Need a Machining service?

[ksafin]

Hi all.

Our team has encountered a part we need machined - unfortunately, we don't have any machining capability (no machines whatsoever).

We're wondering if any team can recommend us an affordable machining service or if any team would be willing to machine a few very small parts for us (for a respective price, of course).

We're hoping to get these parts ASAP but of course machining isn't an "ASAP" process so we understand lead times vary.

In short: please let us know if you can recommend a machining service or if your team could help us.

This is actually for our FTC team rather than our FRC team - we need a standard tetrix rack (from a rack-and-pinion system) machined out of aluminum versus the nylon it is made from.

Thanks!

[DonRotolo]

Don't have a machining recommendation, but consider this:

It is possible for you to make a mold of a nylon rack and then cast a duplicate in Aluminum. The hardest part is melting the aluminum.

Make a flexible silicone mold, cast a rack from wax, add the sprues and vent holes in wax, make a plaster mold, melt out the wax, pour in molten aluminum. Pewter is a reasonable alternative to Aluminum if you can't generate a lot of heat (melts as around 750F), but can accept a somewhat heavier and weaker material.

You can also make a 2-piece plaster mold if you prefer, but a bit more difficult to get good results.

[Seth Mallory]

Originally Posted by DonRotolo

Don't have a machining recommendation, but consider this:

It is possible for you to make a mold of a nylon rack and then cast a duplicate in Aluminum. The hardest part is melting the aluminum.

Make a flexible silicone mold, cast a rack from wax, add the sprues and vent holes in wax, make a plaster mold, melt out the wax, pour in molten aluminum. Pewter is a reasonable alternative to Aluminum if you can't generate a lot of heat (melts as around 750F), but can accept a somewhat heavier and weaker material.

You can also make a 2-piece plaster mold if you prefer, but a bit more difficult to get good results.

There are a lot of artists and some school art departments that cast metal. If you have a mold they could help you out. We used our art department once.

[JVerstraete]

ksafin,

If you still want to go the machining route you would most likely need to find a shop that can do Wire EDM machining. It will not be the cheapest route but, you might be able to find a sponsor out of it.

The other aspect of making the rack will be finding a file to make the rack to. I have not seen a file for the rack and pinion. Granted the last time I looked for one was back in November.

After a little bit of research I found a Wire EDM shop in you area that you might want to see if they can give you hand.

Here is there website. http://www.ligi.com/

I hope you find what you are looking for.

[WIREDFTC]

In the FTC Kit of Parts CAD files they have a model for the rack and pinion gear. It should work fine if you have PTC Creo 2.0, but when I imported it in to Autodesk Inventor Pro 2014 some of the geometry was odd on it.