CNC Router/Mill
 

We are in the process of hopefully getting a grant from our school district. Today our teacher told us that we need a list of tools that we want by tomorrow, after searching for a while we have failed to find what defines a good CNC Router or mill(still not sure what the difference is,sorry) so we decided to take the easy way and go to reliable Chief Delphi for a place to buy a good CNC mill.

Re: CNC Router/Mill
 

Budget determines everything. Have a number?

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apparently its like $100,000 but we're going for a midlevel CNC. A nearby school got $20,000 for theirs so we're expecting something around that maybe a little less

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$20,000 is right in no-man's land between benchtop mills, converted knee mills, and full blown machining centers.

Does that include tooling? You're going to spend at least $5,000 on tooling.

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Ok well for something a little better, what would you suggest? There is a meeting being held soon where our school needs to tell the district what we want. We will include tooling in final costs. Within $20,000-$40,000 (including tooling) what would be suggestible and most advantageous.

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We went with a CNC Jr from CNC Masters (www.cncmasters.com). The control software is a bit buggy and irritating, but now we've played with enough to figure out how to best use it. The whole setup is less than $10k, so you get what you pay for. They're located in SoCal, which is nice and they've been very helpful by phone with any of my needs and questions. Last year, during build season, we blew out a control board when the power to our building went out (yes while the CNC was running). I packed up the control board and sent it to them on a Thursday and had it back the following Wed. Not bad service!!

We've become better with MasterCAM, which is a really cool tool that can speed up and expand your capabilities on a CNC - so don't forget to add on a license or two for that. I think you can get a edu version for about $1k.

There is also microkinetics which has some really cheap CNC offerings. I have one of their desktop mills which will do a lot, but it will do nothing fast and nothing that big. I've made transmission plates on them, but you have to do 5-6 passes for 1/4" aluminum - YAWN!!

Good Luck.

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Thanks for the help. Yes, we would want something consistent, reliable, and efficient....(obviously), but, I will look into that. I know I still have a lot to learn about different specs and such. What kind of range is good to have on an X,Y,Z axis? And, what kind of rotary table, in the sense that, I have seen different options on them, like detachable, 1 degree, etc...?

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I think a rotary table is a bit beyond your spending range, if you want a solid CNC mill that will last the lifetime of your team.

We got one with our VMC last summer, and it totals about $10,000 from Haas. We have yet to even use it. It's nice to have, but not a necessity. You can always put a manual indexer or rotary table on your mill. Odds are any 4th axis work you do is indexing, not contouring.

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Update to my other post, now that I saw the budget... CNCMasters has a Supra CNC which is a more familiar bridgport like knee type mill. A big package is around $10k, add a bunch of tooling and extras (MasterCAM) and you'll be right there around $20k.

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I'd go for a Haas TM-1

You'd be getting a very versatile machine--something with a lot more power and speed than a knee mill, or a benchtop machine. It has the advantages a knee mill has, in that it's got a large table, is familiar (mostly) and can be operated via handwheels, just like a manual mill.

We have a Haas VF-1, which is a machine geared more towards production, but it has the same control. The Haas control is very easy to use, and comes with templates to help you write code, and "quick code" that you can program most simple parts just by entering values into data boxes.

Out the door you're looking at somewhere between $28,000 and $36,000 depending on the options you choose. Haas offers a educational discount as well, I believe. Probably 5-10%.

For tooling I'd say you're looking at around $4,000-$5,000. You can spend a lot more, or a lot less, but for tooling that will actually take advantage of the capabilities of your machine, I'd say around $5,000.

There's a lot of variables to consider. I spent a LOT of time researching every manufacturer out there when we were going through this process. Literally months of time sorting through all the information out there. It can be very daunting. Let me know if you have any questions. I'd be happy to help you out.

[edit] as Doug says, be sure to budget for CAM as well. You can't run the machine very well without CAM. We use MasterCAM also. I've tried CAMWorks and GibbsCAM, but I find MasterCAM the easiest. I think it is right about at $1k for an educational license like he mentioned.

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Ok thank you very much for help/suggestions. Yes just from a lot of personal research I have done already I can tell the the extent of research that is good to have. I will definitely keep in touch with questions as they come up. One thing I saw on the TM-1 is an option of CT or BT taper type, what do those mean?

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CT taper is common in the US. BT is in the rest of the world.

The short answer is they are interchangeable. As you are in the US, you'll buy a CT taper because it's the standard. The actual taper on the toolholder/spindle is identical. The only difference has to do with the drive dogs on the spindle face, and the thread on the rear for the pull-stud is metric on a BT holder.

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Ok, I understand that now. I will look more in to that Haas and do some more personal research. As for tooling. Say, with the TM-1, just get tooling straight from Haas then? Because I saw in the "Build-a-Quote" you can add on tooling like CAT-40 Tool Package. for $2100, as well as 24 Pull Studs (CT40) for $300. Would that be advisable for tooling? And possibly any other accesories to help make it a complete and long-lasting system? Thanks for all of your help so far!

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One of the dozen Haas CNC machines on my campus is a Haas TM-1, and it's definitely a good machine for doing all different kinds of work.

The best thing about it is having the ability to machine plastics (Lexan, delrin, HDPE, UHMW, etc); on most enclosed CNC machines you cannot machine plastic because it'll clog the coolant pumps. On the TM-1, since the coolent pump is "separate", you can machine plastics and still be able to vacuum off the machine.

Just remember, the TM-1 only has a partial shield around the table. So if you set your coolant pump to ludicrous speed when machining metal, then you will spray coolant everywhere, especially to the left of the machine. Most of the time you can avoid this by just adjusting to a slower coolant speed.

And one more thing. Go up in your attic, basement, or garage and dig out all those 3.5" floppy discs, like all those free ones that came with AOL 3.0. Many CNC machines still use floppy discs to load NC programs (these are the programs of G-code that tell the machine how to make your part) onto the machines; the only ones I've seen that have support for USB Flash drives are the larger models, like the Haas VM-3 or VF-4.

When purchasing tooling, just remember that the TM-1 only has a ten-tool changer. Ordering 24 tool holders seems like a bit much.

I would recommend three (or four) drill chucks, five to seven collet tool holders, and three or four tool holders which use a set screw to hold the cutter in place. The drill chucks tool holders are useful for center drills or regular drill bits. The collet tool holders are versatile and can hold any size end mill. The set screw tool holders are useful for something like a face mill, which will most likely just stay in the tool holder.

Also, remember than one of those ten spots in the tool changer will usually be a part probe. At both machine shops on campus, we always leave the probe in T10 (the last tool spot) in the TM-1 and Haas Mini Mills, and T25 (the last tool spot) in the Haas VM-3 and Haas VF-4, which all cost in the $50-$60k and upwards range.

Also, getting good tooling can sometimes mean doubling the price of the machine. That also includes things like vises. A good Kurt vise can set you back up to $700, and if you want to machine long stock, you'll need two vises.

Then there is the question of drill bits and end mills... These start adding up very quickly. :)

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Another option can be found at http://www.tormach.com/Product_PCNC_main.html. This may be a little smaller than what you are looking for but may fit your needs.

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Don't forget to check out one of your local friendly FIRST suppliers, intelitek Inc. (you know, the people who made EasyC)

I'll admit right upfront I'm a former employee (hence the plug) but the Super ProLight 1000 is a sweet machine. It's right in your budget and the best part is they also sell curriculum to support it and it's made for educational use so it's very user friendly and easy to learn.
No worries about crashes and expensive repairs, it's pretty bullit-proof.
Team 40's made tons of robot parts from gearbox sides to give-aways, you name it.

www.intelitek.com or swing by Team 40 at Championships and talk to any of the mentors.

-Sarah (shameless plug over now)

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Take a look at Techno's LC series.
http://www.techno-isel.com/Education1/Ed_LCSeries.htm

We use this one as a teaching machine for class yet is has a large enough table to work on drive-train parts or larger frame / mechanism parts. Mastercam can post nc files.
http://www.chiefdelphi.com/media/photos/25892

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If you are looking for a machine that can hold tight tolerance (for bearing bores and whatnot), high material removal rates, and the ability to handle steels, I'd recommend against a gantry style machine such as this (and a round column mill such as the CNC Jr). They simply don't have the rigidity required.

The Tormach is a nice machine for the price. I've heard good things about it. However, it still is an open loop stepper based system run by Mach software (not the greatest IMHO) and you'll only get 60 IPM and .001" accuracy out of it. If you can afford the HAAS, I'd go for that. I've been using HAAS machines for 5 years and they are very easy machines to learn and operate and have many nice features.

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All new Haas machines now come with USB.

24 pullstuds can be very useful, even if you dont have 24 holders. Eventually they will wear out or break. Our machine has a 20 tool changer, and I have the entire carousel full, plus tools outside of the machine that I swap in for certain operations, so there is a use for having more than the maximum capacity of you toolchanger.

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Ok, I have no clue what is what when it comes to CNC but I do know that if we wanted to start an FRC team next year a CNC mill would come in quite handy (since we need a mill anyway). Since I am cheap and we would only be using this mill for FRC how would something like this work?

http://www.taigtools.com/cmill.html

What would we be limited to with this machine? I know some one here said bearing holes would be hard to cut and it would also take sometime to make anything. Anything else I should be aware of?

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That mill would work for anything up to about the size of a gearbox plate.

If I only had a few thousand dollars to put into a milling machine for a FRC team, I'd be much more likely to look into a good-condition, used manual milling machine before I would get a mini-CNC mill. CNC mills are nice if you already have manual equipment, as there are a lot of occasions where it takes longer to make "easy" parts via CNC than it does to just make them on a manual milling machine.

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Agreed. I doubt the Taig would be able to do anything very useful in a decent amount of time.

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So say buy a cheap used manual mill and then a mini-CNC mill or is that just over kill. How offend are you going to mill something bigger then the CNC mill could do on a standard FRC bot? From what I could see on 303 robot this year we could make everything on the mini-CNC mill.

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That mill doesn't even appear to come with a controller/software.

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He's saying manual. Less time programming/setting up means more parts, unless you have a lot of parts that you need identical (and then you can make a jig to set them up). Size doesn't really matter for FRC, as long as it isn't TOO small.

The mill isn't what will kill your budget, it's the tooling for it. Start with a manual and tools. There are upgrades you can get to make it at least semi-CNC, if you so desire. If Cory's right, then you may as well get a manual mill, as CNCs are useless without controllers.

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I saw one of these running at IMTS in 2006, where they recut the same part over and over (mill air) for demonstration purposes... well, unless they changed something, the TM-1 I saw had run the same part over probably about 60 times by the time I got there and it was STILL cutting dust off the part. It just seems like the repeatability must not be very good if after that many re-runs it was still cutting dust off the part.

BUT! If it works for you, awesome.

Just to throw another name out there... my faaavorite mill I use at work is a Hurco w/rigid tapping (awesome): http://www.hurco.com/Hurco/English/P...ers/VM+Series/

They're very space efficient and have great feature lists for the money, though they're more production oriented than a TM series from Haas.

-q

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I tend to agree with the others comments. The Taig is just a bit too small. Not only is the work envelope limiting but the rigidity of the machine itself limits the cuts you can make. For the same ~$2500 you could get a manual dovetail mill/drill. Take a look at Industrial Hobbies. I don't have nor have I ever used or even seen in person one of their mill/drills but their website sure makes a strong case for their mill/drill over the similar well known Rong-Fu and cheaper house brand imports like Enco, Grizzly, Turn-Pro, etc. For the same ~$2500 you are considereing spending on that Taig CNC mini-mill you can get the Industrial Hobbies basic manual SQUARE COLUMN mill/drill. It is a beast though compared to the Taig so you aren't going to be bringing it along to competition.;) If you search around on their website there is a photo of a popular hobby type Seig X2 mini-mill (Harbor Freight, Homier, Grizzly, Micromark, etc.) sitting on the table INSIDE the Industrial Hobbies mill/drill. The Taig mini-lathe is about the same size as the Seig X2 mini-mills but the Taig is a little less "beefy" if you ask me. If you have the $ consider one of the Industrial Hobbies packages with DROs and power feed included with the mill/drill for about $3700. If you don't have the extra funds for the DROs and/or power feed up front you can always add them later for ~$1500.

So as others have said you are probably better off starting with a manual mill and required tooling first and then step up to CNC later if needed. Never underestimate the cost of tooling. You could easily spend another $2500 on tooling.

As luck would have it Industrial Hobbies has ready made CNC retrofit packages for their mill/drills for ~$4500 which includes software.

As I said I have absolutely no experiance with the Industrial Hobbies machines but I am strongly considering one for myself. I figure for ~$4000 I can get a really nice manual mill/drill with DROs and power feed delivered to my door. Once setup I can later add CNC for ~$4500 if I want and have a really nice setup for a total investment of ~$8500. I have the tooling covered since the Industrial Hobbies mill/drill has an R8 spindle as does my existing Seig X2 mini-mill.

If anyone has any hands on experiance with the Industrial Hobbies machines I would love to hear your opinions of the machine.

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This past year was the first year we made anything on a CNC and it was using the school's Intelitek machine. Ours only had around 6" of travel, but it was great being able to make small plates and parts and allowed our manual mills to be used at the same time.

Good luck on the CNC search. After looking at the model Cory has suggested, it does seem to be a good choice if you have the money for it.

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Ok, thanks for the info! Just gathering information about what my team would need to upgrade to FRC. It just seems that every "good" robot on has CNC parts all over them. I know how to use a mill but when it comes to which one to get I am clueless.

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You'll find that this theory isn't always true. You can have all the CNC / Waterjet / Lasercut machining done to your robot, but if there's not a solid and sound design, it won't matter.

There are plenty of robots made every year with a band saw and a drill press that excel because their design is simple yet effective.

A lot of times it's easier to find a local company or university with the kinds of machinery mentioned in this thread. Do a bit of research and send out a few e-mails, or ask some other local FRC teams that have access to these capabilities. You'd be surprised at how willing people are to help you out.

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Just having CNC equipment won't do you any good either.

You need an experienced operator who knows how to do setups and programming.

I started using a CNC mill about 4 years ago. I've been using one regularly for the last year or so. I've taken 5 classes, and I still barely know what I'm doing compared to a real machinist. I know experienced machinists who could take a drawing and do the setup/programming/cutting in 1/3 the time it would take me. Without a strong background in cnc programming, you're going to be wasting a lot of time making scrap, or nothing at all.

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That is why I am think a manual one is the best then try to get more advance parts made by either a sponsor or another team.

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If you have a manual milling machine, a rotary table, and digital readouts for all three X, Y, and Z axis', you can pretty much make anything you'd ever need in FRC. You may not get all the fancy lightening pockets that is possible with CNC, but you can still achieve tight tolerances and have fully functional parts.

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And you can still make most of those pockets, it'll just not be automatic.

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Team 116 bought one of the Industrial Hobbies mills last year. We bought the CNC upgrade kit this year, and are currently in the process of installing it. The mill is an absolute beast, and wonderful to work with. It is twice as heavy as the Rong-Fu RF-30 or RF-31 mills (or all the Rong-Fu clones that are out there from Grizzly, Enco, HF and others), and much sturdier. The square column is very stiff, and I could not find any measurable flex under heavy machining loads. The stiffer design helps with better surface finishes than we can typically get on the smaller mill-drill machine we have without a lot of extra work. Unlike the smaller mills (which can use 120-volt single phase), you will need 220-volt, 3-phase service for the I.H. mill. The 30" table travel envelope is larger than any other machines of a comparable size, and that has already proven to be useful. The I.H. mill uses standard R-8 tooling, so if you have already been collecting tooling for any of the typical mill-drill machines, it will transfer right over. Otherwise, you should plan to easily spent as much for tooling as you will for the mill. Having the head tilt option is one thing that we have not yet had the opportunity to take advantage of so far, but I have a few plans...

My only regret is that we waited for as long as we did to get the I.H. mill - I wish we had bitten the bullet and purchased it it at least five years earlier.

-dave

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Or to put it another way, just because it's CNC doesn't mean it is better.

You can make absolutely outstanding parts with a manual mill, and you can turn out scrap with a CNC machine. And scrap is even more likely from a cheap CNC machine.

You can also learn more about machining from a manual mill.

There is no such thing as a cheap milling machine. Either you pay up front for good quality, or you pay after the fact in poor quality, frustrating setup & operation, and wear/damage.

If you have $40k for a nice Haas, go for it, you won't be disappointed. But if that gets cut to $10k (or $4k), go for a nice manual mill, used. There are used tool dealers all over who can help you find what you need and can afford.

Don

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Indeed, another thing people don't always realize is CNCs don't always make perfect parts the first time. Be sure to measure them after to verify all dimensions (especially bearing bores, as cutters can be undersize).

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We did the same thing last year. We used the CNC upgrade kit to retrofit a mill from Industrial Hobbies. Its a great mill and I would recommend it to anyone.

But I would NOT, under any circumstances, ever, recommend that anyone try and upgrade the mill themselves. Both the mechanical and electrical challenges we faced were extremely daunting, and we lost much of the accuracy the tool would have had had we left it in its original condition.

My father and an electrical technician (who mentors our team) spent all summer wiring the speed controllers and getting it running. Along the way we fried many components and broke a lot of stuff - not because we were incompetent, but because there was very little documentation on the process.

Add to that the fact that Industrial Hobbies changed hands and most of the technical assistance was temporarily lost :mad:

If you do chose to buy an Industrial Hobbies machine, buy one that is already built for CNC.

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Wow, thanks for the user feedback on the Industrial Hobbies machines guys! It sounds like the IH mills are a solid and accurate manual machine and are a much better buy for the money than any of the similar Enco, Grizzly, or even Rong-Fu machines. I get the feeling the jury is still out on the CNC retrofit though and wonder if the IH mill isn’t best left as a manual mill and not try to make it something it isn’t.

If you guys had it to do over again would you still go for the CNC retrofit or not? With the CNC retrofit installed is it still possible to use the mill manually or does the CNC retrofit kit pretty much remove all manual functionality?

Also, how was the “fit and finish” of the manual machine out of the crate? A lot of the import machines seem to suffer in this area. Was it pretty much ready to run out of the crate or was a total disassembly and cleaning to remove excess packing grease, etc. required? Were the ways straight and properly adjusted or did it require hours of frustrating adjustments to make the machine smooth and accurate? How about the tram?

Thanks again for the info guys!

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It wasn't that the CNC was bad it was that it was VERY difficult to install, and there was almost no instructions or info on how to do it. We would definitely go with the CNC again - we just wouldn't install it ourselves... (IH gives you the choice to buy it assembled or DIY)

The CNC retrofit replaces the big handles with itty-bitty ones that make manual milling very difficult. I worried that total CNC control would be difficult, but once I got used to it, it was supper easy. There's really no need for manual control with a computer hooked up :)

The IH mills are just cheap Chinese mills. They use ACME screws and are not ultra precision. Retrofitting the mill requires replacing the ACME screws with precision ball-screws, which are super accurate. This process is VERY difficult, but when done right it will transform the tool into a high quality machine.

Out of the box everything was smooth and nice. But of course, we had to take it apart to install the new screws - which required re-adjusting it...

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After hearing about manual mill CNC conversions, I'm curious... has anyone in Chief Delphi community built their own from parts/scratch?

We have a router table (6'x12') at work we built from scratch, but it isn't sturdy enough to handle metal cutting, just plastics and woods.

Hachiban VII: Do you have any pictures/videos of you guys installing the ball screws into that mill? I'm guessing you had to take the ways off of it and all... I guess you used an engine hoist or something? That's a ton of work to get your backlash down... :ahh:

Also, it sounds like some people just want a CNC mill to cut shapes, speedholes, etc. out that go all the way through. This past summer (so, the 2008 season being the first one we've used it in) we got one of the PlasmaCam machines out of the back of a Popular Science. It took us a while to get it all up and running, but now that it is... it makes nice parts REALLY fast (for example, it cut out all the brackets for our shooter in about 2 minutes).

We use a Hypertherm Powermax 1000 8.4kW hand torch with our plasma cutting table. The biggest stuff we've cut with it so far was 1/2" aluminum plate, which it cut at about 30 inches/minute. The only two things you have to worry about are 1) You have to wear a welding shield because of how brilliant the energy beam is 2) You need REALLY good ventilation. For us, we open the garage door and put a big Snap-On squirrel cage fan in the shop.

Pair that with a pipe bender, an all-in-one bench top break/shear/roll, a box of U-bolts, and your usual assortment of hand tools... you woudln't believe how much you can make and how fast you can make it. (The whole top of our robot (everything but the frame) was prototyped using these tools alone) :yikes:

If you want to know anything else just let me know... I could go on and on and on... :rolleyes:

-q

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No pics, but there used to be some on the IH website detailing the process.

As you said, we used an engine hoist to remove the ways. But that wasn't very hard for us. The hardest part was getting all the balls and greese and stuff packed in the bearings. We also had to drill and tap some holes in the mill to bolt stuff on - that's really hard to do with a hand drill :eek:

Come to think of it our team spends more time building tools than making robots :) We also built our own pipe bender from primitive equipment donated to us by a blacksmith.

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You seem to have had a much more difficult time with the CNC upgrade installation on the I.H. mill than we have been having. The manual is certainly not the most complete document that I have ever used. However, if you study it carefully (more on this in a moment), you can figure out most of the installation process. Where there were any questions, the folks at I.H. were very helpful and always seemed happy to talk with us on the phone and walk through any steps that were problematic. We were doing the installation right in the middle of the I.H. transition to new ownership, which I would have normally expected to cause a lot of problems. But they were still very responsive and able to get us all the answers we needed.

In our case, the ball screw installation was an operation that required some attention to detail, but it was nothing outrageous. With a little care and planning, one person was able to assemble each ball screw and install it in about an hour.

To do the CNC installation, you do have to completely disassemble the machine. And I do mean completely disassemble it - everything comes apart. You have to strip it down to the base castings. Most of the individual parts can be handled by one person. But you will definitely want at least two people to drop the Z-axis tower and move the X-Y table. A small hoist would be very helpful here if you have one, and is recommended. But if you don't have one handy, these parts can be persuaded to move where you want them to if you are very careful and don't try to rush the job (we used two "old guys" on the team, who managed to move the parts without spraining anything :) ). One lesson learned - as you disassemble the machine, take pictures of each step and each part you remove. These will be invaluable resources later as you put everything back together and are trying to remember exactly where those little copper shims went...

The only item that was an issue for us was that when you disassemble the I.H. mill for the CNC installation, you need to send the Z-axis carrier plate and clevis back to I.H. for some machining. We didn't read the manual as carefully as we thought the first time through (which was completely our fault) and did not realize this until we were half way through the CNC installation. We had to pause the installation process for several weeks while the parts were sent in and modified by I.H. Had we been paying attention up front, we could have avoided this delay in the installation.

I am not sure that I would volunteer to do it this way again - as noted, you can purchase the CNC upgrade pre-installed by I.H. and that may be the way to go for a lot of people. Our installation did take a while an required a lot of effort that might otherwise have gone into machining parts. But there is one irrefutable benefit that came from doing the installation ourselves - we now know that machine inside and out, and any problems that crop up are much, much easier to diagnose and repair than they would be otherwise.

-dave

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One of our engineers bought a like-new Tormach mill that has been good. He blew a stepper controller almost immediately, but he believes it was just defective. I believe Tormach's are pretty cheap as far as CNC's go, and the quality seems pretty well, but we've only been using it for a year.

They have packages, and I think ours is the "Complete PCNC Package," it cost $15,654.35.

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What did you do about wiring the speed contolers? The mechanical stuff was easy compared to the electrical wiring :rolleyes:

The motor they sent us was also not up to the task of raising the Z-axis (it drew crazy current). We had to buy a different motor on ebay and install it.

I looked at the new IH website. The manual looks a LOT better then the one we used. Perhaps the DIY has gotten easier.

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Anyone with a checkbook can order a ready made tool, or order a kit from the back of a magazine...

But be honest... when you look at your home made tools doing the same job if not better than the ready made... don't it give you a sense of pride knowing in was made by your own hands in the USA :D

Great job team!

-p :cool:

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FORGET HAAS!!!!!

You want a Fanuc Robodrill

You can get the robodrill mate for realy cheap. it dose all the things a regular robodrill dose, it just dosent have options that you don't need!!!!

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The Patriot is a machine we have been considering; price, size and versatility attract us to this machine. http://www.shoptask.com/

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Ok, I like this post, a lot of info. We basically bought a lc series 3024. So we are in the process of setting up. Does the CNC using MasterCam, get drawings from Solidworks and start cutting or am I missing a really important step of how CNC machines work?

Re: CNC Router/Mill
 

Yes, but indirectly. the machine doesn't know how to do anything by itself. Nor does MasterCAM. You have to use MasterCAM or your CAM program of choice to choose how to machine features, with what tools, at what speeds and feeds/depth of cuts/etc, and then MasterCAM translates that into code which the machine understands (G-Code).

You need to have a strong knowledge of your CAM program, and a good knowledge of G-code as well. The CAM output is rarely perfect, and as such, your G-code will need to be hand tweaked accordingly.

It is not a simple process. I would recommend finding a local community college that teaches CNC classes and take some of them. There's a lot to learn, and a lot of ways to ruin your part, your machine, or both.

Re: CNC Router/Mill
 

MasterCAM offers a great educational rate.
We just ordered a couple licenses/keys for our router and mill at much less than the listed price.
I was also told that SolidWorks will also be offering software in the 2009 KOP by a rep. Cant confirm this, just what a rep in California told me last week.

Re: CNC Router/Mill
 

That would be so awesome, solidworks in the kit of parts. First just gets better and better

Re: CNC Router/Mill
 

You are talking cnc and tooling and our school is talking about what they are going to do without the teachers they laid off, its a shame.

Re: CNC Router/Mill
 

Hey question, its not quite CNC related, but I rather not start another thread.

I found a Bridgeport "M head" (round ram) milling machine for cheap. Does anyone know how well this mill will suite a FRC team? What should I look for before I buy it? Does anyone know of a good cheap source for DRO that would fit this mill?

And since its a CNC thread, how much is it to convert a Bridgeport to CNC?

Thanks.

Re: CNC Router/Mill
 

Well, I know that some teams have made key portions of robots on a similar machine. Some questions to ask are:
-What tools come with it? (Tools will be the most important part of the machine. Include collets.)
-Maintenance/cleaning
-Does it work? If not, why not?

If the answers are satisfactory, then go ahead.

Oh, one other thing: What size is it? (table travel, spindle travel)

Re: CNC Router/Mill
 

It has some tooling, collets and such.

Looks pretty clean, I still have to go inspect it myself, thats why I asked what should I look for.

Yes it works, and it has a 1 phase VFD as well.

I believe its a 9x32" (42"?), knee is probably 16", and around 3 1/2" of spindle travel.

Re: CNC Router/Mill
 

The M head is really old. It does not accept R-8 collets, which are standard for almost all manual milling machines. It's maximum collet capacity is 0.5" without ordering special tooling. It also has a very weak motor (only 0.5 hp).

Have you seen the mill personally? It's likely been used very hard, due to it's age.

Some things to look for:

Rust. If there's any kind of heavy rust or pitting on the table or ways, avoid it like the plague.

Inspect the table. Is it in good condition? Have people drilled a million holes into it and cut slots through it? Is it flat? (You can check this with a dial indicator, assuming the head is square to the table)

Inspect the ways. They should look like this . This is clearly a very old machine, so they will likely not look nearly as nice as the machine in the picture. You can still check them to see if they're highly worn/pitted/etc.

Run the table to the limits of it's travel in all directions. It should move smoothly and freely throughout it's travel. If it gets drastically harder to move in certain spots, it has major problems.

Check the backlash. All manual mills will have backlash, but you want as little as possible. Our Bridgeport clone has about 0.005". I'd be afraid of anything with a lot more than that. The backlash should also always be a consistent amount. If it varies from movement to movement, the leadscrew and/or half nut are probably shot, which would be a major pain for you to repair.

If it's under power, turn it on, listen to it run. If it's making funny noises, the spindle bearings and/or motor are probably bad.

Ultimately I think it comes down to you either know what you're looking for and can evaluate a machine for it's worth, or you can't. It's very difficult to tell what condition a machine tool is in just by it's outward appearance. Often times previous owners will slap a coat of fresh paint on to cover rust or make a badly worn machine look new. Or they'll sand down the ways to remove rust, pitting, etc. Other machines will have been well cared for and just look old, but perform much better than the cleaner looking machine.

If the cost is substantial, and you don't really feel confident you can spot a lemon from a gem, I'd see if you could find a machinist to go with you and look at it, or avoid it entirely. If it's really cheap and you have the means to transport it, there's not much risk involved, even if it turns out to be a beater.

-Cory

P.S. I came across these articles awhile ago, and thought they were helpful. One is for mills one is for lathes, but the lathe article is relevant to buying any kind of used machinery lathe mill

[edit] I have read good things about this DRO system on some machining forums. If you're handy with electronics, I've also read good things about this DIY solution

Re: CNC Router/Mill
 

Thank you very much!

That pretty much answered everything, but two questions. Will the .5" taper be a major problem and will the 1/2 hp motor have problems making good cuts through the types of metals we will be cutting?

Its either this, finding another mill, or buying a cheap new china made bench top drill/mill. I am thinking that buying a cheaper new one is way worse then finding an older larger knee mill.

Oh by the way, if it is in good shape how much would you pay for it?

Re: CNC Router/Mill
 

I don't mean to sound like a downer, but I've never heard of a flawless manual-to-CNC conversion of a milling machine. Unless you do CNC-conversions for a living, the vast majority (of even technically inclined people) will struggle and spend thousands and thousands of dollars, struggle for months and months (which might stretch to years...), and often end up with something that often needs a lot of "maintenance" to barely keep running.

Honestly, you'd be much better off buying quality tooling, vise(s), a rotary table, and DROs and leaving it as a manual machine. Quality tooling can be expensive, but don't waste money: don't buy the cheapest tooling and don't buy the most expensive tooling. Somewhere in the middle is generally good. As for vises, a good vise, like Kurt, can run you about $700 (but you can also buy cheaper ones in the $200-$400 range if you don't plan on doing any real heavy duty stuff), and a good rotary table can also be a bit expensive. A dual-axis DRO is generally about $1500-$2000. You don't need three-axis DROs, since the weight of the table often keeps the backlash on the Z-axis to a minimum, and tolerances of +/- 0.005 are easy to keep.

With quality DROs and a good machinist, you can easily machine gearbox plates with tight tolerances on a manual milling machine that work flawlessly on a FRC robot.

Re: CNC Router/Mill
 

Thanks, I sort of expected that. Maybe after we are done with it I can do it for a fun project. :P

Re: CNC Router/Mill
 

As long as the people using it know what they're doing backlash can be easily accounted for. If you have a DRO it becomes a nonfactor-the reader that slides along the linear scale won't register backlash-only actual table movement.

You're likely mostly going to be cutting aluminum so the 1/2 hp motor wouldn't be that big of a deal. You will have to take very light cuts though.

I can't imagine that a M head would sell for more than $500-750 even in nice condition, but I'm no expert. If you search around online you can probably find some information on it's worth. It's a really, really old machine, which there's probably not much demand for. Lots of nice looking 2J and J head mills sell for $1000-1500 on Ebay, and those are much more machine than a M head.

Re: CNC Router/Mill
 

So if I can't find a J head, would it be better to get something like a RongFu-31 clone (say like HF) or go for the less powerful Bridgeport?

Also, is there an easy way to upgrade the motor on an M head to say something like 1 hp right (since the motors are cheap)? My guess is the round ram head would not like the extra power.

Re: CNC Router/Mill
 

Sorry to interrupt into this conversation, but I was wondering if anyone could point me into the right direction as where to buy bits for a CNC and where to get the Table Clamps. (The bits are for 7075 grade aluminum and the clamps are for sheets and tubes of aluminum). Thank you CD in advance.

Re: CNC Router/Mill
 

If you're going to go for an imported machine, I've read very good things about this mill on cnczone.com

We have this Rong Fu benchtop mill in our trailer that serves as a mobile machine shop at many west coast regionals. We had this JET mill in our lab, but gave it away to 968 since we had no room for it, and came into possession of a second Bridgeport clone. I would never ever buy one of those round column mills of any type. The fit and finish is terrible, and it just feels cheap and junky.

I'm a big fan of the Rong Fu I linked, as far as benchtop mills go. I have used it many times, and it's actually not bad at all for it's size. For FRC purposes I'd say it's very adequate, if you're on a tight budget. Definitely orders of magnitude better than the round column mill-drills. The only thing that annoys me is the Z downfeed handle is some random number/revolution. It's like 0.090" or 0.110" per revolution or something.

Re: CNC Router/Mill
 

KBC Tools Enco MSC/J&L and tons of other companies sell everything you're looking for. I'm partial to KBC.

Just get some simple 2 or 3 flute end mills. either uncoated or TiCN coating for Al. If it's general purpose stuff ignore carbide, as HSS will work fine.

Anything from the box at the top of this page would work fine.

Your question about clamps is very vague. What exactly are you trying to do? There are a vast number of workholding devices out there for a vast number of applications.

Re: CNC Router/Mill
 

Cory, we are looking for clamps that secure either aluminum sheets or 2x2 tubing on a bed of a CNC. This is what we have.

Re: CNC Router/Mill
 

Do you have vise(s)? If not you need some. At least 2, so you can hold a long length of tubing (for making robot side rails, etc).

To hold a plate to the table, search for step clamps on any of the sites I listed above. if the plates are short enough you can hold them on the top of your vise by moving the jaw plates to the outside of the jaw body.

Re: CNC Router/Mill
 

Maybe its been posted before (forgive me) or you already know but theres a pretty good and large website devoted to CnC's and machinist .
They at www.cnczone.com there a lot of info on building your own and buying , using. Might be worth signing up to them.

-p :cool:

Re: CNC Router/Mill
 

And I happen to be a member. :]

On tool bits, also be sure to look around your area. You might be surprised to find out who's selling end mills, etc. in your area if you just need one or two, and would take the convenience over a little lower cost.

Clamp wise, you really should check out . They've been around since like the '50s, hence the awesome space-race logo, and they REALLY know their stuff. Their clamps range from economical manual cam-over clamps to hydraulic auto clamps for high production fixturing.

CNC wise, if you're looking for a project and OK with upgrading some of the mechanical components of the mill (i.e. building a retrofit pre-loaded power nut assembly to get rid of your backlash, for both the X and Y axes) and doing a large amount of wiring, setup, etc. then an old mill retrofit is for you. And for those who say you really have to watch it with a 0.5hp mill... not terribly so. The nice thing about the 0.5hp motor is that it'll make it only slightly more difficult to melt tools into the workpiece since you don't have quite as much power to play with.

However, if you use sharp, carbide tooling you might be surprised at how fast you can cut. Carbide provides a very efficient cut in aluminum... you should be able to do about 0.05" passes with a half inch cutter at about 3000RPM, maybe 20ipm without an issue on your spindle motor.

Of course, spindle motors are NOT that expensive to upgrade (1HP $108, 2HP $137, 5HP $216, 300HP $6967 made you look!), but remember to watch how much heating you're putting in the gearbox with added power... I don't think I'd go much over 1HP, maybe 2HP. But, before you go off and buy big motors, please get out your machining slide table (free from TRW carbide, Niagara Tool, others) or machinery's handbook and figure out how much power you actually need to do the cuts you want to do. You might be surprised.

Of course, you could always build a CNC... it's fun and takes for ever but cool when you're done (we have a homebrew 6x10 foot CNC at work)... but that's another story I'll only tell if asked. ;)

-q

Re: CNC Router/Mill
 

Carr Lane is quality stuff, but it's also quite expensive. You can get the same stuff (lower quality of course, but still plenty good for almost all uses) for much cheaper from the industrial supply giants.

Re: CNC Router/Mill
 

Awesomely, we found a Bridgeport J head with DRO and powerfeed for 2k, sound like a good deal?

Re: CNC Router/Mill
 

The Series I with J head is a good mill, provided it meets the above qualifications that were posted earlier in the thread.

Re: CNC Router/Mill
 

Its in ok shape.

The table has a few surface holes and scratches, and the backlash is up there, but the DRO and powerfeed is really the plus to me.

Re: CNC Router/Mill
 

Hey CD,

We needed some help on our CNC Router Table.

1. I downloaded a couple of calculators and it says when you switch from cobalt endmills to carbide the spindle rate goes from 4200 to 18000 rpms, is that what you really cut at. We didn't want to lose any more bits testing.

2.Also our CNC doesn't squirt out coolant and we were wondering what to buy as an add on for it. Kinda like a mister that plugs into a compressor???

3. Also what coolant to buy, cutting aluminum, carbon fiber and plastic at the moment (mcmaster carr would be great)

Thanks in Advance,

http://www.techno-isel.com/CNC_route...C_Tabletop.htm

Re: CNC Router/Mill
 

If the spindle and ways are in good condition, that's probably a fair price based on what I've seen them go for on Ebay.

Re: CNC Router/Mill
 

I forgot to check the spindle, but the ways still have scrap makers left on them (even though its worn more in the middle of the ways there still easy visible).

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1) Carbide is generally run 400% faster than HSS. Note that this applies to spindle speed only.

2) McMaster item 1324K52. Any kind of mister is going to make a mess, and it is VERY bad to breathe in the mist. Be careful if you get one.

3) McMaster item 11365K63 is made by the company that makes the misters, for their own product.

Re: CNC Router/Mill
 

Thanks Cory,

Since Carbide runs 400% faster, what feed and speed rate do you use on aluminum. What is another alternative to a mister.

-RC

Re: CNC Router/Mill
 

our spindle goes to 10,000 rpm. I run it at 10,000 RPM for just about any size end mill in aluminum. Most carbide end mills are recommended to be ran at 1000-2000 SFM which works out to close to 10,000 or more for anything under 1".

Feed rate is entirely dependent on the cutting conditions as well as cutter type. The cutting tool manufacturer should have information for SFM and chipload for all their cutting tools.

The only other alternatives are flood coolant and just a plain air blast. I wouldn't use flood coolant because it'll make a huge mess on an unenclosed machine. An air blast will help clear chips but won't do anything to lubricate the tool. That's not an issue with most materials, but can be for aluminum.

Re: CNC Router/Mill
 

At the shop that I worked at over summer used a flood coolant method and it worked beautifully, but I already tried air blast and with aluminum it just doesn't work. Thanks for the info.

Re: CNC Router/Mill
 

If you're cutting at these speeds in Aluminum, you pretty much need flood cooling... kind of wondering why you need to cut so fast, but, whatever.

My faaaavorite multipurpose flood cooling additive has to be Hocut 795 by a long shot. Looks like milk when mixed properly, minus the bubbles. Very biostable, safe for your hands, works as a tapping fluid as well, good foaming resistance when mixed properly with clean deionized water (pretty cheap at your local Aqua Systems/Culligan store).

Specifically, Hocut 795 -FD, -MPC, or -DC should work for you. You can try other Hocut formulas too, but you can't go wrong with the original. We (Engineering Concepts Unlimited, Inc.) use 795 in our shop.

One final note: Since we switched to Hocut 795, we haven't had to drain and completely swap coolant batches on one of our machines in four years... we've only had to add water and occasionally readjust the coolant mix by adding a additive (only a few ounces are necessary usually... we use a refractometer to check concentration)

-q