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A slight background from the Plastic Injection Molding pioneers…
The process of injection molding was invented by John Wesley Hyatt. In 1868, he produced billard balls by injecting celluloid into a mold. Later, he built a plunger type injection machine to facilitate production.
Another inventor, James Hendry, improved on Hyatt´s invention and built a screw injection molding machine in 1946. Both plunger type and screw injection type molding machines are used in the modern plastics industry. The difference between the two is in the way the plastic is transferred to the mold. Screw injection types are more convenient and are widely used.
What is Plastic Injection Molding?
It is a manufacturing process for producing parts from both thermoplastic and thermosetting plastics materials. Material is fed into a heated barrel, mixed, and forced into a mold cavity where it cools and hardens to the configuration of the mold cavity.
After a product is designed, usually by an industrial designer or an engineer, molds are made by a moldmaker (or toolmaker) from metal, usually either steel or aluminum, and precision-machined to form the features of the desired part.
Injection molding is widely used for manufacturing a variety of parts, form the smallest component to entire body panels of cars.
In non-technical words it is a popular and economical industrial process for manufacturing a wide range of plastic consumer products.
These consumer products include:
- Knobs
- Washers
- Valves
- Pulleys
- Gears
- Power tools
- Bottle caps
- Toys
- Car panels
- Computer monitors
- Keyboards
- Furniture
These items are mass-produced using molding machines of various sizes and various specific requirements.
In the plastic molding process, plastic resins are used in pellet or granular form.
Choice of plastic type depends on the kind of product being made, its requirements and the overall budget. Of the hundreds of available plastics, only a few are safe for consumer use.
Some of the ones used in the plastics injection molding process are:
- Polystyrene
- Polycarbonate
- Polypropylene
- Polyethylene
- Polyamide
- Polyvinyl Chlorida
- Teflon
- Delrin
- Nylon
- Acetal
- Acrylic
“Green Plastics”… Reduce and Reuse!
The plastic injection molding process plays a positive role in reducing waste. Plastics used in the process can be reused as often as required.
The plastics pellets or granules are poured into the feed hopper of an injection molding machine. The feed hopper is a larger container that opens into a heating cylinder. In the heating cylinder, the pellets are subjected to intense heat until the plastic melts.
A plunger or a screw then pushes the molten plastics forward through a nozzle into a split-die mold. The mold is the reverse of the part to be made and can have one cavity or several to make more parts at the same time. Molds can be made of durable and expensive steel, or the more affordable, less durable aluminum or beryllium-alloy metal.
As with selecting the right plastic type, selecting the mold metal depends upon product, cost and durability factors. Manufacturers often use a less expensive metal mold for prototype molding, and get the longer wearing, precision-machined molds when the production demand increases.
The molten plastic cools in the mold, hardens and takes on the shape of the mold. The mold then opens and the part is ejected out. It is then either for packing or is prepared for any other secondary operations. The whole plastics injection molding process is completed within a few minutes and can be carried out automatically.
How are these plastics made?
Plastics resins are made by heating hydrocarbons in what is known as the “cracking process”. The goal here is to break down the larger molecules into ethylene, propylene, and other types of hydrocarbons. The amount of ethylene produced depends on the cracking temperature.
Once the cracking process has been completed, the compound is formed into chains that are known as polymers. Different polymers are combined to make plastic resins that have the characteristics needed for different applications. Once the plastics resins have been formed, they are used to make many different kinds of products.
The Industry
The Plastic injection molding industry is an industrial, technological and labor intense manufactory.
Manufacturers guarantee product satisfaction to there customers through there “vast experience” usually starting from ten years of expertise in the Plastic Injection molding.
Engineering and commodities are usually what sets the parameters for an investment evaluation. In other words, the amount of good quality engineering determines the capacity of production of any company.
“ A multi-billion dollar industry!”
Since its invention in 1872, the injection molding process and the plastic industry has become a multi-billion dollar industry, with 32% of all plastics, by weight, processed by injection molding.
Injection molding has made possible the cheap and durable construction of many consumer and industrial items that have had a profound impact on society.
Invest and Cost Drivers of the Plastic Injection Molding Industry
Once a proofable, fullyexperience company decides to open or relocate a Plastic Injection Molding facility, then the next strategic shift is would be to “check” the following drivers:
- Human and machine engineering
- Infrastructure (competitive real estate & large capacity)
- Low cost Labor force (skilled and unskilled)
- Low transportation cost
- Energy
The Plastic Injection Molding industry was concentrated in China and other Asian countries. Companies did not hesitate and established their operations in Asia in order to take advantage of the cheap labor market.
As years passed by, a “reversal trend phenomenon” occurred; the trend started reversing when a large percentage of U.S. companies operating in China started to move back to the United States looking for integrity in their business environment and quality assurance for their customers.
Subsequently, the cost meter started to increase, so companies slowly and strategically started off shoring to Latin-American countries looking for competitive costs and pioneering new markets.
Today, world-class known U.S, European and Asian companies are operating in Central America in the search for quality communication, continuity of supply, skilled and unskilled labor force at most competitive cost, infrastructure and logistics for their customers.
Other related manufacturing business such as: medical, consumer and industrial plastic molding related production are being towed from the Asia market to U.S. and Latin-America, and Green Valley Industrial Park plays a very important role: The future epicenter of the plastic molding industry.
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