Team 4499's first Homemade Gear!

[Michael 4499]

From the time that we bought our Haas VF2 CNC mill last year, we have been wanting to make our own gears due to the mill coming with a 4th axis. This has been a long off-season challenge from getting the 4th axis operational to writing a python program to make the G-Code, it has finally been accomplished. To make this gear we lathed the aluminum to the nominal diameter and then used the mill to cut the teeth with an involute cutter. This is a 24 teeth gear made out of 6061-T6 aluminum and we are hoping to experiment with 1018 steel soon. If you have any questions on our set-up for making gears feel free to ask.

[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)?

[Fusion_Clint]

Nice!

[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.

[frcguy]

Originally Posted by Michael 4499

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.

That's pretty awesome! We're looking at doing something like that when we move in to our new building next fall. Either a used Haas or something newer like a toolroom mill.

Got some photos of the Haas for us machinery geeks out there?

[Michael 4499]

Originally Posted by frcguy

That's pretty awesome! We're looking at doing something like that when we move in to our new building next fall. Either a used Haas or something newer like a toolroom mill.

Got some photos of the Haas for us machinery geeks out there?

Ya, here are some pictures of the Haas and the setup for cutting gears if anyone was interested. I would personally suggest an old Haas if you can find one over a newer one just because you can get more for less money. It is really nice to have a large x-travel to work with while making long tubes for robot chassis.
Here are the photos:

[Cothron Theiss]

Originally Posted by Michael 4499

Ya, here are some pictures of the Haas and the setup for cutting gears if anyone was interested. I would personally suggest an old Haas if you can find one over a newer one just because you can get more for less money. It is really nice to have a large x-travel to work with while making long tubes for robot chassis.
Here are the photos:

That looks awesome! Quick question: how'd you locate the center of the gear for the pilot hole and the broaching?

[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.

[Michael 4499]

Originally Posted by Cothron Theiss

That looks awesome! Quick question: how'd you locate the center of the gear for the pilot hole and the broaching?

We used a lathe to get the material to the correct diameter and then drilled the 1/2" hole for broaching on a three ton press. We used a three jaw to clamp up on the stock.

[RoboChair]

You know what really cuts my gears? Those Highlander guys!

Looks nice, I would suggest making gear stock and cutting pieces off of it as it is likely to be more time efficient. Also use 7075 if you are going to be putting it on a robot, the cost is worth it. If you are not already aware, 7075 has nearly the same structural properties as 1018 steel but the same softness as aluminum. nice and strong but will wear much quicker.

[Thayer McCollum]

Gosh guys! I'd finally got our HAAS working this month and then you guys have to show up and one-up me? But seriously, this is awesome! I don't think I've seen your guys new (old) VF2 in person though. I'll have to come check it out sometime. Thanks for the help you gave us with HAAS training a bit ago. One last question, I can't tell from the picture, does your HAAS have an automatic tool changer?

[Michael 4499]

Originally Posted by RoboChair

You know what really cuts my gears? Those Highlander guys!

Looks nice, I would suggest making gear stock and cutting pieces off of it as it is likely to be more time efficient. Also use 7075 if you are going to be putting it on a robot, the cost is worth it. If you are not already aware, 7075 has nearly the same structural properties as 1018 steel but the same softness as aluminum. nice and strong but will wear much quicker.

Sorry for the late response, finals week is a struggle. We are really hoping to find some 7075 round stock but there isn't many local metal distributors that keep 7075 in stock. If we thought about this sooner we could've ordered it online. I still think that the 1018 might be a better fit for smaller gears due to it's higher durability and 6061 for the bigger gears. Thanks for the suggestion, we will keep an eye out for some 7075.

[Michael 4499]

Originally Posted by Thayer McCollum

Gosh guys! I'd finally got our HAAS working this month and then you guys have to show up and one-up me? But seriously, this is awesome! I don't think I've seen your guys new (old) VF2 in person though. I'll have to come check it out sometime. Thanks for the help you gave us with HAAS training a bit ago. One last question, I can't tell from the picture, does your HAAS have an automatic tool changer?

Haha, I hope you get it up and running for the season. We do have a 20 tool changer in the haas.