Insert Molding | China Manufacturer & Supplier

Insert Molding process by YiguProto China manufacturer — Insert Molding at YiguProto: metal insert placed in the cavity, then encapsulated with resin in one integrated part.

Insert molding is an injection molding process. A metal, ceramic, or engineered-plastic insert is placed into the mold cavity first. Then molten thermoplastic is injected around it. As it cools, the insert and the plastic lock together into one solid component.

Instead of molding a part and then pressing or gluing a fastener in later, insert molding does the joining during the molding cycle itself. No press-fit machine. No second shift. No loose inserts rattling in a box.

Common inserts we handle:

Threaded metal inserts (brass, stainless steel, steel) for screw bosses
Electrical contacts, pins, and terminals for connectors and sensors
Bushings, sleeves, and bearings that need abrasion resistance
Ceramic, plastic, and other heat-resistant hardware

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Inserts spin, pull out, or sit off-center

A weak grip between the plastic and the insert turns into a failed torque test — or a returned batch. It usually comes down to the wrong insert shape, gate location, or wall balance around the insert.

Tooling quotes drag on, then surprise you

Long waits for a number, then mold steel nobody explained, hidden costs for side actions, and no idea when samples will actually ship.

Supplier hand-offs keep breaking

One shop makes the mold, another molds the parts, a third does inspection. When something slips, nobody owns it — and you are the one explaining the delay to your customer.

Factory-direct pricing — no trading-company markup, no agent in the middle
Quotes within 24 hours, most within a few working hours
Free DFM feedback before you place the order — we flag risks, not after the tool is cut
In-house tooling and molding — mold making, injection, and inspection under one roof
Threaded inserts we commonly stock: PEM, Dodge, Tri-Star, Spirol, and Tappex compatible types
Strict quality checks on every batch, with reports on request

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In-house tooling and molding at YiguProto factory — Mold making, injection molding, and inspection — all handled in-house at our factory.

Rapid Tooling & Prototyping

Need to prove the design before committing to a full production mold? Aluminum 7075-T6 tooling gives you functional samples fast, so you can confirm fit, retention, and market interest while keeping tooling spend low.

Aluminum, S50C, P20, and NAK80 tool inserts available
MUD (Master Unit Die) quick-change mold base system
Side actions handled with hand-pick inserts
T1 samples off a steel tool in as fast as 10 business days

Production Tooling

When the design is locked, we build stand-alone production tools, owned by you, sized to your real volume. We align steel grade, cavity count, and gate design with the insert geometry so retention stays stable run after run.

P20, H13, S7, NAK80, and SS420 insert steel available
Single-cavity, multi-cavity, and family molds
Mold polished to remove visible tooling marks
Designed for stable, repeatable output at production volumes

Capability	What we offer
Process	Metal, ceramic, and engineered-plastic insert molding (single-shot encapsulation)
Best for	Threaded inserts, electrical contacts and terminals, bushings, sleeves, reinforced housings
Insert materials	Brass, stainless steel, steel; ceramic and heat-resistant plastic inserts
Mold materials	Aluminum 7075-T6 (rapid), P20 / H13 / S7 / NAK80 / SS420 (production)
Molded materials	Wide range of thermoplastics; liquid silicone rubber (LSR) on request
Tolerance	Down to ±0.025 mm (±0.00098 in), depending on geometry
Typical part size	From small connectors up to 800 × 1000 × 400 mm envelope
Mold validation	T0 / T1 / T2 samples provided before mass production
Volumes	One-off prototypes, low-volume bridge runs, and full production — no strict MOQ
Lead time	Mold making to sample delivery: 15–45 business days; molded parts 3–10 business days
Inspection	First Article Inspection (FAI), full in-process and final checks
Certifications	ISO 9001 quality management; ISO 13485 available for medical programs

1

Upload Your Design

Send STEP, STP, IGES, STL, SLDPRT, IPT, or a PDF drawing with quantities, material, and tolerances.

2

Get a Quote & DFM in 24h

A clear, itemized quote plus free design-for-manufacturing feedback — insert type, gate location, wall thickness, and risk callouts.

3

We Build & Mold

Tooling and molding are done in-house. We run T0/T1/T2 samples and share results before mass production.

4

Inspect, Pack & Ship

Every batch is inspected, securely packed, and shipped worldwide with full documentation and tracking.

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One integrated part, no press-fit step

The insert is locked in during the molding cycle, so you remove a downstream joining operation from the build.

Lower labor and handling cost

Fewer secondary operations and fewer loose components mean a lower total program cost versus molding and assembling separately.

Stronger, more reliable retention

Plastic flows around the insert to form a permanent bond — better wear resistance and structural integrity than a pressed-in fastener.

Lighter and more compact

Insert molded parts can stay lighter and smaller than an all-metal construction doing the same job.

Multi-material integration

Mix metal conductivity, plastic insulation, and abrasion-resistant bushings in one component.

Scales with your program

Same process from a single prototype through low-volume bridge runs to full production — no re-qualifying a new supplier later.

Consumer goods

Toothbrushes, power-tool handgrips, shampoo bottles, and shaving razors — products that need both utility and a clean appearance in one molded assembly.

Medical devices

Instrument housings, handheld tools, and sensor components — biocompatible material selection available, with ISO 13485 programs supported.

Automotive & aerospace

Gears, housings, brackets, connectors, and controls where retention stability, strength, and certified quality are non-negotiable.

Electronics & communication

Threaded inserts in molded enclosures, encapsulated wire plug connections on cables, and compact connector bodies.

Industrial & robotics

Bushings and sleeves for moving joints, reinforced mounting points, and abrasion-resistant hardware interfaces.

Microelectronics

Connectors, switches, and sensors that demand high precision and tight tolerances.

Insert Molding — pre-placed insert

A preformed part — usually metal — is loaded into the mold, then overmolded with resin in one shot. Best when you need a permanent, load-bearing joint and want to eliminate a separate assembly step.

Typical use: threaded inserts, bushings, electrical contacts, metal-reinforced housings.

Overmolding — two shots, two materials

A rigid substrate is molded first, then a second material — typically a soft TPE — is molded over it. Best when you want a soft grip, seal, or cosmetic contrast on a part that already exists.

Typical use: toothbrush handles, soft-touch tool grips, seals and gaskets.

Still unsure? Send us the part and we will tell you which route costs less and performs better for your application.

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How fast can you make a quote?

Send your drawings or 3D files. Most quotes come back within a few hours on business days, and never more than 24 hours.

Do you keep my files confidential?

Yes. All customer files and ideas are treated as confidential, and we sign an NDA when you need one.

Can you help with design for manufacturing (DFM)?

Yes. Our engineers review your design and suggest changes that cut cost, improve insert retention, or speed up delivery — before the tool is cut.

What is your minimum order quantity (MOQ)?

For insert molding, we support one-off prototypes and full production runs. There is no strict MOQ.

Do you offer free samples?

We can make samples for your approval. The sample cost depends on the process, and it is credited back against a production order.

What is your lead time for insert molding?

For molded parts, typical lead time is 3–10 business days. From mold making to sample delivery, plan for 15–45 business days depending on quantity and complexity.

Can you handle low and high volumes of insert molding?

Yes. We support one-off prototypes, small bridge runs, and full production volumes using the same process and the same team.

Which threaded inserts do you work with?

We commonly use PEM, Dodge, Tri-Star, Spirol, and Tappex-compatible inserts, and we can source other types on request.

What materials can be molded around the insert?

A wide range of thermoplastics, plus liquid silicone rubber on request. We will recommend the resin based on your strength, temperature, and cosmetic requirements.

Do you provide mold validation samples?

Yes. We provide T0, T1, and T2 samples before mass production so the insert position, retention, and appearance are confirmed before you commit to volume.

Insert Molding Service by a Trusted China Manufacturer & Supplier

One Shot. One Strong, Permanent Bond.

Most Insert Molding Headaches Start Before the Tool Is Cut