Injection moulding service clear plastic case

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

Injection molding of transparent plastic boxes is a model of optical-grade precision injection molding. It has reached the ultimate requirements for transparency, purity, no internal stress and no flaws. Any minor defect will be infinitely magnified on the transparent part.

The following is a detailed professional process for the injection molding of transparent plastic boxes, strictly adhering to high-standard requirements for optical products.

Professional process for injection molding of transparent plastic boxes

Phase One: Material Selection & Pre-treatment

This is the cornerstone that determines the final transparent effect, and "purity" is the core requirement.

Material selection

Polycarbonate (PC) : The preferred material for high strength and high impact resistance. It features excellent toughness and high heat resistance (up to 120℃), and is widely used in boxes that require shock resistance and disinfection capabilities (such as medical equipment boxes and electrical appliance casings). The disadvantages are that it is prone to stress cracking and may turn slightly yellow after long-term UV exposure.

Polymethyl methacrylate (PMMA/acrylic) : The king of transparency (over 92%). It has extremely high gloss, high hardness, is scratch-resistant, has good weather resistance and is not prone to yellowing. The drawback is that it is brittle and has poor impact resistance. It is often used in high-end display boxes and cosmetic packaging.

Polyethylene terephthalate (PET/APET) : High transparency, high rigidity, food-grade safety. It has good chemical stability and is often used in food packaging boxes and cosmetic boxes. It is more brittle than PC and PMMA.

Polypropylene (PP) : There are transparent modified grades (such as transparent PP), which have the lowest cost. However, their transparency, hardness and surface gloss are all inferior to the above materials. They are mostly used for daily packaging where optical performance requirements are not high.

Material pretreatment

It must be thoroughly dried! PC, PMMA and PET all have extremely strong hygroscopicity.

PC: It is recommended to dry it in a dehumidifying dryer at 100-120℃ for more than 3-4 hours, with a moisture content of less than 0.02%.

PMMA/PET: It is recommended to dry at 70-80℃ for 3-4 hours.

Clean environment: The storage and transportation of raw materials must be carried out in a low-dust environment. It is best to use a central feeding system and sealed pipelines to prevent any dust contamination.

Phase Two: Mold Design & Manufacturing

The quality of the mold is 1:1 replicated onto the product surface, with "mirror finish" being the core objective.

Mirror polishing: The cavity surface must undergo the highest level of mirror polishing (reaching VDI A0 / SPI A1 grade). Any scratch, pinhole or defect will be clearly visible on the product.

Mold steel: It is necessary to use high-grade, impurity-free and fine-textured polishing special steel, such as S136H from ASSab of Sweden and NAK80 from Daido of Japan, etc.

Hot runner system: It is strongly recommended to use needle valve type hot runners.

Advantages: No cold material handle, reducing flow marks and stress, allowing for more precise control of pressure holding, and achieving fully automated production.

Adequate exhaust: Precise exhaust slots (typically 0.015-0.02mm in depth) must be provided to prevent trapped air from causing silver streaks (material streaks) or charring (black spots) on the products, which are absolutely fatal defects on transparent parts.

Cooling system: It must be highly uniform, with a well-designed cooling waterway to ensure consistent cooling rates and prevent warping or vacuum bubbles caused by uneven contraction.

Gate design: The gate size should be large enough to reduce shear stress. The position is usually set on the non-exterior surface or the bottom of the box. Sometimes, fan-shaped gates or film gates are used to improve flow and avoid flow marks.

Phase Three: Injection Molding Process

The process is the key to controlling internal stress and optical effects, and "high mold temperature and low stress" is the core principle.

High mold temperature: Adopt a relatively high mold temperature (for example, PC can use 80-100℃, PMMA can use 60-80℃). High mold temperature is the most crucial parameter for eliminating flow patterns and ripples, reducing internal stress, and achieving the highest transparency.

High material temperature: Under the premise that the material does not decompose, a relatively high melt temperature is used to ensure good fluidity.

Multi-stage injection: Adopt an injection method that starts slowly and then speeds up. The initial low speed prevents spray marks, and the subsequent high-speed filling ensures consistent temperature at the front of the melt, avoiding flow marks and melt lines.

Multi-stage pressure holding: A low-pressure, long-duration pressure holding curve is adopted to fully compensate for shrinkage while avoiding the introduction of excessive internal stress.

Sufficient cooling time: Ensure that the product is fully cooled and set to prevent ejection and deformation.

Phase Four: Post-Processing and Extreme Quality Inspection (Post-Processing & QC

The inspection standards for transparent parts are extremely strict, and "zero tolerance" is the core attitude.

Post-processing

Annealing treatment: For PC and PMMA products, annealing must be carried out. Place the product in a constant-temperature oven and heat it for a period of time at a temperature 10-20℃ lower than its heat distortion temperature (depending on the wall thickness), then cool it slowly. This measure can effectively eliminate internal stress, prevent stress cracking during future use, and significantly improve its optical performance and dimensional stability.

Ultrasonic welding: If a box with a lid needs to be made, ultrasonic welding is commonly used to join the upper and lower LIDS together. The design of the welding line is of vital importance.

Ultimate quality inspection (100% full inspection)

Appearance optical inspection: Under a dedicated light source box, each product is inspected from multiple angles by the naked eye or an automated visual inspection system (AOI) to eliminate any defective products.

Absolutely not allowed: bubbles, silver streaks, black spots, impurities.

Strictly prevent: scratches, shrinkage, flow marks, spray lines, yellowing, and uneven luster.

Dimensional inspection: Use calipers and 2D image measuring instruments to measure key dimensions such as length, width, height, and wall thickness.

Stress test: Detection is carried out using a polarization stress meter. Place the product between the orthogonal polarizers and determine the magnitude and distribution of the internal stress by observing the resulting colored stripes (rainbow patterns). This is the most scientific and intuitive method to test the annealing effect and the quality of the process.

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

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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.