The first part of the paper presents the influence of the processing temperature by injection of HDPE, of PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when other factors that can influence the injection remain unchanged. The second part of the paper presents the influence of subsequent pressure by injection of HDPE, PMMA, and PC+ABS blend on the indentation hardness and on the indentation modulus, when the other factors remain unchanged. The HDPE samples were obtained at the following injection temperatures: 180, 190, 200, 210, and 220�C, and at the following subsequent pressures: 800 bar, 900 bar, 1000 bar, 1100 bar, and 1200 bar. The PMMA samples were obtained at the following injection temperatures: 220, 230, 240, 250, and 260�C, and at the following subsequent pressures: 450, 550, 650 , 750, and 850 bar. The PC+ABS samples were obtained at the following injection temperatures: 230, 240, 250, 260, and 270�C, and at the following subsequent pressures: 500 bar, 600 bar, 700, 800, and 900 bar. The G-Series Basic Hardness Modulus at a Depth method was used to obtain the indentation hardness and the indentation modulus. It was observed that by increasing the processing temperature and subsequent pressure, in the case of HDPE, leads to an increase in indentation hardness and in indentation modulus. It was observed that increasing the processing temperature by injection in the case of PMMA, from 220 to 250�C, leads to a slight increase in indentation hardness and in indentation modulus, whereas increasing the subsequent pressure of PMMA, from 450 bar to 850 bar, leads to a slight decrease in indentation hardness and in the indentation modulus. Increasing the processing temperature by injection in the case of PC+ABS, from 230 to 250�C, leads to a slight increase in indentation hardness and in indentation modulus. By further increasing the processing temperature by injection, from 250 to 270�C, leads to a decrease in indentation hardness and in the indentation modulus. Alternatively, increasing the subsequent pressure from 500 bar to 900 bar leads to not only a decrease in indentation hardness but also to a decrease in the indentation modulus.

This paper analyzes the indentation hardness and the indentation elastic modulus variation depending on the variation of the grind percentage of polymer, when the other factors that can influence the injection molding remain unchanged. The analyzed polymers were: acrylonitrile butadiene styrene ABS MAGNUM 3453, polyamide PA 6.6 TECHNYL AR218V30 Blak and polyoxymethylene POM EUROTAL C9 NAT. The samples that were studied had different compositions in new and grinding material. The G-Series Basic Hardness Modulus at a Depth method was used. The increase of the grind percentage of ABS (from 0 to 100 %) leads to insignificant changes in the indentation hardness, indentation modulus, and maximum force applied to samples of tested material. The maximum hardness (0.137 GPa) of PA 6.6 is recorded in the case of the sample with 80% grind content, and the maximum hardness of POM is recorded as well in the case of the sample with 80% grind content, as being 0.215 GPa. The variation of the grind content in the analyzed samples determines changes in the evaluated parameters, depending on the type of polymer. Combining the new material with grind in proportions experimentally established for each techno polymer leads to changes in their mechanical properties.

This paper presents the influence of the grinding percentage on some electrical properties, when the process of injection is used in the production of technical commodities, made of polyamide 6.6 (PA 6.6), polyoxymethylene (POM) and acrylonitrile butadiene styrene (ABS), for different industries. The specimens produced had the following compositions: new material 100%, new material 80% + grinding 20%, new material 60% + grinding 40%, new material 40% + grinding 60%, new material 20% + grinding 80% and 100% grinding. The measurement of the electrical properties was carried out using the methods for the determination of relative permittivity and of the dielectric dissipation factor, with the method of zero by Schering bridge. It was found that increasing the percentage of grinding in samples, from 0% to 100%, determined a slight increase in the values of relative permittivity at all three polymers tested and the increase of measurement frequencies for acrylonitrile butadiene styrene and polyoxymethylene led to insignificant changes in the values of relative permittivity, while in the case of polyamide, increasing the measurement frequency led to a slight decrease in the values of relative permittivity. It was also found that increasing the proportion of grinding in the specimens, from 0% to 100%, determined a slight increase in the values of the dielectric dissipation factor in the case of polyamide and polyoxymethylene, while in the case of acrylonitrile butadiene styrene increasing the percentage of grinding in the samples resulted in insignificant changes. The increase in the measurement frequencies for the three tested polymers resulted in a decrease in the values of the dielectric dissipation factor.

This paper analyses the influence of processing temperatures of acrylonitrile butadiene styrene (ABS), polyamide 6.6 (PA 6.6) and polyoxymethylene (POM) on some electrical properties when injecting items used in the automotive industry. The ABS specimens were made at the following injection temperatures: 220, 230, 240 and 250�C. The PA 6.6 specimens were made at the following injection temperatures: 280, 290, 300, 310 and 320�C. The POM specimens were made at the following injection temperatures: 180, 190, 200, and 210�C. The determination of electrical properties were carried out using the methods for determining the relative permittivity and the dielectric dissipation factor using zero method with Schering bridge. It was found in the three polymers analysed that the temperature rise processing by injection leads to insignificant changes in relative permittivity (er) and dielectric dissipation factor (tgd).

No abstract