Moulding injection nylon bush

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

Nylon (polyamide, PA) is a very commonly used engineering plastic. Its excellent wear resistance, high mechanical strength, good self-lubrication, and chemical resistance make it an ideal material for manufacturing wear-resistant parts such as bushings, gears, and bearings. However, its injection molding process has its own unique requirements.

The entire process is divided into three stages: pre-molding preparation, injection molding, and post-molding processing. Each stage requires specialized treatment tailored to the characteristics of nylon.

Stage 1: Pre-molding Preparation - The Core is "Moisture Prevention"

This is the most critical step in the success of nylon injection molding, and the key lies in thoroughly drying the raw materials.

Raw Material Selection and Pretreatment:

Material Selection: Select the appropriate nylon grade based on the operating conditions of the bushing (load, speed, temperature, etc.), such as PA6, PA66 (most commonly used), PA46 (high-temperature resistant), or reinforced nylon (such as those with added glass fiber GF for increased strength and heat resistance).

Drying and Dehumidification: This is a necessary step!

Reason: Nylon is a highly hygroscopic material. It absorbs moisture from the air. If pellets containing moisture are directly injected into the mold, the moisture will vaporize at high temperatures, causing bubbles and silver streaks on the surface of the product. This will also cause polymer hydrolysis, resulting in a decrease in molecular weight, severely impacting the mechanical strength and toughness of the product.

Processing: Drying is typically performed in a forced-air oven or dehumidifier at 80-100°C for 4-6 hours. For certain demanding products, 120°C may be required. The material layer thickness should not exceed 30mm.

Requirements: After drying, the pellets should be used immediately or temporarily stored in an insulated hopper (around 90°C) to prevent re-absorption of moisture. Re-drying is recommended if the pellets are exposed to air for more than half an hour.

Mold Preparation:

When designing the mold, the high shrinkage (typically 0.8%-2.0%, with reinforced grades being much smaller) and anisotropy of nylon must be fully considered, and the cavity dimensions must be accurately calculated.

Since bushings are typically cylindrical, the mold typically uses a three-plate mold or hot runner to ensure point-gating, minimal sprue material, and easy removal.

Runner and gate design must ensure smooth filling and avoid excessive shear that could cause material degradation.

The mold cooling system must be uniform and efficient to ensure product dimensional stability.

Phase II: Injection Molding Process - The core is "temperature control" and "feeding."

Mold closing and clamping: Similar to conventional injection molding.

Injection and holding pressure:

Barrel temperature: Nylon has a relatively high melting point, and the barrel temperature is typically set between 240-290°C. The specific temperature depends on the nylon type (PA66 is 10-20°C higher than PA6), whether it is reinforced, and the product structure. Excessively high temperatures can lead to decomposition, while excessively low temperatures can result in poor plasticization.

Mold temperature: It is recommended to use a mold temperature controller to control the mold temperature, typically between 60-90°C.

Reason: Higher mold temperatures can:

Reduce internal stress in the part, preventing deformation or cracking later in the process.

Improve melt flow, preventing underfill and cold marks.

Promote crystallization, resulting in better mechanical properties.

Reduce shrinkage marks at the interface between thick and thin parts.

Injection Speed: Medium-to-high speed injection is preferred. Nylon has a distinct melting point and solidifies quickly, so high-speed injection facilitates filling thin-walled areas.

Holding Pressure and Time:

Holding pressure should not be too high, generally 60-80% of the injection pressure.

The holding time should be long enough to compensate for the volumetric shrinkage of the nylon due to crystallization shrinkage, preventing product shrinkage and internal hole deformation. However, excessive holding time will increase internal stress.

Cooling and Setting: The nylon crystallization process releases heat, so sufficient cooling time is required to ensure the product is fully set. The cooling time depends on the wall thickness.

Mold Opening and Ejection: After cooling, the nylon bushing has a strong clamping force, requiring a sufficient draft angle and smooth mold walls (use a release agent if necessary). The ejection system must be balanced and uniform to prevent whitening or deformation.

Phase 3: Post-Molding Processing - The core is "humidity adjustment" and "stabilization."

Gate Treatment: The product is removed by a robot or manually, and the gate is trimmed.

Humidity Conditioning:

Purpose: This is a post-treatment process unique to nylon products.

Relieves internal stress: Improves dimensional stability and toughness, preventing brittle cracking.

Achieves optimal performance: After nylon absorbs a certain amount of water, its toughness and impact strength reach their peak (although stiffness and hardness will decrease slightly).

Method: Soak the product in hot water (80-100°C) for a period of time, or "cook" it in boiling water for a period of time (boiling treatment). The treatment time varies depending on the product wall thickness and can range from a few hours to over ten hours.

Inspection:

Dimensional Inspection: Key inspections include checking the inner diameter, outer diameter, and roundness to ensure compliance with tolerances.

Appearance Inspection: Check for defects such as bubbles, silver streaks, burn marks, and shrinkage.

Performance Testing: Samples are tested for wear resistance and strength.

We are a moulding injection nylon bush manufacturer, providing high-quality moulding injection nylon bush manufacturing. As long as you want to customize/develop moulding injection nylon bush 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:

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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.