Dip Molding Industry Information
IQS Newsroom Articles on Dip Molding
Dip molding is the process of molding plastic parts, products and
consumables by dipping a mold into liquid plastic then treating the
product with heat. Most dip molding manufacturers also provide dip coating
services, which use a similar process to partially or fully coat parts
and products in various types of polymers. Both processes are common in
consumer industries, medical equipment and electronic connectors. Dip molders produce plastic closures like plastic caps and plastic plugs for packaging and furniture industries, as well as latex gloves, handle grips, bellows and condoms for consumer industries. Plastic coating is typically a polymer coating or vinyl coating, the most common being PVC coating and plastisol coating. In outdoor applications, UV coating is used to guard against harmful ultraviolet rays. Polyethylene coatings and urethane coatings are also applied by dip coaters. Dip moldings may be made from all of these materials as well.
During
the dip molding process, the polymer or vinyl material is kept in a
liquid state while heated and primed aluminum or steel "mandrels", or
molds, are dipped into the plastic from an overhanging rack. Wall
thicknesses can be determined by how long the mandrels are left in the
plastic as well as at what temperature the liquid plastic and mandrels
are kept. Double walls may be applied with multiple dippings.
Plastisol, which is a vinyl compound and the most common polymer used
in dip molding and dip coating, is liquid at room temperature,
solidifying permanently when heated. The polymer on the mandrel is
heat-treated even if it is not plastisol, as most polymers` properties
are improved with some heat processing; when the polymer has fully
solidified, it is stripped from the mandrel and moves on to secondary
processing. In this way, a long list of protective parts and products
are made, including gas pump handles, floats, boots, cleaning gloves,
end caps and hole plugs.
Dip coating is
performed the same way dip molded parts are manufactured, except that
instead of dipping mandrels into liquid polymers or plastisol, the
parts which require coating are hung from an overhead rack and dipped.
Some products and parts may be fully immersed, such as plastic coated
fences, wire forms or racks, while others are half-coated to serve as
grips, tool handles, electrical connectors or cushion covers. Many
types of garden tools, fitness equipment and outdoor equipment have
protective plastic handle grips or foot grips to make for easier, safer
handling and longer equipment life. Electronic connectors such as
jumper cable connectors have insulating plastic-dipped grips to protect
from electric shock while handling. Although plastisol is by far the
most commonly used polymer for plastic dip molding and dip coating,
other polymers such as vinyl, PVC, latex, neoprene, urethane, silicon
and rubber are used to manufacture dip coatings and dip molded parts as
well.
Plastic dip molding and dip coating fill
a unique niche in manufacturing which no other plastic or rubber
processes are fully capable of replicating. Dip moldings and coatings
are highly cost-effective, as there are no dies to fabricate, and most
plastic coated and molded parts require little - if any - secondary
processing. Labor costs are low, and the dip molding and coating
processes can manufacture high volumes in a short time. In addition to
providing a colorful, attractive finish to various products, plastic
coatings and plastic caps provide corrosion resistance, scratch and
wear protection and a smooth, tactile, resilient grip for safe, easy
handling. A variety of finishes are available for dip molded parts and
coatings, from smooth satin finishes to rough matte finishes.
Specialized types of urethane or nitrile molding can coat or mold
products in the form of foam, providing extra cushioning.
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Dip Molding and Dip Molder
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