There are three main technical approaches to measuring the piston diameter:
1. Direct Measurement: Using an outside micrometer (0.01mm accuracy) or a dedicated knife-edge caliper (0.02mm grade), accurately measure the bulge at the widest part of the piston skirt. Pay attention to the measurement technique; for example, when using a micrometer, rotate the caliper until you hear three "clicks" before stopping.
2. Dedicated Equipment Testing: Using a syringe slippage tester or an MST01 medical syringe tester, ensure coaxiality (≤0.01mm) with high-precision clamps, and simultaneously measure the resistance value (0.5-1.2N) and the fitting clearance (0.03mm).
3. Indirect Estimation: First, measure the inner diameter of the syringe barrel (three times each at the top, middle, and bottom sections), then combine this with the dimensions of the piston head and skirt to estimate the fitting clearance. For pistons with complex structures (such as those with sealing rings), a 0.5μm-grade imaging measuring instrument can be used for precise testing.
