The vertical molding machine, also known as a plastic injection machine, is a piece of core mechanical equipment for processing, producing, and manufacturing plastic products, especially in the fields of secondary molding (overmolding) and insert molding. For manufacturers pursuing high precision and high efficiency, understanding its process flow and classifications is the foundation for choosing the right equipment.
As a professional manufacturer in the industry, MINHUI Machinery is here to provide an in-depth analysis of the working principles of vertical injection molding machines and their classifications based on different material applications.
The Six Process Steps of Vertical Molding Machines
A complete injection molding cycle might seem complex, but under MINHUI’s efficient control system, it can be broken down into six standardized steps:
- Preparation: This is the foundational step, which involves checking the equipment status and preparing the raw materials required for production.
- Feeding: Plastic pellets are added to the hopper. MINHUI’s design ensures smooth material flow to prevent bridging.
- Mold Closing & Melting: The machine starts working, and the mold closes under high pressure. Simultaneously, the heating system heats the plastic in the barrel to a molten state (plasticization).
- Injection & Holding Pressure: The screw injects the molten plastic into the mold cavity at high pressure and maintains a certain pressure (holding pressure) to compensate for voids caused by material shrinkage during cooling.
- Cooling & Setting: The product inside the mold solidifies and takes shape under the action of the cooling system.
- Mold Opening & Ejection: The mold opens, and the ejection mechanism removes the finished product.
If continuous production is needed, the equipment will automatically return to step 3 to enter the next cycle; if processing is complete, purging and shutdown procedures are performed.
Classification of Plastic Vertical Molding Machines by Use
The industry typically classifies injection molding machines into two main categories based on the physical and chemical properties of the plastic. MINHUI provides mature solutions for both requirements:
1. Thermoplastic Injection Molding Machines
This is the most common type currently.
- Characteristics: The plastic softens and flows when heated and hardens when cooled.
- Advantage: The process is reversible, meaning the material can be repeatedly plasticized and recycled.
2. Thermosetting Injection Molding Machines
Targeting specific industrial parts (such as electrical insulation components).
- Characteristics: The plastic softens and flows upon the first heating but undergoes a chemical reaction to cross-link and solidify at a certain temperature.
- Note: Once solidified and hardened, it cannot be softened by heating again, so it cannot be recycled for re-plasticization.
Why Choose the “Vertical” Structure
In terms of classification, “Vertical” refers to machines where the injection system and clamping system are arranged vertically. Compared to horizontal machines, MINHUI vertical injection molding machines possess unique advantages:
- Small Footprint: The vertical design saves valuable factory floor space.
- Ideal for Insert Molding: This is the biggest selling point of vertical machines. Since the mold surface faces upward, placing metal inserts (such as screws or terminals) is very convenient and stable. Gravity helps keep them in place, significantly improving the yield rate of secondary molding.
Whether it is a standard Rotary Plastic Vertical Injection Molding Machine, or a specialized BMC Vertical Molding Machine, Liquid Silicone Rubber (LSR) Vertical Molding Machine, or even a Two-Color Vertical Molding Machine, MINHUI can provide the production solution that best matches your product needs.
