Injection molding has always been one of the most widely used methods for manufacturing a wide range of intricate plastic parts with great precision. A huge variety of parts varying in size, application, and complexity can be manufactured using this molding technique. Different types of plastics are used in this manufacturing method. Of the many types, PVC or Polyvinyl Chloride is one, which is used on a large scale today. Different PVC injection molding techniques are in use today. Why? Owing to its various advantages. Are you interested to find out more about this material? This material can only be used for injection molding if certain conditions are achieved. What are these conditions? Please read the following post to know everything about Polyvinyl Chloride and its use in injection molding.
What is Polyvinyl Chloride?
Polyvinyl Chloride is a thermoplastic polymer, which is white, and brittle. As compared to the other plastic materials, PVC has been around for longer period. There are two basic types of PVC, namely, unplasticized or rigid polymer (uPVC or RPVC) and flexible polyvinyl chloride. Also referred to as regular or plasticized PVC, the flexible polyvinyl chloride is widely used in construction as insulation for electrical wires in hospitals, homes, etc. The rigid polyvinyl chloride material is also used in construction as pipe for plumbing.
What Characteristics of PVC material Make it Suitable for Injection Molding?
What makes this material suitable for the injection molding are its characteristics. The following are some significant properties of the PVC material:
- Strength: The rigid polyvinyl chloride is known for its excellent tensile strength, which makes it durable.
- Density: The specific gravity of the PVC material is 1.4, and is denser as compared to the other types of plastics.
- Hardness: This is yet another property of the material, which makes it popular. The rigid PVC material has an outstanding hardness.
- Easily Available: Last, but not the least, the PVC material can be availed easily, and that too at cheaper prices as compared to other plastic materials.
What Are the Ideal Conditions for Using PVC Compounds in Injection Molding?
All the characteristics explained above are the reasons behind increasing use of polyvinyl chloride in injection molding. However, there are certain necessary conditions for their use. What are they? Read below:
- Injection Speed: In order to achieve an optimal consistency, it is necessary to have the injection pressure 20% to 40% of the maximum value.
- Heater Band Setting: You are required to set the nozzle temperature to 10 degrees lower than the suggested stock temperature. Similarly, the barrel temperature should be set 20 degrees lower than recommended stock temperature.
- Stock Temperature: You will get the exact value of the recommended stock temperature by referring to the technical data sheet. This temperature is controlled by adjusting the screw back pressure, screw rpm, and heater band settings.
- Mold Temperature: The temperature of the inlet water should be within the range 70 to 100 degrees Fahrenheit. However, the temperature on the ejector side should be colder by around 10% to 20%.
- Rotation Speed: The machine, which is responsible for carrying out injection molding, should have the screw rotation speed of 35 to 50 rpm.
- Screw Back Pressure: Generally, the screw back pressure is 60 to 100 PSIG. However, it can vary depending on the machine used.
- Holding Pressure: The holding pressure should be maintained at 50% of the injection pressure.
- Injection Pressure: For achieving an optimal consistency, it is necessary to around 20% to 40 % of the maximum pressure.
Hope this post helped you get a thorough knowledge and understanding of using polyvinyl chloride in injection molding. You can consult an injection molding expert for further information. One such expert, whom you can approach is Veejay Plastic, which has a good experienced in providing polyvinyl chloride injection molding services to its clients across various industries.
