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Control of protective atmospheres during sintering
Conference. proceeaings
Featuring selected abstracts from EURO PM 2000 and the PM2000 World Congress.
originating during mould filling and part solidification and to study sensitivity to mould pressure during solidification.
Factors in the choice of MIM, in preference to other methods, were reviewed with respect to costs and quality.
Sintering in part production by MIM
Rheology and related properties of injection moulding feedstocks
B.Kiebacket al. (Univ. Technology,Dresden,Germany.) Sintering of injection moulded parts was discussed with reference to removal of last traces of binder and densification. Mechanisms in sintering were considered with the role of particle size and arrangement. It was noted that alloy elements influence sintering by, for example, the formation of a liquid phase. Experimental results were presented.
Powder injection moulding symposium Description of debinding of a polyacetyl binder M.B//~nacheret al. (BASFAG, Ludwigshafen,Germany.) Thermal debinding of injection moulded parts with polyacetyl binder was described. Debinding is done at moderate temperature in a protective atmosphere containing a little vaporized acid, which depolymerizes the binder from the surface, and results in complete debinding in short times. A model was constructed based on weight loss measurements.
Injection principles and effects on PIM parts U.Haupt, H. Walcher. (ArburgGmbH, Germany.) Methods for control of the injection process were discussed with respect to actuators and feedback. Hardware, valve-piston and electromechanical systems and software were considered. Various systems were explained. Results concerning reliability and consistency were presented, including part weight and mould cavity pressure, with regard to optimization.
Injection moulding of thick sections J.R.G.Evans. (Queen Mary and Westfield College, London, UK.) The challenges presented in making thick parts by injection moulding, without defects, was discussed. The stages in the process where defects arise may be difficult to identify. The paper gave details of defects occurring at each step and the means of healing them. Design of binders and debinding systems were considered. It was reported that catalytic debinding had allowed sections up to 35 mm thick to be made, to allow identification of defects
44
MPR October 2ool
Control of protective atmospheres during sintering P.Beiss. (Inst. for MaterialsScience, Aachen, Germany.) Atmospheres used in sintering injection moulded materials were discussed, in particular, vacuum, N-H and H based. Difficulties in use of vacuum in respect of alloying were noted. Protective atmospheres were considered to be more suitable, notably for control of surface C content.
High strength injection moulded materials G.Schlieper,J.Mascarenhas. (INETI, Lisbon, Portugal.) It was reported that co-operative researches were in progress to compile databases of properties of injection moulded materials for the benefit of parts designers. Studies of fatigue properties of higher strength materials were reported. The intentions were to demonstrate the potential of the tested alloys and to indicate future lines of research.
Corrosion of injection moulded stainless steel J.Picaut. (CETEHOR, Besancon, Fram:e.) It was reported that some samples of 316L stainless steel showed rust pitting after 24 hours salt spray testing but other samples were unchanged after 600 hours. Compositions of parts and powders, microstructures and localized defects were investigated and related to process conditions. Effects of process parameters were described.
Production of stainless steel watch cases by metal injection moulding M.Sondereggeret al. (ETA SA, Grenchen,Switzerland.) The use of injection moulding to manufacture stainless steel watch cases was reviewed.
L.Nyborg et al. (Chalmers University of Technology, GOteborg, Sweden.) The importance of knowing the characteristics of injection moulding feedstock was emphasized. Tests were reviewed, including melt flow index and capillary rheometry, with respect to parameters affecting properties. Non-Newtonian behaviour was shown to lead to errors. Feedstock homogeneity was considered for its effects.
Batch or continuous debinding and sintering? P.Vervoort, I.Cremer. (Cremer Thermoprozessanlagen GmbH, Duren, Germany.) Development of continuous processing for debinding and sintering of injection moulded parts was reviewed. This was shown to reduce costs and scrap rates and to allow improvements in process control. Batch and continuous processing were compared. Options for automation were presented. Developments for high temperature sintering and integrated rapid cooling were outlined.
Microscale PIM C.Kukla. (Battenfeld Kunstoffmaschinen GmbH, Kottingbrunn, Germany.) The trend for miniaturization and the demand for much smaller injection moulded parts and parts with microstructured areas on them were discussed. Characteristics of micropowder injection moulding were described.
Workshop on soft magnetic materials Soft ferromagnetic powders for AC magnetic applications C. Gelinas. (QuebecMetal PowdersLtd, Tracy, Canada.) It was noted that Fe powders are commonly used for high frequency applications and laminated Fe for low frequencies. It was reported that recent development in water atomized, high purity, highly compressible Fe powders had enabled Fe powders to be used in low frequency AC magnetic applications. Characteristics of these were described in respect of applications includingFe powder-resin composites.
www.metal-powder.net
Featuring selected abstracts from EURO PM 2000 and the PM2000 World Congress.
originating during mould filling and part solidification and to study sensitivity to mould pressure during solidification.
Factors in the choice of MIM, in preference to other methods, were reviewed with respect to costs and quality.
Sintering in part production by MIM
Rheology and related properties of injection moulding feedstocks
B.Kiebacket al. (Univ. Technology,Dresden,Germany.) Sintering of injection moulded parts was discussed with reference to removal of last traces of binder and densification. Mechanisms in sintering were considered with the role of particle size and arrangement. It was noted that alloy elements influence sintering by, for example, the formation of a liquid phase. Experimental results were presented.
Powder injection moulding symposium Description of debinding of a polyacetyl binder M.B//~nacheret al. (BASFAG, Ludwigshafen,Germany.) Thermal debinding of injection moulded parts with polyacetyl binder was described. Debinding is done at moderate temperature in a protective atmosphere containing a little vaporized acid, which depolymerizes the binder from the surface, and results in complete debinding in short times. A model was constructed based on weight loss measurements.
Injection principles and effects on PIM parts U.Haupt, H. Walcher. (ArburgGmbH, Germany.) Methods for control of the injection process were discussed with respect to actuators and feedback. Hardware, valve-piston and electromechanical systems and software were considered. Various systems were explained. Results concerning reliability and consistency were presented, including part weight and mould cavity pressure, with regard to optimization.
Injection moulding of thick sections J.R.G.Evans. (Queen Mary and Westfield College, London, UK.) The challenges presented in making thick parts by injection moulding, without defects, was discussed. The stages in the process where defects arise may be difficult to identify. The paper gave details of defects occurring at each step and the means of healing them. Design of binders and debinding systems were considered. It was reported that catalytic debinding had allowed sections up to 35 mm thick to be made, to allow identification of defects
44
MPR October 2ool
Control of protective atmospheres during sintering P.Beiss. (Inst. for MaterialsScience, Aachen, Germany.) Atmospheres used in sintering injection moulded materials were discussed, in particular, vacuum, N-H and H based. Difficulties in use of vacuum in respect of alloying were noted. Protective atmospheres were considered to be more suitable, notably for control of surface C content.
High strength injection moulded materials G.Schlieper,J.Mascarenhas. (INETI, Lisbon, Portugal.) It was reported that co-operative researches were in progress to compile databases of properties of injection moulded materials for the benefit of parts designers. Studies of fatigue properties of higher strength materials were reported. The intentions were to demonstrate the potential of the tested alloys and to indicate future lines of research.
Corrosion of injection moulded stainless steel J.Picaut. (CETEHOR, Besancon, Fram:e.) It was reported that some samples of 316L stainless steel showed rust pitting after 24 hours salt spray testing but other samples were unchanged after 600 hours. Compositions of parts and powders, microstructures and localized defects were investigated and related to process conditions. Effects of process parameters were described.
Production of stainless steel watch cases by metal injection moulding M.Sondereggeret al. (ETA SA, Grenchen,Switzerland.) The use of injection moulding to manufacture stainless steel watch cases was reviewed.
L.Nyborg et al. (Chalmers University of Technology, GOteborg, Sweden.) The importance of knowing the characteristics of injection moulding feedstock was emphasized. Tests were reviewed, including melt flow index and capillary rheometry, with respect to parameters affecting properties. Non-Newtonian behaviour was shown to lead to errors. Feedstock homogeneity was considered for its effects.
Batch or continuous debinding and sintering? P.Vervoort, I.Cremer. (Cremer Thermoprozessanlagen GmbH, Duren, Germany.) Development of continuous processing for debinding and sintering of injection moulded parts was reviewed. This was shown to reduce costs and scrap rates and to allow improvements in process control. Batch and continuous processing were compared. Options for automation were presented. Developments for high temperature sintering and integrated rapid cooling were outlined.
Microscale PIM C.Kukla. (Battenfeld Kunstoffmaschinen GmbH, Kottingbrunn, Germany.) The trend for miniaturization and the demand for much smaller injection moulded parts and parts with microstructured areas on them were discussed. Characteristics of micropowder injection moulding were described.
Workshop on soft magnetic materials Soft ferromagnetic powders for AC magnetic applications C. Gelinas. (QuebecMetal PowdersLtd, Tracy, Canada.) It was noted that Fe powders are commonly used for high frequency applications and laminated Fe for low frequencies. It was reported that recent development in water atomized, high purity, highly compressible Fe powders had enabled Fe powders to be used in low frequency AC magnetic applications. Characteristics of these were described in respect of applications includingFe powder-resin composites.
www.metal-powder.net