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 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 plastic parts moulding products, we can make corresponding plastic parts, which is mainly done through injection molds.

Stage 1: Pre-molding Preparation

This is the cornerstone for ensuring product quality and stable production.

Raw Material Selection and Pretreatment

Material Selection: Select appropriate plastic raw materials based on the product's intended use (such as strength, transparency, heat resistance, chemical resistance, and food contact requirements). Common plastics include:

General-purpose plastics: ABS, PP, PS, PE

Engineering plastics: PC, PA (Nylon), POM, PBT

High-performance plastics: PPS, PEEK

Drying: For highly hygroscopic materials (such as PC, PA, ABS), a dryer must be used to remove moisture. Undried raw materials will cause silver streaks and bubbles during injection molding, resulting in reduced strength. Drying temperature and time vary depending on the material.

Color Matching: To achieve a specific color, purchase pre-colored plastic pellets or add a color masterbatch to the original color material and mix in the injection molding machine hopper.

Mold Installation and Adjustment

Molds: Injection molds are expensive, precision tools typically made of steel or aluminum, containing complex structures such as the cavity, runners, gates, cooling channels, and ejector mechanisms.

Installation: The mold is hoisted and secured to the movable and fixed platens of the injection molding machine. Cooling water pipes are connected, and the ejector stroke is adjusted.

Cleaning and Maintenance: The mold cavity must be thoroughly cleaned before and after installation to ensure it is free of dust, oil, or residue from previous production cycles.

Phase 2: Injection Molding Cycle (Core Process)

This is a highly automated, repetitive process, typically lasting from a few seconds to several minutes.

1. Mold Closing

The injection molding machine's mold closing system drives the movable mold toward the fixed mold, ultimately locking the mold under high pressure to create a sealed cavity that can withstand the high pressure of subsequent injections.

2. Injection and Holding

Plasticization: As the mold closes, plastic granules in the hopper fall into the barrel. They are conveyed and sheared by the rotating screw, and then heated by a heating ring outside the barrel, melting them into a uniform, viscous melt. The screw then retracts under the back pressure of the melt, reserving a fixed amount of melt for the next injection (called "metering").

Injection: The screw stops rotating and, driven by a high-pressure hydraulic cylinder, violently propels the melt forward, injecting it into the enclosed mold cavity at high speed and high pressure through the nozzle, runners, and gates of the mold.

Holding: After the mold cavity is filled, the screw maintains a certain pressure (holding pressure) and continues to slowly replenish the melt to compensate for the volume loss caused by cooling shrinkage. The holding process is crucial for preventing product shrinkage and ensuring dimensional accuracy.

3. Cooling and Plasticization

Cooling: The melt is cooled and shaped by circulating cooling water within the mold. Cooling time accounts for more than half of the entire molding cycle. Insufficient cooling time can cause product deformation, while excessive cooling time reduces efficiency.

Plasticization: While cooling, the screw begins rotating again to plasticize and meter the material for the next cycle. The simultaneous cooling and plasticization process is key to efficient production.

4. Mold Opening and Ejection

After cooling is complete, the mold opens, and the injection molding machine's ejector system (ejector pins and ejector plate) pushes the ejector plate forward, ejecting the cooled and solidified plastic part from the mold cavity.

A robot or automated equipment typically automatically reaches in to grasp the part and runner solidification (sprue material) and place them in a designated area.

Stage 3: Post-Processing and Inspection

The part just removed from the mold is only a semi-finished product and requires the following processing.

Sprue Material Separation

The part is separated from the runner system (main runner, branch runners, and gate, collectively referred to as "sprue material") manually, using a clamp, or using specialized equipment. Sprue material is typically crushed and recycled by mixing it with new material in a proportional manner.

Post-Processing

Annealing: The product is heated at a specific temperature for a period of time and then slowly cooled to eliminate internal stresses. This is crucial for materials such as PC or products subject to external forces and high temperatures during use, as it prevents stress cracking.

Humidifying: For hygroscopic materials such as nylon (PA), soaking or steaming is performed to achieve moisture balance, thereby achieving optimal dimensional stability and toughness.

Surface Treatment: Examples include spraying, electroplating, silk screen printing, and ultrasonic welding.

Inspection and Packaging

In-Personal Quality Control (IPQC): The operator conducts first-article and patrol inspections to check product appearance (for missing material, flash, shrinkage, bubbles, color difference, etc.).

Full Quality Control (FQC): 100% or sample inspection of finished batches is performed. This may include dimensional measurements (using calipers or CMMs), functional testing, and strength testing.

Packaging: Qualified products are packaged in appropriate packaging materials (such as PE bags, bubble wrap, or cartons) to prevent scratches or contamination during transportation and storage.

Core Process Parameters (Critical Control Points):

Temperature: Barrel temperature, nozzle temperature, and mold temperature.

Pressure: Injection pressure, holding pressure, and back pressure.

Speed: Injection speed and screw speed.

Time: Injection time, holding time, and cooling time.

Position: Screw metering stroke and holding pressure switching position.

In summary, plastic injection molding is a complex manufacturing process that integrates materials science, precision machinery, mold technology, and automated control. Only by precisely controlling the parameters of each step can high-quality plastic parts be produced efficiently and consistently.

We are a plastic parts moulding manufacturer, providing high-quality plastic parts moulding manufacturing. As long as you want to customize/develop 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.