest would probably be to use the "extrude" method for this shape.

Something like this (not to scale...):
https://cad.onshape.com/documents/d82feafe295a0de50d9f8fc9/w/f365a52750336cf7e75de52c/e/33560aee52a50b49f4353b48?renderMode=0&rightPanel=sheetMetalPanel&uiState=655bd8d641c7e17edcf6fb0c

Nice job. Slightly off topic, is this part manufacturable? With the curve, and the angled flange, and the angled flange ending to nothing? I only have a few projects with sheetmetal under my belt, and none had features like these..

nick_papageorge073

@peter_cuthbert from reading your steps, I believe you may be trying to add a flange to a solid that is not actually a sheetmetal model, but instead a regular solid model. Please double check its sheetmetal first before adding flanges.

martin_kopplow

@peter_cuthbertIt looks like the model you attempt calls for a flange added directly to a flange (or bend), which does not work. There just has to be a straight length between flanges. That makes abloute sense when it comes to manufacturability, anyway. It works, when you set the flange lenght to 1mm longer than the radius is.

https://cad.onshape.com/documents/920c65251b0d8fc9627e4b15/w/79e556df62f710cbc5455249/e/2139db3ec1630b2b837da4c9?renderMode=0&uiState=655c905ad894656739a6e593

peter_cuthbert

Hi Everybody

Many thanks for taking an interest in this little project and for your interesting looking suggestion.  I am on the phone just now so will look in details when I get back to base and can fire up the desktop.

Much appreciated.

Regards

Pete

peter_cuthbert

Hi Eric, Nick and Martin,

Thanks for the responses.  Your model Eric certainly captures the shape of the part very well.  I am not sure about the 'nick' where the hinge mount flange goes.  That would possibly be a source of leakage of combustion gases.  However, it may be necessary for manufacture which is a whole area of ignorance I have yet to explore.

Thanks Nick for pointing out that I cannot bend a solid.  Clearly that should been obvious to me but in the switch from 2D to 3D some of the obvious things don't seem to catch my attention.  I think the part is manufacturable as there is a prototype that has been operating for at least 4 years (I will post a picture).  However, I think the prototype was hand built whereas this drawing exercise is to try to create a manufacturable version for our website (mono-tube.org.uk).

I like the idea of a 1mm flat as that solves the problem nicely.  I must admit I had been thinking that the major curve would have to be added by hand after the doors had been manufactured.

'Tis time for me to have go and see if I can get anywhere close.

Regards

Pete

eric_pesty

peter_cuthbert said:

Hi Eric, Nick and Martin,

Thanks for the responses.  Your model Eric certainly captures the shape of the part very well.  I am not sure about the 'nick' where the hinge mount flange goes.  That would possibly be a source of leakage of combustion gases.  However, it may be necessary for manufacture which is a whole area of ignorance I have yet to explore.

The "nick" you are talking about is an auto-relief. I updated the model to move the flange "outside". There will be some slight distortion around a flange coming to a sliver like this for sure so not ideal. Having a slight "step" at the end of the flange will make it form more reliability.
You'd want to work with the manufacturer to sort out what they need to reliably form that feature.

peter_cuthbert

Hi Eric, Nick and Martin,

Thanks for the responses.  Your model Eric certainly captures the shape of the part very well.  I am not sure about the 'nick' where the hinge mount flange goes.  That would possibly be a source of leakage of combustion gases.  However, it may be necessary for manufacture which is a whole area of ignorance I have yet to explore.

Thanks Nick for pointing out that I cannot bend a solid.  Clearly that should been obvious to me but in the switch from 2D to 3D some of the obvious things don't seem to catch my attention.  I think the part is manufacturable as there is a prototype that has been operating for at least 4 years (I will post a picture).  However, I think the prototype was hand built whereas this drawing exercise is to try to create a manufacturable version for our website (mono-tube.org.uk).

I like the idea of a 1mm flat as that solves the problem nicely.  I must admit I had been thinking that the major curve would have to be added by hand after the doors had been manufactured.

'Tis time for me to have go and see if I can get anywhere close.

Regards

Pete

peter_cuthbert

Hi Everybody

I am still working on this particular part and like the way that the Table and Flat View are available.  However, I would like to print the flat view or at least download it.  I have found how to print/download the 'drawing' window but the other one has defeated me.  Likewise the help database which does not seem to like Flat View.

A second issue that has me flummoxed is the fitting of the hinges.  I did a parallel Assembly and the hinges seem to have embedded themselves into the flaps rather than lying flat on them.  I have altered the X limits, but still get the error " Mate Connections are on the same instance".  Sadly the Guide seems less than helpful on this.

Best wishes

Pete

[https://cad.onshape.com/documents/bd083bf178f1ffd429dbe3af/w/d0bbf57ae789d43bc25cd73a/e/53e564e1a51c579789218b52?renderMode=0&uiState=65609d7942bb635395a1967f]

martin_kopplow

Hi @peter_cuthbert , I just looked into your file, and I believe you are just making it more complicated than it is. With sheet metal, I'd always avoid sharp angled pointy parts and rather go for the beefy shapes. Keep in mind that while bending, the bending bench's jaw needs a certain width contact area, to hold the part down, which usually fails on pointy parts. It appears you are trying to attach the heavier sheet hinges to the thin sheet door: Wouldn't it make sense to make the flanges on the hinges, where the bend would be much sturdier, and leave the door as a straight sheet in that region? I can imagine this would make the whole assembly process much more stable. Also, you'd avoid the nick in the door.

https://cad.onshape.com/documents/123fe7fc1df36f9181e790ad/w/6c9557249373bea768d0b209/e/91fc8e0a9204f2066464a97d?renderMode=0&uiState=6560caace9702508f59d4531

glen_dewsbury

A quick look at your assembly indicates that all 3 parts are "fixed". Any further constraints will over define. Only one part should be fixed.

Couldn't help but notice all he transforms in your document. Not needed at all. This sample shows creating parts in place which is something OS does well so that updates to one part can propagate through others and hold relationships. Working way too hard by transforming parts.

I like Martin's version of the side brackets as well. Simplifies the main cover.
https://cad.onshape.com/documents/c34ea8221d89437c7bb321e1/w/c39f451e35b06203d6c38a9d/e/9b5bd8ee9d5dba4b73773e7d

peter_cuthbert

Hi Glen

Yes, way too many transforms, but that was all down to drawing the part in the wrong place and wrong orientation.  Transforms seemed a simpler solution than re-drawing in the correct place.  I suppose it is the 'Dog with bone' approach - don't let go!

I am coming around to the idea of starting this assembly from scratch and hopefully getting it right first time.

Regards

Pete

peter_cuthbert

Thanks again Martin

You have clearly saved my bacon again with a nice elegant solution.  The original hand-built prototype had the wedge shaped hinges welded to the edge of the door.  I added the flaps as I don't weld, but then again I don't do sheet metal work either and it shows!

I will buzz off and draw the equivalent of your rather smart hinges and see if I can get them attached in the right place.

There is another little problem.  I have managed to find out how to save the flat sheet version as DXF and have checked it in my 2D CAD system.  I am puzzled to find that the basic door dimensions are not what I would have expected given the initial dimensions at the start of the 3D CAD sketch.  I will need to check and see if all the dimensions are different by the same proportion.  If that is the case I expect that has arisen with the change from one file type to another.

Many thanks for your support.

Regards

Pete

peter_cuthbert

Hi Everybody

I am still working on this particular part and like the way that the Table and Flat View are available.  However, I would like to print the flat view or at least download it.  I have found how to print/download the 'drawing' window but the other one has defeated me.  Likewise the help database which does not seem to like Flat View.

A second issue that has me flummoxed is the fitting of the hinges.  I did a parallel Assembly and the hinges seem to have embedded themselves into the flaps rather than lying flat on them.  I have altered the X limits, but still get the error " Mate Connections are on the same instance".  Sadly the Guide seems less than helpful on this.

Best wishes

Pete

[https://cad.onshape.com/documents/bd083bf178f1ffd429dbe3af/w/d0bbf57ae789d43bc25cd73a/e/53e564e1a51c579789218b52?renderMode=0&uiState=65609d7942bb635395a1967f]

glen_dewsbury

Good morning @peter_cuthbert

I kinda thought that might be the case. It's something I used to run into when rushing to started to use in context edits.
Pretty much use the origin as my start reference now in stead of picking a part face. I can pick a reference part face once in the part studio to make my sketch.
For my own practice I did this as a cold smoker. Something I'm hoping to make next summer. This sample uses my current methods to avoid the parts out of place issue. There are 2 contexts for door open and closed. In busier designs, trying to move parts into place after the fact can get extremely messy with things still out of place.
While it's not a requirement to start initial part at the origin it can be very handy later.

Cheers

https://cad.onshape.com/documents/c34ea8221d89437c7bb321e1/w/c39f451e35b06203d6c38a9d/e/8133c5790597b23f515c1405

BTW If my initial post sounded a bit abrupt, it was not my intent. Having some ups and downs while I fight of a covid infection.

dirk_van_der_vaart

I,m a bit late on this on.
In my opinion these simple construction,s are easy done in One single Part studio, all part,s related to each other and perfectly editable.

https://cad.onshape.com/documents/54d97e027be00435d8cb3131/w/c535d447bec8dd0e3d549898/e/5bba3faa5fb9f3c6eb629360

peter_cuthbert

Hi Glen

Yes, way too many transforms, but that was all down to drawing the part in the wrong place and wrong orientation.  Transforms seemed a simpler solution than re-drawing in the correct place.  I suppose it is the 'Dog with bone' approach - don't let go!

I am coming around to the idea of starting this assembly from scratch and hopefully getting it right first time.

Regards

Pete

peter_cuthbert

Hi Dirk and Glen

Many thanks for your contributions.  Your versions of the boiler casing are so good.  I will have to 'reverse engineer' your steps to see how it is done.

Sorry to hear that you have been under the weather with Covid Glen. Hope that you get on top of it soon.  It certainly seems to knock some people for six so I am appreciative of your taking the trouble to respond to my questions. Indeed I am very grateful to everybody who contributes to these Forums as so many pieces of software seem impenetratable to the newbie.  It also amazes me that folk are willing to contribute possibly at the end of a long working day. You are all 'Stars' in my book.

Best wishes

Pete

dirk_van_der_vaart

@peter_cuthbert
For a newbie this is a realy good one to start with.
https://learn.onshape.com/courses/fundamentals-multi-part-part-studios
In 2016 I was in the same state as you are now so I understand your difficulties.
Take it easy and start with the basics of Onshape first, good luck

peter_cuthbert

Hi Dirk and Glen

Many thanks for your contributions.  Your versions of the boiler casing are so good.  I will have to 'reverse engineer' your steps to see how it is done.  Thanks too for the link.  I will chase that up this morning.

Sorry to hear that you have been under the weather with Covid Glen. Hope that you get on top of it soon.  It certainly seems to knock some people for six so I am appreciative of your taking the trouble to respond to my questions. Indeed I am very grateful to everybody who contributes to these Forums as so many pieces of software seem impenetratable to the newbie.  It also amazes me that folk are willing to contribute possibly at the end of a long working day. You are all 'Stars' in my book.

Best wishes

Pete