Purchasing CNC VMC things to consider?

[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?