Re: pic: Custom Machined Aluminum #25 Sprocket
 

A beautiful piece--great job!!

I'd love to see an FEA analysis as well.

Re: pic: Custom Machined Aluminum #25 Sprocket
 

Yes, the teeth were milled. Off the top of my head, I believe these are the operations we performed. It was a couple of months ago so the feeds and speeds might not be 100% accurate.

5/8" roughing endmill 1000rpm 4"/min roughs out tooth face and bore
1/2" ball nose endmill 1200rpm 2"/min put radius' around bolt holes
1/4" roughing endmill 1800rpm 2"/min roughs out medium sized pockets
1/4" plain endmill 2000rpm 6"/min finishes medium sized pockets and bearing bore.
1/8" plain endmill 2500rpm 1.25"/min mills small pockets, spot drills bolt holes, and outside sprocket teeth.

CAD files are available for anyone who wants them. As for FEA, if anyone wants to do it, go nuts.

Re: pic: Custom Machined Aluminum #25 Sprocket
 

Wow, those feeds seem really slow. Must have taken a while. What machine were you using?

Re: pic: Custom Machined Aluminum #25 Sprocket
 

i'd say those feeds look pretty good to me, based on the machines i have used and the total size of the sprocket

Re: pic: Custom Machined Aluminum #25 Sprocket
 

Will the sprocket be anodized, or nicely buffed? (I'd tend to prefer buffing, since aluminum really works well)

Re: pic: Custom Machined Aluminum #25 Sprocket
 

Would you mind posting the .dwg for this? You will be my BFF :)

Re: pic: Custom Machined Aluminum #25 Sprocket
 

Seems really slow to me too.

I machine aluminum all the time at around 100 ipm (or even all the way up to 200ish).

Granted I believe 1114 has a small, benchtop CNC mill, which definitely isn't going to run like a VMC will.

Re: pic: Custom Machined Aluminum #25 Sprocket
 

Coolant coolant coolant... i know the machine we used had this very very bad spray coolant...if you have flood coolant i can easily see these rates skyrocketing, but based on what we had to do with hardly any coolant, we had to take things quite slow

Re: pic: Custom Machined Aluminum #25 Sprocket
 

Corey's right. 1114 uses a small bench top CNC mill by RedCAM. Our coolant system consists of a freshman with a squirt bottle. We recently upgraded to a fish tank pump and a bucket. This was a vast improvement.

We've broken more than our share of endmills, and we try to extend tool life as much as possible, so we stick to slow feeds. It can be very time consuming, but student labor is cheap.

Re: pic: Custom Machined Aluminum #25 Sprocket
 

(old thread... but im going for it anyway)

what kind of mill did you use?