Injection molded plastic parts moulding

In addition, our company has established cooperative relationships with plastic raw material suppliers, printing manufacturers, etc. to ensure the supply of raw materials and printing quality. Through our rich experience and perfect supply chain, our company can provide customers with high-quality customized injection molded plastic parts moulding products to meet their specific needs. At the same time, we have 10 years of professional foreign trade service experience, understand the foreign trade process, and better serve our customers. For injection molded plastic parts moulding products, we can make corresponding plastic parts, which is mainly done through injection molds.

Standard Process for Complete Plastic Part Injection Molding (Comprehensive Version)

The entire process comprises seven core stages: pre-production preparation, raw material pretreatment, mold installation and commissioning, mass production (injection cycle), post-processing/trimming, quality inspection, and warehousing. It is applicable to a wide range of plastic products, including home appliances, electric vehicles, motorcycles, storage containers, and small precision parts.

I. Pre-production Preparation

Drawing and Process Confirmation

Verify product 3D drawings, wall thickness, assembly tolerances, and aesthetic requirements; establish the standard process sheet, including raw material grade, color code, regrind ratio, mold temperature, melt temperature, and cooling time.

Equipment and Mold Inspection

Ensure the injection molding machine tonnage matches the mold size; inspect the hydraulic system, heating bands, cooling water circuits, robotic arms, and temperature control units; check the mold for rust, clogged air vents, or stuck ejector pins; and clear debris from the parting surface.

Preparation of Tooling and Auxiliaries

Prepare cutters, grinding tools, shaping jigs, drying hoppers, masterbatch, specialized mold release agents, EPE foam, packaging pallets, and inspection calipers.

II. Raw Material Pretreatment

Material Blending

Load virgin resin, masterbatch, and functional additives (UV stabilizers, flame retardants, antistatic agents) according to the specified ratios; if recycling is required, add clean regrind material at the prescribed proportion. Mix using a low-speed mixer for 5–12 minutes to ensure uniform dispersion of colorants and fillers, preventing defects such as streaks or white spots.

Drying and Dehumidification (Critical Step)

Hygroscopic plastics—such as PC, ABS, ABS+PC, and Nylon—must be dried to eliminate defects like silver streaks, bubbles, and paint delamination; PP, PE, and TPO require drying only for short periods in high-humidity environments.

After drying, seal the material container and transfer it to the injection molding machine's airtight hopper to prevent re-absorption of moisture.

Barrel Purging

When switching between materials or colors, purge residual material from the barrel using a purging compound to prevent material contamination, delamination, color inconsistency, or performance degradation. III. Mold Installation, Preheating, and Debugging

Hoisting and Clamping

Lift the mold using an overhead crane and position it against the injection molding machine platens; evenly tighten the clamping plates; connect cooling water and mold temperature controller lines; and run water to check for leaks.

Mold Preheating

Activate the mold temperature controller and set the temperature according to process specifications; maintain a constant temperature for 20–30 minutes to ensure uniform and stable cavity temperature.

Equipment Heating

Heat the barrel and nozzle in stages; once the standard molding temperature is reached, maintain it for 10–20 minutes to ensure the raw material is fully melted.

Trial Molding and Parameter Adjustment

Perform manual air shots to purge cold material; conduct trial shots at low speed and low pressure, gradually adjusting injection speed, injection pressure, holding pressure, and cooling time; produce 5–10 consecutive sample shots and inspect for short shots, flash, sink marks, warpage, and weld lines; iteratively optimize the process until the samples meet quality standards.

First-Article Confirmation

Submit the first article to Quality Control for measurement of dimensions, appearance, and strength; mass production may only commence after sign-off confirmation.

IV. Automated Injection Molding Mass Production Cycle (Standard Single-Mold Steps)

The following actions are repeated for each molding cycle:

Mold Closing: Slow closing → rapid advance → low-pressure protection → high-pressure locking (to prevent mold damage from foreign objects).

Material Accumulation/Pre-plasticizing: The screw rotates and retracts, melting and accumulating raw material at the front of the barrel.

Injection and Filling: The screw advances, forcing molten plastic through runners and gates to fill the cavity; multi-stage speed control is applied (slow at the gate, fast in the middle, and decelerated at the end to facilitate air venting).

Staged Holding Pressure: First-stage holding fills the cavity; second-stage low-pressure holding compensates for shrinkage as the plastic cools, eliminating sink marks.

Cooling and Solidification: Continuous water cooling of the mold allows the plastic part to solidify within the cavity; cooling time is controlled to prevent deformation after demolding.

Mold Opening: Slow opening with three-stage deceleration to prevent pulling or deforming the plastic part.

Ejection: Staged low-speed ejection with uniform multi-point pushing to prevent stress marks ("white spots"), puncture, or product bending. Part Removal: Robotic arms automatically pick up plastic parts and simultaneously separate gate/runner waste, sending the waste to a granulator bin; for setups without robotic arms, manual removal is performed with care to avoid scratching cosmetic surfaces.

V. Post-Molding Processing and Trimming

Gate and Runner Removal

Pin gates and submarine gates allow for automatic separation; large gates are cut flush using hydraulic shears.

Precision Deburring

Fine flash at parting lines, ribs, and snap-fits is removed in batches using pneumatic grinders, sandpaper, or vibratory finishing to ensure smooth edges free of sharp points.

Thermal Reshaping/Correction

PP and long, thin-walled parts prone to warping are placed in matching metal fixtures to cool and set at low temperatures, correcting flatness and assembly gaps.

Annealing for Stress Relief (Required for sprayed/painted parts)

Cosmetic parts made of ABS, PC, or ABS+PC blends are baked at a constant 60–70°C for 1–3 hours; slow cooling releases internal stress, preventing future paint cracking or structural failure due to thermal cycling.

Surface Finishing

Products requiring aesthetic upgrades undergo processes such as electrostatic dust/oil removal, spray painting, UV curing, screen printing, or overmolding; parts for food contact or children use only eco-friendly water-based paints.

VI. Multi-Stage Quality Inspection Process

Patrol Inspection: Samples are drawn every 30 minutes for visual inspection and caliper measurement of critical assembly dimensions.

Functional Spot Checks

Drop tests for load-bearing parts; immersion tests for airtight components; fire-resistance tests for flame-retardant parts; high/low-temperature cycling tests for outdoor parts; reciprocating friction tests for wear-resistant parts.

Finished Product Full Inspection

Screening for defects such as silver streaks, bubbles, burn marks, color variations, warping, burrs, micro-cracks, or stiff snap-fit engagement; defective parts are isolated and granulated, with rejected load-bearing or safety-critical parts strictly prohibited from being reused in functional component production.

VII. Sorting, Packaging, and Warehousing

Sorting and Classification: Qualified products, reworkable items, and scrap parts are stored separately and clearly labeled. Protective Packaging: Separate visible parts using EPE foam and seal them in light-proof plastic bags to prevent scratches and yellowing caused by light exposure.

Warehousing Records: Label raw material batches, machine IDs, and production dates; establish a quality traceability log; and store materials in a dry, light-protected warehouse.

Production Wrap-up Procedures

Before shutting down, empty the machine barrel and turn off the heating and cooling systems; clean the mold parting surfaces, hopper, and granulator; spray the mold with anti-rust oil and move it to the mold storage area; and organize process records and production reports.

We are a injection molded plastic parts moulding manufacturer, providing high-quality injection molded plastic parts moulding manufacturing. As long as you want to customize/develop injection molded plastic parts moulding products, you can find us. We have professional injection mold design and mature manufacturing technology, providing you with one-stop service, from product design-mold making-product production-product packaging-product transportation, we can help you in every link. As long as you come to us, we will provide you with the ultimate service and satisfy you in terms of product quality, production time, information dialogue, etc.

Plastic Injection Mould making

Plastic molding specifications

Mold design:

Transaction process:

Mold testing:

Product packaging

Factory

We are Custom Plastic Mold factory. Our factory is plastic injection mold maker. we has 17 years of experience in professional custom plastic mold and 10 years of foreign trade experience. We are custom Plastic Mold supplier. We can provide custom Plastic Mold service. Our factory can make the Injection molded plastic parts, and the quality of the products will satisfy you.

We have more than 50 high-end machines and hundreds of engineers and designers. We can provide one-stop service, from product design - mold making - product production - product packaging - transportation. We have a complete production chain. We can meet all your requirements.

Services we provide:

Professional custom mold service, Plastic mold design and manufacturing .plastic product production, product design, mold design, blow mold customization, rotational mold customization, die-casting mold customization. 3D printing services, CNC manufacturing services, product packaging, customized packaging, shipping services.

We always adhere to the principles of quality first and time first. While providing customers with the highest quality products, try to maximize the production efficiency and shorten production time. We are proud to tell every customer that our company has not lost any customer since its establishment.If there is a problem with the product, we will seek a solution actively and take responsibility to the end.

FAQ

Q1: Are you trading company or manufacturer ?

A: We are manufacturers.

Q2. When can I get the quotation?

A: We usually quote within 2 days after we get your inquiry.

If you are very urgent, please call us or tell us in your email so that we can quote for you first.

Q3. How long is the lead-time for mold?

A: It all depends on the products' size and complexity. Normally, the lead time is 25 days.

Q4. I have no 3D drawing, how should I start the new project?

A: You can supply us a molding sample, we will help you finish the 3D drawing design.

Q5. Before shipment, how to make sure the products quality?

A: If you don't come to our factory and also don't have the third party for inspection, we will be as your inspection worker.

We will supply you a video for production process detail include process report, products size structure and surface detail, packing detail and so on.

Q6. What is your payment terms?

A: Mold Payment: 40% deposit by T/T in advance, 30% second mold payment before sending out the first trial samples, 30% mold balance after you agree the final samples.

B:Production Payment: 50% deposit in advance, 50% before sending out the final goods.

Q7: How do you make our business long-term and good relationship?

A:1. We keep good quality and competitive price to ensure our customers benefit for best quality products.

2. We respect every customer as our friend and we sincerely do business and make friends with them, no matter where they come from.