Shanghai Daoqin Plastics Co., Ltd.

        选区激 light technology (SLS) is types application increase manufacturing technology, using/adopting type dispersion /材 material principle, according to processing type has 效截面信息, 由计算 machine 操纵激 light according to 特定 扫描路径, 烧结扫描区域 inner powder 末, more powder can molding [1]. in SLS molding process in, powder hot adhesion, temperature degree decline, material shrinkage solid 化, parts degree difficult ensure, therefore control molding parts shrinkage rate separation important. in parts molding process in, combined process parameters for decrease small molding parts shrinkage rate, improve/increase degree 起 至关 important function.

         currently, 陶瓷, 木塑, polycarbonate (PC) (PC), wax and metal and other can used for SLS technology in. polystyrene (PS) (PS) powder tool has wet rate small, powder flow property good and other excellent property can, therefore PS powder already by widely used in SLS technology in, 但PS molding parts rate high, shrinkage rate large, degree 差. polymethyl methacrylate (PMMA) (PMMA) tool has degree high, price low, tough property strong/high, resistant tensile and other advantages, 且PMMA separation 子支链 is short 链, more good filling PS 空隙, decrease small molding parts rate.

        西安科技 large 学以PS/PMMA composite/compounding powder is raw materials, through a large amount of 烧结实验, research effect/influence parts shrinkage rate factors, for 结果进行 drop 噪处理 and analysis, obtain most excellent process parameters combined, in most excellent combined lower 进行烧结实验, through positive for type positive 补偿精 degree, decrease small parts shrinkage rate.

        以 front a large amount of data is 支撑, to relatively is combined process parameters combined is: light rate 30 W, XYSTA扫描 methods, preheating temperature degree 100℃, speed degree 2400 mm/s, delamination thick degree 0.25 mm, 扫描间距0.30 mm. is mono process parameters (preheating temperature degree, speed degree, delamination thick degree, 扫描间距) for PS/PMMA烧结 parts shrinkage rate effect/influence 规律, upper combined in mono process parameters mono factors 实验, testing parts degree shrinkage rate.

         preheating temperature degree for PS／PMMA烧结 parts shrinkage rate effect/influence

        SLS molding front can step/link is for raw materials 进行一定 time preheating. time preheating, as inner formed stability uniform temperature degree 场, 避免 激 light 束直接照射 powder 末时, 烧结区域 powder and powder temperature relatively large, molding parts warpage phenomenon, meanwhile decrease small melt can amount.

        经 research 出, preheating temperature degree is 94~106℃, temperature degree upper rise, water direction shrinkage rate overall decline trend, data relatively small, in 2.57% left right. direction shrinkage rate large upper rise. preheating temperature degree is 94℃时, direction shrinkage rate is negative value, preheating temperature degree relatively low, light 扫描区域 powder and 未扫描区域 powder temperature degree large, parts warpage, parts dimensions large 于理论 dimensions. preheating temperature degree rise high, and between temperature degree degree decline, warpage phenomenon decrease/reduce, made parts degree good. in 103℃时接近PMMA 玻璃化转变 temperature degree (Tg) 105℃, molding parts shrinkage rate obvious upper rise, powder separation melt. thermoplastic property material preheating temperature degree generally low 于Tg, in 97℃时 made parts dimensions most 接近理论 dimensions, therefore 选取97, 100, 103℃ is positive 交实验 water value.

        扫描 speed degree for PS／PMMA烧结 parts shrinkage rate effect/influence

        扫描 speed degree not only effect/influence light in molding material upper 扫描照射 time long short, but also effect/influence molding efficiency. therefore in combined scope/range inner selection speed degree.

        选取 扫描 speed degree scope/range is 1800~3000 mm/s. research 出, 随扫描 speed degree increase large, water direction shrinkage rate upper rise rear decline. direction shrinkage rate overall upper rise trend. in 1800~2000 mm/s时, shrinkage rate is negative value. 此时扫描 speed degree small, light powder time long from powder 末接收 can amount large, 次烧结 phenomenon 出现, dimensions large 于理论 dimensions. 当扫描 speed degree large 于3000 mm/s时, molding efficiency fast, light 束照射 powder time short, powder difficult separation melt, and between adhesion 不足, powder easy by remove 掉. therefore 选取2100, 2400, 2700 mm/s is positive 交实验 water value.

         delamination thick degree for PS／PMMA烧结 parts shrinkage rate effect/influence

         delamination thick degree is type sheet/slice thick degree, powder thick degree. powder 末粒径, molding efficiency and other more factors 共同确定 delamination thick degree large small. delamination thick degree small, molding efficiency low. delamination thick degree large, “台阶效应” phenomenon obvious, parts degree 变差.

        选取 delamination thick degree scope/range is 0.19~0.27 mm. research 出, delamination thick degree increase, water direction shrinkage rate slow upper rise, is positive value. direction shrinkage rate obvious upper rise. delamination thick degree in 0.19~0.21 mm时, direction shrinkage rate is negative value, this is is delamination thick degree small, light in powder upper property strong/high, 扫描区域底部 powder by melt adhesion in made parts upper, 导致烧结 parts dimensions large. delamination thick degree increase, light property low, phenomenon 逐渐消失, parts degree improve/increase. 兼顾烧结 parts quality and molding efficiency, 选取0.23, 0.25, 0.27mm is positive 交实验 water value.

        扫描间距 for PS／PMMA烧结 parts shrinkage rate effect/influence

        扫描间距 is versus strip/profile light 束扫描线 between 垂直距离. 扫描间距 取 value generally and light has 关.

        选取 扫描间距 scope/range is 0.24~0.32 mm. research 出, 扫描间距 for water direction shrinkage rate effect/influence degree small, value in 2.5% left right 波动. 随扫描间距 increase large, direction shrinkage rate upper rise trend. direction shrinkage rate in 0.24~0.26 mm is negative value, 即实际 dimensions large 于理论 dimensions. this is is 扫描间距 small 时, versus light more 次照射 heavy 叠区域, 此区域 can amount high, separation can amount toward lower 延伸, formed phenomenon, parts adhesion phenomenon heavy, parts dimensions large, degree 变差. 扫描间距 large 时, 未接收 to can amount 区域变 large, separation powder 末处于未熔状态, easy by powder 时清掉. comprehensive 考虑选取0.26,0.28, 0.30 mm is positive 交实验 water value.

        经测 amount 计算, positive rear parts water direction shrinkage rate is 0.947%. direction shrinkage rate is 1.015%. 发现, parts warpage, 卷边, and other defect, parts quality good, is rear research 奠定基础.

        该 research project is 国家863 plan project, project is 2015AA042503

        该文章出自杨 侠, 桂玉莲, 白祥, and other PS/PMMA composite/compounding material 选区激 light molding shrinkage one article. 该文发 table/sheet in engineering plastics application 2019 year 第47卷第4期 48–52转79 upper