Shanghai Daoqin Plastics Co., Ltd.

mold temperature degree is injection molding in most important amount ——无论 injection molding types plastics, must ensure formed mold surface basic wet lubricating. hot mold surface make plastics surface long time maintain liquid 态, in type inner formed pressure. if type 腔填满 but also in table/sheet 皮出现 hard front, type pressure can will soft/flexible plastics pressure in metal upper, that type surface made high. 另一方面, if in low pressure lower type plastics 暂停, time more short, that it and metal light micro 接触都会造 formed 污点, has by is gate 污斑. for/regarding types plastics and plastics parts, in mold surface temperature degree 极限, ultra- this 极限就 can can 出现一 types or more more defect effect/influence （例如: parts can flash/burrs ）. mold temperature degree more high flow retardant force more small. in many injection molding machine upper, this 自然就意味 more fast 流 浇, gate and type 腔, is use injection molding flow control 阀并不纠 positive this 改变, filling more fast in and type inner more high has pressure. can can formed material flash/burrs. due to more hot type 并不冻结 that in high pressure formed front 进入溢 material 边区域 plastics, material can in ejection 杆周围溢 material flash/burrs 并溢出 to separation 割线间隙 inner. this table/sheet need has good injection speed rate control, 而一 现代化 flow control device 也确实 can to this 点. usually, mold temperature degree rise high decrease/reduce plastics in type has cold 凝层, make melt material in type inner more easy flow, from obtain more large parts weight and more good surface quality. meanwhile, mold temperature degree improve/increase also make parts force strong/high degree increase. • mold temperature methods many mold, especially is engineering use thermoplastic property plastics, in versus for relatively high temperature degree lower 运行, 如80摄氏 degree or 176华氏 degree. if mold has temperature, to gas and injection molding machine upper hot amount can very easy and material 缸流失 一样 more. therefore need will mold and machine sheet/plate thermal insulation, if can can, will mold surface thermal insulation. if use hot runner mold, decrease/reduce hot separation and cooling injection molding parts between hot amount 交换. this methods can decrease/reduce can amount and preheating time. 一, mold temperature degree control 【一】 temperature degree control necessary property （１） temperature degree control for formed property and as is formed product appearance, material material property 质, formed ring and other, 受模仁 temperature degree effect/influence, is significantly. generally molding 情况, temperature degree maintain relatively low, can improve/increase injection shot relatively is 理想, and formed product 形状(模仁构造) and formed product material types type has formed ring 亦寄赖于必需 improve/increase 模仁充填之 temperature degree. （２） is anti force as temperature degree control is formed product material issues, requirements has ※ cooling speed degree. cold time short, make has 一部份 hard 化一部份尚 soft combined, still can due to 不均一 shrinkage 引起应 force. 亦即适当之 temperature degree control can for cooling force property 质改良. （３） formed material crystallization degree adjustment 之做之 temperature degree control poly 硫氨（ nylon ）, poly acid 数脂, polypropylene (PP) and other crystallization material for crystallization degree adjustment, and machine property 质改良, generally need relatively high temperature degree. 【二】 technology issues （１） temperature degree control hot 传面积模仁 hot 传面积之计算式 is t1: formed 形材之熔 melt temperature degree t0: formed product 取出时 temperature degree cp: formed material ratio hot sh:每 small injection shot formed 形次数移动 hot amount Q=shx*cp*(t1-t0)kacl /hrhw: cooling tube/pipe 路侧之 table/sheet film hot 传系数d: cooling 孔直径(m)u: viscosity (kg/mses)μ:流 speed (m/ses)λ: cold hot rate (kcal/m2 hrc)ΔT:模 type and cold (hot)媒间之平均 temperature degree 差则Hw:λ d(dug/μ) (cp u /λ)(kcal/ hr℃) hot 传面积 can lower 式求 之 A=Q/hw x T （m2）此际 for outer gas hot, type sheet/plate, nozzle and other hot 传俱行略 不计. ２） cooling tube/pipe distribution formed ring time shrink short has types types factors, cooling 效果卓越之模 type manufacturing is heavy large issues. cooling 不均一, 实行急遽 cooling, will make formed product internal generate force, deformation and crazing. therefore versus 应穴形状 and thick, 考虑模仁构造, make can has 实施均一而 high efficiency cooling property can. again 者, type tube/pipe processing combined comprehensive 考虑, tube/pipe 路之数 amount and large small. 例如图１ 示, same formed product 面积之场 combined, 模仁（ａ） has ５ strip/profile relatively large tube/pipe 路, type 模（ｂ） has ２ strip/profile relatively small tube/pipe as comparison, hot 传路径略图 示, type 模（ａ）之 type surface has versus and other hot 传, has 均一之 cooling 效果, relatively is suitable. 图二示 type tube/pipe and tube/pipe surface temperature degree 变化约略之 and other temperature 曲线. 图（ａ）示 use relatively large tube/pipe temperature degree 变化, tube/pipe in ring water temperature degree is 59.83℃, type surface as ring temperature degree is 60℃之60.5℃, relatively small tube/pipe 路（ｂ） in, ring water temperature is 45℃, type surface temperature degree 发生53.33℃至60℃之 temperature degree 变化. types surface 关联之 relatively large temperature degree 变化虽亦 can as is 充份之 formed conditions, for 模仁之 temperature degree control has 不当. again 者, hot rate high degree hot system efficiency relatively 佳, hot amount 传出之 control good. hot rate high 之模仁 surface temperature degree relatively small, 反之, rate low 者, temperature degree relatively large. generally 情形, for hot cooling system add attention/notes is: １） heavy type 模仁设置 has strip/profile water 路孔者, cold water 先行进入注道附近, rear temperature water ring outer 侧（图三）２） use polyethylene (PE) 时, formed shrinkage large, cooling tube/pipe 路不宜沿 shrinkage direction 设置, make deformation. ３）心 type cooling （图４）尽 can can type 形廓设置 tube/pipe 路. 二, plastics material material property introduction 【一】质 light in specific gravity 0.9～2.3 between, foaming can drop 至0.01. （远 ratio aluminum 2.7, iron 7.8 small ） 【二】 processing easy in 30℃ below/following can melt 胶, flow molding, less rear processing. （ melting point ratio aluminum 600℃, iron 1530℃ low ） 【三】 property can need different mono can combined formed property plastics, different plastics can composite/compounding property 质, add filling material or strong/high material can improvement certain property 质. 【四】 chemical stability property good resistant property 佳, acid, alkali, 油, salt, water, gas, gas 侵蚀. 【五】 light features good and color easy PS, PMMA, PC transparent; can easy easy molding 玻璃; plastics add color can good color 调. 【六】 insulation property good can resistant electrical 5～50千伏／ mm, can add conductive filling material, magnetic property. 【七】摩 scratch property good wear resistant bearings material.