How to Start Up Mori CNC Milling Machine

• 1
  What matters most when you start up Mori CNC milling machine
• 2
  Pre-start checks on a cold Mori machine
• 3
  Why the warm-up window matters for tolerance
• 4
  First-part checks after you start up Mori CNC milling machine
• 5
  Mistakes that turn a startup into a crash
• 6
  Step-by-step power-up and reference return
• 7
  Daily start vs. after a long shutdown

Most startup damage happens before the spindle ever turns. Walk the machine first. Look for a clamp left loose on the table, a tool sitting in the spindle taper, or a chip pile under the way covers that will get dragged into the linear guides. On a Mori Seiki (now DMG MORI) VMC, the table and the ATC arm travel close together, so anything left in the work envelope becomes a crash waiting for the first tool change.

Confirm the plant air supply is connected and dry. Mori tool changers and spindle brakes typically expect 0.5–0.7 MPa. If the regulator sits below 0.5 MPa, the tool changer can drop a tool mid-cycle or stall between pots. Drain the filter bowl and check the desiccant if the shop runs humid. Wet air also ruins the air-blast used to clean the taper.

Check the automatic lubrication unit. The way-lube reservoir should be between the low and high marks, and the pump should show pressure within a few minutes of power-on. A dry guideway on a machine that rapids at 30 m/min will score the rail before you hear anything. Also verify the coolant level and concentration, and confirm the chip conveyor and any mist collector are clear.

• 1
  Safety gearSafety glasses, steel-toe shoes, no loose sleeves or jewelry near the spindle.
• 2
  WorkholdingVise or fixture bolted and torqued; no loose parallels or shims on the table.
• 3
  Air line0.5–0.7 MPa, filter drained, no water in the bowl.
• 4
  Lube and coolantWay-lube between marks; coolant at the specified concentration and level.

A machine that has been off overnight is not the same machine it was at 4 p.m. yesterday. The spindle grows as it heats, the ballscrews expand, and the column and bed follow. On a machine held to ±0.005 mm, a few microns of thermal drift is the difference between a part that passes and one that does not. That is why the warm-up is a process step, not a courtesy.

A practical warm-up does two things. It brings the spindle and structure to a stable temperature, and it distributes oil across the guideways and ballscrews before they see load. If you skip straight to a tight-tolerance cut, the first few parts will drift and the operator will chase the offset instead of the process.

How long is enough depends on the machine and the shop. A small VMC in a temperature-controlled room may stabilize in 10 minutes. A large machine, or one in a shop that swings 8 °C between night and day, may need 20 minutes or more. The test is simple: cut a test part, measure it, and cut a second one 30 minutes later. If the two do not match, the machine is still moving.

For work held tighter than ±0.01 mm, run the warm-up on the spindle speeds you will actually use. A warm-up at 1,000 rpm does not prepare a spindle for a 12,000 rpm finishing pass. On a Mori with a high-speed spindle, step up through the speed range so the bearings see the same thermal load as production.

• 1
  Step the speed500, 1,500, 3,000, 6,000 rpm, 3–5 minutes each, then the production speed.
• 2
  Move the axesExercise X, Y, Z and any rotary axis through their normal travel, not just a few millimeters.
• 3
  Check the roomLog shop temperature at startup. A drift over the shift explains drift in the part.

The first part off a cold machine is a process check, not a production part. Measure it fully: critical dimensions, datums, and any feature that depends on tool length or work offset. If the part is out but consistently out, adjust the offset once. If it is out and inconsistent, stop and find the cause before running the second part.

Watch the spindle load and the sound of the cut on that first part. A load that climbs steadily through a pocket usually means chip evacuation is failing, not that the tool is dull. A chatter that appears only at one corner of the travel can point to a loose clamp or a fixture that is not seated.

Record what you changed. Offset corrections, tool length edits, and warm-up time are the data that make tomorrow's startup faster. A shop that keeps a startup log finds drift patterns that a single operator never sees.

If the machine sat idle for more than a week, treat the startup as a return-to-service, not a daily start. Check the lube system for a full cycle, confirm the spindle taper is clean and dry, and run a longer warm-up before any production cut.

• 1
  Measure the first partCheck critical dimensions against the drawing before releasing the run.
• 2
  Listen and watch loadRising load or new chatter points to chips, clamping, or tool wear.
• 3
  Log the correctionsNote offsets and warm-up time so the next startup starts from data, not memory.

The most expensive startup mistake is a wrong tool length offset. It happens when a tool is changed and the length is not re-measured, or when the offset is loaded from the wrong tool number. The dry run with override at 25% and single block on is what catches it. Skipping the dry run to save five minutes can cost a spindle and a fixture.

The second most common error is zero-returning an axis into an obstruction. If a fixture or a rotary table is sitting in the travel path, the machine will find the hard stop instead of the reference. Jog clear first, then zero-return. On a machine with a rotary table, confirm the table is at its safe index before you move X or Y.

A third error is ignoring the air supply until the tool changer alarms. A pressure drop at the wrong moment drops a tool onto the table. Check the regulator at startup, and if the shop shares air with other equipment, check it again after the first tool change.

Finally, do not clear an alarm and keep running without reading it. Mori controls log alarms with a timestamp. A drive overload at startup, a lube pressure fault, or an over-travel alarm each point to a different cause. Reading the code takes ten seconds; guessing takes an hour.

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  Wrong tool lengthRe-measure changed tools; dry run with 25% override and single block.
• 2
  Axis into obstructionJog clear before zero return; check rotary index position.
• 3
  Air pressure dropVerify 0.5–0.7 MPa at startup and after the first tool change.
• 4
  Unread alarmRead the code and timestamp before resetting and restarting.