PVC Fittings Injection Molding Basics

Successful PVC fittings injection molding is dependent on various factors including but not limited to PVC material, PVC fittings mould and machine, PVC injection molding parameters. So here, we list the PVC fittings injection molding basics for your reference from two major aspects.


1. PVC and Its Properties

What’s PVC

PVC (Polyvinyl Chloride) is the third widely used thermoplastic behind Polyethylene and Polypropylene, it usually comes in two kinds: rigid and flexible. And the applications of PVC are water distribution piping, house siding, business machine housings, electronics packaging, medical apparatus, etc. And here talked is rigid PVC and PVC injection molding especial for fittings.

PVC Properties

The features of PVC include low combustibility, toughness, outstanding stability and high resist of oxidizing. Furthermore, PVC could be used with suitable components (plasticizer, stabilizer, lubricant, and colorants…) to improve the final fittings’ specification and production. Besides, PVC is also a plastic absorbs moisture slightly.

But there is a property making PVC different than others – it would emit some hydrogen chloride (HCl) fumes under 150℃ but large amount of HCI under 180℃, HCI is a harmful corrosive toxic gas – make its injection molding dangerous which requires skill operators for PVC fittings injection molding.


2. PVC Fittings Injection Molding Tips

– Dry

As the slight moisture absorbing, it’s not necessary to dry the PVC usually, but if for better pipe fittings molding, drying PVC material about 1 hour under 75 – 90℃ is suggested. And of course that it shall consider other components special added which may require longer dry.

– PVC Injection Molding Parameters

Mould Temperature: usually it could be 10 – 70℃ (50 – 158 F), it also be different for different mould parts.


Melt Temperature: it must be controlled well to ensure the safety PVC fittings injection molding.


Injection Speed: it must be the suitable one to avoid PVC decomposition, and usually it is slower for just starting machine, then increase gradually for the stable PVC fittings production.


Injection Pressure: Up to 150 MPa to ensure the best production.


Holding Pressure: Up to 100 MPa to ensure the complete fittings’ molding.


Special Requirement for PVC Fitting Molding Equipment

One basic requirement is that the parts of machine and mould where touch PVC directly must be anticorrosion.

And there must be regular and frequent maintenance for machine and mould.


By what mentioned for PVC fittings injection molding, you can see the basic tips for safety PVC injection molding, as for the details, kindly contact us now, we would help you more in the PVC pipe fittings injection molding solution.

 (PS: and if you are total new in plastic industry, welcome to learn the Plastic Moldings, which is the basic info helpful for you.)

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