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Multiple (very different) parts, but with shared dimensions
marcus_8
Member Posts: 3 ✭✭
I am working on a detailed mechanical model which will have somewhere around 150 unique parts (I believe around 600 total parts). I am working from a set of engineering drawings. The designs were originally made for traditional machining, but I am planning to attempt a 3D printed version. I am doing the initial version for an FDM printer. The tolerances may need general adjustment later, and I also want to keep my options open to adjust all of the tolerances for a different (more accurate) type of 3D printing.
The parts have different fitting requirements. Some of them require a forced fit while others require a sliding clearance fit and various fits in between. An FDM printer can print these mechanical fit types, but they will need different tolerances than the drawings specify. The same goes for other types of printing.
With so many parts and different types of fits, is there any way I can define these various tolerance types (basically dimensions) in one place and alter them in one place, but have all of my parts in this document updated from the one set of values?
Also of note is that I am not a mechanical engineer, but a software engineer by profession so I may be using improper terminology or have some concepts wrong.
The parts have different fitting requirements. Some of them require a forced fit while others require a sliding clearance fit and various fits in between. An FDM printer can print these mechanical fit types, but they will need different tolerances than the drawings specify. The same goes for other types of printing.
With so many parts and different types of fits, is there any way I can define these various tolerance types (basically dimensions) in one place and alter them in one place, but have all of my parts in this document updated from the one set of values?
Also of note is that I am not a mechanical engineer, but a software engineer by profession so I may be using improper terminology or have some concepts wrong.
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ilya_baran Onshape Employees, Developers, HDM Posts: 1,210In terms of having a small defined set of values driving multiple dimensions possibly in multiple part studios, there isn't a good way to do this yet, but we are working on it -- this is a high-priority feature for us.Ilya Baran \ VP, Architecture and FeatureScript \ Onshape Inc5
Answers
I do plan on there being a little bit of an iterative process getting parts to fit properly, but I hope to limit it after having printed a few simple mechanical fit tests I designed up quickly.
Thanks for the help!
FWIW, I've been using a $2k FDM printer lately for some mechanical models and have been finding that it is usually best to make holes a little undersize and drill or ream them out. Also beware your STL export settings - if they are not fine enough you will get facets on curved surfaces rather than continuous curves.
Mike
in SolidWorks we do this with configurations. We pick some key dimensions and configure models at the tolerance extreme. This is a bit of a tedious process but we set up sensors to flag up pass fail scenarios for the overall assembly. But it is still a manual process of turning configs on and off and checking.
so, moving forward, with Onshape, could we not design to a nominal size, select key dimensions and have Onshape automatically create branches with the models at different tolerance extremes?
Then we set up our sensor like pass faill scenarios and Onshape runs through the tolerance ranges, populating a table with each result, and flags up the fails. This would be a killer feature for many.
How would you set up sensors in Onshape? Would you include collision detection?
Tolerances and collision detection are difficult area when working with wood since it's difficult to tell the software that it's not a collision when nail or tapped screw contacts wood. Or if connection is based on 'tight fit'.