PVC Injection Molding - Immould

PVC Injection Molding

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Polyvinyl chloride or PVC is an industrial thermoplastic. This material is extensively used across industries for a variety of purposes. Because of its flexibility which ranges from soft and hard to rigid, PVC finds uses in many different ways. PVC is a strong compound and has commendable durability, which makes it ideal for pipes and injection molding. 

The compound is also very resistant to chemicals, flames, and abrasion. PVC is in great demand at any given point in time. The right manufacturer for injection molding who makes use of polyvinyl chloride is important. Any manufacturer will tell you that because of PVC’s dimensional stability, it is an excellent choice for injection molding. 

What is PVC or Polyvinyl Chloride?

PVC molds
Source: Deposit Photos

Both polyvinyl chloride and PVC are well-known names of this thermoplastic polymer. This polymer is strong but can prove brittle until elasticity is added by infusing it with plasticizers—the B.F. Goodrich Company was the first organization that made use of this compound commercially in the 1920s. Polyvinyl chloride is used in both its flexible and rigid forms. PVC infused with plasticizers can bend, whereas the rigid form is primarily used for industrial purposes where durability and stability take priority. 

Some examples of the flexible type of polyvinyl chloride include insulation for electrical wires and cables, flooring for homes, and in some cases, a replacement for rubber. The rigid type of PVC is used on a larger scale as plumbing pipes, vinyl siding on buildings, and business machine housing. 

Polyvinyl chloride is formed through three main processes. These are:

Polyvinyl chloride or PVC Advantages and Disadvantages

Source: Deposit Photos

Advantages

Polyvinyl chloride is a popularly used polymer because of its innumerable advantages that range from inexpensiveness to greater accessibility. Apart from these, there are many properties of polyvinyl chloride that can be taken advantage of by manufacturers for plastic injection molding service and otherwise alike. These are listed as follows:

Disadvantages

Apart from these advantages, there are also some disadvantages that come with the manufacture and decomposition of polyvinyl chloride. During production, gassing can cause health problems which can be tackled by ventilating the room in which the manufacturing is happening. Even if shrink wraps are used to reduce health concerns, they are not very eco-friendly, which is why polyvinyl chloride is unsustainable.

Common Uses of Polyvinyl chloride or PVC

PVC Pipes
Source: Deposit Photos

PVC is used in multiple industries for various purposes. From dashboards to bottle caps, PVC is also extensively used in packaging. Among the common uses of polyvinyl chloride are automotive parts, wire spools, window handles, pocket combs, and parts for construction. PVC is not yet used for advanced prototype molding because of its corrosive nature. A 3D printer nozzle specially catering to PVC has been developed, but manufacturers still prefer materials like ABS and PLA when it comes to 3D printing.

Polyvinyl chloride or PVC Properties

Steel-mold-in-an-injection-molding-machine
Source: Deposit Photos

Polyvinyl chloride is a durable and favorable material for manufacturing because of its high melting point. The melting point of PVC falls in the range of 212°F to 500°F as the type may vary depending on the infusion of other materials. The properties of PVC do not undergo any change or degradation when the material is heated and reheated for molding repeatedly in case of change in mould design. The many additives that can be added to polyvinyl chloride include fillers, stabilizers, lubricants, plasticizers, pigments, processing aids, and impact modifiers. The polymers can be joined together either through rubber or through solvent cement. 

The tensile strength of polyvinyl chloride is 6,500 psi which lends the polymer its durability. One of the advantages of using PVC for injection molding is that this material has very low shrinkage. The shrinkage while molding amounts to 0.002 – 0.006 mm/mm, which is just 0.2 – 0.6%. The drying temperature of the mold once made ranges between 75-90°F. The packing pressure of mold can be up to 100MPa.

Polyvinyl chloride or PVC Processing Temperature in Injection Molding

Chemical Formula

(C2H3Cl)n

Melting temperature

320-428°F

Mold temperature

68-158°F

Melt Temperature

212 – 500 °F (100 – 260°C)

Heat Deflection Temperature (HDT)

92 °C (198 °F)

Injection Molding Process with Polyvinyl Chloride (PVC)

Injection molding factory
Source: Deposit Photos

Polyvinyl chloride begins in a powder or pellet form, which needs to be melted for processing. The pellets are heated after putting them in a barrel. During this heating process, a plasticizer to help with fluidity, a lubricant for better removal of the mold, a stabilizer to help with thermal stability may be added to the mixture. Other additives include fillers and dyes. For an injection mold, the mold making process uses the liquified PVC through an injection. This custom mold has two sides. After the liquid has cooled, it is allowed to dry to set fully. The post-processing includes final touches that might need to be made.

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Conclusion

Polyvinyl chloride has a high tensile strength which is why it is chosen for its strength and durability in a variety of applications. Whether it is mold making, overmolding, or manufacturing other products, PVC is versatile because it can be heated and molded into any shape possible. The material can also be reheated and remolded over time over and over without any degradation to its chemical properties, which is why it is one of the most easily available recyclable plastics. Injection molding is a great use of polyvinyl chloride because it can be liquified and hence can be used in injection molding. Industrial applications are common uses of PVC because of its lasting properties.