When you buy a used vertical machining center, check the spindle, the ways and ballscrews, the control, the tool taper, and the coolant and chip system. The spindle and axes decide whether the machine still holds tolerance. The control and taper decide how easy it is to program, support and tool up. Everything else is easier to fix.
The Spindle
The spindle is one of the most expensive things to repair on a VMC, so start there. If the control tracks spindle hours, write them down. Run it up through the speed range after a warm up and listen for rumble, whine or a change in pitch. Feel the head for heat after a few minutes at speed.
Put a test bar in the taper and indicate it for runout, close to the nose and out at the end. Check that the drawbar pulls a holder in tight and lets it go clean. Look at the taper for fretting, rings or pounding marks from bad tool changes. If the spindle drive has trouble, we have a FANUC spindle amplifier in stock, listed by its exact part number.
Ways, Ballscrews and Geometry
A VMC rides on either box ways or linear guides. Box ways are heavy, damp vibration well and suit hard cuts. Linear guides have less friction and allow faster rapids. Either can be a good machine. What matters is the wear.
- Look for scored or chipped ways, torn wipers and dry surfaces. Make sure the way lube pump is working and the reservoir is not full of sludge.
- Indicate each axis for backlash by moving a small amount, reversing, and watching the dial. Note the numbers for X, Y and Z.
- Check the table for flatness and the T-slots for cracks. A table with deep cuts in it was run by someone in a hurry.
- Pull back the way covers if you can. Chips getting under them wear the ways and the screws.
Axis drive problems can come from the servo motor, the amplifier or the cables. Any replacement has to match the number on your unit, including the suffix, and that is how we list our FANUC servo amplifiers.
The Control
FANUC controls are everywhere in North American shops, which makes programmers, manuals and parts easier to find. The Samsung MCV 50 we have runs a FANUC 0i control. On any control, check for standing alarms and look at the alarm history. Ask whether the parameters have been backed up and when the memory battery was last changed. A dead battery can wipe the parameters.
Write down the options list. Two machines with the same model name can be set up very differently. If you need control hardware, we stock FANUC CNC control and MDI units, including a FANUC 18i, a FANUC Series 160i and an A02B-0236-C205.
Tool Taper and Tooling
Find out what taper the spindle takes before you buy a single holder. CAT 40 is the common taper on small and mid size VMCs. CAT 50 is the bigger, heavier taper on larger machines built for heavy cuts. HSK uses a short hollow taper with face contact and shows up on higher speed spindles. Pull studs are specific to the machine, so match them to the builder's spec.
A machine with no tooling can still be a good buy, but budget for it. Our used tool holders include:
- CAT 40 end mill holders in 1/2 inch, 3/4 inch and 1-1/4 inch sizes
- CAT 50 tool holders from Lyndex and Sandvik, and CAT 50 collet holders from Valenite
- face mill holders from Parlec and Sandvik
- TSD Microbore boring heads
- a tapping head and an HSK 63 holder
Coolant, Chips and Air
Look in the coolant tank. Sludge, tramp oil and a bad smell mean nobody has kept up with it. Run the pump and watch the flow at the nozzles. Check that the chip conveyor or augers turn and that chips are not packed under the table.
If you plan to run through spindle coolant, the spindle has to be set up for it. A high pressure unit like our ChipBlaster high pressure coolant system supplies the pressure. Most VMCs also need clean shop air for the tool changer, so make sure your rotary screw air compressor and refrigerated air dryer can keep up.
Tool Changer and Work Envelope
Cycle the tool changer through every pocket. Watch for hesitation, missed grabs or a carousel that drifts. Then check that your largest part and fixture fit the table and the travels with room to spare. For big parts that need indexing, we also have a Pratt and Whitney 30 inch vertical rotary table.
Vertical Mills and Related Machines in Stock
Inventory turns over. See each page for what is available today.
- Used vertical machining centers: listings include a Samsung MCV 50 with FANUC 0i control, 2010, and a Bridgeport Series 1
- Invema FR40-1500 radial drill
- Used CNC machines: the full list
- Machine shop liquidations: lathes and plant equipment
If you would rather spread out the cost, look at our equipment financing options.
Related Guides
Selling a Machining Center?
We buy used CNC machines, from one mill to a full shop. Start with our sell your CNC machinery page, or ask about a machine appraisal.
All machines ship FOB Imlay City, Michigan, and the buyer arranges freight. Call 586-752-0090, extension 1 for sales, or reach our sales team.