In the process of product testing, when test the same program or the same parts for many times, it is found that testing data differences is large, the output is not consistent, or different from actual assembly condition, it needs to check and analysis from several aspects. Following are points.
When most users measuring parts, they think that the self-weight of the work-piece can make it no position shift when measuring. Actually the granite table is very smooth, if put the work-piece directly on the table, there will be position shifting because of machine center of gravity moving or vibration, which will cause the change of measured results. Especially when the work-piece is small or light.
For batch testing, must adopt scientific way to fix, that is 3 points support localization, and must have a reliable and convenient locating datum to ensure the accuracy of the clamping repetition.
B. Choose the right stylus
1. The right diameter of the stylus ball
Some "blank piece" is without grinding processing or burr processing. Because self-error is large, it can also cause large repeatability. In this case, it is suggested to choose the large diameter of the stylus, and collect more points on the characteristics to get the relatively average effect and get good repeatability.
2. The reasonable length of stylus
The length and weight of the stylus and extension have a great influence on the measurement accuracy and repeatability. Probe load capacity and probe sensitivity (also is the precision of measuring probe) is often a pair of contradictory value. The stylus and extension which beyond the probe load can make produce interference error and shorten the service life of the probe. So, when using the longer stylus, choose corresponding larger load of suction cups or measuring probe.
3. Probe calibration
The correctness of the probe calibration is the assurance of measurement accuracy, especially probe position and star probe calibration, must be checked to ensure the accuracy of the measurement.
When using sphere and in the case of higher measuring accuracy, we need to increase calibration points in each layer; In the case of complex surface and curve characteristics, we need to appropriately increase number of check layers.
Please inform us if any questions or advice