ADVANCED MULTI-MATERIAL

Two Shot (2K) Injection Molding

Rapidaccu delivers advanced two shot injection molding technology for complex multi-material plastic components. Our 15 years of expertise ensures perfect material bonding, precise registration, and superior product quality.

2-Shot
Technology
15+
Years Exp
100%
Bond Quality
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Two Shot Molding 1 Two Shot Molding 2 Two Shot Molding 3 Two Shot Molding 4
Two Shot Molding Main

What is Two Shot Injection Molding?

Two shot injection molding, also known as 2K molding or multi-shot molding, is an advanced manufacturing process that combines two different materials or colors into a single component in one molding cycle. This eliminates the need for secondary assembly operations while creating strong molecular bonds between materials.

The process uses specialized molding machines with two injection units and a rotating or sliding mold system. The first material is injected and partially cooled, then the mold rotates or opens to allow the second material to be molded onto or around the first shot.

Key Advantages

  • Eliminates assembly operations and reduces labor costs
  • Creates permanent molecular bond between materials
  • Enables complex multi-material designs
  • Improves product aesthetics and functionality

Multi-Material

Combine hard and soft plastics in one part

Multi-Color

Create vibrant color combinations without painting

Strong Bonding

Molecular adhesion for permanent assembly

Cost Effective

Reduce assembly and labor expenses

Material Combinations We Offer

Hard + Soft Plastics

PC + TPE/TPU

Rigid structure with soft-touch grip areas

ABS + TPE

Durable base with rubber-like seals

PP + TPE

Flexible functionality with rigid support

Ideal for tools, handles, consumer products requiring ergonomic grip zones and sealing applications.

Multi-Color Combinations

ABS + ABS

Different colors in single component

PC + PC

Transparent and opaque combinations

PP + PP

Contrasting or complementary colors

Perfect for automotive trim, consumer electronics, and products requiring distinctive visual design without painting.

Engineering Plastics

PA + TPE

High strength with flexible elements

PBT + TPE

Electrical insulation with sealing

POM + TPU

Precision mechanics with dampening

Designed for technical applications requiring superior mechanical properties and performance characteristics.

Two Shot Molding Process

1

First Shot Injection

First material injected into primary mold cavity to form base structure

2

Partial Cooling

First shot cools sufficiently to maintain shape during transfer

3

Mold Rotation

Part transfers to second mold station via rotating or sliding mechanism

4

Second Shot Injection

Second material injected onto or around first shot creating bond

5

Final Cooling & Ejection

Complete part cooling followed by ejection of finished component

Technical Capabilities

Our advanced two shot injection molding equipment and expertise enable complex multi-material component manufacturing with exceptional precision and repeatability.

Rotary & Transfer Systems

Both rotary table and core-back transfer mechanisms for optimal part design flexibility

Precision Registration

Tight tolerance control ensures perfect alignment between first and second shot materials

Temperature Control

Independent barrel temperature management for each material optimizes bonding and quality

Specifications

Machine Tonnage 150-650 tons
Shot Capacity Up to 500g per shot
Typical Cycle Time 30-90 seconds
Registration Accuracy ±0.05mm

Applications & Industries

Automotive Interior

Dashboard components, control knobs, gear shifters, and interior trim with soft-touch surfaces

  • • Multi-color instrument clusters
  • • Soft-grip steering wheel controls
  • • Door handles with sealing

Power Tools

Ergonomic tool housings combining rigid structure with comfortable rubber grips

  • • Drill and driver handles
  • • Impact wrench grips
  • • Saw and grinder housings

Consumer Electronics

Device housings with integrated seals, buttons, and decorative elements

  • • Mobile phone bezels
  • • Wearable device bands
  • • Remote controls

Medical Devices

Surgical instruments and diagnostic equipment with integrated seals and grip zones

  • • Handheld diagnostic tools
  • • Syringe components
  • • Medical device housings

Household Products

Appliances and consumer goods with enhanced aesthetics and functionality

  • • Kitchen appliance controls
  • • Toothbrush handles
  • • Razor grips

Gaming & Toys

Controllers and toys with multi-color designs and ergonomic features

  • • Game controllers
  • • Action figure components
  • • Educational toys

Design Considerations for Two Shot Molding

Key factors to optimize your multi-material design

Design Best Practices

  • Material Compatibility: Select materials with compatible melting temperatures and chemical bonding properties
  • Bonding Surface: Design adequate surface area contact between materials for strong adhesion
  • Draft Angles: Incorporate appropriate draft for both materials to ensure proper ejection
  • Wall Thickness: Maintain uniform wall thickness within each material zone to prevent warpage

Common Challenges

  • Flash Formation: Proper mold design and clamping force prevent material overflow at parting lines
  • Poor Bonding: Material incompatibility or improper processing temperatures can cause delamination
  • Registration Issues: Misalignment between shots requires precise tooling and machine control
  • Cycle Time: Balancing cooling time between shots while maintaining quality and throughput

Frequently Asked Questions

What materials can be combined in two shot molding?

Materials must be chemically compatible for molecular bonding. Common combinations include rigid plastics (PC, ABS, PP) with soft elastomers (TPE, TPU), or same-family plastics in different colors. Our engineering team can recommend optimal material pairings for your specific application requirements.

How strong is the bond between materials?

When properly processed with compatible materials, two shot molding creates a molecular bond that is stronger than mechanical fastening or adhesive bonding. The bond strength typically exceeds the tensile strength of the weaker material, making delamination virtually impossible under normal use conditions.

Is two shot molding more expensive than traditional molding?

Initial tooling costs are higher due to more complex mold design and specialized equipment. However, eliminating secondary assembly operations, reducing labor costs, and improving product quality often result in lower total production costs for medium to high volume applications. We provide detailed cost analysis for your project.

What is the minimum order quantity for two shot molding?

Due to specialized tooling and setup requirements, two shot molding is most economical for production volumes starting from several thousand pieces annually. For lower volumes, we can recommend alternative multi-material solutions. Contact us to discuss your specific volume requirements and project feasibility.

Can you provide DFM support for two shot parts?

Yes, our experienced engineering team provides comprehensive Design for Manufacturing analysis for two shot molding projects. We review material selection, bonding interfaces, gate locations, and part geometry to optimize manufacturability, quality, and cost-effectiveness before tooling begins.

Why choose Rapidaccu for two shot injection molding?

With 15 years of injection molding expertise, specialized two shot equipment, comprehensive material knowledge, and ISO-certified quality systems, Rapidaccu delivers reliable multi-material components. Our Shenzhen facility combines advanced technology with skilled technicians to ensure consistent results for global customers.

Start Your Two Shot Molding Project

Experience the advantages of advanced multi-material injection molding technology

Contact Rapidaccu

Manufacturing Facility

Rongli Industrial Park, Dalang, Longhua District, Shenzhen, China

Experience

15 years of injection molding expertise

Two Shot Advantages

Specialized two shot equipment
Material compatibility expertise
Complex mold design capability
Comprehensive DFM support
ISO certified quality systems

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