Using a special coated sand as the material of the selected laser sintering (SLS), the authors test and investigate the strength change of the test samples in terms of different sintering parameters (scanning speed, l...Using a special coated sand as the material of the selected laser sintering (SLS), the authors test and investigate the strength change of the test samples in terms of different sintering parameters (scanning speed, laser power, sintering thickness, and so on). The characteristics of coated sand hardening by laser beam are analyzed. The sintered mold (or core) for given casting is poured with molten metal.展开更多
Selective laser sintering(SLS),as a kind of additive manufacturing technology,which uses a laser beam to scan and heat powder material layer by layer to form parts(models),is widely used in the field of casting,mainly...Selective laser sintering(SLS),as a kind of additive manufacturing technology,which uses a laser beam to scan and heat powder material layer by layer to form parts(models),is widely used in the field of casting,mainly for preparing casting coated sand cores,investment casting patterns,etc.The SLS technique facilitates rapid casting and shortens the casting production periods by eliminating mold preparation.In this study,we reached conclusions for the basic principles and characteristics of SLS methods,and focused on the research status,key technology and development trend of SLS in the fields of forming coated sand-casting molds and investment casting patterns.展开更多
This paper presents initial development of polymer application. PNC materials containing a polyamide （PA） and nano to improve the mechanical properties. Commercial polyamide 6 nanocomposites （PNC） material for rap...This paper presents initial development of polymer application. PNC materials containing a polyamide （PA） and nano to improve the mechanical properties. Commercial polyamide 6 nanocomposites （PNC） material for rapid manufacturing （RM） particles （5 wt%） were produced by solution blending with the aim （PA6） was dissolved in formic acid （HCO2H） together with two different types of nano particle materials： yttrium stabilised zirconia （YSZ） and Hectorite clay （Benton 166） and spray-dried to create powder, creating powder with particle sizes in the range of 10-40 μm. The materials were processed on a CO2 selective laser sintering （SLS） experimental machine. Mechanical properties of the PNCs were evaluated and the results were compared with the unfilled base polymer. Good dispersion of additives was achieved by solution blending, however the PA6 was degraded during the material preparation and spray drying process which resulted in the formation of porous structure and low strength. However the addition of 5 （wt%） nano particles in the PA6 has shown to increase strength by an average of 50-60%. Further work on powder preparation is required in order to fully realize these performance benefits.展开更多
One of the most important issues to resolve in parts manufactured from rapid manufacturing (RM) technologies is to know their behavior working under real conditions. Total quality manufacturing (TQM) is only possible ...One of the most important issues to resolve in parts manufactured from rapid manufacturing (RM) technologies is to know their behavior working under real conditions. Total quality manufacturing (TQM) is only possible if mechanical properties are well known in the design stage depending on the processing parameters. This work is mainly focused on testing of several samples made with different selective laser sintering (SLS) parameters and technologies. This procedure is the starting point to establish a basis for designing for RM and the standardization of RM testing. The experiments and the analysis of variance (ANOVA) analyzed the effects of several factors on mechanical properties. The SLS technologies were 3DSystem and EOS. The results show which factor has a large effect on the variables and the interaction between them. The conclusions are very useful for developing rules for designing (designing for RM) and creating new standard rules (ISO, AISI, and DIN) for RM materials and parts testing. The ANOVA gives a better knowledge of the effects of these factors and eliminates unimportant parameters.展开更多
文摘Using a special coated sand as the material of the selected laser sintering (SLS), the authors test and investigate the strength change of the test samples in terms of different sintering parameters (scanning speed, laser power, sintering thickness, and so on). The characteristics of coated sand hardening by laser beam are analyzed. The sintered mold (or core) for given casting is poured with molten metal.
基金supported by the National Key R&D Program of China(2020YFB2008300,2020YFB2008304)the National Natural Science Foundation of China(51775204,51375190,59635040)。
文摘Selective laser sintering(SLS),as a kind of additive manufacturing technology,which uses a laser beam to scan and heat powder material layer by layer to form parts(models),is widely used in the field of casting,mainly for preparing casting coated sand cores,investment casting patterns,etc.The SLS technique facilitates rapid casting and shortens the casting production periods by eliminating mold preparation.In this study,we reached conclusions for the basic principles and characteristics of SLS methods,and focused on the research status,key technology and development trend of SLS in the fields of forming coated sand-casting molds and investment casting patterns.
文摘This paper presents initial development of polymer application. PNC materials containing a polyamide （PA） and nano to improve the mechanical properties. Commercial polyamide 6 nanocomposites （PNC） material for rapid manufacturing （RM） particles （5 wt%） were produced by solution blending with the aim （PA6） was dissolved in formic acid （HCO2H） together with two different types of nano particle materials： yttrium stabilised zirconia （YSZ） and Hectorite clay （Benton 166） and spray-dried to create powder, creating powder with particle sizes in the range of 10-40 μm. The materials were processed on a CO2 selective laser sintering （SLS） experimental machine. Mechanical properties of the PNCs were evaluated and the results were compared with the unfilled base polymer. Good dispersion of additives was achieved by solution blending, however the PA6 was degraded during the material preparation and spray drying process which resulted in the formation of porous structure and low strength. However the addition of 5 （wt%） nano particles in the PA6 has shown to increase strength by an average of 50-60%. Further work on powder preparation is required in order to fully realize these performance benefits.
基金the participant members of ASERM (Spanish Association of Rapid Manufacturing) in this project, particularly the following technological centers: AIJU (Toy Institute Research Association), CTAG(Automotive technological centre of Galicia) and AITIIP Foundation (Plastic Injection Research Association), and the Spanish government (Industry Minister) for supplying some funding to this research project
文摘One of the most important issues to resolve in parts manufactured from rapid manufacturing (RM) technologies is to know their behavior working under real conditions. Total quality manufacturing (TQM) is only possible if mechanical properties are well known in the design stage depending on the processing parameters. This work is mainly focused on testing of several samples made with different selective laser sintering (SLS) parameters and technologies. This procedure is the starting point to establish a basis for designing for RM and the standardization of RM testing. The experiments and the analysis of variance (ANOVA) analyzed the effects of several factors on mechanical properties. The SLS technologies were 3DSystem and EOS. The results show which factor has a large effect on the variables and the interaction between them. The conclusions are very useful for developing rules for designing (designing for RM) and creating new standard rules (ISO, AISI, and DIN) for RM materials and parts testing. The ANOVA gives a better knowledge of the effects of these factors and eliminates unimportant parameters.
