Injection Molding Process
Injection molding, along with extrusion ranks as one of the prime processes for producing plastics products. It is an extremely fast process that ensures quality and product consistency during high volume manufacturing. Therefore injection molding is the perfect match for consumer and commodity products, from highly engineered components to disposable packaging.
Injection molded parts are everywhere around us during our daily lives. As the injection molding process is extremely reliable, flexible, consistent, and versatile, it is the perfect manufacturing process for products which are small (parts of a diabetic needle) and large (commercial refuse bins).
The injection molding process has helped significantly to push the boundaries of plastic designs in many ways whilst improving its green credentials at the same time. With an improved design, the relentless pursuit to lightweight packaging continues to reduce material usage, energy consumption, and carbon emissions. Even though plastic packaging is often considered ‘less premium’, its effect on the environment is extremely positive compared to other traditional methods of paper and glass. Polypropylene (PP) can be recycled infinitely without seriously depreciating its quality. Recycling is a great way to ensure old products are turned into new and raw material usage is kept to a minimum.
The Process (Injection molded cycle)
Granular plastic is fed from a hopper into a heated barrel. As the granules are slowly moved forward by a screw-type plunger, the plastic is forced into a heated chamber where it begins to melt. As the plunger advances, the melted plastic is forced through a small nozzle that leads directly into a cooled mould. The plastic solidifies almost as soon as the mold is filled. The mold then opens and the part is ejected.
Please see the animation below created by the British Plastics Federation.
Take the tour of an Amaray facility.