What are the characteristics of injection molding processing of plastic parts for household appliances？

Introduction

With the rapid development of the home appliance industry, the industry’s demand for plastics is also steadily increasing. Plastics have become an Indispensable application material for the home appliance industry.

Injection molding has always been one of the main means of producing plastic parts. Product plasticization has become an important feature of the home appliance industry. Injection molding’s unparalleled precision, efficiency, and versatility make it the first choice for manufacturing a wide range of plastic parts.

In this article, we will conduct an in-depth study of the characteristics of plastic parts in household appliances and how to improve their efficiency and user experience.

II.Injection Molding Precision and Consistency

1.How injection molding ensures high precision and consistency

Injection moulding is renowned for its ability to achieve high precision and uniformity in the manufacture of plastic parts. This precision is achieved through a tightly controlled process in which molten plastic is propelled under powerful pressure into carefully designed mold cavities. These cavities are crafted with extreme precision, ensuring that every component manufactured meets specified specifications.

2.Unparalleled Precision in Crafting Plastic Components for Home Devices

The crafting of plastic components for domestic devices places a premium on the necessity for exacting tolerances. The operational efficiency and functionality of a home device are often contingent upon the precise calibration of its integral parts. Through the process of the injection molding machine, these exacting tolerances are meticulously maintained, ensuring that components interlock with seamless perfection. This precision fosters uninterrupted functionality and maximizes efficiency.

3.Complexity and Exactitude in Form Through Injection Molding

The injection molding production process excels at producing parts with complex geometries and precise measurements that exceed the capabilities of other manufacturing methods. From the detailed patterns engraved on the mixer housing to the precision-engineered parts inside the mold cavity, the plastic injection molding process enables a level of detail and precision unparalleled in the production of plastic parts. This method not only enables the creation of aesthetically designed injection-molded parts from plastic mold but also ensures the functional precision of the components, which is crucial for the seamless operation of household appliances.

III. Material Selection and Compatibility

Plastic materials have the advantages of being lightweight, having high specific strength, no rust, good insulation, good processability, low processing cost, and suitable for mass production. Plastic materials play a very important role in household appliances.

According to reports, in recent years, the plastic consumption of American home appliances has accounted for 4.7% of its total plastic pellets consumption, while the plastic consumption of Japanese home appliances has accounted for 12.3% of its total plastic consumption.

Most of the plastic shells used in household appliances are thermoplastics, accounting for more than 90%. Polypropylene, PS, and ABS are the most widely used varieties.

1.Versatility in Injection Molding Material Selection

Most of the plastics used in the manufacture of home appliances are thermoplastics. General plastics, engineering plastics, modified plastics and plastic alloy materials are increasingly used in the home appliance industry. Plastics have become the fastest growing material in the field of home appliances. Product plasticization has become an important feature of the home appliance industry.This versatility enables manufacturers to choose materials based on the specific requirements of the product, such as strength, flexibility, heat resistance, and aesthetic appeal. The process involves melting the chosen material and injecting it into a mold, where it cools and solidifies into the desired shape. The ability to use different materials makes injection molding suitable for a wide range of applications, from simple household items to complex automotive components.

2. Thermoplastic resins commonly used in household appliances

ABS, HIPS

1. It has good strength and toughness, high surface gloss, wear resistance, and excellent overall performance. It is the most widely used plastic variety in household appliances.

2. The annual consumption of ABS/HIPS in my country’s household appliance industry is more than 10 million tons, which is the largest amount of plastic materials used in household appliances.

3. Used in plastic casings of household appliances such as TVs, radios, tape recorders, fans and vacuum cleaners, refrigerator linings, drawers, etc.

PP

1. It has good strength and toughness, heat resistance, fatigue resistance, many varieties, low price, and easy modification. It is the most used plastic material in household appliances after ABS.

2. Used for the inner and outer barrels and base of washing machines. Covers, switch boxes, fan motor covers, refrigerator back covers, motor support covers and a small amount of fans, TV casings, refrigerator door linings, drawers, etc.

PS and SAN

1. It has good transparency, good rigidity, high surface hardness, stable size, good strength and toughness, good surface decoration and low price. It is the most widely used transparent plastic variety in household appliances.

2. Used in refrigerator fruit and vegetable boxes, egg racks, trays, tape boxes and other transparent parts.

PVC

1. It has rich sources, low price, strong applicability and wide adaptability, but it is currently rarely used in household appliances.

2. In China, it is mainly used for refrigerator door sealing strips and sealing sleeves of various household appliances.

3. It is used abroad to replace part of PP, ABS, HIPS injection plastic and alloy with ABS to prepare home appliance casings.

Nylon series

1. Nylon for household appliances includes PA6, PA66, PA 10102, etc.

2. High strength, good toughness, wear resistance, small friction coefficient, and self-lubricating.

3. Used in plastic gears, bearings, and sliding wear-resistant parts in household appliances.

PC

1. Engineering plastic material with the best toughness, good creep resistance, good heat and cold resistance, long-term use temperature -60℃-120℃, aging resistance and good transparency.

2. Used in hair dryers, electric heater plastic shells, plastic gears, shelves, transparent covers, CDs, washing machine side covers, hot water contact parts, etc., and other transparent plastic shells such as refrigerator fruit and vegetable boxes, egg racks, trays, tape cassettes, etc.

Polyester

1. The polyesters used in household appliances are mainly polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), which have good toughness, creep resistance, wear resistance, and heat resistance. Features.

2. Used in transparent plastic shells such as refrigerator fruit and vegetable boxes, egg racks, trays, tape boxes, etc.

Thermoset plastic

1. Phenolic resin: good rigidity, good electrical properties, heat resistance, dimensional stability, small friction coefficient, used in fan chassis, switches, switch boxes, terminal posts, wiring boards, and printed circuits.

2. Amino resin: translucent, similar in performance to phenolic, can be used for door handles, knobs, shells, etc.

3. Epoxy resin: good mechanical, electrical and chemical resistance properties and dimensional stability. Used for printed circuits and sealing materials.

Commonly used modified materials and functional plastics

1. Magnetic plastics: including structural magnetic plastics (such as Japan’s PPH) and composite magnetic plastics (magnetic powder and plastic resin mixture), used in motors, electrical components, refrigerator seals, etc.:

2. Electromagnetic shielding plastics: including structural shielding plastic materials (such as polyacetylene) and composite shielding plastic materials, with a volume resistance of 10¯²-10¯¹¹Ω, used for electrical appliance plastic casings and circuit plastic parts.

3. Consider material compatibility for optimal performance and durability

Material compatibility is crucial in the design and manufacturing of parts, especially when multiple materials are used together. Compatibility affects not just the physical and mechanical properties of the components but also their long-term durability and performance. Factors to consider include:

Chemical Compatibility: Ensuring that materials do not react negatively with each other or with substances they may encounter during use.

Thermal Compatibility: Materials should have compatible thermal expansion rates to prevent warping, stress, or detachment when exposed to varying temperatures.

Mechanical Compatibility: The materials used together should have compatible strength, flexibility, and wear resistance to ensure the part functions as intended over its lifespan.

Manufacturers must carefully select materials that meet the product’s requirements while ensuring they are compatible with each other to avoid failure. Advanced simulation software and testing are often used to assess material interactions before moving to production, ensuring that the final product will perform as expected under real-world conditions.

IV. Design Flexibility and Complexity

High-pressure injection allows the plastic to enter the deepest parts of the mold, allowing complex shapes and designs to be achieved, minimizing the need for additional processing after molding.

Molding produces high part volumes very quickly. Although it may take some time to design and finalize each injection molding parameters, the manufacturing process proceeds very quickly after that. Once you have the mold designs on hand, you can use them indefinitely.

Injection molding makes it easy to add fillers to change the state of the plastic. Inserts and other parts within the plastic injection molds can allow for more complex processes such as overmolding.

V. Efficiency and Cost-effectiveness

Injection molding is highly efficient for mass production of plastic parts. The process allows for rapid production cycles, with each cycle typically lasting only a few seconds to a few minutes, depending on the complexity of the part. This rapid production rate enables manufacturers to produce large quantities of parts in a relatively short amount of time, making injection molding ideal for meeting high demand.

In addition to its efficiency, injection molding is also cost-effective for producing plastic parts. The initial tooling costs for creating injection molds can be significant, but once the molds are made, they can be used repeatedly for mass production runs. This amortization of tooling costs over the production lifecycle of the part helps to reduce the per-unit cost of each part, making injection molding process a cost-effective option, especially for high-volume production.

Injection molding allows for the integration of multiple features into a single molded part, streamlining assembly processes and reducing the need for additional components. For example, complex parts with built-in hinges, snaps, or other mechanical features can be molded as a single piece, eliminating the need for separate assembly steps. This integration not only saves time and labor costs but also enhances the overall reliability and durability of the final product.

Conclusion

Judging from the development of home appliance technology in the future, the humanization of household appliances will be more prominent, the product varieties will be more complete, and traditional home appliances will develop in the direction of miniaturization and large-scale. The future development trend of small household appliances is low-noise, energy-saving and environmentally friendly, nutritious and healthy, intelligent IoT, convenient and easy-to-use, humanized and fashionable industrial design. The large demand for home appliances will further increase the demand for parts produced by plastic injection molding machine, which requires improving injection molding production design technology to provide more production power for the entire home appliance industry.