Overmolding & Insert Molding

Founded in 1978, Zhongde is a professional cnc machining company focusing on
OEM & ODM customized services. Based on 40 years technology deposition, we have
developed a one-stop solution from mold designing and rapid prototyping to mass
production. Our manufacturing capabilities include plastic injection molding
service, compression molding service, CNC machining service, metal stamping
service, 3D printing service, custom molding service, overmoulding services,
etc.

Zhongde can provide over-molding and insert overmolding to produce unique
multi-material parts. Our production materials range from thermoplastic to
elastomer-rubber, as well as metal. We've broken down the differences and
similarities between the two processes. Let us help you decide which process is
right for your project.

Both over-molding and insert molding processes involve putting two types of
materials together to make one part,also named molding over molding.
Overmolding is a two steps process that one to create the substrate and one for
the oversold that goes on top of it. Insert molding is a slightly faster
process as it takes only one step that the two materials are molded at the same
time.

Guideline of Overmolding & Insert Molding

Insert molding injection is a process where a single part is created using two
or more different materials in combination. Traditonally, overmolding starts
with injection molding a hard plastic resin that has a higher melting point.
Once that part is cooled, another material is injection molded over the first
part, resulting in a single, finished product.We also offer injection molding
threaded inserts.

Insert molding combines metal and plastics into one single part. It allows
plastic to bond to insert pieces, mostly brass or stainless steel metal
component, which go inside a mold cavity. There are many options for insert
that can be placed into the mold. A few of examples are warming labels,
threaded bushings, wires, batteries, etc.

Size of Overmolding & Insert Molding

Below table shows the size of Overmolding & Insert Molding parts we usually
make. If you need a larger size, we can also help you achieve it.

Size Metric Inch
Length 2500 98.4
Width 2000 78.7
Height 1500 59
Available Material of Overmolding And In sert Molding In addition to the
general materials listed below, Zhongde can also modify the materials
according to the special needs of customers. Our professional engineers will
adjust the raw material formula to meet the unique conditions of use.

Overmolding & Insert Molding Plastic

ABS Acrylonitrile Butadiene Styrene

PA 6 Polyamide 6, Nylon 6

PA 6/6 Polyamide 6/6, Nylon 6/6

POM Acetal Polyoxymethylene, Delrin

PP Polypropylene

PE Polyethylene

LDPE Low-Density Polyethylene

HDPE High-Density Polyethylene

UHMWPE Ultrahigh Molecular Weight Polyethylene

PTFE Polytetrafluoroethylene

PEEK Polyether Ether Ketone

PC Polycarbonate

PMMA Polymethyl Methacrylate, Acrylic

PS Polystyrene

PVC Polyvinyl Chloride (Shore D)

PU Polyurethane

Overmolding & Insert molding Rubber
NR Natural Rubber

NBR Nitrile Rubber

SBR Styrene-butadiene Rubber

HNBR Hydrogenated Nitrile

CR Neoprene Rubber

VMQ Silicone

LSR Liquid Silicone Rubber

FVMQ Fluorosilicone

FKM Fluorocarbon

FFKM Perfluorocarbon Rubber

EPDM Ethylene-Propylene Diene Monomer Rubber

IR Polyisoprene Rubber

IIR Butyl Rubber

Additives of Overmolding & Insert Molding
Name Description
UV absorbers Absorb UV radiation, slowing down the degradation of the
material when used outdoors.
Flame retardants Prevent ignition and inhibits spread of fire.
Plasticizers Increase flexibility and promotes plasticity, reducing
brittleness of the material.
Colorants Used to color plastics.
Carbon fibers Increase strength, toughness, and rigidity of the material at
the expense of making the material more brittle.
Glass fibers Increase strength, toughness, and rigidity of the material at
the expense of making the material more brittle. It is more flexible than
carbon fibers.

Surface Finishing of Overmolding & Insert Molding

Name Description
Glossy The mold is smoothed and then polished with a diamond buff, resulting
in parts with a mirror-like finish.
Semi-gloss The mold is smoothed with fine grit sandpaper, resulting in
parts with a fine surface finish.
Matte The mold is smoothed using fine stone powder, removing all machining
marks.
Textured finish The mold is first smoothed with fine stone powder and then
sandblasted, resulting in a textured surface.
As-machined finish The mold is finished to the machinist's discretion.
Tool marks may be visible.

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