CNC Routers for FRC Robotics


#421

548 does the same thing, except we use a bit of scrap or a washer as clamps to hold down the edges of the sheet for the drilling operation. Also, since we use twist drills to make all of our holes, we can have one student changing the tool while another screws down parts.
The only recommendation I would make is to use torx/star drive screws on a fast cordless drill-driver. With torx, you don’t need downward force to transmit torque, so it is very easy and fast to screw and unscrew.
I don’t think there is any better alternative. Tape (or super glue) doesn’t work to well or is a pain, and tabbing still requires good holding of the sheet. Both require cleanup after cutting. With screws, all you have to do is deburr the parts and they are ready to go.


#422

For me, it usually only takes 5-10 minutes to screw down sheets of gussets. Cutting out tabs not only takes longer on its own, but you then also need to sand off the tabs, which takes time and ruins surface finish. Billion screws is reasonably quick as long as you keep a drill and a bucket of brass screws next to the router.
Also, tabs are usually placed manually in CAM, which takes a few minutes as well.


#423

Just a little bit of a proposition here. Would it make sense for cnc routers to have their own forum on CD since they are common enough we are bound to see many more threads relating to them?


#424

After ordering our Omio on 11/29 we received it today with literally zero shipping issues or additional charges. Unsure what additional costs other users have reported, but I did not get contacted about anything after purchasing.


#425

Ditto. Ordered 11/30, arrived in NYC 12/7. No issues at all.


#426

Ours should be arriving Thursday! Looks like I’m going to be spending the Christmas break working on trying to learn to machine a few parts. Hahaha.


#427

You can get rid of step 1 by using washer head screws or washers with your screws and just clamp the edge.
For your remaining steps you could go the route of use a few screws spread out and tabs to keep it more together.

Buy a set of ER collets for whatever size spindle you have and get single flute carbide endmills. Use the linked 1678 feeds and speeds table as a starting point and run at 30-50% feed rate to start, WITH some lube/coolant and air. That should give you a good starting point and help keep you from breaking endmills early while learning. Start with drill bits first drilling holes because those are cheap.

That is not a bad idea. Sure would make browsing CNC threads to find info nice and easy.


#428

The 12mm length of these are some of the best you can get for the money. Several teams have started using them with great results.
Start them at 42 inches per minute, 24,000 RPM, at a .04" depth for slotting. For pocketing, run up to 1/4" thick material with a 4* ramp down helix with .04" stepover, at 45-50 inches per minute. I recommend joining the FRC Discrod as well- there are many CNC Router owners there that can help you if you run into issues.


#429

Dang, I already put in an order for a few from McMaster. https://www.mcmaster.com/8866a322 - I wasn’t sure what else to do. Will these been good? They look like they have all the right properties, other than I ideally wanted to go single flute.


#430

Those should work fine, but for a 6mm endmill with 2 flutes, you’re looking at something like the following:
12k RPM
48 IPM
0.03" DOC when slotting, 0.03" WOC when pocketing (at full plate DOC)

Start at the above values, then increase WOC and DOC until it starts sounding bad. You should hit the limits of the Omio before you hit the limits of the 6mm endmill.


#431

Awesome Akash!

Recommend working it hard and failing often - we haven’t been able to fail badly yet… keep us informed how you progress!


#432

Single flutes are under router bits at Mcmaster

https://www.mcmaster.com/3317a23


#433

Man thank you guys for all your help. Hopefully last thing, I’m probably planning to put a fogbuster set up on it to keep it cool. I know it needs a compressor, do you guys have a recommended one (keeping in mind our unfortunately tight space constraints)? I see the California Air Tools one associated with it a lot. Is it a good option / are there cheaper / better options available? Also, quiet is a huge bonus, as we’re stuck in that relatively small classroom.


#434

This is the compressor I use on my router:

It is decent, but can’t sustain more than what I would call a weak-ish airflow. It gets the chips out, but nothing fancy.
If you can, upgrade to t he 2HP model:

I believe this is the one 1072 has in the shop and it is pretty quiet (although louder than my 1HP one) and sustains a much stronger airflow.


#435

Ugh, yeah, sadly there’s no way I could fit the 2HP one in there. I’ll take a look at the 1HP.


#436

Oh, another quick question - coolant recommendations for the fog buster and/or for the spindle?

EDIT: Okay, also I’ve figured out (maybe) a space solution to some of my issues. I can store the compressor and water bucket a little farther away and save myself some space on the bench top, IF you guys think that the compressor could push the air over about a 10ish foot run of tubing and the water about the same distance. Thoughts? Is this doable or would there be too big a pressure drop? I feel like the compressor could handle it but maybe not the water…

EDIT EDIT: A few more small questions, trying to get all my ducks in a row. Should I just use a water bucket, or something like a CW3000 chiller to keep the spindle cool? Or just a coolant in the water?


#437

Currently our team has a DIY CnC router that we are using. The current router that is on the machine is a Bosch Colt router. I would like to upgrade it to a spindle with a VFD.

I have seen a lot of talk on this thread about the spindles and the VFDs but I have not seen any links to ones that people recommend. I have about $1,000 dollars to spend on a spindle and collects and tooling before the season starts.

I am mainly looking to try and find out what spindles and VFDs people are using. Any response would be great.


#438

I just recently replaced our Velox with a water cooled spindle we bought off of Amazon for about $450. I did have to machine the spindle mount myself to mount it. Pretty much any 2.2 kW spindle you see on Amazon with generally positive reviews will do just fine, China is really good at making motors and bearings. I’m going to post my steps that I took to incorporate the various changed to our Velox CNC so that others in the community can copy what we have done.


#439

We’re using Mobilcut 100 as our coolant across all our machines including the Fog Busters. It’s the general coolant that Mobil makes but they have specialized stuff for Aluminum. I don’t know if there’s really a practical reason for us to buy it (our kids are going to crash more cutters into stuff than we’ll break by excess wear). But for full disclosure we just installed our fog busters a month ago and haven’t run more than 5-6 hours of time on them yet.

I was reading a page or two back and saw some questions about cutters. For whatever reason I found that Garr 2 flute carbide end mills (220M series) seem to hold up better on our router than other brands. It was our first year using the machine so maybe we were just stupid but now that’s all we use. We have some single flute Micro 100 bits that we haven’t tried yet either; but that’s because we’ve been waiting for our 2 flute bit to break and it’s just held up super well. I bought Gwizard and have been using conservative speeds and feeds to start on the Router and did some trial and error to find our sweet spot we can crank up to.


#440

My compressor pushes air through at least 20ft of hose. You’ll be fine on that front, at least.
My water pump is at maximum about 15-20ft of tubing away from the router (after you considering all the cabling and such). So again, you’re probably fine.