topic Re: Semiproduct with machining allowance in 3D Part & Assembly Design

Semiproduct with machining allowance

mbonka — Sun, 13 Dec 2020 02:27:26 GMT

Hello, l really need some inspiration from our clever PTC community. l will describe my problem as simply as possible. See attached files, that l used to describe my problem. 1) Target: Parameter ROZMER shows a semiproduct size that should be order from a shop and should be delivered

Re: Semiproduct with machining allowance

TomU — Thu, 18 Dec 2014 13:19:55 GMT

I think what you're looking for are the bounding box dimensions of the model (plus some additional added for rough stock). Unfortunately these are not easy to retrieve. You will need to either do something with Model Check or create a custom program (J-Link, VB, etc.).

The only workaround I can think of is to create a solid surface copy of the model and use planes some arbitrary distance away to measure to this surface from each of the 6 directions. Simple math would produce the equivalent bounding box dimensions. Of course the problem with this approach is that you need to make sure any new features are always created prior to this surface copy.

Re: Semiproduct with machining allowance

mbonka — Thu, 18 Dec 2014 13:35:28 GMT

Forgot about example parts.

See attachment please.

Re: Semiproduct with machining allowance

mbonka — Thu, 18 Dec 2014 13:36:58 GMT

Sounds too comlicated.

l can´t imagine how present thise to my colleagues...

Re: Semiproduct with machining allowance

dschenken — Thu, 18 Dec 2014 14:00:28 GMT

Start with ROZMER sized initial feature and only allow cuts to remove material in the models.

For sheet metal, start with flat piece.

Re: Semiproduct with machining allowance

TomU — Thu, 18 Dec 2014 14:12:49 GMT

Agree! Treat the CAD model like the actual piece of material. No model "sculpting". (Adding and removing material over and over again.) Never add material after the first feature.

Re: Semiproduct with machining allowance

TomD.inPDX — Thu, 18 Dec 2014 17:16:55 GMT

Known as "raw material". If you must specify the raw material you will have to create a part that meets that specification so it can be ordered. It may or may not have a drawing. It will in all likelihood have a specification that controls the raw material.

The 1st level assembly (CAD assembly) will be the fabrication detail, which is always removing material. You can even do operations like welding by adding more materials (assembled parts) and also doing material removal operations at this level and subsequent levels. It is all about how much control you need as to how many levels you are creating on your bill of material.

Some raw materials will be ordered in standard length. These are considered "bulk materials" and planning needs to go into these as well... for instance, if you need an I-beam 4 feet long and your raw material comes in 10 foot lengths, you can can only get 2 pieces out of a 10 foot beam. What are you going to do with the 2 footer? Do you even need to acocunt for the 2 footer. Hopefully purchasing can get a 12 or 16 foot beam and your design can live with 3 foot 11 inches to maximize yields.

P.S. I don't do RAR files on principle.