Case Study: In Process Measurement for Precision Turning

Medical devices are constantly getting smaller and tolerances tighter. The use of 5 axis swiss turning machines is a common solution for these challenges. Tolerances are often only a few ten thousands of an inch and maintaining a process capable of continuously meeting these tolerances is key. Thermal changes in the machine and tool wear are ongoing problems that must be constantly monitored and compensated for.

PQI Has worked with multiple medical device manufacturers to design, develop and implement in process measurement systems to accomplish this. Our solution applies a Renishaw MP 250 high accuracy probe system deployed on PQI designed and manufactured probe mounting. The system below is featured on our website at

In Process Measurement for Precision Turning

Our Solution

The Renishaw MP 250 probe system offers .00025 mm or .000010” repeatability and .001 mm or .000040” 3D measurement performance. A PQI Custom software interface enables the user to input inspection frequency for each feature and gather part counts and cycle time along with key part feature measurements.

The collected data is analyzed and charted in real time, looking for out of tolerance conditions and trends in feature dimensions. The first part of every new batch is inspected and the follow up check frequency is begun.

Based on designated trend patterns, tool offsets are updated and the next part produced is inspected to determine if the tool compensation corrected the trend. If a failed part is found, the part is cut off and the next part produced. Consecutive bad parts of a preset number shuts down the process and alarms the operator.

In Process Measurement for Precision Turning

The complete solution enables unattended 24/7 operation with automatic process control, statistical analysis, historical data archiving and email process alerts. This data forms the basis for making predictive decisions on tool life and machine maintenance.

In Process Measurement for Precision Turning

Have you encountered any difficulties with process control for tightly toleranced parts? Could easily understandable data and graphic reporting help improve things? Would you benefit from offline inspection tasks being eliminated or greatly reduced by in process measurement? Please give us a call to discuss how we can build and implement a comprehensive tool management solution unique to your needs.