The shape, size and rate of agglomerates in polypropylene (PP) filled with calcium carbonate (CaCO₃) have been characterized by scanning electron microscopy (SEM), scanning acoustic microscopy and light scattering. Stearic acid was used as a modifier. PP and CaCO₃ were mixed on a two-roll mill and thin films were prepared by compressing the mixed compound in a heated press.
Using SEM images, the size and rate of agglomerates in PP/CaCO₃ compounds were evaluated based on a binarization method. The rate of agglomerates (Diameter of equivalent circle>10μm) gradually decreased with mixing time. The degree of decrease of agglomerates in unmodified system was less than that of stearic acid modified system. Furthermore, the difference in particle size distributions of the agglomerates has been recognized for unmodified and stearic modified systems.
The heterogeneous structure observed by scanning acoustic microscopy drastically decreased with mixing time and by modification of CaCO₃. On the other hand, the radius of gyration from Guinier plot (light scattering) was not dependent on mixing time and modification of CaCO₃.

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This paper describes the detection method of the injection speed and the dynamic characteristic using an encoder for the screw position detection of a screw type injection molding machine. It explains the mechanism of the injection speed detection of the digital methods that those methods are Δt-method which measures the movement distance of a screw and Δx-method which measures the movement time of a screw, comparing with the analogue method using the analogue differential circuit. And, the injection speed of an injection molding machine is measured with the digital injection speed detection equipment which uses the microprocessor. It is found that the main factors of the detection error of the injection speed are dominated by the accuracy of the position detection. Furthermore, we propose a practical system, which makes the error decrease by introducing the averaging detected values. The detection accuracy by averaging a reasonable number of the detected values is calculated.

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The deformation pattern and the thickness distribution of a product in a thermoforming process with blowing, stretching and vacuuming had been obtained by computer simulation and presented in former reports. Through the simulation it had been confirmed that the consideration of the distributed temperature in a specimen sheet and the variation of the temperature in successive stages of the process were most important factors. Only a small difference of the temperature in a specimen sheet influenced to the thickness distribution of the product. Then, to controll the temperature distribution of a specimen sheet was expected to be able to controll the thickness distribution of the product. For the forming of a square box from a rectangular sheet of acrylic-modified PVC, the above expectation was tried for the confirmation by computer simulation with non-linear elastic FEM and it was succeeded to optimize the thickness distribution of the product by the adjustment of the temperature distribution of the specimen sheet. Evaluations of the strengths of the products with some different thickness combinations were also done by linear FEM. The optimization procedure was proposed in this report.

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