Mould injection for bottle caps

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 mould injection for bottle caps 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 mould injection for bottle caps products, we can make corresponding plastic parts, which is mainly done through injection molds.

The bottle cap injection molding process exemplifies high-speed, high-precision, and fully automated production. The core challenge is consistently producing millions of bottle caps with precise dimensions, a secure seal, clear threads, and a flawless appearance within extremely short cycle times.

The following is a detailed process for bottle cap injection molding, highlighting its large-scale production capabilities.

Bottle Cap Injection Molding Process

Phase 1: Raw Material Preparation and Processing

Material Selection:

Polypropylene (PP): The most commonly used material. It offers high hardness, excellent rigidity, and chemical resistance, making it suitable for packaging applications such as water, beverages, and edible oils. A variety of colors can be achieved by adding masterbatches.

Polyethylene (PE): High-density polyethylene (HDPE), in particular, is more flexible and is often used for squeeze-open caps and pharmaceutical bottle caps.

Additives:

Masterbatch: Provides the desired color.

Slip agent: Reduces friction between caps, facilitating conveying on high-speed filling lines.

Antistatic agent: Prevents dust from attracting caps.

Drying:

Although PP/PE does not absorb much water, during high-speed, precision injection molding, a brief drying step (e.g., 2-3 hours at 80-85°C) is still required to remove trace surface moisture and ensure optimal quality.

Phase Two: Mold Design and Features

The bottle cap mold is the core of the technology, and its design directly determines production efficiency and cap quality.

Ultra-High Cavity Molds:

A mold typically has 48, 72, 96, 144, or even more cavities. This is key to achieving low-cost, high-efficiency production.

Hot Runner System: Absolutely standard.

A needle-valve hot nozzle precisely controls the injection of glue into each cavity, ensuring balanced filling.

Advantages: No waste (no sprue material), saving raw material; extremely short cycle times; and fully automated.

Thread Processing:

Forced Demolding: Most PP/PE bottle caps have serrated threads, leveraging the elasticity of the plastic to force the cap out during ejection via a thread rotating mechanism or cam. This is the most intricate part of the bottle cap mold.

Internal Thread Sliders: For rigid materials or special threads, internal thread slides or unscrewing mechanisms are required, which are more complex.

Cooling System:

The design must be extremely efficient and uniform. The thinness of the caps requires rapid cooling. Uniform cooling is crucial to ensuring consistent dimensions, deformation, and warping of all caps.

Venting System:

Precision venting grooves are designed at the ends of the mold cavity and in areas where air may be trapped to prevent trapped air from causing adhesive defects, burning, or glossing.

Stage 3: Injection Molding Process

This is the core of achieving high-speed production, achieving "multiple caps per second."

Fully Automatic Loading: Dried raw materials are automatically drawn into the injection molding machine hopper via a central feeding system.

Injection Molding Stage:

High-Speed, High-Pressure Injection: The screw injects molten plastic into the mold at extremely high speed and pressure, ensuring that all cavities are filled in a very short time.

Low Holding Pressure: Due to the thinness of the bottle caps and limited shrinkage, very low holding pressure and time are required, primarily to prevent flash (burrs).

Cooling and Mold Opening:

Extremely Short Cooling: The bottle caps cool in an extremely short time, typically only 2-4 seconds. The entire production cycle can be controlled within 3-6 seconds.

Ejection and Demolding:

After the mold is opened, a robot automatically enters, and its dedicated gripper removes all the bottle caps at once.

During ejection, the bottle caps are separated from the threaded core by mold rotation or a forced ejection mechanism.

Stage 4: Post-Processing & Quality Control

Post-Processing:

No Degating: This step is not required in hot runner production.

Inner Gasket Installation: For beverage caps requiring airtightness (such as those for carbonated beverages), a PVC or PE foam gasket is pressed into place using specialized equipment after removal.

Quality Inspection (100% full inspection or high-speed spot checks):

Dimensional Accuracy: A dedicated go/no-go gauge is used to check the inner and outer diameters of the cap opening; the threads are inspected for smooth fit.

Sealing Test: Samples are tested for sealing using a negative or positive pressure tester.

Opening Torque: The torque required to open the cap is tested to ensure it is within the specified range (neither too loose nor too tight).

Appearance Inspection: A high-speed visual inspection system is standard in modern factories. It automatically captures and removes caps with defects such as burrs, missing material, color differences, and contamination.

Packaging:

Fully automated packaging equipment is used to pack the caps into plastic bags or cartons according to the specified quantity and pack them for storage.

As a core competency provider of excellent bottle cap molds and injection molding, demonstrate your absolute advantages to clients (such as beverage and bottle cap manufacturers):

Ultra-Efficient Production Capacity:

"We have a 144-cavity mold, coupled with an electric injection molding machine, with a stable cycle time of 3.5 seconds, and a daily output exceeding one million pieces."

"The entire line achieves fully automated, unmanned production from raw materials to finished caps."

Ultimate Cost Control:

"We use needle-valve hot runner technology, achieving 100% raw material utilization and zero waste, minimizing costs."

"Our optimized ultra-short molding cycle time allows for... Energy consumption per unit is minimized."

Precision Mold Technology:

"Our molds utilize threaded forced-release technology, resulting in a stable structure and long lifespan. They eliminate the need for complex unscrewing mechanisms and simplify maintenance."

"The mold cooling system, optimized through mold flow analysis, ensures uniform cooling of each cavity and highly consistent product dimensions."

Strict Quality and Compliance System:

"We only use FDA-certified food-grade ingredients."

"A 100% online visual inspection system ensures a shipping yield exceeding 99.95%.."

"Our production environment complies with GMP standards, eliminating the risk of contamination."

We are a mould injection for bottle caps manufacturer, providing high-quality mould injection for bottle caps manufacturing. As long as you want to customize/develop mould injection for bottle caps 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.