【正文】 Causes of brittleness Brittleness is caused by material degradation due to 脆化是由于材料講解引起的： Improper temperature setting 不合理的溫度設(shè)定 Improper screw design 不合理的螺桿設(shè)計(jì) Black specks/black streaks 黑斑或黑痕 Discoloration 色變Remedies Adjust the material preparationSet proper drying conditions before molding. 成型前設(shè)置適合的干燥條件Brittleness can be caused by excessive drying time or drying temperature such as at full heat for several days. Excessive drying either drives off volatiles in the plastic, making it more sensitive to processing, or degrades the material by reducing the molecular weight. Material suppliers can provide optimum drying conditions for the specific 。材料供應(yīng)商會(huì)對(duì)各種材料提供適合的干燥條件。Change to a highstrength material since lowstrength materials tend to bee more brittle if processed ，如果 強(qiáng)度材料容易脆化，則改用高強(qiáng)度材料Alter the mold designEnlarge the sprue, runner, and/or 、分流道、澆口。Select a proper machine/machine ponentGet a better screw design for the material you39。Adjust molding conditionsReduce the barrel temperature and nozzle If the barrel and nozzle temperature are too high, the material in the barrel will be overheated, leading to thermal degradation and the color ，料筒內(nèi)材料將過熱，導(dǎo)致降解或顏色變化Reduce the back pressure, screw rotation speed, or injection speed. since shear heating can result in material 、螺桿轉(zhuǎn)速、或注射速度，因?yàn)榧羟袩釙?huì)導(dǎo)致材料降解Within the limit not to overheat the material, increase melt temperature, mold temperature or injection pressure if the weld line has a tendency to crack. See Weld lines and meld lines for more ，在材料過熱極限范圍內(nèi)增加熔體溫度，模具溫度或注射壓力Burn marks What is a burn mark? Burn marks are small, dark or black spots that appear near the end of the flow path of a molded part or in the blind area where the air trap forms. 燒焦是小，暗或黑色斑點(diǎn)出現(xiàn)在成型零件的流動(dòng)末端或形成困氣的盲點(diǎn)區(qū)域。跑馬場(chǎng)效應(yīng)較為嚴(yán)重時(shí)，不合理的排氣系統(tǒng)的設(shè)計(jì)獎(jiǎng)產(chǎn)生困氣。Material degradation Burn marks can also result from the degraded (charred) materials being carried downstream and then appearing on the surface of the molded part or near the venting areas. Material degradation is caused by: 燒焦也有可能是因?yàn)橐呀?jīng)降解的材料被帶到下游并出現(xiàn)在成型零件靠近排氣區(qū)域，材料降解原因：High melt temperature If the screw speed is too high during the plasticization period, it will create too much frictional heat, which could degrade the material. 在熔體塑化階段，如果螺桿的速度過高，會(huì)產(chǎn)生較多的剪切熱，這會(huì)導(dǎo)致材料降解。 When the melt flows through restrictive nozzle, runner, gate, or part sections, it creates a lot of shear (frictional) heat, which could degrade the material. 當(dāng)熔體流經(jīng)限制性的噴嘴、流道、澆口或制品截面時(shí)，將產(chǎn)生大量的剪切熱，導(dǎo)致材料降解。 Black specks/black streaks Discoloration Remedies Alter the mold design改變模具設(shè)計(jì)Place an adequate venting system throughout the mold to help vent out the entrapped 。Enlarge the sprue, runner, and/or 、分流道或澆口Restrictive sprue, runner, gate, or even part design could cause excessive shear heating that aggravates an already overheated material, causing material degradation.Adjust the molding conditions 調(diào)節(jié)注射條件Reduce the likelihood of burn marks by avoiding excessive melt temperatures during the molding process:避免成型過程中熔體溫度過高，減少燒焦的可能性。FIGURE 1. Delamination causes layerwise peeloff on the surface of a molded part Causes of delamination 層脫原因Delamination can be caused by several factors, including: Too much mold release agent being used during the molding process 注射成型過程使用過多的脫模劑。 Low melt temperature in the cavity 型腔內(nèi)的熔體溫度過低 Sharp corners at the gate and runner 澆口或流道拐角處有尖角Remedies Change the material preparation 做好材料的成型前準(zhǔn)備Avoid using foreign material or contaminated regrind material in the molding ?？梢酝ㄟ^修整脫模機(jī)構(gòu)或其他可以消除脫模困難問題的方法來代替使用過多脫模劑Follow the predry instructions for the specific material and predry the material properly before ，在成型前對(duì)材料進(jìn)行充分的預(yù)干燥。Increase the barrel temperature and mold If the melt temperature is too low, layers of material are formed because they can39。Dimensional variation What is dimensional variation? Dimensional variation is a defect characterized by the molded part dimension varying from batch to batch or from shot to shot while the machine settings remain the ，成型制品尺寸按批次或件數(shù)變化。 Unstable machine control 機(jī)臺(tái)控制不穩(wěn)定 Improper process conditions settings 成型條件設(shè)計(jì)不合理 Unstable material property 材料性能不穩(wěn)定Remedies Improve the material preparation改善成型前準(zhǔn)備Contact the material vendor and change the material lot if the material has patchtopatch Predry the material before molding if the material is too ，進(jìn)行成型前預(yù)干燥L(fēng)imit the percentage of regrind material added to the origin The irregular particle size can cause different levels of mixed melt material, and lead to unstable molded part dimensional ，并導(dǎo)致不穩(wěn)定的零件尺寸變化Change a mold design/ponentFix or adjust the ejection system if the molded part is bowed or distorted during ejection.Design a proper runner and gate system for a specific mold and Use plastic injection molding simulation software to optimize the runner system dimension to assure a smooth melt flow into the cavity使用塑膠注射成型仿真軟件優(yōu)化流道系統(tǒng)尺寸確保熔體進(jìn)入型腔流暢。s color having changed from the original material color. 色變是塑料成型制品顏色上區(qū)別于原材料的變化Causes of discoloration This defect can be caused by either material degradation or contamination from the following problems: 色變是由材料降解或受污染引起的。 The material staying in the barrel too long. 材料停留于料筒時(shí)間太長(zhǎng) Contamination caused by reground material, different color material, or foreign material. 來自于再生料、不同顏色的材料、外來料的污染Other defects resulting from the same causes Brittleness s important to avoid foreign material or different color materials mixing together before 。Fish eyes 魚眼What are fish eyes? Fish eyes are a surface defect that results from unmelted materials being pushed with the melt stream into the cavity and appearing on the surface of a molded part. 魚眼是未熔化的材料進(jìn)入型腔并呈現(xiàn)在成型零件表面的一種表面缺陷。 If the barrel temperature is too low to melt the materials pletely, the unmelted pellets will merge with the melt stream, marring the surface of the ，未熔化的塑料顆粒被熔融塑料帶出并造成制品表面損傷。 太多的再生料The shape and size of regrind is irr