[skyline]

Hi newb here, don't quite know if Im posting in the right area but here goes.... anyways I'm looking to purchase a quality used machine in the 10k-15k range and was wondering what are things I need to consider and look for. In terms of what brand, things to look for as far as the condition of the machine, machine capabilities, and such. Just some good general information would be extremely helpful. I'm looking to cut aluminum and some steel.

Thanks

[DareBee]

I think rigid tapping is a very important feature.
For aluminum work you will want a high speed spindle. I only have 10k spindle and wish for 20K.

Just to get the thread started for you ;-)

[skyline]

All the machines that I've looked at that were in my price range were under 10k rev/min. So if I can find anything that gave me more would def. be a bonus. So what brands of used machines should I be looking for? Quality driven hopefully.

[Caprirs]

Number one is to determine how comfortable you are fixing the machine yourself compared to having to call someone else for service. The features and initial price of the machine might be minor when the machine quits and requires a long time to repair. An advantage of brand name machines like Haas and Fadal is parts and service are readily available and will be for some time to come. There are better machines available at better prices but you have to know that the machine will be a good investment over time. Sometimes, shops sell machines because they are having trouble getting support and the down time is too much to bear. Remember that every machine tool builder has a service staff because even the top of the line Makinos and Moris crap out. All machine tools break down eventually and it will always happen at the worst time.

Other features are determined by your applications and needs. Quick tool change is important if you run productions of short cycles but is less important if you do mold work with several hour cycle times. High spindle speed is great in aluminum if you take advantage by running the feeds higher. Box ways are great for rigidity but consume lots more way lube than a linear guide machine and this contaminates the coolant quicker reducing the coolants useful life. I agree with DareBee that rigid tapping shouldn't be an option.

A machine under power is always more attractive than one that "was running fine when disconnected". You can listen to the spindle, observe the tool change, hear the coolant pump, etc.

All the documentation/manuals are helpful if you're not familiar with the control. Some factories charge several hundred dollars for new manuals so that is something to consider when looking at the price.

If you buy through a machine tool dealer, get in writing what sort of warranty he's willing to offer after the machine is on your floor along with installation, shipping, and any on-site training. Be very clear what each party is responsible for and make him earn the commission/mark-up. Verbal agreements are shaky when dealing with this much money.

[skyline]

Thanks Caprirs and DareBee for the advice. I was looking at a Mori Seki MV Jr but am worried about the age of the machine. The ones in my price range are over 2 decades old and I'm not to thrilled in the prospect of having to spend more time and money troubleshooting than actually making chips. Would you guys recommend a machine tool seller in the Southern California Area, that actually services and calibrates there used machine before putting it on the market... if ones do exist.. thanks once again

[skyline]

And I'm really not looking to put these machines into production, just more of a very capable machine for hobby and learning purposes (for now). But one requirement of my is that it must be CAD/CAM capable. Ports and such.

[DareBee]

Not sure what you mean be CAD/CAM capable?
Most 20a old machines are G-code capable and have tape drive input - if you are lucky an RS232 port. Most machines with a tape drive can be converted to RS232.
If you are looking for what I would interpret as CAD/CAM capable you will need a machine with conversational programming. This means you will need to buy a late model machine and you probably won't get a knee mill with an Anilam for your budget price.
If you can up your budget a great choice would be a Prototrak made in the last 5a or so.
Fadal is Ca based, their mini VMC is maybe $40k, they sell remans as well.

[lakeside]

If your look at small mills, one thing to think about is dnc upload time. Prototrak with just the age3 controller is a dog for upload time (if you have a lot of quick moves). They do have an upgrade with E-network card and wil greatly increase upload speed. I have done some very large files with the mx3 cycle time was 12 hours but with upload time is was more like 20 hours total cycle time. MX3 baud rate 4800

[skyline]

What I meant by CAD/CAM capable was the ability to DNC through an RS232 port as I know machines that old would not be capable of supporting ethernet I don't think.. I will do most of my programming with a CAD/CAM program. But I don't think conversational is necessary as you can post out in standard G & M codes. So anything else to look for? Anyone have any experiences with a Kitumura MyCenter 1 machine? I've seen some in my price range...

[ctate2000]

You want to make darn sure not to buy something that has limited parts availability. Anything with Fanuc control would be good to look at. You want to avoid machines from high production facilities. They most likely will be run to death and abuse is rampent with those machines. I know, I work in an automotive plant we run them till they puke and then cobble back together. I would look for linear guides. Linear is less rigid construction but much easier and less expensive to repair. I owned Fadal in another life. They would be my first choice for general machine work. They will perform well using DNC and are very easy to program and set up. Parts are easy to come by and not outrageous in price. Examine all machines carefully for wear and abuse. Holes in the table and broken or missing way covers are firat signs or abuse. Take an indicator to check spindle run out and table slop. Put indicator on spindle taper and turn machine on at very slow RPM and watch for wiggle. No more than .0005. Stop the spindle, push and pull to measure deflection no more than .0005. Same with table you should not be able to deflect the table more than .0005. If it sounds to good to be true it probably is.

[Caprirs]

I bought my two Dynamechtronics CNC VMCs for $25K including vises, tooling, and phase converters. They use Mitsubishi M3 controls with 64K memory and run G/M codes. I can transfer files at 19200 baud which is fast enough for the file sizes I have. And I just use Windows Hyperterminal for all the file transfers. No fancy software and best of all, it's free with Windows! The machines have 10K rpm spindles, 10 tool ATC, flood coolant, rigid tapping and 14" x 10" travels.

If you're not in a hurry, keep shopping until you're comfortable. Kitamuras are good machines but usually have pretty small work envelopes.

[skyline]

Thanks everyone for the advice. I'm really not in a hurry to jump into this as I rather take my time and not rush this sort of commitment, as I've got lots of considerations. I mean there's shipping and freight to deal with, along with rigging, getting a decent 3 phase converter, making sure my foundation in my garage is going to support the immense weight of the machine, along with many other considerations. Not to mention the machine. Do you guys have any recommendations as far as used converters are concerned? Or do you think it would be viable to build one of those rotary phase converters?

Anyone see a used Hass Super Mini for sale? This might be an option. Are they pretty reliable, what's the take on these machines?

[dertsap]

when you see what you like , check everything out and i mean everything , you have to wonder why anyone who is making money would be selling a machine , check the slides, covers , listen to the spindle and all axis for worn bearings , do multiple tool changes are they somewhat smooth , are the coolant pumps working , does the machine leak coolant or oil all over the place , hows the hydrolics etc etc
buying a used cnc is way more risky than buying a used car and far more expensive to have repaired , most companies buy them and get the most out of them ,run em into the ground then sell them just before it is too far gone not to be able to get rid of for a decent price , and at the price of a cnc mill ,i cant say i blame them ,their in the buisiness to make money , as nice as most cnc s are they eventually become an anchor just like everything else does
i know a guy who recently bought a small mitsui seiki worked great when he bought it ,got it all set up , did a tool change , ,dogs were broke ! i forget what he said the parts alone were but it was rediculous ,
but i beleave it was the only real problem he had , could have been worse,
my word of advice is be carefull , don t rush into it ,
hope you have the best of luck in finding exactly what you want and need

stay away from fadal ,terrible for blown spindles

[DareBee]

My uncles Fadal is a 95 mine is a 94, we are both on our second spindle (10k RPM), I feel this is VERY acceptable for life expectancy.
Spindles for Fadal are cheap (reman is $3300).
If you are cutting mostly steel (average max RPM 5000) the spindles will last a VERY long time.
Graphite and aluminum cutting, where running 10k RPM all the time, then life is obviously shortened.
Both his and mine have had a lot of 10k RPM operation.

[dertsap]

no offence to fadal owners , but i new someone would jump on my opinion of the
fadals in myexperience the support HERE was terrible and almost insulting , i remember having the coolant shut down in the middle of a part about a dozen times one morning ,scraped a few parts due to the melt down factor (aluminum) ,so we got in their repair guy , he told me to load a part and run , so 5 minutes pass coolants still on , he says see theres nothing wrong , i say give it time , 10 minutes says the same thing , time passes he says this a number of times and starts joking about it as though to make me feel stupid , i say are you calling me a liar ,so of coarse over the hour he was there no problems so he leaves , he probably wasn t two blocks away, when the coolant shut down again , so i investigated and found the fuse was no good ,he looked at nothing recommended nothing
another time the other machine was dropping tools after a tool change,out of the spindle onto the parts , so my buddy calls support ,they say NO IT WON T DO THAT!
your doing something wrong , the job ran for 2weeks with no problems no changes , try explaining that to the moron, the guy kept telling him no the machine wont drop tools, my my buddy who is quite calm was so angry i had to peel him off the cieling, but the support kept demanding the the machine was fine ,he wouldn t listen to anything, after this there were other issues ,numerous spindles ,and i know of a number of companies with the same spindle problems ,
my experience with fadal has been nothing but bad and even if they were able to claw their way to the top i will still never want anything to do with them or their reps

i know lots of you guys have them and like them and im glad for you but to me they are the Lada of cnc

[skyline]

Well I've been looking to purchase a machine in my area in and around Southern California to keep the cost of freight low. I've seen some machine dealers of used machines in Santa Ana called PM Machines anyone ever dealt with this outfit? I don't think there machines are under power, but will see if they can oblige me by putting it under power so I can run some test as mentioned. To check the slides do I put a dial indicator on the table and translate to check for runout? How do you guys check the accuracy of the positioning, backlash, etc...

[Caprirs]

Backlash in the ballscrew can only be checked under power by putting a good indicator (.0001" resolution or better) in the spindle and measuring against a fixed stop like the side of a vise. It is not always sufficient to use the handwheel to check for backlash as some machines compensate and some do not. I use the following code because the machine only makes one direction reversal:

G1 G91 X.5 F10
G1 X-.5
M0
G1 X-.005
G1 X.005
M0
M99

This will move the indicator .005" into the stop, then back and pause allowing you to zero the indicator. Pressing cycle start will keep the machine moving the same direction as prior to the pause with only one reversal and pause again. This will give a good indication of the backlash. Compare the difference in readings to what is stored in the machine parameters to figure actual backlash in the ballscrew.

Also, as stated earlier, you can push and pull on the table to determine play in the ways. More than .0005" TIR means you'll have trouble making good parts. On a box or dovetail way machine, some gib adjustment can tighten up a sloppy table/saddle. I have no experience with linear guides so I don't know what adjustments are available.

On a VMC, there should be essentially no measureable runout on the spindle.

[husseinte]

I need mastercam post for heidenhin

[Chris64]

I bought a hobby machine just for learning/playing around with too...It sounds like you're looking at better equipment though. I ended up with an early 80's knee CNC with a bandit controller. I upload programs to it through Hyperterminal but I program it all manually (no real 3d). I got it from someone locally and the thing was in great physical shape but hadn't been touched in so long that it needed a major overhaul before I could even begin using it.

As far as backlash goes, check it from the handles if possible. Like it was said earlier, CNC's often compensate for backlash but that won't prevent the table from getting moved around while cutting.

My biggest complaint is that my controller won't support drip feeding. My second complaint is that It doesn't have a tool changer.

Try to get one from someone going out of business (good deal & they're probably not unloading a lemon). If you buy from a business, they'll probably only give you the machine. All the little parts really add up!!! I can't emphasize this enough. Cutters, Tool holders, vises etc.

As far as phase converters go: search for American Rotary...Great pricing (best I found), real quiet and looks nice. Can't say enough good things.

Good luck. I'm having a good time with mine right now but it's still a big learning curve for me.

[nervis1]

I did that, twice. Bought a used Fadal VMC 15 1995 and a Mazak QT-8.

Both were running when shipped but both required a lot of upkeep and repair to get them running like new.

If you buy something inthat price range it's like buying a 500 dollar car. You will be fixing something.

Just about every repair will be between 300-1000 bucks, more if you need a spindle or a few cards.

Make sure you get a brand that is supported in your area. Nothing is worse than not being able to get service. Nothing is more worthless than a non functioning CNC machine. 8000 lb paperweight.

If I was you I'd save the cash, save up and get a new Haas or other lower dollar brand like Sharp etc.

I like Haas because everyone has one, very easy to get support and help. Replacement parts are VERY cheap compared to Mazak!

I'll tell you nothing is more disapointing than flipping the switch on a 15k purchase and getting a blank screen. That hurts bad.

Course you might run into the fabled "used at a local vo-tech school" 200 hrs, pristine, not a scratch, runs like new, cut only cotton balls, never crashed, selling to pay for hip replacement, machine. In that case go for it.