So my question is if we have to decide between a mill or a lathe, which do you feel is better for a robotics team. I am not an educated enough machinist to know the full capabilities of either machine so i would love to hear people’s reasoning.
If your team has way too much money, I would suggest a CNC Machine. It uses a computer to control servos and motors and mills according to the CAD drawing you give it. This is how teams go about getting their delicious chasis.
If you don’t feel like spending $30,000 go with a combo mill/lathe.
Our team uses a Smithy 3-in-1. It works extremely well and is good for almost every job (custom shafts, rings for clips, milling swerve drive modules).
It depends on how precise you want to be. Right now you can’t do anything with cylindrical objects. Your shop right now can drill holes. If you need slots, holes drilled with precision, counter bores etc more than working with cylinders, get a mill. If you are happy with being able to drill holes and such with your drill press and don’t need the extra functions of a mill, then get a lathe.
If you really want a complete shop, you should see if you can find a way to get both. Maybe just get some smaller cheaper stuff for starters, or you can see if you can get discounts or possibly something for free.
Look around for companies that switched to CNC’s not long ago. My team went to a company that had a lot of old manual machines that they weren’t using and we got a mill and a lathe for free. (of course it wasn’t quite that easy, but take a look around, a lot of companies are probably willing to help).
Go with a mill. I have seen machinists put round stock in a collet (not the same collet used for mill tooling) and put a lathe tool in a vice and essentially turn a mill into a lathe. One can also take a boring bar, flip the tool around, and do outside turning on a mill, in addition to simply using a boring bar to bore out round pieces. Sure a lathe will do any of these better, but a lathe cannot slot, cut angles, chamfer square edges, etc.
Do note, depending on what your going to do with the machine this might not be a very good option. Your mostly limited to smaller workpieces and some what limited functionality (like you can’t use both functions at the same time). Yet, it does come at a very nice price and fits in a much smaller space than separate machines. Yes I know the quality is somewhat poor and its not the most ridgid machine in the world, but for most robotics applications it will work fine.
So if your looking to machine small brackets, shafts, hubs, bolt circles, gearbox plates, and etc, this would do a fine job (given you have the right tooling).
I would highly recommend against the 3 in 1 machines. You get one machine that does 3 things poorly, instead of 1 machine that does 1 thing pretty well.
I’d recommend a lathe. I think we use ours more than our manual mill and our experience in the past has been that it’s very easy to find machine shops to donate time to manufacture milled parts.
I completely agree that its not ideal and that separate machines would do a much better job.
But if the question is only having one or the other (budget reasons), I much rather have the capability of doing simple mill operations along with simple turning operations, since its a whole lot better than not begin able to do anything.
Some teams aren’t so lucky to find such machine shops because of location or other reasons.
Anyway, if I could only have one, I would get a good sized lathe first and then a mill after that (don’t dis the usefulness of a milling machine, its a whole load better than a drill press). If you take the time to look around on craigslist or ebay you can sometimes find older machinery that will be well suited for robotics at pretty cheap prices. I got an older J-head Bridgeport for $500 along with a vise, beats any import machine that you could ever get for the money.
After thinking about this issue for a while, I realized that I almost never use our mill. For this reason alone, I’d say get a lathe. You can currently print out a hole pattern sheet and glue it on to your metal to make your chassis with a drill press or even a hand drill. With a lathe, you’d be able to make so much more.
I’d say it really depends on the type of team you are, and how you guys usually make your bots. If you find yourself doing complex cuts a lot, then get a milling machine, if you make custom drive trains, axles, or round things, lathe.
I would figure out what you can get done around you, via other teams or otherwise, before making a decision. Maybe your sister team or friend down the street has a lathe which will make the decision easy.
Given one or the other, I would rather have a lathe. I’ve had stuff made on a lathe a lot more than on a mill. When you consider how many standoffs, spacers, shafts, and other turned parts you have on your robot, it’s pretty clear the lathe gets a ton of use. How else do you put in your snap rings anyway?
Stuff like lightening patterns that you’d mill can be done (albeit less efficiently) with a drill press and round holes. I don’t think I milled anything in 2009 (we had our ball tower routed with a laser cut guide, though, which would have been much harder and more time consuming with a drill press). This year, Shaker had its chassis CNC milled, but if we didn’t have access to mills we could have gotten away with C-Channel or something.
Tough decision but I am leaning torwards the lathe slightly. 237 normally has 2 lathes running every build night plus 1 Bridgeport mill, and even two at times. We custom build alot of our parts though.
If you use the kit bot parts mostly then the mill isn’t likely to be in as much demand.
Don, how does your team handle making custom brackets and such? Bandsaw and file/grind? I’m just curious as this is the first time I’ve heard of a team having the ability to mill and not taking advantage of it.
Our team just ordered a 4-axis CNC mill, which really has the best of both worlds, it’s a CNC Mill, with a CNC controlled rotating grip that basically works like a lathe.
That seems to be the opposite of what I’ve experienced. For several years we had 4 mills and 4 lathes, generally the mills were all full and the lathes were left open. Even this year we used a lathe for two parts. I’ve found that virtually all spacers/shafts/standoffs can be had as OTS parts or simply sliced-up round stock. McMaster FTW.
