What factors should be considered when choosing an injection molding machine?

An injection molding machine, also known as an injection molding machine or injection molding machine, is an industrial device used to form thermoplastics or thermosetting plastics into specific shapes. It works by melting plastic pellets into a fluid through heating, then injecting the molten plastic into a mold cavity under high pressure. After cooling, the mold opens, resulting in the desired plastic product.

It consists of three main components:
Injection system: This is responsible for melting the plastic and injecting it into the mold. The core of this system is the screw and barrel, whose rotation and reciprocating motion convey, compact, heat, and inject the plastic.

Clamping system: This opens and closes the mold and provides strong clamping force during the injection process to prevent the mold from expanding under high pressure. Key components of this system include the platen, tie rods, and hydraulic cylinders.

Control system: This is like the brains of the injection molding machine, controlling the entire injection process. It precisely manages temperature, pressure, speed, and timing to ensure consistent quality for every product.

So how do you choose the right injection molding machine for your product? First, you must clearly understand the specific requirements of your product.

This includes:
Product size and weight: This is the primary basis for selecting the injection molding machine's tonnage (clamping force) and injection volume. The larger and heavier the product, the greater the clamping force and injection volume required.

Mold size: The injection molding machine's platen size, tie rod spacing, and mold opening stroke must accommodate your mold. Ensure that the mold fits smoothly into the machine and has sufficient space for mold opening and ejection.

Product material: Different plastics (such as PP, PE, PC, PVC, ABS, etc.) have different melt temperatures and properties. You need to select an injection molding machine with a screw design and plasticizing capacity suitable for your material.

Injection molding machine specifications and performance
Clamping force (tonnage): Clamping force is one of the most important parameters of an injection molding machine. It must be sufficient to withstand the pressure generated during injection and prevent the mold from expanding. Generally, the larger the projected area of ​​the molded product, the greater the clamping force required.

Injection volume and injection pressure: The injection volume must be sufficient to fill the entire mold cavity. Injection pressure influences the plastic filling and molding process, and is particularly important for thin-walled or complex products that require high pressure to fill.

Mold opening and ejection stroke: The mold opening stroke must be sufficient to allow smooth part removal, while the ejection stroke must ensure the part is completely ejected from the mold.

Plasticizing capacity: This determines how much plastic the machine can melt per unit time. Efficient plasticizing capacity helps improve production efficiency.

Energy consumption: Energy-efficient injection molding machines are increasingly popular. Choosing a machine with servo motors or variable frequency technology can significantly reduce energy consumption and operating costs.

Key Injection Molding Machine Maintenance Tips

Daily maintenance of injection molding machines is crucial for their long-term, efficient, and stable operation. A well-maintained maintenance plan can effectively reduce downtime, extend machine life, and ensure product quality. The following are several key points for injection molding machine maintenance:

1. Daily Inspection and Cleaning
Keep the Machine Clean: Before and after each start-up, clean dust and oil from the machine surface, especially the mold plates, tie rods, and guide rails. A clean machine reduces wear and tear and makes it easier to detect potential problems.

Lubrication: Regularly check and refill the lubricant or grease in moving parts such as tie rods, hinges, and ejector rods. Ensuring smooth operation of all moving parts significantly reduces mechanical wear.

Screw and Barrel Cleaning: When shutting down or changing materials, thoroughly clean any remaining plastic from the screw and barrel to prevent carbonization or cross-contamination.

2. Hydraulic System Maintenance
Hydraulic Oil Inspection: Regularly check the hydraulic oil level, color, and cleanliness. If the hydraulic oil is discolored or contains impurities, replace it promptly. The quality of hydraulic oil directly impacts machine stability and the lifespan of hydraulic components.

Oil Filter Cleaning/Replacement: Hydraulic oil filters remove impurities from the oil. Regularly cleaning or replacing the filter element prevents clogging and wear of hydraulic components.

Hydraulic Pipe and Seal Inspection: Inspect all hydraulic pipes for cracks, aging, or oil leaks. If any problems are found, replace them immediately to prevent hydraulic fluid leaks from causing insufficient pressure or environmental contamination.

3. Electrical System Maintenance
Circuit and Wiring Inspection: Regularly check the wiring in the electrical box for tightness and signs of looseness, aging, or short circuits.
Temperature Control: Ensure the temperature control systems of the barrel, nozzle, and mold are functioning properly. Accurate temperature control is critical to ensuring product quality.
Sensors and Switches: Check the proper functioning of all limit switches, safety switches, and sensors, and ensure that the machine's safety interlocks are effective.

4. Mold Maintenance
Although the mold itself is a separate tool, it works closely with the injection molding machine, and its condition directly impacts production. Mold Cleaning: After production, thoroughly clean the mold cavity and surface and spray with rust inhibitor to prevent rust.
Wear Inspection: Inspect the mold's guide pins, guide bushings, and ejector mechanism for wear and replace them promptly.

5. Regular Screw and Barrel Inspection
Wear Inspection: Regularly inspect the screw, barrel, and check ring for wear. Wear on these components can significantly affect plasticizing efficiency and product quality.
Screw Alignment: Ensure screw concentricity to prevent unnecessary vibration and wear during high-speed rotation.

By following these maintenance tips, you can minimize injection molding machine failures and ensure continuous, stable operation of your production line.

Choosing the right injection molding machine and understanding its daily maintenance can ensure the stable operation of the injection molding machine and improve production efficiency. I hope this article can help you choose the right injection molding machine!