Over Molding

Over molding of keyplast is a special plastic molding process. Overmolding
custom injection molding is similar to the two-color molding or two-shot
molding process. Over moulding can make the surface of the product full of
softness and increase product functionality and added value.

With this technology, product functions can be increased, such as noise
reduction, vibration reduction, waterproof, anti-collision and added value.
Overmolds is widely used in mobile phone protective shells/mobile phone
protective sleeves.

Overmolding Process
Plastic overmolding has a process in which a certain materials used in
injection moulding is molded in a primary plastic mold, and the molded part is
taken out and placed in a secondary molding mold to inject the same or another
plastic material into tpu overmolding process. Overmolding process has key
factors as below:

1. The chemical or mechanical bonding strength between the polymers is not
enough, and the material of single or multiple parts is not completely filled;

2. Flashing of burrs on single or multiple material parts.

3. The injection molding machine must maintain the consistency of injection
molding.

Insert Molding VS Overmolding
Insert molding and overmolding injection molding are very similar, but there
are significant differences between the two processes. Injection overmolding is
a two-step process in which two separately molded parts are combined to enhance
product functionality. While insert injection molding is a slightly faster
process because the two plastic materials are molded at the same time. Besides,
over molding can not only give designers and engineers more creative freedom,
but cost-savings of assembled parts as well. Whether you choose insert molding
or over moulding, we understand the importance of creating a strong bond
between components. We'll recommend the right innovative polymer solution, like
thermoplastic polyurethane overmolding (TPU overmolding) to deliver the
chemical adhesion you need.

Overmolding VS Two Shot Molding
01
Two-shot injection molding
Two-shot injection molding is also called two-color mold injection. 2 shot
injection molding, also called 2k injection moulding, is to inject two plastic
materials on the same injection molding machine in two moldings, but the
product is only ejected once. The mold is usually completed by a set of molds
and requires a special two-color Injection molding machine.

The same back mold, different front molds, high production efficiency, good
product quality, suitable for mass production.

02
Over molding
Over molding, the two plastic materials are not necessarily injected on the
same injection molding machine, but are molded in two parts; after the product
is taken out from one set of molds, it is placed in another set of molds,
inject molding. Therefore, this molding process is usually completed by two
sets of molds, without the need for a special two-color injection molding
machine.

Injection overmolding is to first take part of the product out of injection
molding, and then put it into another injection molding machine for injection
molding. The efficiency will be slower and the cost will be higher, so it is
suitable for small batch production.

Why so many manufacturers like over molding?
Regarding this problem, we can learn one or two of the advantages of
overmolding injection molding.

First, the product quality of over-molding can be improved. Injection
overmolding can optimize the copolymerization of hard and soft materials to
form strong molecular bonds. The result is a single part with production and
feature advantages. It can be used for various product designs in injection
moulding applications. The injection overmolding also allows the use of
transparent plastics, colorful graphics, and fashionable finishes for molding,
thereby improving your product functionality and market value.

Second, plastic injection overmolding can reduce the cost of production.
Complete the entire production process in one injection molding machine,
overmolding injection molding effectively reduces unit costs, reduces
processing and secondary assembly, and reduces costs and waste associated with
assembly defects, thereby shortening the molding cycle and improving work
efficiency.

Furthermore, china injection molding factory can also improve people's
experience. Over the past 10 years, it has completely changed the aesthetic
standards, design ideas, and functional requirements of consumer products. The
use of plastic materials with different textures has improved the touch and
function of products. Many of the common toothbrushes and mobile phone
protective cases in our lives are products produced by using injection
overmolding technology.

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