Contact Us
13922298476（Mr. Huang）
020-32039131, 32030604
Address: 2514-2516, building T1, Vanke center, No. 1080, Huangpu East Road, Huangpu District, Guangzhou
[Injection defect] What should I do if the surface of the high-gloss product is fogged! ?
[Injection defect] What should I do if the surface of the high-gloss product is fogged! ?
- Categories:Industry knowledge
- Author:Xiao Cheng
- Origin:
- Time of issue:2020-12-11 16:57
- Views:
(Summary description)High-gloss and high-bright products are indeed a difficult product for injection molding companies, because they cannot hide external defects. Even the dust in the workshop can cause different levels of defects in the products. For example, trachoma, pitting, contamination, etc., so the environment is also one of the key factors affecting such products.
[Injection defect] What should I do if the surface of the high-gloss product is fogged! ?
(Summary description)High-gloss and high-bright products are indeed a difficult product for injection molding companies, because they cannot hide external defects. Even the dust in the workshop can cause different levels of defects in the products. For example, trachoma, pitting, contamination, etc., so the environment is also one of the key factors affecting such products.
- Categories:Industry knowledge
- Author:Xiao Cheng
- Origin:
- Time of issue:2020-12-11 16:57
- Views:
Fogging on the surface of high-gloss products
High-gloss and high-bright products are indeed a difficult product for injection molding companies, because they cannot hide external defects. Even the dust in the workshop can cause different levels of defects in the products. For example, trachoma, pitting, contamination, etc., so the environment is also one of the key factors affecting such products.
Before
After
Why is the surface of high-gloss products foggy?
In the blanking stage, there is a certain gap between the plastic and the plastic, which is brought into the barrel after being sheared by the screw. During the shearing process of the screw, the inside of the material will change physically, from the glass state to the high elastic state, and from the high elastic state. State to viscous flow state.
The process of this change may only take a few seconds to tens of seconds. (Depending on the size of the machine or product), a complex process needs to be transformed in such a short time. Injection molding defects will also occur immediately, and the gaps between the plastics will be compressed to Gas is generated inside the melt. If the gas cannot be discharged to the outside of the barrel during plasticization, the existing gas will be wrapped in the melt and injected into the mold cavity. Whether the mold can be discharged smoothly depends on whether the exhaust of the mold is good. , The phenomenon of fogging or scorching occurs.
Obviously, white fog is also a phenomenon of trapped air. Many people engaged in injection molding technology mistakenly believe that only burnt is trapped, or if trapped air occurs, they go to open the exhaust slot. This is unscientific. The burnt is due to The trapped gas is too serious, and the gas is compressed under high pressure and high speed and cannot be released. The combustion temperature can reach 600-800℃ instantly, which is the highest state of trapped gas.
Solution!
1. Mould
Exhaust is not completely solved by the mold. In terms of the characteristics of the PP material, the temperature range is very wide, and its flow performance is superior. If the exhaust groove of the mold is opened too large or the position is incorrect, the exhaust cannot be properly exhausted, and it is easy to cause flying. The edges are bad, so correct exhaust is useful.
2. Craft
Mastering the correct tuning skills is very effective in actual work.
1) If the screw rotation speed is reduced, the temperature of the molten material can be uniform, and the chance of air entrainment is small. If the screw rotation speed is too fast, there will be more opportunities for air entrainment; the melt material is subjected to the screw shearing force and friction occurs. The heat causes the temperature of the molten material to be uneven, and the molten material decomposes to produce gas.
2) Increasing the mold temperature can benefit high pressure and slow filling to gain time. If the mold temperature is too low, the product surface is prone to premature freezing, and slow filling cannot be achieved, which may lead to lack of glue.
3) Reduce the injection speed, the faster the speed, the faster the gas compression, and the higher the temperature. The slower the speed, the slower the gas compression, the more conducive to the discharge of the gas.
4) Clamping force. The greater the clamping force, the worse the exhaust effect of the cavity surface. The smaller the clamping force, the better the exhaust effect of the cavity surface.
Scan the QR code to read on your phone
Relevant Information
Contact
13922298476（Mr. Huang）
Address: 2514-2516, building T1, Vanke center, No. 1080, Huangpu East Road, Huangpu District, Guangzhou
Copyright © 2021Guangzhou Zhenshun plastic material Co., Ltd Powered by：www.300.cn guangzhou.300.cn 粤ICP备20004324号
