topic Pressure formed sheet in Inventor Forum

Pressure formed sheet

tigfur — Sun, 29 Sep 2019 18:13:15 GMT

Hello,

i would like to design a pressure formed sheath (leather/kydex).

How would one go about doing this in inventor?

In real life these kind of sheaths are made for example by placing two moldable sheets of thermoplastic into a foam press with the object that should hold between them. (google kydex sheath forming)

So i was thinking to maybe do some form of sheet metal and then using the object designed to "bend" the shape into the sheet metal. Havent really figured out how to do it.

All tutorials i found only have simple shapes and are made by hand, not using an existing object.

Imagine having a very complex object already made and wanting to somehow "press" it into the sheet.

Is it possible?

Thank you for your help or any ideas.

Re: Pressure formed sheet

JDMather — Sun, 29 Sep 2019 18:46:15 GMT

Design in finished form.

You can generate the mold(s) from the finished form.

Attach image or link to something similar to your Design Intent.

I have an old beginner level tutorial on doing something similar - but I suspect that your Design Intent is not a beginner level endeavor.

Also, what version of Inventor are you using?

Re: Pressure formed sheet

tigfur — Sun, 29 Sep 2019 21:15:02 GMT

Here are some random pictures from google.

I would like to make the plastic part, its basically a sheet formed to the shape of the object. (or two sheets each of them making a half.

I imagine this way of object forming is common in large production scale so there should be a way to manage it in inventor.

Thanks for your help.

Re: Pressure formed sheet

JDMather — Sun, 29 Sep 2019 21:30:34 GMT

Those are relatively easy to model - I was expecting something much more difficult.

Unfortunately I am really tied up with work this week - hopefully someone else will come along and offer solution.

I recommend that you Attach your attempt here and indicate what version of Inventor you are using.

Re: Pressure formed sheet

tigfur — Mon, 30 Sep 2019 08:14:09 GMT

I am using Inventor 2018.

My attempt so far ended with just a slim extrusion to make a flat sheet, after that i dont know how to proceed.

If someone just shows me how to do this with an example object like a random loft that would be enough to get me started.

Re: Pressure formed sheet

JDMather — Mon, 30 Sep 2019 10:30:19 GMT

The examples in your images can be done with Extrudes, Fillets, and then Shell.

Re: Pressure formed sheet

JDMather — Mon, 30 Sep 2019 11:21:54 GMT

Here is a really quick 5 minute example.

Re: Pressure formed sheet

tigfur — Mon, 30 Sep 2019 18:00:41 GMT

I have to say for five minutes thats very impressive!

But its not quite what im looking for. You see the object the sheath is supposed to be made for can be complicated and already made and one doesnt wish to repeat all of the steps to manually retrace the sheath. One might not even know how the object was made.

It would be best if it could somehow copy and offset the entire object resulting in a blanket like cover.

I have made a simple yet complicated enough object to show what i mean. As you saw in the pictures it can also be much more complex. (like a gun with safety, trigger, lots of small extrusions etc, possibly even something made in freeform)

Is it possible to do it in some easy way?

Re: Pressure formed sheet

tigfur — Mon, 30 Sep 2019 19:39:50 GMT

I think i just replied but it didnt seem to post so ill write it again.

I tried to do it by extruding the sheath form completely over the knife and then using combine to subtract the knife from it (it didnt work with only one half, not sure why)

then i made aonther sketch and extrusion to delete the extra half (split with XZ plane didnt work)

and delete face to only get the surface.

I cant seem to select it for thicken or really do anything with it so it was useless.

The entire process was very cumbersome so im sure i did it completely wrong and there is a better way, but it will most likely be something along those lines and then some fillets to make it more fluid or maybe some scaling to make a tiny gap. Just guessing.

Please edit the previous file rather than editing this one, its a failed experiment by trial and error and seeing what it

lets me do. I have no idea what im doing honestly 🙂

Thank you

Re: Pressure formed sheet

JDMather — Mon, 30 Sep 2019 19:53:21 GMT

I would probably Derive Component and then Offset and Trim/Stitch surfaces.

But this all gets into advanced surface modeling techniques.

Re: Pressure formed sheet

swalton — Mon, 30 Sep 2019 20:48:39 GMT

I'm not aware of an "easy button" method to mimic the production method of draping a hot plastic sheet over an object with Inventor.

Instead, you will have to make the shape you want, and check to see if reality matches your design. 3d printing may be your friend.

I expect that this will be a surfacing project where you will have to create some starting geometry, then adjust it to suit.

I'd begin by making a simplified model of the object that is fully closed. (closing off the trigger hole in a pistol, for example) You might try the Shrinkwarp tool to simplify your source object, then get into the derive surface workflow that @JDMatheris suggesting. Are you planning to form the parts yourself,? If so, you can use the simplified model as the basis for your forming tool. If you use a thermoforming service, you will provide them with the final shape you want, and they will make all the tooling to produce the sheath.

Another option would be:

Place the object in an assembly and ground it at the origin.
Place an empty part (.ipt) file in the assembly and ground it at the origin.
Edit the part in the context of the assembly.
Create a series of work planes and sketches to represent the inner surface of the kydex at various points on the object. Think of cross sections in the drawing environment.
Use those sketches as the input to a surface loft to generate the inside of the sheath.
Thicken the resulting surface to form the basic part.

In any case, welcome to complex part modeling.

Note that real-world thermoformed parts will not have a uniform thickness, so be cautious with designing related parts until you have production samples in hand.

Re: Pressure formed sheet

tigfur — Tue, 01 Oct 2019 08:27:30 GMT

Thank you for your suggestion,

i will give it a try.

Making a simplified version of the solid is reasonable. The rest i have to look up first.

I expected it to be some surface work. I dont mind learning more about it.

This is more for rendering purposes and to learn with inventor. Just to see what it would look like and where the holes can be (in real world i cant move them around)

I am not too worried about production as thats a very simple process.

I might try 3D printing it though.

Re: Pressure formed sheet

tigfur — Tue, 01 Oct 2019 10:03:52 GMT

Deriving components is basically the same as loading the finished part file of the object?

I dont quite understand how that helps if i already have the object modelled.

Same with shrinkwrap, i dont really understand what it does other than that i need more files and an assembly instead of just creating a single part.

i found this tutorial

https://www.youtube.com/watch?v=uP4Zal-5x4k

That basically did the same thing i have done in the second file, just in a different way.

Still it ends with a simple cutout extrusion piece and i dont know how to make it into a surface in order to thicken or offset it.

I have another idea how it could maybe be done but i am not sure how to do it:

make a surface extrusion of the sheet sketch in the middle plane through the object

? - somehow make the entire object to surface

stitch and trim so i have just the sheath shape i need

? - somehow copy/move/offset/thicken given surface to give it a thickness, ideally expanding in all dimensions nut just up or so.

fillet the inner and outer side to make it more realistic

Like this it would sound simple but i am not sure if its possible.

I cant seem to find a good way to convert an object to surfaces, Delete face left just a thin layer but it still seems to behave like a solid and the other tools i know are for converting surfaces to objects rather than the other way around.

Re: Pressure formed sheet

JDMather — Tue, 01 Oct 2019 10:17:16 GMT

I have another idea using a couple of tricks with the Mold Tools, but I would need for you to zip and Attach an example assembly to experiment with.

Re: Pressure formed sheet

tigfur — Tue, 01 Oct 2019 11:33:22 GMT

I am currently unable to access my computer, would it be enough for you to use the sheath experiment.ipt and insert it into a new assembly?

Re: Pressure formed sheet

JDMather — Tue, 01 Oct 2019 11:38:11 GMT

@tigfur wrote:

... would it be enough for you to use the sheath experiment.ipt and insert it into a new assembly?

I do not see this attachment.

Currently you must zip files to Attach here.

Re: Pressure formed sheet

tigfur — Tue, 01 Oct 2019 12:34:31 GMT

So i have been referencing two attachments this whole time without anyone being able to see them? 😄

Well that explains the confusion. It looked like they uploaded without any issue.

Ill post them here in about ten hours.

Re: Pressure formed sheet

JDMather — Tue, 01 Oct 2019 12:41:45 GMT

Whenever making an Attachment - come back and verify that it was in fact successful.

The forum has been having difficulty with Attachments for the last 2 weeks.

Re: Pressure formed sheet

tigfur — Tue, 01 Oct 2019 20:21:40 GMT

Here is the attachment

first version is just the object for test purposes (re-read mone of my previous posts for details)

the second version is a bad attempt at making the sheath as i mentioned above as well.

Re: Pressure formed sheet

JDMather — Wed, 02 Oct 2019 00:47:52 GMT

I only have Windows OS on my machine - l don’t own a rar extractor.