Matz C, Bauer-Brandl A, Rigassi T, Schubert R, Becker D
Universität Freiburg, Pharmazeutische Technologie, Germany.
Drug Dev Ind Pharm. 1999 Feb;25(2):117-30. doi: 10.1081/ddc-100102152.
The Portable Press Analyzer (PPA; Puuman Oy, Finland), a commercially available instrumentation for rotary tablet presses, was tested for accuracy of determination of force and displacement. The calibration of the force transducers (strain gauges) was tested under a static condition. The calibration of the displacement transducers (plastic film potentiometer) was compared for static and dynamic recordings. Force measurement was found precise (deviation < 1.1%) after alterations in the calibration procedure. Displacement measurement was affected by punch tilting and the application of the transducers. If tilting of punches was not considered, the deviation of displacement measurement from the true value (using steel tablets as a reference) was found up to 110 microns. By modifying the original PPA system by supplementing additional displacement transducers in the adjacent turret positions of the punches and adding a custom electronic device (Tilting Compensation Device), the accuracy of distance measurement was improved to 18.1 microns (+/- 3.64). Furthermore, machine and tooling deformation were recorded and found different under static and dynamic conditions. Correction of punch displacement for elastic deformation therefore should preferably be made from dynamic recordings.
便携式压力分析仪（PPA；芬兰Puuman Oy公司）是一种用于旋转式压片机的商用仪器，对其力和位移测定的准确性进行了测试。在静态条件下测试了力传感器（应变片）的校准。比较了位移传感器（塑料薄膜电位器）在静态和动态记录下的校准情况。在校准程序改变后，发现力测量是精确的（偏差<1.1%）。位移测量受冲头倾斜和传感器应用的影响。如果不考虑冲头倾斜，发现位移测量与真实值（以钢片为参考）的偏差高达110微米。通过对原始PPA系统进行改进，在冲头相邻转塔位置补充额外的位移传感器，并添加定制电子设备（倾斜补偿装置），距离测量的精度提高到了18.1微米（±3.64）。此外，记录了机器和模具变形情况，发现在静态和动态条件下有所不同。因此，冲头弹性变形位移的校正最好根据动态记录进行。
