1. Plastic processing.
After 24 hours at room temperature, the water absorption is less than 0.02%, so it is not necessary to dry.Such as must be dry, 60-70 ℃ hot air furnace can be put in 3 hours, 1-1.5 hours or 80 ℃ drying machine.
The recycled materials can be used up to 20% and the new material is mixed. The amount of recycled materials depends on the final use of the products.The abuse of recycled materials can cause the failure of the injection molding, not only the recycled components, but also because the material has been reprocessed many times.The quality of the recycled material decreases more every time.
2. Selection of injection molding machine.
Due to the large melt viscosity and easy decomposition, the decomposition products have a corrosive effect on iron, and the plastic parts and temperature control system must be used for injection molding.
Ramada has a special UPVC plasticizing injection system for each type of clamping force model covered by the product, and is equipped with a special safety door device for the core of UPVC pipe fittings.In general, as long as the injection quantity can meet the weight requirements, this series of UPVC injection molding devices can be used to produce high-quality products.
3. Mold and gate design.
Mold temperature can be set to 40.The length of the runner is shorter and the diameter is larger to reduce the pressure loss and the pressure can be transferred to the cavity.Gate as short as possible, die cut to round, minimum 6 mm diameter, nozzle mouth, into a cone, an internal Angle into 5 °.
The cutting surface of the main channel also needs to be round, which is formed by combining with the cold material well, connecting the main channel and gate with the cutting radius, and the diameter can be 7mm.
The sprue is used to connect the plastic parts of the circular shape, the shorter the better, the cutting surface should be smooth.
The cold well can prevent semi-solidified material from entering the cavity, and its importance is often neglected.
Gate position correctly, making the material flow on the flow smoothly, don't stop in the sharp corners, debris and metal traces, lest appear compression or decompression, should maintain a smooth flow smooth.
Mold application stainless steel casting, chromium content at least 13%, preferably 16%, rockwell hardness of at least 55, hard steel mold can be treated with chromium plating, forming protective effect.
After the production is finished, apply the gentle lye carefully to clean the surface and then spray the oil spray or silicon spray.
4. Melt temperature
The available air - shooting method is measured from 185-205.The accurate melt temperature of UPVC can be obtained from the smoothness of the injection material.If the material is rough after injection, it is proved that the material is not uniform (plasticizing), indicating that the temperature is too low;If a bubble bursts and a large amount of smoke rises, the temperature is too high.
5. Infusion speed
The shooting speed should be slow. Otherwise, excessive shear will reduce the material quality. When using UPVC to produce extremely smooth and thick wall products, the filling speed of multi-stage injection mold should be adopted.