【119】Three-coordinate measuring instrument: Competing for 0.001 millimeters

【119】Three-coordinate measuring instrument: Competing for 0.001 millimeters

The new college student, Xiao Liu, burst into tears in front of the three-dimensional measuring instrument. It wasn't because he was feeling aggrieved, but because the detection program he spent three days debugging finally improved the positioning accuracy of that 0.5-millimeter tiny hole from ±0.003 millimeters to ±0.001 millimeters.

Where is this hole? It's at the tip of a kind of neuro-interventional catheter, a component that is even thinner than a needle tip. The requirements of the medical device company are that the center position deviation of the hole must not exceed 0.002 millimeters; otherwise, it will affect the accuracy of the drug liquid spraying. Our current detection method can achieve 0.003 millimeters, which is already above the industry average, but the customer said: "We want to make the best product in the world, so we need the best precision in the world."

When taking on this task, the veteran quality inspector tried to persuade Xiao Liu: "It's almost good enough. 0.003 millimeters is already quite remarkable." But Xiao Liu refused to believe him. He began to study all the functions of the three-coordinate measuring instrument - this million-dollar device, of which we only utilized 30% of its capabilities in daily use. He consulted the German manual, contacted the German engineer of the equipment manufacturer, and even self-studied measurement uncertainty analysis.

The problem lies in the deflection deformation of the probe. To measure a 0.5-millimeter hole, a probe with a diameter of 0.3 millimeters is required. This fine needle will bend by about 0.0005 millimeters when in contact for measurement - this can be ignored for regular measurements, but for the 0.001-millimeter target, this is an insurmountable gap.

Xiao Liu's solution was highly creative: he made five measurements on the same hole, with the probe touching from different directions each time, and then used an algorithm to eliminate the deflection error. This idea required the writing of a complex compensation program, and he stayed up for three consecutive nights. On the third day at dawn, when the repetitive report on the screen showed "0.0008 millimeters", this 25-year-old young man lay on the control console and cried.

Later, the chief engineer of the medical device company came for the inspection and personally conducted twenty measurements. The data was so stable that it was hard to believe. "I worked at a German medical device factory for fifteen years," he said. "This is the most precise micro-hole detection scheme I have ever seen."

This story quickly spread throughout the workshop. Now, every quality inspector is pondering: Is there any room for improvement in my inspection method? The 0.01mm flatness detection that was once deemed "adequate" has been optimized by Old Zhang to 0.005mm; the color difference visual inspection that has been used for many years has been replaced by Xiao Wang using a spectrophotometer, and it has been quantified with ΔE < 0.5.

The most interesting thing is that this "competitive" spirit has spread to the production department. The injection molding technicians began to study ways to reduce the weight fluctuation of the products from ±0.15 grams to ±0.08 grams; the mold workers started to challenge themselves to further improve the processing accuracy of the mold parts by one level.

Last month, we produced a batch of sensor casings for aerospace enterprises. The required coaxiality was 0.005 millimeters. When we delivered the products, the inspection report we attached showed that the actual value reached 0.003 millimeters. The purchasing director of the other party called: "You always exceed our expectations. This makes us very uncomfortable - how should we set the standards next time?"

I replied with a smile, "Then let's set a standard that you think is impossible. Let's give it a try."

In a world of 0.001 millimeters, there is no room for compromise - Golden Eagle Precision Inspection measures every perfect detail for you.