Many customers notice a phenomenon when purchasing vertical injection molding machines: an LSR (liquid silicone rubber) machine and a standard plastic machine with a similar appearance and tonnage can have a significant price difference. Where does this price gap come from? The answer lies in two completely different molding processes and the core construction of the machines. For this reason, this article will provide an in-depth look at the three core differences behind the price.
Core Difference 1: How the Molding Principle Affects the Machine Price
This is the starting point for understanding all other differences.
- Standard Plastics (Thermoplastic): “Heat to melt, cool to shape.” The machine’s barrel is responsible for heating and melting the plastic, while the mold cools it to solidify.
- LSR Liquid Silicone (Thermosetting): “Heat to cure, cool to de-mold.” The process is exactly the opposite. LSR material is a liquid at room temperature and engineers cure it into a solid shape by heating the mold.
This fundamental distinction dictates that designers must create the core components of the two types of machines completely differently.
Core Difference 2: The Construction of Three Key Components
It is these specialized components, tailor-made for the LSR process, that constitute the main part of the price difference.
- Feeding System:
- Standard Machine: It uses a simple hopper that relies on gravity to feed material.
- LSR Machine: It must use a high-precision, dedicated LSR feeding system. Specifically, this system needs to draw the A and B liquid components in a strict 1:1 ratio, mix them evenly in a static mixer, and then inject them into the barrel under high pressure. This system is technologically complex and costly. For example, to ensure the highest precision and stability, MINHUI selects feeding systems from renowned German brands for our LSR equipment.
- Injection Unit (Screw and Barrel):
- Standard Machine: The barrel is covered with heater bands to melt the plastic pellets.
- LSR Machine: The barrel has no heating elements. Instead, engineers must equip it with a water cooling system to keep the LSR material in a low-temperature liquid state before injection, preventing it from curing prematurely inside the barrel. The screw design is also completely different.
- Mold Heating System:
- Standard Machine: The mold requires cooling water to lower its temperature.
- LSR Machine: The mold must integrate electric heating elements to precisely heat it to 160-180°C, which cures the LSR material.
Core Difference 3: The Brands and Precision of Components
In addition to the structural differences above, LSR injection molding requires extremely high precision. Therefore, its core components—such as feeding pumps, screws, and electrical accessories—are often sourced from top-tier brands from countries like Germany, Japan, and Austria to ensure production stability and product quality. The cost of these high-quality imported components is naturally much higher than the general-purpose parts used in standard machines.
In conclusion, the higher price of an LSR vertical injection molding machine is not without reason. It stems from its unique molding process and the three core systems tailor-made for it, which are composed of high-precision, high-quality imported parts. This higher initial investment buys the stability and precision necessary to produce high-value-added LSR products, such as medical supplies, baby products, and precision seals.
