Top Unite has a professional technical team and rich industrial experience, which can provide complete plastic injection molding solutions.

The melting temperature of PPSU is around 340°C, mica band heater cannot provide enough heating power to melt the PPSU material, so we change the Ceramics band heater to replace it, which increases 50% of heater capacity. To prevent high temperature heats conduction brings influence to the feed entrance, we also add a water manifold to cool the heat from the heater, which also protects the injection unit to extend the service life.

“Why TPE rubber overcoating on PC cracks?” This question has been interpreted differently. Which part cracks, the TPE rubber coating or the PC part? We think most customers have met with PC parts failure.

In this case study, we will discuss how Top Unite helping this client to solve the injection problem in the Advance-Engineering Plastic "PPSU" production and how to make our plastic injection molding machines able to apply on the PPSU material production, and at the same time satisfy the customer's product quality and Demand for maximum production capacity.

When TPE or TPR is overmolded on PC products, the destruction of internal stress in the PC molded parts may surface. Particularly when overmolding in a wide area and/or on thin PC parts, the extensive shrinkage of the overmolding rubber will trigger the stress to develop cracks on PC parts.

With the assistance of TopUnite Machinery, the pipe fitting production output now is sustainable growth, so far, the customer has begun to expand the production equipment to meet the continuous additional product orders.

Top Unite provides customers with a full range of consulting services to create high-efficiency, low-cost production lines and enhance company competitiveness.

刊登日期：2016-07-13Souce:  http://www.21cp.com/  “Why TPE rubber overcoating on PC cracks?” This question has been interpreted differently. Which part cracks, the TPE rubber coating or the PC part? We think most customers have met with PC parts failure. Those who are familiar with engineering plastics surely know that cracking on PC (polycarbonate) products are quite common. PC products may easily develop cracks, mainly due to the internal stress of the product. During molding of PC products, molecules are forced to certain orientation which causes internal stress. After the molded parts cool down, the poor flexibility of benzene rings in the molecular structure do not move or reorient themselves easily. In such situation, stress will be retained. Therefore, during molding of PC products, improper measures of stress release such as setting of a too low mold temperature and insufficient cooling time could deter the molecules from releasing their stress, in other words, the molded products still retain internal stress; when the stress goes up to certain level (exceeding the cracking threshold), the PC products crack. When TPE or TPR is overmolded on PC products, the destruction of internal stress in the PC molded parts may surface. Particularly when overmolding in a wide area and/or on thin PC parts, the extensive shrinkage of the overmolding rubber will trigger the stress to develop cracks on PC parts. Solution: Use higher mold temperature, properly extend the time of molding pressure and cooling shall reduce or eliminate internal stress of the PC parts. TPE/TPR coating cracks In the case of cracking on the overmolding layer of TPE/TPR, the problem usually appears some time later after overmolding. Cracking of overmolding layer is mainly due to poor aging performance of TPR and TPE. Overmolding materials may age and crack with time passing by. Solution: Choose TPE and TPR products with better aging performance.

This client now is a professional PPSU pipe fitting production factory. The first time they contact these kinds of products is around 6 years ago. Because of lacking experience in PPSU production, soon they are facing some problems. Next, we will bullet out these problems to discuss.

In the case of cracking on the overmolding layer of TPE/TPR, the problem usually appears some time later after overmolding. Cracking of overmolding layer is mainly due to poor aging performance of TPR and TPE. Overmolding materials may age and crack with time passing by.

Customized plastic injection molding machine is designed for advanced engineering plastics. In recent years, the quality standard of plastic products getting strict than before. For meeting these standards, lots of new plastic have been launched in the past few years, especially advanced engineering plastics. The advanced engineering plastics require acid and alkali proof, high-temperature resistance, halogen-free, and high structural strength. By upgrading the hydraulic system output pressure to 200kg/cm², improve the cooling system, build a special screw barrel, and increase the motor power and heater capacity, the Top Unite achieves a high-performance injection molding machine for advanced engineering plastics. If you need more detail of product information or buying consultation, please contact us.

The PPSU has a strong acid and alkali-proof, and during plasticizing, the melting PPSU becomes a high corrosiveness substance. After about 3 months of production, the melting PPSU will cause erosion on the surface of the screw. Thus we placed an order of PPSU special screw tubes from a world-famous screw-barrel manufacturer. This special screw-barrel is processing arc spraying and specially designed L/D ratio of the screw, this process, not only improves the surface hardness raises the resistance of acid and alkali proof but also brings a long-term service life and high stability production.

molecules are forced to certain orientation which causes internal stress. After the molded parts cool down, the poor flexibility of benzene rings in the molecular structure do not move or reorient themselves easily. In such situation, stress will be retained. Therefore, during molding of PC products, improper measures of stress release such as setting of a too low mold temperature and insufficient cooling time could deter the molecules from releasing their stress, in other words, the molded products still retain internal stress; when the stress goes up to certain level (exceeding the cracking threshold), the PC products crack.

Solution: Use higher mold temperature, properly extend the time of molding pressure and cooling shall reduce or eliminate internal stress of the PC parts.

Those who are familiar with engineering plastics surely know that cracking on PC (polycarbonate) products are quite common. PC products may easily develop cracks, mainly due to the internal stress of the product. During molding of PC products,

As we know the physical properties of PPSU are high-temperature and high-impact resistance, which means it is hard to inject into a mold cavity even if under the melting status. For that, we choose a traditional hydraulic system injection machine to produce this product. The benefit of the traditional motor is it could stay in a high-pressure condition for a long period without overheat, we took this advantage to apply it in the holding pressure process. Therefore during the holding process, the traditional motor could keep providing a high pressure to maintain the product shape inside the mold cave till the material cools down to prevent product shrink.