Team 4499's first Homemade Gear!

[Michael 4499]

Originally Posted by asid61

That looks shiny. I'm sure it'll come in handy during the season for those odd tooth sizes.
Have you considered getting a rotary broach to make the hex bore?
What made you choose to write a program to generate the G-code over a CAM plugin for your CAD software, or a similar solution (like MasterCAM)?

We actually haven't looked into rotary broaches. What are the advantages of them? For the g-code, we went with a python generated program so then it is very simple to change the number of teeth, the thickness of the material, and the amount of material being cut. Also we were having trouble with making the program in hsmworks.

[sanddrag]

That's quite an expensive machine. Is it used for something else in addition to FIRST robotics? Also, I'm curious what involute cutter you're using and where you bought it.

[Michael 4499]

Originally Posted by sanddrag

That's quite an expensive machine. Is it used for something else in addition to FIRST robotics? Also, I'm curious what involute cutter you're using and where you bought it.

We bought the machine used, it is a 1993 model that we got for $17000 with all the parts and tools. The machine is only used for FRC and other projects that alumni are working on. The involute cutters that we got are 14 and 1/2 degree pressure angle with a diametrical pitch of 20. For this particular gear we used the fourth involute cutter. Here is a link for the one that we purchased.

[asid61]

Originally Posted by Michael 4499

We actually haven't looked into rotary broaches. What are the advantages of them? For the g-code, we went with a python generated program so then it is very simple to change the number of teeth, the thickness of the material, and the amount of material being cut. Also we were having trouble with making the program in hsmworks.

Rotary broaching is slightly less accurate (0.001" oversized broach, 0.001"-ish loss of concentricity), but my thought was that you can load the broach into the toolchanger and do it on the CNC instead of doing a secondary operation off the mill. That being said, the way your 4th axis is set up at the moment, I don't think it would be easy to integrate.

EDIT: If you are using a lathe to turn the initial diameter, you can use a rotary broach in the tailstock to broach the hex instead of going to the press.