亚洲va中文字幕欧美不卡-亚洲va在线va天堂成人-亚洲va在线va天堂va手机-亚洲va在线va天堂va888www-久一视频在线-久污tv

Welcome to Shenzhen Zhongyuan Plastic Co., Ltd!

News



Tel:(0755)27151698
Fax:(0755)27150611
Mailbox:szzyzcl@163.com / szzy@szzy99.com
Add:Building A1 and A2, No.1 Industrial Zone, yuliu property company, Gongming town, Bao'an District, Shenzhen
Industry information

當(dāng)前位置:

首頁 News Industry information

Solution to surface crack of plastic shell of power supply

Release time:2023-05-06

Plastic shell of power supplyDuring injection molding, cracks formed by surface cracking are called cracks. We solve this problem through fault analysis and troubleshooting.


1. Residual stress is too high

In terms of mold design and manufacturing, the direct gate with small pressure loss and high injection pressure can be used, and the forward gate can be changed into multiple needle point gates or side gates to reduce the gate diameter. When designing the side gate, the convex gate that can remove the broken part after forming can be used.

From the perspective of process operation, reducing the injection pressure is a relatively simple method to reduce the residual stress, because the injection pressure is in direct proportion to the residual stress. The temperature of the barrel and the mold should be appropriately increased, the temperature of the melt and the mold should be reduced, and the cooling time and speed of the parison in the mold should be controlled, so that the oriented molecules have a longer recovery time.


2. Residual stress concentration caused by external force

Generally, this kind of fault always occurs around the ejector rod. In case of such failure, the ejector shall be carefully checked and calibrated, and the ejector rod shall be set at the position with large demoulding resistance such as boss and stiffener. If the number of ejector pins cannot be expanded due to the limitation of pushing area, the method of small area and multiple ejector pins can be adopted. If the mold cavity demoulding slope is not enough, the surface of the plastic shell of the power supply will also be scratched to form wrinkles.

圖片3-1.png


3. There are differences in thermal expansion coefficients between raw materials and metal inserts

Metal inserts should be preheated, especially when cracks appear on the surface of the plastic shell of the power supply at the initial stage of startup, most of which are caused by the low temperature of the inserts.

In addition, in the selection of insert materials, try to use materials with linear expansion coefficient close to resin characteristics. When selecting raw materials for molding, high molecular weight resins should be used as much as possible. If low molecular weight molding raw materials must be used, the thickness of plastic around the insert should be designed to be thicker.


4. Improper or impure selection of raw materials

Practice shows that low viscosity loose resin is not easy to crack. Therefore, in the production process, appropriate molding raw materials should be selected according to the specific situation. During operation, pay special attention not to mix polyethylene, polypropylene and other resins together, which is easy to produce cracks. During the molding process, the release agent is also a foreign matter for the molten material. If the amount is improper, it will also cause cracks, so the amount should be reduced as much as possible.


5. The structural design of the plastic shell of the power supply is poor

The sharp corners and cracks in the structure of the plastic shell of the power supply are easy to produce stress concentration, resulting in cracks and cracks on the surface of the plastic shell of the power supply. Therefore, the outer and inner corners of the plastic shell shape structure of the power supply should be made into an arc with the largest radius as far as possible. The experiment shows that the best transition arc radius is that the ratio of arc radius to wall thickness at the corner is 1:1.7.


6. The cracks on the mold are reflected on the surface of the plastic shell of the power supply

In the process of injection molding, due to the repeated action of injection pressure on the mold, fatigue cracks will occur at the edges with acute angles in the cavity, especially near the cooling hole.

When the cracks on the surface of the mold cavity are reflected on the surface of the plastic housing of the power supply, the cracks on the surface of the plastic housing of the power supply always appear continuously in the same shape and position. When such cracks appear, immediately check whether the cavity surface corresponding to the cracks has the same cracks. If the crack is caused by reflection, the mold should be repaired by machining.

Copyright: Shenzhen Zhongyuan Plastic Co., Ltd. | mold processing customized manufacturer. If you want to know the processing price of the factory, how much is it, and which is good, please contact us Yue ICP Bei No. 17060480
主站蜘蛛池模板: 视频一区二区三区欧美日韩 | 一级人做人a爰免费视频 | 日日摸夜夜爽人人添 | 窝窝女人体国产午夜视频 | 欧美一级淫片免费观看 | 日日噜噜夜夜躁躁狠狠 | 天天做夜夜操 | 色综合久| 日韩丝袜亚洲国产欧美一区 | 香港全黄一级毛片在线播放 | 色婷婷一区二区三区四区成人 | 日韩黄色免费观看 | 日韩亚洲综合精品国产 | 性夜黄a爽影免费看 | 色美女在线| 日韩黄色免费观看 | 字幕网资源站中文字幕 | 午夜精品久久久 | 亚洲免费三区 | 亚洲成人激情在线 | 日本三级2020 | 人人干人人上 | 婷婷久久综合网 | 天堂 在线最新版在线 | 在线视频日韩精品 | 伊人二区| 亚洲一级毛片 | 日本色综合网 | 中文字幕欧美日韩久久 | 视频二区欧美 | 色综合色狠狠天天久久婷婷基地 | 亚洲天堂伦理 | 亚洲第一黄网站 | 日韩视频在线观看中字 | 日韩a无v码在线播放免费 | 欧美一区视频在线 | 中文一区在线观看 | 欧洲97色综合成人网 | 午夜影院在线观看 | 日本高清免费一本视频无需下载 | 日本中文在线视频 |