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[Tom Ore]

Originally Posted by AdamHeard

It's not so much what is essential/non-essential, it's more about how much detail is needed;

You probably mean how many points to use to define the involute. The involute can have a few points like 5 or 6, or many points like 20 or 30. You'll get basically the same tooth form if the CAD software and/or waterjet blends the points together into a single curve. It sounds like the problem you had was too many points along the involute and the waterjet stopped / started before each point.

If anyone is interested in the math, I posted a spreadsheet in CD Media that creates a file to import gears into Pro/E. (It only does full fillet gears - sorry but flat root gears are against my religion.)

[R.C.]

Originally Posted by Tom Ore

You probably mean how many points to use to define the involute. The involute can have a few points like 5 or 6, or many points like 20 or 30. You'll get basically the same tooth form if the CAD software and/or waterjet blends the points together into a single curve. It sounds like the problem you had was too many points along the involute and the waterjet stopped / started before each point.

If anyone is interested in the math, I posted a spreadsheet in CD Media that creates a file to import gears into Pro/E. (It only does full fillet gears - sorry but flat root gears are against my religion.)

I'd be interested to give this a try, could you have it export the data in .txt for Solidworks?

Or into something else that more CAD packages can read?

Thanks,

-RC

[Tom Ore]

Originally Posted by R.C.

I'd be interested to give this a try, could you have it export the data in .txt for Solidworks?

Or into something else that more CAD packages can read?

Thanks,

-RC

It would be easy to modify if you can tell me exactly what the file format needs to be.

[EDIT] Actually, Solidworks may be able to read the IBL file - I found a reference to it in their online help. Give it a try and let me know if it works.

[Akash Rastogi]

Originally Posted by AdamHeard

It's not so much what is essential/non-essential, it's more about how much detail is needed; it's the same feature either way (the tooth profile). The gear tooth profile is not just a simple arc, it's a changing curve. You can approximate it as less curves and still get reasonable accuracy (which you'll notice a lot of people/companies have done on their CAD models). I also imagine different machines might not get "confused" by the new curve.

If you google some about how to draw spur gears, you'll see what I mean and it will make total sense.

I can't make the blanket statement about water versus laser, just that the run of lasered parts we did this year that were .125 thick had a much cleaner and smoother edge than this run of waterjetted parts. I did tell the waterjetter to cut everything very fast though (to test if we get the same functionality out of less sponsor time), not sure how valid of a comparison that is. There are an awful lot of machines on the market as well, combined with the fact that machine settings can also have a huge effect on finish.

So I got a chance to check out gear tooth profiles in my work's copy of the Machinery's Handbook. DEFINITELY understand what you mean now about the curvature of the tooth haha.

To propagate the curve, how many points should I use if using a laser, or should I just use whatever the gear generator in SW does?

Thanks again!

[Tristan Lall]

GearGen is another quick and dirty way of generating a pretty good involute for gears.