TEBATE SERVICES
Insert Molding Service
Unlike molds that use secondary injection molding to produce the final part, insert molding usually consists of a preformed part (usually metal) loaded into the mold and then encased in plastic to create an improved function or mechanical property.
One method of molding using inserts is threaded inserts, which enhance the mechanical properties of the plastic parts’ ability to fasten together, especially during repeated assembly. Bushings and sleeves are another good way to improve the durability of parts for fitting parts that require higher wear resistance due to moving parts.
What is Insert Molding?
Insert injection molding is forming or molding plastic parts around other non-plastic parts or inserts. The components inserted are usually simple objects, such as threads or rods, but in some cases, the inserts can be as complex as a battery or motor.
In addition, insert molding combines multiple combinations of metal and plastic or materials and components into a single unit. The process uses engineering plastics to improve wear resistance, tensile strength, weight reduction, and metallic materials to improve strength and electrical conductivity.
Insert molding involves injecting plastic around a pre-placed insert to form a strong, durable, and permanent bond between the molded plastic and the insert. During production, inserts are placed in empty mold cavities, filled with molten thermoplastic, and cooled to form solid parts.
Cost-effective, accurate, and consistent insert molding for small to high-volume production.
Basic Guide of Plastic Overmolding
Unlock the potential of your encapsulation molding project with the following injection molding design considerations, including mold details, available materials and colors, and finishing and post-processing options
Design Guide of Insert Molding
Right Substrate
The initial component or substrate is the foundation of the overmolded product. The substrate must be able to withstand the overmolding process, and its shape must be compatible with the overmolding material. Common substrate materials include metals, plastics, and composites.
Parting Line
The parting line is the point where the two materials meet. The parting line should be located in a non-critical area of the final product to minimize any visible lines or parting marks.
Wall Thickness
Maintaining uniform wall thickness throughout the part is important to ensure consistent strength and prevent warping or sink marks. Varying wall thickness can cause uneven cooling during the molding process, leading to defects.
Ensure that the wall thickness of the substrate and the thickness of the cladding die are uniform from the beginning of the process. The 0.060″ to 0.120″ (1.5 mm to 3 mm) wall thickness will ensure good adhesion in most cladding applications.
Corners
Sharp corners can cause stress concentrations that weaken the part and make it more prone to failure. It’s better to use rounded corners or fillets to distribute stress and strengthen the part.
Draft Angles
Draft angles are angled surfaces that allow the part to be easily ejected from the mold. A minimum draft angle of 1 degree is recommended to ensure smooth ejection and avoid damage to the part.
Gate
The gate is the location where the molten material enters the mold. Gates should be located in areas where the overmolded material will flow uniformly and bond well to the substrate. Common gate locations include the edge of the part, the center of the part, or the end of the part.
TEBATE’s Capabilities of Insert Molding
Maximum Part Size
- 800 x 800 x 400 mm
- 31.5 x 31.5 x 15.7 in
Minimum Part Size
- 5 x 5 x 5 mm
- 0.2 x 0.2 x 0.2 in
Tolerance
- Standard tolerance: ±0.005″ (0.127mm)
- Best achievable tolerance: ±0.001″ (0.025mm)
Delivery Time
- As low as 2 weeks for T1 samples
- After T1 sample approval, lead time for < 10,000 parts is as low as 1 week
Tool validation
- Standard process is to produce a small set of T1 samples for approval before initiating full production
Maximum Press Size
- 1200T
MOQ
- 1Pcs
Mold Information
Rapid processing
Mold with steel cavity and core, injection life of 5,000 to 10,000 times
Usually processed within 2 weeks.
Production tooling
Steel tool with a projectile life of up to 1 million cycles
Can integrate side pull or CAM action
It is usually completed within 3 weeks
Multi-cavity or set mold
Multiple identical cavities or parts series are machined into a single tool
Allowing more parts to be produced per injection minimizes unit cost
Insertion Parts
Inserts are placed in a mold and molded around it to extend tool life for key features
Allows you to mold inserts, such as spiral coils, into your design
Plastic Materials of Insert Molding
Most Common Materials
Additives and fiber
Additives and fiber
Acrylonitrile Butadiene Styrene (ABS)
Nylon (PA 6, PA66, PA12)
UV absorbers
Polyethylene (PE)
Polycarbonate/Acrylonitrile Butadiene Styrene (PC/ABS)
Flame retardants
Polypropylene (PP)
Polyurethane (PU)
Plasticizers
Polycarbonate (PC)
High Density Polyethylene (HDPE)
Colorants
Low Density Polyethylene (LDPE)
Glass fibers
Polyvinyl chloride (PVC)
POM (Acetal/Delrin)
Polyethylene Terephthalate (PET)
Thermoplastic Elastomer (TPE)
Insert Materials
Most Common Materials
Plastics
Brass
PP
Stainless Steel
Nylon
Aluminum 6061
ABS
Aluminum 7075
Surface Finishes of Overmolding
Coloring
Surface Roughness Grade
Post-Processing
Pantone color matching
A1 – A3
Pad printing
RAL color matching
B1 – B3
C1 – C3
D1 – D3