Plastic Injection Molding
Built for Precision Work
Our plastic injection molding service handles high-precision components by injecting molten thermoplastic into custom molds under pressures hitting 200 MPa, producing complex parts with tolerances down to ±0.004″. We run conventional molding, two-shot, overmolding, and insert molding depending on what your application needs – serving automotive, medical devices, and other industries where specs aren’t negotiable. From prototype through production, we deliver injection molded plastic parts that actually meet your requirements without the usual back-and-forth over dimensional issues.
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What is Plastic Injection Molding?
Plastic injection molding is a manufacturing process that creates precision parts by injecting molten plastic into custom-designed molds. The process involves injecting molten plastic through six critical stages: clamping, injection, dwelling, cooling, mold opening, and part removal. Cycle times range from seconds to minutes, with cooling typically taking 70-80% of the total cycle. Our state-of-the-art injection molding machines operate with pressures from 50 to 500 MPa and clamping forces from 1 to 3000 tons, accommodating everything from micro-components to large-scale consumer products.
Key Process Parameters
| Parameter | Range | Impact |
|---|---|---|
| Injection Pressure | 50–500 MPa | Determines fill quality and detail precision |
| Mold Temperature | 20–120 °C | Affects surface finish and cycle time |
| Material Melt Temperature | 160–350 °C | Controls flow characteristics and molecular structure |
| Cooling Time | 3–120 seconds | Most time-consuming phase; reducing by 1 second can save weeks annually |
What Injection Molding Services do We Offer?
Yijin Hardware provides comprehensive custom plastic injection molding services including conventional molding, two-shot (2K) molding, overmolding, and insert molding technologies. Our injection molding service delivers high-volume production with exceptional part-to-part repeatability of ±0.004″. The injection mold tooling we create enables complex multi-material or multicolor parts in a single cycle, while our custom injection mold capabilities apply a second material layer over primary components for enhanced functionality.
Advanced Molding Technologies
- Gas-Assisted Injection Molding: Incorporates pressurized gas to create hollow sections, reducing weight while maintaining structural integrity
- Water-Assisted Injection Molding: Utilizes high-pressure water for faster cooling, improved finish, and decreased cycle times
- Foam Injection Molding: Creates lightweight parts with foam cores ideal for automotive components and furniture applications
- Thermoset Injection Molding: Processes silicone, polyurethane, and epoxy materials for specialized applications
How does Our Scientific Molding Process Work?
Our Scientific Injection Molding (SIM) process ensures exceptional part quality through data-driven manufacturing and rigorous quality control. The plastic injection molding process requires an injection molding machine and begins with comprehensive material analysis to determine optimal processing parameters including melt temperatures, injection pressures, and cooling rates. During production, our machines capture 20+ process variables per cycle with specialized sensors monitoring cavity pressure, melt temperature, and cooling uniformity. This approach helps us maintain dimensional stability within ±0.004″.
Scientific Molding Benefits
- Reduced cycle times by up to 15%
- Elimination of common defects including sink marks, flash, and warping
- Documented process validation for regulatory compliance, including ISO standards
- Decoupled molding techniques for maximum precision and repeatability
- Precise mold cavity tolerances of ±0.005″ with additional ±0.002″ per inch for shrinkage compensation
What Materials Can We Process?
Yijin Hardware processes a comprehensive range of plastic material options for injection molding applications. Our molding materials include engineering thermoplastics such as ABS, PC, PA (Nylon), POM (Delrin), and high-performance polymers like PEEK and PEI (Ultem). We also process commodity resins including PP, PE, PS, and specialized formulations with glass fiber, carbon fiber, or mineral reinforcements for production parts.
Material Selection Guide
| Material Type | Properties | Applications |
|---|---|---|
| Engineering Thermoplastics (ABS, PC, PA, POM) | High strength, temperature resistance | Automotive parts, electronics |
| High-Performance Polymers (PEEK, PEI) | Extreme heat/chemical resistance | Aerospace, medical devices |
| Elastomers (TPE, TPU, TPV) | Flexibility, impact absorption | Grips, seals, gaskets |
| Bio-Based Polymers | Renewable sources, biodegradability | Sustainable packaging, consumer products |
Which Industries Benefit From Our Molding Solutions?
Our plastic injection molding company supports critical applications across a wide range of industries requiring precision plastic components. The medical industry utilizes our ISO 13485-certified clean room for surgical instruments and diagnostic equipment. Automotive clients depend on our high-tolerance parts for interior systems and sensor housings that withstand demanding environments. Compared to CNC machining, injection molding offers cost advantages for high-volume supplier production.
Industry Applications
- Medical: ISO 13485 compliant components with biocompatibility for Class I, II, and III devices
- Automotive: Parts meeting IATF 16949 standards for interior, exterior, and powertrain systems
- Electronics: Precise housings, connectors, and insulators with controlled electrical properties
- Consumer Products: Aesthetically pleasing components with complex geometries and finishes
- Aerospace: Lightweight, high-strength components meeting rigorous industry specifications
How do We Optimize Designs for Manufacturability?
Yijin Hardware optimizes injection molded designs through comprehensive Design for Manufacturability (DFM) analysis and simulation. Our engineering team evaluates wall thickness uniformity to prevent warping and sink marks in the final plastic part, recommending optimal thicknesses between 1.0 and 3.0 mm for most applications. Part geometry receives particular attention, with our standard recommendation of 0.5° minimum draft for smooth surfaces and up to 3-5° for textured areas.
Design Optimization Elements
- Wall Thickness Analysis: Uniform wall thickness prevents sink marks and warping
- Gate Location Optimization: Strategic placement prevents flow lines and weld lines
- Draft Angle Implementation: Minimum 0.5° for smooth surfaces, up to 5° for textured areas
- Mold Flow Simulation: Computer modeling of material flow identifies potential defects before tooling
- Shrinkage Compensation: Material-specific shrinkage rates (0.4-2%) factored into production tooling dimensions
Why Choose Yijin Hardware for Plastic Injection Molding?
Yijin Hardware delivers full-service high-quality injection molded parts through our scientific approach, automation, and comprehensive quality control. Our facility operates injection molding technology with clamping forces from 50 to 1500 tons, accommodating everything from molded prototypes to production parts with exceptional precision. Unlike competitors, our in-house tool department creates, maintains, and modifies molds with rapid lead times to optimize your supply chain.
Quality Assurance System
- First Article Inspection (FAI): Comprehensive verification of first production parts
- Statistical Process Control (SPC): Continuous monitoring of critical dimensions and parameters
- Computer-Aided Inspection (CAI): Automated dimensional verification to ±0.001″
- Material Certification: Full traceability and testing for critical applications
- Standards Compliance: ISO 9001:2015, ISO 13485, and ASTM D638 test methods for plastic manufacturing
What Our Clients Say
Plastic Injection Molding FAQs
Operating an injection molding machine follows the SPI injection molding process. First, verify proper mold installation and cooling connections. Program control parameters including temperature settings, injection pressure, and cycle times. The raw plastic material is first melted in the injection unit, then injected into the mold where it solidifies into the final plastic part. Modern machines feature process monitoring systems that maintain part quality throughout production runs through automatic adjustments based on real-time data.
Calculate injection size by determining the volume of material needed for the part plus runners and sprue. Start with the part volume from your CAD model, add 10-15% for cold runner systems, and convert to weight using your resin’s specific density (typically 0.9-1.4 g/cm³). For high-performance applications, conduct a short shot study during process validation to determine optimal shot size, ensuring complete cavity filling without excess material that could cause defects in molded parts.
A 3 plate mold consists of a stationary plate (A), middle plate (B), and movable plate (C). This design automatically separates runners from parts during ejection, ideal for applications requiring multiple gate locations or center gating. While more complex than standard 2 plate molds, 3 plate designs reduce secondary operations, decrease cycle times, and minimize gate vestige on high-precision thermoplastic parts. This tooling configuration is particularly valuable for complex geometries in both prototype and high-volume production where part quality is critical.
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