| |
Plastic Molding Industry Information
Injection plastic molding is the most common method
used by plastic suppliers in the plastic processing industry. Since its
invention in 1872, plastic molding and the plastics industry has become
a multi-billion dollar industry, with 32% of all plastics processed by
injection plastic molding. Injection plastic molding machines are used
to produce complex plastic parts. An injection plastic molding machine
has a barrel section which is heated first. Plastic pellets or granules
are fed into a hopper where a screw pushes them to the heated barrel.
In the barrel, the pellets or granules are heated to the melting point.
The molten plastic material is then injected into the cavity of a split
die chamber/mold, which is then clamped shut. The plastic resin cools
as water or other fluids circulate through the cooling system of the
mold, extracting the heat. The molded plastic part is held in the mold
under high pressure until the part solidifies. The plastic part is finally
ejected from the plastic mold, and the process begins again.
Plastic suppliers accomplish the injection molding process using equipment
that is available in many configurations. Most commonly, a hydraulic
oil injection molding machine is used to produce many molded parts. Hydraulic
oil machines use the force of hydraulic fluids to move the mold through
the machine. Next in popularity is the toggle plastic molding machine.
Toggle machines use mechanical links to advance the mold in the machine.
Hybrid hydraulic/toggle machines are beginning to emerge in the plastic
molding industries. Hybrid machines are used to eliminate some of the
problems of other injection plastic molding machines, such as slow processing
rates of parts and rapid wear and tear of machines. All injection molding
machines inject molten plastic material into a mold, but they may use
various methods to move the mold, move un-melted plastic pellets and
accomplish other parts of the process.
There are many advantages to the injection plastic molding process.
Some advantages of injection molding include high production rates and
a wide range of plastic material which can be used. Normally there is
little need to finish parts after the molding is complete. The cost per
part is very low despite the high cost of tooling. Injection plastic
molding can produce very complex parts, and often parts for which no
other process is available. Other advantages of the injection molding
process include the efficient use of materials and energy, precision-formed
parts and a negligible amount of waste produced.
From medical equipment, computer and automotive parts to office supplies,
toys and tools, molded plastic parts are found in almost every sector
of industry and our lives. Some specific examples of parts made using
the injection plastic molding process are screwdriver handles, catheters,
contact lens containers, monitors, mop buckets and video game cartridges.
Injection plastic molding is primarily used for thermoplastics. However,
a small amount of thermosets and elastomers are also subjected to this
process. Biodegradable plastics are also molded. Products such as biodegradable
cutlery and plastic pots are now being produced using this molding process.
Injection molding has made possible the inexpensive and durable construction
of many industrial items that have a profound impact on industry and
society.
|
|
