Three-coordinate maintenance

Three-coordinate maintenanceWithin Zhejiang Province, on-site maintenance can be arranged on the same day for the three coordinate system. Introduction:

As a precision measuring device, the malfunction of a coordinate measuring machine (CMM) is often closely related to environmental factors, mechanical wear, pneumatic systems, and software operation.

According to the information I have compiled, the most common faults of CMM are mainly concentrated in the areas of decreased accuracy, abnormal motion (abnormal noise/lagging), probe alarms, and software communication failures.

To help you quickly locate the problem, I have classified common faults into the following four categories:

📏 1、 Abnormal measurement accuracy (core issue)

This is the most fatal fault of CMM, usually manifested as unstable measurement data, poor repeatability, or large deviation from standard parts.

1. Large deviation in measurement results

*Temperature effect: This is the most common reason. The ambient temperature exceeds the range of 20 ± 2 ℃, or the temperature difference between the workpiece and the machine is large, resulting in thermal expansion and contraction.

*Probe contamination: The probe ball head (ruby) has absorbed oil and dust, resulting in a larger measurement diameter.

*Calibration failure: The calibration (verification) operation of the measuring head is not standardized, or the surface of the standard ball (reference ball) is dirty and worn.

*Mechanical loosening: Loose anchor bolts, uneven belt tension, or increased screw clearance.

2. Poor repeatability accuracy

*Air bearing problem: Unstable air pressure or small scratches on the air bearing block, causing the motion trajectory to drift.

*Grating ruler contamination: The surface of the reading head or grating ruler is contaminated with oil and dust, causing coordinate readings to jump.

🏃 2、 Mechanical motion and pneumatic faults

CMM relies on air bearing suspension motion, and any abnormalities in the air path and mechanical structure will be directly reflected in the operating state.

1. Abnormal noise or stuttering during exercise

*Guide rail dirt: There is dust, cutting fluid, or dry oil stains on the marble guide rail, which causes the air floating block to rub against the guide rail (this is a precursor to serious failure).

*Belt/bearing wear: Loose or aged transmission belt, or bearing oil shortage/damage.

*Unclean air source: Compressed air contains water or oil, causing blockage or rusting of air bearing, resulting in "squeaking" sound or vibration.

2. Air pressure alarm/unable to start

*Insufficient air pressure: If the gas supply pressure is lower than 0.4MPa (different models require different requirements), the machine will automatically lock for protection.

*Emergency stop pressed: The emergency stop button on the control panel has not been reset.

*Filter blockage: The oil-water separator or air filter is clogged, causing poor airflow.

🖥️ 3、 Software and electrical faults

1. Probe collision alarm

*Program path error: During automatic program execution, the safety plane was set too low, causing the probe to collide with the workpiece during movement.

*Workpiece clamping offset: The actual position of the workpiece does not match the programmed position, resulting in collision when the measuring head "walks blindly".

2. Software error/crash

*Communication interruption: Loose data cables or oxidized interfaces result in the computer being unable to control machine movement.

*System compatibility: Automatic updates on the Windows system can cause measurement software to be incompatible or crash.

*Driver loss: The control card driver program is damaged, causing the machine to be unable to return to zero or the axis to malfunction.

🔧Three-coordinate maintenanceFault Quick Check Table

Common causes of malfunction and recommended solutions

Decreased accuracy/inaccurate data, temperature exceeding the standard, dirty measuring needle, wear of standard ball, constant temperature control. Clean the measuring needle/standard ball with anhydrous ethanol and recalibrate

There is abnormal noise/shaking during operation. The guide rail is dirty, the air source contains water, and the belt is loose. Clean the guide rail (refueling is strictly prohibited), check the air source filter, and adjust the belt

Probe collision alarm, insufficient safety height, program path error, modify program safety plane, check whether the workpiece clamping is firm

The machine cannot start due to insufficient air pressure, the emergency stop has not been reset, and the power supply has not been turned on. Check the air pressure (>0.4MPa is required), unscrew the emergency stop button, and check the power supply

The grating alarm grating ruler is dirty and the reading head is loose. Use cotton cloth dipped in anhydrous ethanol to gently wipe the grating ruler and tighten the reading head

💡 Expert maintenance suggestions

1. It is strictly prohibited to add oil to the guide rail: this is very important! The vast majority of CMM uses air bearing, and the guide rail must be kept dry and clean. Adding oil to the guide rail will attract dust, which can lead to a decrease in accuracy and even scratch the guide rail.

2. Daily "draining": Before starting up each day, be sure to check the oil-water separator of the air compressor and filter to drain any accumulated water. Water is the number one killer of CMM pneumatic systems.

3. Cleaning tools: When cleaning the guide rail and measuring head, please use anhydrous ethanol and cotton cloth (or special dust-free cloth). It is strictly prohibited to use cotton yarn or ordinary paper towels to avoid fiber residue.

4. Constant temperature is key: ensuring that the temperature in the measurement room is stable at around 20 ℃ and avoiding direct air conditioning blowing on the machine can solve 80% of "unknown cause" accuracy deviations.