In today's manufacturing industry, plastic products, with their numerous advantages such as light weight, corrosion resistance, and ease of processing, are widely used in various fields, from everyday consumer goods to precision components in industrial production. Plastic products are ubiquitous. As the core equipment in the production of plastic products, the performance and quality of plastic injection molding machines directly determine the production efficiency, quality, and cost of plastic products.
However, faced with a dazzling array of plastic injection molding machine brands and models on the market, choosing the right machine has become a challenge for many companies. Different product needs, budget constraints, and factors such as brand and after-sales service all make the selection process complex and crucial. This article will provide detailed answers on how to choose a plastic injection molding machine, focusing on how to determine key parameters based on product needs, balance performance and cost under different budgets, and evaluate brand and after-sales service quality.
Key parameters of plastic injection molding machine are determined according to product requirements:
Product Dimensions and Mold Dimensions
In the process of injection molding process, product dimensions closely related to the clamping force of injection molding machine. Clamping force is the maximum clamping force that the clamping mechanism of the injection molding machine can exert on the mold. Its function is to prevent the molds from separating due to the impact of high pressure molten plastic during injection molding and to ensure the molding quality of the product.
Clamping force is usually calculated according to the welding area of the product. In general, clamping force (F) can be estimated by using the formula F = P × A, where P is the projection pressure of molten plastic on mold parting surface (the projection pressure varies between 15 and 40 MPa depending on the plastic material) and A is the projection area of the the product and the flow path on the mold parting surface. For example, if the projected indentation area of the product and the flow path is 500 cm2 and the projected indentation pressure of the selected plastic material is 30 MPa, the required clamping force is at least 30 x 500 = 15000 kN. When choosing an injection molding machine, the clamping force of the injection molding machine must be greater than the calculated value.
At the same time, mold size must match the mold size and mold capacity of injection molding machine. The size of the mold determines the maximum size of the mold that can be installed, while the bearing capacity of the mold refers to the maximum and minimum thickness range of the mold that the injection molding machine can accommodate. If the mold size is too large, it cannot be installed on the injection molding machine; if the thickness of the mold exceeds the injection injection molding machine capacity range, it cannot be properly installed and used. Therefore, when choosing injection molding machine, the mold size must be measured accurately, and the mold size must match the relevant parameters of injection molding machine.
Plastic Material Characteristics
Different plastic raw materials have different properties, which has great influence on screw parameters of injection molding machines. Plastic materials are mainly divided into thermoplastics and thermosetting plastics. Common thermoplastics are polypropylene (PP), polyethylene (PE) and acrylonitrile butadiene-styrene (ABS) copolymers with good fluidity and plasticity.
For good flowability plastic materials such as PP, the screw length ratio can be relatively small, generally around 20:1- 22:1. Conversely, for poor flowability plastic materials such as ABS, a larger screw length ratio, typically between 22:1- 25:1, is required to increase the plasticizing time and effect of the screw. The screw diameter selection needs to be determined according to the product's injection volume and the injection molding machine's specifications to ensure that the screw's plasticizing capacity meets production requirements. The screw compression ratio affects the compression and exhaust performance of plastics, and different types of plastic materials also require appropriate compression ratios to ensure molding quality.
When special raw materials are used, such as plastics (e.g., glass fiber) or flame retardants with fiber enhancers, there are special requirements for barrel heating and screw design of injection molding machine. In injection molding process, Fiber reinforcements material is easy to wear screw and barrel, thus wear resistant screw and barrel materials, such as bimetallic screws and barrel. At the same time, in order to ensure uniform dispersion of fiber in plastic, special design of screw structure, such as increasing a shearing section, is needed. For plastics with flame retardants, barrel heating system require good sealing and corrosion resistance because flame retardants decompose at high temperatures and produce corrosive gases.
Production Batch Size and Efficiency
The size of batch number directly affects the injection speed and plasticizing ability of injection molding machine. In small batch production, the production cycle is long, which can reduce the requirement of injection speed. However, injection molding machine needs to have good flexibility and adaptability, can quickly adjust process parameters, production of different types of products. In this case, there are a number of versatile injection molding machines to choose from, with injection molding speeds typically between 100 and200mm/s.
In mass production, in order to improve production efficiency and reduce production cost, injection molding machine needs to have higher injection speeds and plasticization ability. High-speed injection molding can shorten injection time and improve the production cycle, while efficient plasticizing capacity ensures that plastics are fully plasticized in a short period of time, guaranteeing the quality of products. Therefore, the high speed injection molding machines with injection speed above 200mm/s is usually used in mass production, and whose plasticizing capacity can meet the need of continuous production.
The repeatability, stability and ejection system capability of injection molding machine are required in the production of multi-cavity die. Repeatability refers to the consistency of injection volume, injection pressure and other parameters of injection molding machine in the course of multiple injections. High repeatability ensures consistency in product dimensions and quality and reduces scrap rates. Stability refers to the injection molding machine in long-term operation of the process, can be stable performance, no obvious fluctuations. Ejection system capability requires the ability to eject more than one product at a time to ensure smooth demolding and to prevent product deformation or damage due to ejection defects.
Product Accuracy Requirements
Product accuracy is one of the important indexes to measure the quality of plastic products, including dimension accuracy and surface quality. Product precision is closely related to the mold clamping system of injection molding machine and the precision of injection system of injection molding machine.
The precision of the mold clamping system mainly affects the size accuracy and flash of the product. If the mold clamping system accuracy is less accurate, the gap will appear when the die is closed, causing plastic melt to overflow, producing glitter and affecting the size accuracy of the product. Therefore, the production of high precision products requires injection molding machines high-precision mold clamping systems, such as injection molding machine with high precision guide column and bushing, and advanced die clamping mechanism.
The accuracy of injection system mainly affects the weight repeatability and intrinsic quality of the product. Theprecision injection system can control the injection volume and the injection speed, ensure the weight of each product is the same, and reduce internal stress concentration and defects, thus improving internal product quality.
The control system of injection molding machine plays an important role in the production of high precision products. Temperature control accuracy and pressure control accuracy are two key indexes. Precise temperature control ensures a stable temperature for plastics during plasticization and injection and prevents size change or quality degradation due to temperature fluctuations. High precision pressure control ensures the stability of injection pressure, so that molten plastic fills the mold cavity evenly and improves the molding quality of the product.
Balancing Performance and Cost of Plastic Injection Molding Machines Under Different Budgets
Low Budget Situation
For companies with limited budgets, domestically produced economical injection molding machines are a good choice. These machines are relatively inexpensive, generally ranging from tens of thousands to hundreds of thousands of yuan. Their basic performance characteristics can meet the production needs of some simple plastic products, such as daily necessities and simple toys.
In a low budget situation, prioritizing key performance parameters that meet basic production needs is crucial. Key performance parameters include clamping force, injection volume, and plasticizing capacity; these parameters directly affect whether qualified products can be produced. For example, if the product size is small and the clamping force requirement is not high, then an injection molding machine with a slightly lower clamping force but a lower price can be selected. At the same time, some non-critical performance aspects, such as aesthetic features (e.g., a beautiful machine body, a colorful operating interface) and some automation (e.g., automatic mold changing system, automatic mold adjustment system), can be sacrificed to reduce equipment costs.
When choosing an injection molding machine with a low budget, it is also necessary to pay attention to the stability of the equipment and the quality of its components. Injection molding machines with poor stability are prone to malfunctions during production, affecting production efficiency and product quality. The quality of components directly impacts the equipment's lifespan and maintenance costs. You can assess the equipment's stability and component quality by checking the manufacturer and user reviews.
Medium Budget Situation
With a medium budget, you can choose domestically produced mid-to-high-end injection molding machines as well as some imported entry-level machines. Domestically produced mid-to-high-end injection molding machines have significantly improved performance, offering more stable performance, higher precision, and more comprehensive automation functions, generally priced between tens and hundreds of thousands of yuan. Imported entry-level injection molding machines, leveraging advanced technology and brand advantages, also offer a certain level of performance and quality assurance, but are relatively expensive, typically costing hundreds of thousands of yuan or more.
Within this budget, a balance between performance and cost can be struck. Choosing equipment with comprehensive performance and some automation functions can meet production needs while improving production efficiency and product quality. For example, choosing an injection molding machine with automatic mold adjustment, automatic lubrication, and automatic glue extraction functions can reduce manual operation, lower labor intensity, and increase production efficiency.
Simultaneously, further selecting the appropriate machine model based on the type of product being produced is also crucial. Different types of products have different requirements for injection molding machines. For example, producing thin-walled products requires injection molding machines with high injection speeds and pressures, while producing large products requires injection molding machines with larger clamping forces and injection volumes. Therefore, selecting an injection molding machine with corresponding advantages based on the characteristics of the product being produced can better utilize the equipment's performance and improve production efficiency.
High Budget Situation
For companies with ample budgets, high-end imported injection molding machines and high-end series from top domestic brands are ideal choices. These machines utilize advanced technologies, such as all-electric injection molding technology and two-platen clamping technology, offering superior performance.
All-electric injection molding machines employ an electric drive system, offering advantages such as high precision, fast response speed, and energy efficiency. Their injection speed and pressure control precision can reach a very high level, enabling the production of high-precision plastic products. Two-platen clamping technology offers advantages such as a large mold opening stroke and uniform mold platen stress, making it suitable for producing large and complex plastic products.
With a high budget, companies can pursue high-precision, high-efficiency, highly automated, and intelligent production to meet the demands of complex products and high-quality production. For example, by equipping advanced robotic systems, fully automated production processes such as automatic material feeding, automatic part handling, and automatic packaging can be achieved, significantly improving production efficiency and product quality stability.
Furthermore, high-performance equipment also has significant advantages in energy conservation and environmental protection. Adopting advanced energy-saving technologies and environmentally friendly materials can reduce energy consumption and environmental pollution, meeting the requirements of sustainable development.
Quality Evaluation Plastic Injection Molding Machines Brand and Aftersales Service
Brand review
Internationally renowned brands such as Demag (Germany), Sumitomo (Japan) and Engel ( (Austria), as well as well-known domestic brands such as Haitian Taste, Chen Hsong and Yizumi, all enjoy high brand recognition and market reputation in the plastic injection molding machine industry.
Demag (Germany) has a worldwide reputation for its advanced technology, superior quality and reliable performance. Products are widely used in automotive, electronics, medical and other high-end areas. Sumitomo (Japan) has a strong advantage in the field of small injection molding machine, providing high accuracy and stability. Engel (Austria) is an industry leader with its innovative two-platen clamping technology and all-electric injection molding technology.
Haitian is a well-known brand in China and one of the largest plastic machinery production bases in China. The company's full range of products, covering a variety of specifications, models of injection molding machines, in the China market share is high. Chen Hsong focuses on technological innovation and product quality, and its products have a significant advantage in value for money. In the field of high-end injection molding machine, Yizumi has continuously developed a series of products with advanced international standards.
Different brands provide different products with different characteristics and technical advantages, and their application areas are different. When choosing a brand, enterprises need to take into account brand influence, product characteristics and technological advantages according to their own production needs and development strategies. Brand influence affects not only the quality and technical level of equipment, but also after-sales service and market recognition. Firms with strong brand influence tend to offer better products and more comprehensive after-sales service, and their products have relatively high market liquidity and resale value.
Quality assessment of after-sales service
After-sales service is very important for the normal use and long-term stable operation of injection molding machines. After-sales service includes equipment installation and commissioning, operation training, maintenance, spare parts supply, etc..
Installation and commissioning of equipment is the first step to ensure the normal operation of injection molding machine. The professional installation and commissioning team can carry out the installation and debugging of the equipment accurately according to the production environment and product requirements of the company to ensure that the equipment performance indicators reach the optimal state. Operations training can help the company's operators quickly master the operation skills and precautions to improve production efficiency and product quality.
Maintenance is key to ensure the long-term stable operation of the equipment. Regular maintenance can detect and eliminate potential faults in equipment in time to extend its the equipment's lifespan. The timeliness of spare parts supply directly affects maintenance efficiency and production schedule. Delays in the supply of spare parts can lead to production losses owing to prolonged downtime for repairs.
The quality of after-sales service can be assessed in the following ways. Looking at the size and professionalism of the after-sales service team, a larger, more professional team can respond to customers' needs faster and provide better service. Understand the coverage of after-sales service network; extensive network to ensure timely support throughout the country. In addition, the review of user reviews and case studies is essential. Communicate with other users about their experiences and manufacturers' after-sales service to assess service quality more directly. At the same time, communicate with manufacturers, understand the terms and policies of after-sales service, clarify the content, duration and responsibilities of after-sales service, and avoid disputes during use.
Conclusion:
Choosing a suitable plastic injection machine requires a combination of factors, including product demand, budget, brand and after-sales service. Determining the key parameters of injection molding machine according to factors of product size, raw material characteristics, output and precision is the basis of ensuring the production of qualified products. Under different budget constraints, the appropriate balance between performance and cost and the selection of equipment suitable for one's own enterprise can improve productivity and competitiveness. At the same time, the impact of the brand and after-sales service quality assessment, to ensure the long-term stable operation of equipment.
When enterprises choose plastic injection molding machine, they should choose scientifically and rationally according to their specific situation. They should not blindly pursue high-end equipment, nor should they choose unreliable equipment in order to reduce costs. Only by choosing injection molding machine suitable for their own production needs can enterprises improve production efficiency to the maximum extent and remain competitive in the fierce market competition.
