Shanghai Daoqin Plastics Co., Ltd.

[转] product molding defect and its countermeasures 2六, cracking, cracks, micro and has molding made parts has local 破碎, is surface generate micro fine cracking, according to its degree and appearance upper 差别, relatively heavy cracking or 裂缝, relatively light micro micro or crazing. its in micro not only molding rear generate; rear or and solvent agent gas and other 接触时也会发生. 而ABS and resistant impact polystyrene (PS) 根本不 generate this type of phenomenon, 却以顶杆推顶部位发白 形式 performance 出, using/adopting hot add temperature can remove this type of phenomenon. 1, generate upper phenomenon causes has lower 两几点. 1． demolding 不畅, molding 时模 拔模斜 degree 不足, formed is 例拔模斜 degree, or light 极差, therefore made parts demolding difficult, 往拄造 formed made parts loss or 发白. due to 主浇道抛 light good make made parts viscous in 静模, or 者动模 upper, has 侧壁凸凹并 using/adopting hard property demolding 时, more easy generate this type of phenomenon. 总之发生 this type of defect 时, 首先应 attention/notes injection molding parts mold light, in increase large 拔模斜 degree meanwhile in molding made parts cracking 处附近 increase 设顶杆, make made parts bending, combined demolding. for/regarding polymethyl methacrylate (PMMA) molding made parts, plastics relatively 脆, surface requirements has gloss, large more using/adopting injection molding parts mold molding. however electroplating tool has 平面不 easy property 质, easy to 转角处; formed is 倒拔模斜 degree, therefore must especially attention/notes. 2． filling due to separation molding shrink 孔, 结果注入棋腔 熔 material more, make molding made parts internal generate large 应变. this shrinkage very small, 不但容 easy cracking, and 放置一段 time rear internal more easy formed micro 裂. need remove filling cracking can improve/increase material temperature degree, reduce injection pressure, improve/increase injection molding parts mold temperature degree, need ensure material easy 于注入 mold cavity can. according to molding made parts appearance and other has causes, must filling methods molding 时, is make made parts 不发生 micro 裂, molding rear 应进行塑化处理, this for remove internal is has 效. 3． cooling separation in full hard 化时就 will made parts ejection, has 时顶仟周困 cracking or 发白. ‘ through separation cooling or injection molding parts mold cooling methods and other, can remove this 利, defect. 4．嵌 parts cracking 置入嵌 parts molding due to plastics shrinkage, force significantly in in parts 周围. this force although can solid maintain parts, is force large parts plastics cracking. need decrease/reduce parts cracking, has is preheating parts or amount shrink small shrinkage 差, 进行塑化处理效果 more obvious. 七．熔接痕 molding material combined generate fine by 称做熔接痕, this is low temperature material versus combined can full combined generate. this type of 熔接痕 发生 in material combined 部位, is 说, in belt/tape molding made parts, or more gate molding made parts, strong/high degree low its it separation. and other made parts 熔接痕出现 in in 心, for strong/high degree and appearance has effect/influence. 熔接痕 detailed 情况叙述如 lower. 1, 熔接痕位置不当 熔接痕 generate and gate, made parts has 关, can remove it to effect/influence appearance quality 位置. is 此, need 考虑移动 gate 位置, gate dimensions unchanged 衡 改变 made parts thick and other methods. 2, material flow property 不足, if material flow property 不足, 熔接处 熔 material temperature degree will more low, and pressure loss large, make 熔接痕 obvious, strong/high degree decline; therefore decline make 熔接痕 still in 原 位置 upper, make obvious, decrease/reduce for appearance and strong/high degree effect/influence. measures is make material high temperature, high pressure to combined 处; '若 can reduce flow retardant force more good therefore, 应采取 rise high material temperature degree high flow property; add fast injection speed degree make material drop temperature to combined 处, s rise high injection molding parts mold temperature degree decrease/reduce material drop temperature; expand large gate or add thick to combined 处路径 upper made parts thick, decrease/reduce flow retardant force. use flow property good plastics has decrease light 熔接痕. using/adopting more gate molding 时肯定会 generate 熔接痕, use mono gate can molding 时, can can generate 熔接痕. 3．存 in gas or formed separation 熔接痕 although upper is difficult 免, in material flow 时首先应 空 gas or formed separation troubleshooting 掉‘ if gas 不畅, 熔接痕当然变 obvious. this type of 情形严 heavy also 会引起 filling or 烧伤(参照 filling 不足, 烧伤); to has this type of can can 时, has necessary utilizing parts 缝隙排 gas or 设置排 gas 孔道, for/regarding gas formed 熔接痕恰 good and usually remove 熔接痕 methods versus 反. has 时甚至 need reduce injection speed degree can make 熔接痕不 obvious. 4. demolding agent formed mold cavity surface coating has demolding agent 时, by material to 熔接处, demolding agent and material versus 互不熔 combined generate 熔接痕. use silicon demolding agent 时, this type of phenomenon more heavy. if this type of 熔接痕 coarse heavy, make made parts 变 脆 low, and easy cracking (参照脆 low). 5. color agent formed if add aluminum or micro color agent molding sheet/slice made parts, 熔接痕 obvious color agent property 质变化. remove this type of 熔接痕 is difficult (参照 color 不匀). 八, 波 纹 谓波纹, is material mold cavity rear 出现 以 gate is in strip/profile 纹. this is due to mold cavity 各面熔 material cold hard non-uniform generate. detailed 说明如 lower. 1． plastics viscosity large. material viscosity large 时一接触 to mold cavity surface very fast cold 凝, rear 面流 熔 material make cold material flow from generate strip/profile strip/profile generate causes more is injection molding parts mold temperature degree 不适当. can use molding conditions, improve/increase material temperature degree and injection molding parts mold temperature degree remove. 2．熔 material temperature degree non-uniform in injection machine 喷咀头部 熔 material, and molding made parts demolding 时一起 remove 掉. has 残余部 separation or has 主浇道 and cooling cold material, by mold cavity, 也同样 generate 波纹. 一开始就注入 hot material can 消陈波绞. heavy light injection machine nozzle, rise high nozzle temperature degree, injection molding parts mold upper design large cold material and other can remove 波纹. 3, injection molding parts mold temperature degree 不适宜 injection molding parts mold temperature degree low, low temperature 部位 熔 material 就立即 cold 凝, generate 波纹. although improve/increase injection molding parts mold temperature degree can remove this type of defect, is this will long molding cycle. 九, filament this is in made parts surface material flow direction upper white 纹理; this type of phenomenon causes although very more, main/primary is raw materials drying 不彻底, water separation or formed separation formed. generate silver streaks 时, need use drying pellets material molding 实验, this 样尚不 can remove, can other causes silver streaks generate specific causes separation lower; 1．由 water separation or formed separation if use 未经充 separation drying plastics molding, water separation or formed separation in material inner by gas 化, 并随熔 material from nozzle mold cavity. this type of add gas 体 熔 material 一接触 to mold cavity cold hard 化, gas 体妨碍熔 material and type surface 密贴, flow direction formed white 纹理, this is in made parts upper silver streaks. 进行充 separation drying, full remove water separation or water separation can anti silver streaks, however 梅雨季节空 gas wet degree high, has drying material in material inner 吸潮也会 generate silver streaks. for/regarding thick large made parts due to gas and injection amount 不足 也容 easy generate silver streaks. screw 形式也 is generate silver streaks has factors, make in same conditions lower, screw different generate silver streaks 状态也不 same. 2．由 plastics separation understanding plastics separation understanding, or add stabilizer, anti belt/tape electrical agent and other separation understanding, generate gas 体, this and full dry 操 情形 same, 往往也 generate silver streaks. this is make plastics separation understanding, reduce material temperature degree molding, meanwhile also shrink short material in material inner time. 3．卷入空 gas 引起 随 pellets material from material 斗进入 material 筒 空 gas, 经 螺秆 and material between 缝隙, or 者校塞 and material between by toward rear 方; screw injection machine 卷入 空 gas 一直运送 to nozzle. from nozzle injection 出夹杂 gas 体 熔 material, and type surface 不密贴而 generate filament. if will material lower separation cooling; or make material rear temperature degree low, can solution this issues. more molding conditions reduce screw 转数, improve/increase back pressure, can 避免出现 silver streaks. 4, material temperature degree low 引起． if mold cavity material temperature degree low generally performance is 波纹, has injection molding parts mold 往往出现 silver streaks. this type of and in 2． same, 因而采取 measures same, improve/increase material temperature degree, add large injection molding parts mold cold material and other can remove silver streaks. 5． mold cavity surface water separation or formed separation if mold cavity surface has water separation; by material gas rear 往往造 formed silver streaks defect. this made parts surface dark (, film), if remove dark this defect, meanwhile 也就消 remove silver streaks defect （参照晕: color film; gloss 不佳部 separation). 6, plastics powder formed use pellets material, 而直接 use powder material molding 时, or 者往颗 material in a large amount of powder material molding 时, very easy 卷入空 gas. this and upper 述3． same, therefore 应遵循3． requirements solution silver streaks defect need using/adopting powder material molding, using/adopting pressure shrink ratio large, 不卷入空 gas screw ． 7． mixed types plastics versus easy combined types plastics mixed combined molding, although 会引起层状剥离(参照剥离), is has 时也会出现 silver streaks defect. 彻底清洗 material 简． use by raw materials can solution this issues. 十, 烧伤烧伤 phenomenon is 熔接痕部 separation and type 腔末端 local plastics by 烧焦变黑. this in filling 不足 5. in and 熔接痕 3． in to 一样, type internal gas 排不出, by hot pressure shrink high temperature, make plastics 焦化而 generate 烧伤. solutions and front to same. reduce injection speed degree, 留出空 gas from separation type 面排出 time, or 者改变 injection molding parts mold structure, make gas can from parts 缝隙, 顶秆 孔隙, in separation type upper shallow and other 处排出. 十一, black strip/profile molding made parts upper formed 照线叫 black strip/profile 纹, its causes main/primary has lower 面几点. 1． plastics hot separation understanding 引起; plastics or add outer absorption agent, anti belt/tape electrical additives and other in material inner hot separation understanding, or in material inner time long separation understanding, formed black. if will plastics type 腔, formed molding made parts black strip/profile 纹. need anti plastics in material inner long time or hot, can coating this type of defect. therefore use 柱塞式 injection machine generate this type of defect can can property very small, if use screw injection machine, most good reduce material molding temperature degree. however, how to has necessary 不定期清洗 material 筒. is anti belt/tape electrical agent and other additives ratio plastics heat resistant property 差, this type of additives 时应十 separation attention/notes material temperature degree. ‘ 2. gas by hot pressure shrink 引起 空 gas in material inner by hot pressure shrink high temperature, formed black strip/profile 纹. generally has use slip property non injection molding parts molding pellets material 时才会 generate this type of phenomenon. 3. add hot and other by bad 引起 当 add hot and 逆止阀 and other loss 时, from its 缝隙会漏出烧焦 plastics, has 时会出现 black strip/profile 纹. in this type of lower, remove 立即修理 and more outer, has other solutions. 十二, color film (发 dark), gloss made parts surface gloss to plastics light degree, this type of 模糊发 dark phenomenon gloss 不佳. 此时, in surface formed white film, make transparent parts transparent, or transparent degree reduce, specific generate causes has lower types. 1. injection molding parts mold light molding made parts surface is mold cavity surface again 现, if injection molding parts mold light 不佳, its micro small will make gloss reduce, from make transparent made parts light transmittance decline, transparent 反变差. improvement injection molding parts mold light can solution this issues, requirements full transparent 时, will mold cavity surface 镀铬就 can improve/increase made parts degree. 2． plastics flow property 不足 熔 material 一接触 to mold cavity surface if cold hard formed fine micro 凸凹, made parts for surface light degree property 变差, reduce made parts gloss. can decrease plastics cold hard 化, can remove this type of defect, therefore can using/adopting improve/increase material temperature degree, injection speed degree and injection molding parts mold temperature 皮 办 method. 3．由 plastics in formed separation plastics in formed separation hot 而蒸发, 一接触 to mold cavity poly in surface upper, 妨碍 熔 material and mold cavity 密贴, can can again mold cavity surface gloss. can anti plastics hot separation understanding generate gas 体, can solution this issues. therefore, separation 进行领先 drying, make formed separation full 挥发掉 is good. most good will material temperature degree reduce to plastics or additives separation understanding temperature degree scope/range inner and shrink short time. 4． mold cavity surface in demolding agent if mold cavity surface demolding agent, retardant material and mold cavity 密贴, make made parts surface 模糊发 dark. demolding agent more has formed 波纹, has made parts 变脆, therefore must prohibited amount use. 5． injection molding parts mold temperature degree 不适当引起 has plastics gloss injection molding parts mold temperature degree different has significantly 变化, in certain: — temperature degree below/following, full has gloss; if improve/increase temperature degree, gloss 就会变 good, will injection molding parts mold temperature degree improve/increase to Idemitsu temperature degree, can gloss 不佳.