[PCS74]

Hello,

I have been a regular reader here for the last couple of months. This is my first post and I need you guys to point me in the right direction. I am looking to purchase a used 3-axis CNC vertical mill and need some recommendations on good machines to look into. I have up to $10k to spend now but would like to spend no more that $8500. I could go a few thousand over 10 (If I put off the purchase for a while) to get the quality of machine I am looking for.

My Info:

1. Uses: Primarily aluminum/steel/stainless steel milling, high accuracy and presision paramount, large amounts of material removal per part but MRR does not need to be stratospheric, low production levels.

2. I want a machine that will last me a lifetime with proper care and maintainance, literally. Machine must be built right and have a reputation for quality parts and workmanship, excellent reliability and high precision. Must be servicable.

3. I would really prefer a VMC or bed mill( for the additional z travel), but a big solid knee mill would probably work equally well.

4. I would really prefer a high torque 4 to 7.5hp machine. I would consider a 3hp machine but I am not sure it would work for me so I am open to suggestions here. To me more power is always better.

5. NMTB 40 or 50

6. I would really prefer a 6k rpm machine. I would consider a 4k rpm machine, but I am not sure it would work for me. Again, I am open to suggestions.

7. Belt driven

8. X travel ~30in

9. Y travel ~15in

10. Z travel I would like to be able to fit a 4th axis at a later time so I need suggestions here

11. Controller: open to suggestions. My part files are primarily solidworks, and autocad, and I have access to mastercam and delcam powermill for toolpaths.

Currently I have been looking at Tree's, Hurco's, Milltronics' and Bridgeport's. I don't have any idea how these manufacturers stack up in term of quality, reliability or precision. I have also seen Supermax, Dan Lih, Leadwell etc, but again I have no idea if they are high quality machines or throwaways.

I would like recommendations on the manufacturers and/or model numbers of machines that may fit my requirements. Also, my requirements are not set in stone, if you have other recommendations or think something sounds odd with mine please discuss. I have alot to learn so please any suggestions, critiques, concerns or insight is greatly appreciated.

Thank you very much,

Chris Skarzenski

[nervis1]

With all due respect.

What you want does not exist.

You need to open the wallet a little wider if you want to cut stainless, x-30 Y15, great precision, and "last a lifetime". Anything with 30 X 15 or bigger will have a 10-15 HP motor (or more) on it if it's a VMC.

NMTB 40 or 50...why? go CT40, lot's more options there as far as tooling and cheaper probably too. I have never seen a VMC with NMTB taper, maybe they are out there but certainly not common.


You need to look for a very good condition (but old) Mori, Okuma, Mazak (insert Japanese name here). Beware some controls are quirky (like my Mazak lathe I'm still getting used to that), stick to Fanuc is my advice, everyone seems to know it and support and parts are easy to find.

Hell even a beat up Fadal from 1988 will be 10k and that won't do what you are looking for.

Don't even bother looking at knee mills.

Remember anything you get will break. Better to have something that is still supported not some obsolete boat anchor. Stick to big brand names if you are looking for a keeper.


Think 20k- 30k would be better. If you get a 20k machine just plan on putting in 3-5k in the first year to fix whatever needs fixing (remember they are selling it for a reason), tooling, fluids, etc etc.

Pray you don't get a dog....go look at the machine under power and watch it cut parts before you pay.

Get ALL of the documentation and manuals.

Let us know how it goes.

Dave

Dave

[PCS74]

Dave,

Thanks for the info.

First, I thought nmtb40 = ct40 = 40taper = #40. I have heard and read the taper is the same, I guess somewhere along the line I equated them.

Next, where I work we have a Leadwell kmc-5p(5hp), and mvc-1000p(15hp), Gorton 2-30(5hp) and a few others. Any of these machines would remove material fast enough for what I need to do and I have cut steel/aluminum/stainless on them without issue. With the right endmills they could remove material alot faster than I have ever needed them to. I have no problem with more than 7.5hp and would love a 15hp machine, but most I see run around 10 and most of the knee mills run around 5 so I just ballparked 4 to 7.5 for what I feel I would actually need.

30x 15y is the approximate work envelope I would like, not the part size I need to machine. Most knee mills I look at have comparable travel to this and the VMC's tend to have a more square envelope which is fine. I can trade a little here and there. To be honest, I have never had a part I needed to machine that I could not do on the Gorton and have plenty of travel left, but if I am going to spend money on a machine I want some extra "just in case".

Still looking for more input

Thanks,

Chris S

[nervis1]

naw, nmtb is found mostly on knee mills, not made for auto tool changers. CT40 gets rid of the nub on top but has the same taper angle, different flange I think as is BT.

Again look at older Japanese machines, they are built to last, almost all are still supported, have fanuc controls. Get a tool changer with at least 20 tools, and an enclosure. If you are going to buy once and keep it forever do it right the first time.

Let me give you a link or two for an idea

[nervis1]

http://www.kdcapital.com/itemphotos.cfm?Item=2775

16k....and it's still making parts!


http://www.kdcapital.com/itemphotos.cfm?Item=2915

This one looks like a cream puff.

Lots more at KD (no connection besides being a customer)

Lots more all over the web.


http://www.kdcapital.com/itemphotos.cfm?Item=3127

Check out this tank. Toyoda makes a sturdy machine I hear.

[dpuch]

Be patient and check with dealers of used machinery, as well as check for auctions. Do not forget to check on the cost of moving and installing the machine as well. Your probably talking about a mid to late 80's machine for that price.
Heh even E-bay has some.

Your best bet is if you can get one directly from someone selling it rather than thru a dealer. The price will probably be 3/4 to 1/2 as much.

Dale

[Caprirs]

Nervis hit the best points.

Skip the Bridgeport and Milltronics. They are lightweights and you won't be happy with them. From your description, it sounds like Haas and Fadal are out also. In fact, most anything with tiny linear guide ways will be too flimsy for high accuracy pushing against stainless.

Really research the service aspect as a some builders no longer support certain older models. Contact the builder directly and ask. Don't take the seller's word for it.

Whenever possible, see the machine under power. Hearing the spindle bearings, coolant pump, and ballscrews is worth a lot over a mystery machine that was "running great" when unplugged. And typically, the last guy who ran it "doesn't work here anymore" so you can't get answers to your questions.

If you're working with a dealer, ask around about their reputation for after-the-sale support. Make them earn that commision and make sure they protect and support you.

I also agree that your price range and features are going to make finding something challenging. But I think it can be done if you have time and patience. Where are you located? Different parts of the country have a better market than others.

[PCS74]

Dave, Dale and Caprirs,

Thanks for the help. I looked at a bunch of machines today. Mostly Leadwells, but a few Kitamura, Hardinge and several offbrands.

There was a newer Leadwell that was stripped down to the frame. The castings looked much more massive than I expected and the build quality seemed good. It did have linear guide ways. I didn't have alot of time to look it over, but I am going back next week to poke around and ask alot of questions. I still have alot of learning to do and the tech's there were very informative and upfront.

Since I don't plan on doing any real heavy cuts with this machine, but I will be removing alot of material should I still stay away from linear guides? I won't be doing any high volume production and lead times will not be such that I need ultra quick turnaround. I need high accuracy and precision and I understood linear guide ways to be very beneficial here. Please educate me.

Thanks again for you time and input,

Chris S

[dpuch]

Another specific model that would probably work for you is an Excel-810. This is an older used machine, so depends on the condition of it.

Linear guides are ok for light to medium steel work, but box ways will do a lot better the heavier a cut you take. It is a judgment call, but it sounds like you could use a linear guide machine.

Dale

[Caprirs]

Some builders do linear guide ways right and some don't. Bridgeport and Haas are examples of flimsy ways. On the other hand, Makino uses linear guides on some of their very impressive HMCs. Linear guide ways doesn't necessarily mean not rigid. Normally, a quick look at the "trucks" and rails will reveal how stout they are.

There are two reasons why some folks don't like box ways. The first is way lube consumption is much higher compared to linear guide machines which results in more tramp oil in the coolant sump. The second reason is what's sometimes referred to as "stick-tion". It is more obvious when using the handwheel and a very good indicator. Small moves are commanded in .0001" increments but the table doesn't move then suddenly jumps .0005". It can make setups annoying but has no effect on machining accuracy.

You keep repeating that precision and accuracy are important. Can you define more explicitly what you're aiming for? Most builders will quote positioning capabilities of +/- .0002" and repeatability of about half that. However, those numbers are only achieved with a properly installed machine. By comparision, the best knee mill would be rated at +/- .0005". Do you need roundness when interpolating a circle? Positioning for drilling?