Student User Group Needs Some Help

richard_doyle

Hi Everyone,
We have two very excited students - Imants Smidchens (yes, Alnis' brother) and Lillian Gellings that have volunteered to lead a student user group. The first meeting is scheduled for today, but there are only 3 people registered. There are a lot of reasons why, but none of them have anything to do with these two fine young people. They have decided to go ahead with the meeting and the presentations (two good ones), and are already planning for a second meeting. A lot of other people would have been discouraged, but not Imants and Lillian.

So I'm asking the folks here, if you have a few moments at 4:00pm PDT/7:00pm EDT, stop by the meeting and show some support. You might even enjoy the sessions and learn something .

You'll have to register, but its easy and here is the direct link - https://us02web.zoom.us/meeting/register/tZIvfu2qrDovGtf9DKuCny65tgFd7DTmKeVi

TIA,

Richard

nick_papageorge073

I'm double the age, but I'll attend:)

richard_doyle

nick_papageorge073 said:

I'm double the age, but I'll attend:)

I appreciate that Nick. BTW - I'm triple the age

john_mcclary

I'll try to make it

richard_doyle

john_mcclary said:

I'll try to make it

Thanks John.

bryan_lagrange

Good meeting. Hopefully we can get the word out and grow the attendance for the next one.

john_mcclary

sorry I didn't make it until the end.. but the last few minutes told me I probably missed something good. I could tell in those last moments they were completely in touch with the power of true parametric CAD.

nick_papageorge073

That was fun, thanks!

I checked out both the spur gear FS's. They don't have what I was mentioned of "profile shift". The adjustment it has is to thin the whole gear by offsetting its surface for backlash is something different. Profile shift is a specialized tooth modification when the number of teeth becomes too small, that there is undercutting on the tooth, which minimizes its strength. Its dependent only on pressure angle and module. For a 20 module gear, any tooth number under 18, for example, would have undercutting.

Actually, now that I played around with this more, this FS is inaccurate for smaller number of teeth. It might work ok for 3D printing hobby stuff, but it could not be used for mass production at a gear vendor. Its doing something wrong with smaller number of teeth. Its not undercutting them (which would be accurate). Then, the designer could add a profile shift to get rid of the undercut. A corresponding profile shift in the opposite direction on the mating gear would need to be made so the gear pair meshes properly.

This is the sort of stuff you need the specialized gear profile generators, that typically only gear mass producers have. That's been my experience with injection molded gears years ago.

Here is a web link of what I'm talking about:

https://khkgears.net/new/gear_knowledge/abcs_of_gears-b/gear_profile_shift.html


An 8 tooth, 20 deg pressure angle gear should not look like this:





Here is a 

S1mon

Yes. Molded gears are very tricky as you're designing the tool, not the end result. So variable amounts of shrink need to be taken into account from tip to root. Larger gears may have more than one gate, and the pitch circle of the tool may not be round in order to end up with something round when the part cools. If the gears are only used for a single product, they are often designed specifically for each stage.
https://www.geartechnology.com/ext/resources/issues/0500x/Kleiss.pdf

That said, whatever specialized software these companies use for gear design could, in theory, be ported to Featurescript. 

Similarly, I'd love to see spring design tools ported to Featurescript.

https://www.uts.com/Resources/Brochures/ProductBrochure_AdvancedSpringDesign7.pdf