TL;DR
EDM positioning drift causing part dimension errors is usually thermal expansion of the machine casting, encoder scale contamination, or worn drive components. Allow the machine to thermally stabilize before cutting aerospace parts.
What you might see
- part dimensions drifting over a long cut or a full shift
- reference round trip test shows increasing error
- positioning alarm on X or Y axis
- parts at the start and end of a shift measure differently
Likely causes
Thermal expansion of the machine casting during warm-up shifting the axis zero
Linear scale encoder contaminated with dielectric fluid or erosion particles
Ball screw or linear guide lubrication insufficient causing binding and positioning error
Servo drive following error increasing from mechanical wear or drive parameter drift
Required tools
- Lint-free cloths and isopropyl alcohol
- Grease gun with machine-specified grease
- Reference sphere or gauge block for positional check
- LOTO kit
Safety first
- Do not adjust servo drive parameters without OEM guidance. Incorrect gain settings can cause axis runaway.
- Lock out before cleaning encoder scales or lubricating guides to prevent unexpected axis motion.
Procedure
- 1
Run the machine warm-up cycle for at least 20 minutes before cutting precision aerospace parts. Allow the thermal state to stabilize.[1]
- 2
After warm-up, run a positional accuracy check using the machine's self-test feature or by probing a reference sphere. Record the result.[1]
- 3
Lock out the machine and inspect the linear scale encoder strips for dielectric fluid contamination. Clean gently with a lint-free cloth and isopropyl alcohol.
- 4
Lubricate the X and Y axis linear guides and ball screws with the grease type and quantity specified in the Mitsubishi maintenance schedule.
- 5
Check the servo drive following error parameter on the control. Increasing following error indicates mechanical binding or drive tuning drift.
- 6
If positioning error persists after warm-up and lubrication, contact Mitsubishi service for a full axis calibration procedure.
Sources
Mitsubishi Mitsubishi MV2400R / MX600 EDM (Wire / Sinker) general technical documentation, Mitsubishi
Mitsubishi EDM maintenance documentation, axis accuracy, encoder maintenance, and lubrication schedule (general)
More guides for Mitsubishi Mitsubishi MV2400R / MX600
How to manage dielectric fluid contamination on a Mitsubishi MV2400R / MX600 EDM
Contaminated dielectric fluid causes arcing instability, reduced cut speed, and surface quality degradation. Replace or treat the dielectric when conductivity and color fall outside the acceptable range.
How to reduce wire break frequency on a Mitsubishi MV2400R / MX600 wire EDM
Frequent wire breaks are usually caused by incorrect feed rate for the material and thickness, degraded dielectric fluid, or contaminated wire guides. Check flushing pressure and dielectric conductivity first.
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