Shanghai Daoqin Plastics Co., Ltd.

1. crazing crazing is plastics products relatively Common types defect, generate main/primary causes is due to force deformation 致. main/primary has residual stress, external force and external ring generate force deformation. （－） residual stress crazing residual stress main/primary due to below/following types 情况, 即充填 剩, demolding launch and metal parts formed. as is in 充填 剩 情况 lower generate crazing, its solution methods main/primary can in below/following 几方面入手: （1） due to gate pressure loss most small, therefore, if crazing most main/primary generate in gate 附近, can 考虑改 use more distribution gate, gate and gate methods. （2） in ensure resin separation understanding, poor front lower, improve/increase resin temperature degree can reduce melt viscosity, high flow property, meanwhile can reduce injection pressure, decrease small force. （3） generally lower, mold temperature relatively low easy generate force, 应适当 improve/increase temperature degree. injection speed degree relatively high 时, make mold temperature low 一, can decrease low force generate. （4） injection and holding pressure time long generate force, will its shrink short or 进行Th次 holding pressure 切换效果 relatively good. （5） non crystallization property resin, AS resin, ABS resin, PMMA resin and other relatively crystallization property resin polyethylene (PE), polyoxymethylene (POM) and other easy generate residual stress, 应予以 attention/notes. demolding launch 时, due to demolding degree small, injection molding parts mold type and coarse 糙, make launch force large, generate force, has 时甚至 in launch 杆周围 generate whitening or phenomenon. need fine crazing generate 位置, can causes. in injection molding parts molding meanwhile metal parts 时, most easy generate force, but also easy in 经 一段 time rear generate crazing, 危害极 large. this main/primary is due to metal and resin thermal expansion coefficient versus 差悬殊 generate force, but also time 推移, force ultra- 逐渐 poor resin material strong/high degree generate cracks. is anti generate crazing, as is experience, thick 7” and metal outer general purpose type polystyrene (PS) basic upper 不适于宜 add parts, 而镶嵌 parts for nylon effect/influence most small. due to glass fiber reinforcement resin material thermal expansion coefficient relatively small, comparison combined parts. another, molding front for metal parts preheating, tool has relatively good 效果. （二） external force crazing this external force, main/primary is design combined 理而造 formed force in, especially is in 尖角处 more attention/notes. 由图2－2 can 知, can 取R／7”一0．5～0．7. （三） external ring 境引起 crazing chemical product, 吸潮引起 water degradation, and recycled material more use make material property poor 化, generate crazing. 二, short shot short shot main/primary causes has below/following several 方面: i. resin amount 不足. ii. type inner add pressure 不足. iii. resin flow property 不足. iv. gas 效果不 good. as is improvement measures, main/primary can from below/following several 方面入手: 1） add long injection time, anti due to molding cycle short, formed gate solid front resin 逆流而 difficult 于充满 type 腔. 2） improve/increase injection speed degree. 3） improve/increase injection molding parts mold temperature degree. 4） improve/increase resin temperature degree. 5） improve/increase injection pressure. 6） expand large gate dimensions. generally gate high degree and other products thick 1／2～l／3. 7） gate in products thick most large 处. 8）设置排 gas 槽（平均 deep degree 0．03mm, wide degree 3～smm） or gas 杆. for/regarding relatively small parts more is important. 9） in screw and injection nozzle between has 一定 （约smm）缓冲距离. 10） selection low viscosity and other grade material. 11） add lubricant. 三, and generate this type of defect causes in essence upper and short shot same, is degree different. therefore, solution methods and upper methods basic same. especially is for flow property relatively resin （如 polyoxymethylene (POM), PMMA resin, polycarbonate (PC) and PP resin and other ） more need attention/notes increase large gate and injection time. 四, shrink shrink causes and short shot same, upper can through 剩充填 add solution, 但却会 has generate force 危险, in design upper attention/notes thick uniform, can can decrease/reduce add strong/high 肋, and other 方 壁 thick. 五, for/regarding 溢边 处理 focus/key point main/primary in injection molding parts mold improvement 方面. in molding conditions upper, can in reduce flow property 方面 手. specific can using/adopting below/following types methods: 1） reduce injection pressure. 2） reduce resin temperature degree. 4） selection high viscosity and other grade material. 5） reduce injection molding parts mold temperature degree. 6）研 abrasion 溢边发生 injection molding parts mold 面. 7） using/adopting relatively hard injection molding parts mold 钢材. 8） improve/increase clamping force. 9） adjustment injection molding parts mold combined and other 部位. 10） increase injection molding parts mold 支撑柱, increase rigid property. ll） according to different material different gas dimensions. 六, 熔接痕熔接痕 is due to different direction melt resin front separation by cooling, in combined can full melt combined generate. generally lower, main/primary effect/influence appearance, for coating 装, electroplating generate effect/influence. heavy 时, for products strong/high degree generate effect/influence （ especially is in fiber reinforcement resin 时, is heavy ）. can below/following 几项予以 improvement: l） adjustment molding conditions, high flow property. 如, improve/increase resin temperature degree, improve/increase injection molding parts mold temperature degree, improve/increase injection pressure and speed degree and other. 2） increase gas 槽, in 熔接痕 generate 处设置 launch has 利于排 gas. 3）尽 amount decrease/reduce demolding agent use. 4）设置 process material as is 熔接痕 generate 处, molding rear again 予以切断 remove. 5）若仅 effect/influence appearance, can 改变烧四位置, 以改变熔接痕 位置. or will 熔接痕 generate 部位处理 is dark gloss and other, 予以修饰. 七, according to machine 械, injection molding parts mold or molding conditions and other different causes 引起 烧伤, solutions different. 1） machine causes, 例如, due to conditions formed material hot, make resin high temperature separation understanding, rear injection to products in, or due to material inner nozzle and screw 螺纹, 止回阀 and other 部位造 formed resin 滞流, separation understanding color rear belt/tape products, in products in belt/tape has color 烧伤痕. this 时, 应清理 nozzle, screw and material 筒. 2） injection molding parts mold causes, main/primary is is gas defect 致. this type of generally in solid 定 方, easy and types difference. this attention/notes add gas 槽反排 gas and other measures. 3） in molding conditions 方面, back pressure in 300MPa above 时, make material separation hot, formed 烧伤. screw speed high 时, generate hot, generally in 40～90r／min scope/range inner is good. in 没设排 gas or gas relatively small 时, injection speed degree high 会引起 hot gas 体烧伤. 八, 银线银线 main/primary is due to material wet property 引起. therefore, generally in ratio resin heat deflection temperature (HDT) low 10～15C conditions lower dry. for requirements relatively high PMMA树腊 series, need in 75t） left right conditions lower dry 4～6h. especially is in use 自动烘 dry material 斗时, need according to molding cycle （ molding amount ） and drying time selection combined 理 容 amount, also in injection front small 时先行开 machine material. another, material inner material time long generate 银线. different types type material mixed combined 时, polystyrene (PS) and ABS resin, AS resin, polypropylene (PP) and polystyrene (PS) and other 都不宜 mixed combined. 九, 喷流纹喷流纹 is from gate flow direction, bending 如蛇行一样 痕迹. it is due to resin gate injection speed degree high 导致. therefore, expand large 烧四横截面 or low injection speed degree is can selection measures. another, improve/increase injection molding parts mold temperature degree, can decrease and type surface resin cooling speed rate, this for anti in 充填初期形 formed surface hard 化皮, tool has good 效果. 十, warpage, deformation injection molding product warpage, deformation is very issues. main/primary from injection molding parts mold design 方面 手 solution, molding conditions adjustment 效果则 is very has 限. warpage, deformation causes and solution methods can below/following 各项: 1）由 molding conditions residual stress formed deformation 时, can through reduce injection pressure, improve/increase injection molding parts mold make injection molding parts mold temperature degree uniform and improve/increase resin temperature degree or using/adopting methods 予以消 remove force. 2） demolding defect 引起应 force deformation 时, can through increase 推杆数 amount or 面积, demolding degree and other methods add solution. 3） due to cooling methods combined 适, make cooling non-uniform or cooling time 不足时, can adjustment cooling methods and long cooling time and other. 例如, can can can in deformation 方设置 cooling 回路. 4） for/regarding molding shrinkage deformation, must positive injection molding parts mold design. its in, most important is attention/notes make products thick 一致. has 时, in already lower, good through amount products deformation, versus direction injection molding parts mold, add positive. shrinkage rate relatively large resin, ～般 is crystallization property resin （如 polyoxymethylene (POM), nylon, polypropylene (PP), polyethylene (PE) and PET resin and other ） ratio non crystallization property resin （如PMMA resin, polyvinyl chloride (PVC), polystyrene (PS), ABS resin and AS resin and other ） deformation large. another, due to glass fiber reinforcement resin tool has fiber toward property, deformation large. 十一, whitening whitening phenomenon most main/primary in ABS resin products launch separation. demolding 效果不佳 is its main/primary causes. can using/adopting reduce injection pressure, add large demolding degree, increase 推杆 数 amount or 面积, decrease small injection molding parts mold surface coarse degree value and other methods improvement, 当然, demolding agent is types methods, attention/notes need for rear 续工序, hot stamping, coating and other generate defect effect/influence. 十二, bubbles according to bubbles generate causes, solution countermeasures has below/following several 方面: 1） in products thick relatively large 时, its outer surface cooling speed degree ratio in fast, therefore, cooling 进行, in resin shrinkage toward surface expand 张, make in generate short shot. this type of by is true bubbles. solution methods main/primary has: a） according to thick, combined gate, dimensions. generally gate high degree is products thick 50％～60％. b）至 gate combined is 止, has 一定 补充 injection material C） injection time relatively gate combined time long. d） reduce injection speed degree, improve/increase injection pressure, e） using/adopting melt viscosity and other grade high material. 2） due to property gas generate formed bubbles, solution methods main/primary has: a）充 separation 进行预 drying. b） reduce resin temperature degree, generate separation understanding gas 体. 3） flow property formed bubbles, can through improve/increase resin and injection molding parts mold temperature degree, improve/increase injection speed degree solution.