The motor shell is generally made by injection molding,which protects the motor.The Moldflow analysis of the part forming process was carried out by Moldflow software.The response surface model was established with the mold temperature,melt temperature,holding pressure and cooling time as the response variables,and the warpage deformation of the part as the response target.The regression equation and variance analysis were used to optimize the forming process parameters of the part.The results show that when the mold temperature is 70℃,the melt temperature is 220℃,the holding pressure is 120 MPa and the cooling time is 15 s,the minimum warpage deformation of the part is 2.386 0 mm,which is 1.732 3 mm lower than that before optimization.The influence of various factors on the warpage deformation of the parts is as follows:cooling time>holding pressure>melt temperature>mold temperature.The response surface method can effectively reduce the warpage deformation of the part,which provides a reference for the optimization of similar warpage deformation process parameters.
HM4560UA,a special polyethylene material for IBC barrel,was successfully trial-produced in the 300,000 t/a slurry double-loop polyethylene plant of Zhejiang Petrochemical Company.The structure and properties of DMDB4506,TR580M and HM4560UA for IBC barrels were compared and analyzed by high temperature gel permeation chromatography(GPC),capillary rheometer and melt flow rate meter.The results show that HM4560UA(7001G,7001E,7001B)has better environmental stress cracking resistance compared with other two kinds of materials.Weight average molecular weight,melt strength and oxidation induction period are also high,and the difference in mechanical properties is small.Under the same processing conditions,the products have strong environmental durability and antioxidant capacity,which is more suitable for the needs of the application fields of products.However,its melt flow rate is low,and when γ is the same,ηa is high,so its processability is poor.
In order to improve the flame retardancy of polyvinyl chloride(PVC)used for wires and cables,zinc borate(ZB)was added to PVC to prepare PVC composites,and its flame retardancy and mechanical properties were studied.The mechanical properties test showed that with the increase of ZB content,the tensile properties of PVC composites decrease dgradually.However,when the ZB content was less than 6%,the tensile properties of PVC composites decreased slightly,which still met the requirements of relevant standards.The flame retardant test showed that the flame retardant of PVC composites increased with the increase of ZB content.When the content of ZB was 6%,the comprehensive properties of PVC composite(4#)were excellent.Compared with the composite without ZB,the flame retardancy of the 4#sample was significantly improved,the oxygen index reached 40.1%,the vertical combustion grade reached FV-0,the smoke density decreased to 72,the HCl release decreased to 41 mg/g,the peak heat release rate(PHRR)was decrease by 19.9%,the total heat release(THR)was decreased by 36.5%,and the total smoke production(TSP600 s)was decreased by 69.7%.The tensile strength of the composite was decreased by 10.8%,and the elongation at break was decreased by 12.7%.
Aiming at the problem of warpage deformation in injection molding of automobile interior panel,the molding process was analyzed by Moldflow software.The mold temperature,melt temperature,holding pressure and cooling time were taken as process variables,and the response surface model was established with the warpage deformation of the product as the target,and the best combination of molding process parameters was obtained.The results show that when the mold temperature of the part is 56℃,the melt temperature is 250℃,the holding pressure is 120 MPa and the cooling time is 21 s,the maximum warpage deformation of the part is 2.305 mm,which is 1.105 mm lower than that before optimization.The influence of factors is as follows:cooling time>holding pressure>mold temperature>melt temperature.Under the condition of the optimal process parameters,the quality of the parts essentially meets the industrial requirements,and the overall forming quality of the parts is better.
Polyetheretherketone/polytetrafluoroethylene(PEEK/PTFE)composite spline was prepared by injection molding with carbon fiber(CF)as reinforcing phase and nano boron nitride(h-BN)with different contents.Tensile test was carried out by mechanical testing machine,surface friction test was carried out by friction testing machine,wear mark data and three-dimensional morphology were observed by a white light instrument,and wear mark was observed and analyzed by SEM.The results show that with the increase of h-BN content,the maximum spline stress of PEEK/PTFE composites first increases and then decreases;When h-BN content is 3%and 6%,the maximum stress of PEEK/PTFE composite spline is 174 MPa and 165 MPa,respectively.Compared with PEEK/PTFE,the friction coefficient of the sample with CF alone decreased to 0.23.When CF and h-BN are added at the same time,the friction coefficient of composite spline decreases.When the content of h-BN is 3%and 6%,the friction coefficients of composite splines are 0.06 and 0.09,respectively.With the increase of h-BN content,the wear of PEEK/PTFE/CF/h-BN composites first decreased and then increased.When the content of h-BN is 3%,the wear rate of composite spline is the lowest.
