TOGOHK is commencing a comprehensive introduction to the lsr injection molding. Our engineers will provide in-depth insights into various aspects, including the working principles of liquid injection molding machines, the pros and cons, application scope, considerations in design and manufacturing, material selection, and more. Before you consider opting for the lsr silicone rubber injection molding process, please read this article carefully to gain a better understanding of the relevant information.
What is LSR Injection Molding?
LSR (Liquid Silicone Rubber) Injection Molding is the process of extracting LSR silicone rubber material and injecting A-type and B-type liquid materials simultaneously through two different pipelines. The mixed material is then injected into the mold cavity through a nozzle. After molding, it undergoes curing at specific temperature and time to solidify the LSR material.
The selection of A-component and B-component in the liquid material is based on specific reasons. It’s similar to adding yeast when making a cake to facilitate the fermentation and expansion of the flour, ultimately forming through high-temperature baking. In this process, the curing agent in the B-component plays the role of yeast, catalyzing the curing process.
How Does Liquid Silicone Rubber Molding Work?
The following video comprehensively demonstrates the entire workflow of liquid silicone rubber molding: from raw material preparation, mixing stage, screw advancement injection, mold closure to the final forming process. The video will provide detailed insights into each step, helping you gain a comprehensive understanding of how liquid silicone rubber molding works.
Advantages and Disadvantages of LSR Molding
Advantages:
- High mold precision
- Odorless and non-toxic
- Good biocompatibility
- High resilience
- High and low-temperature resistance
- Suitable for mass production
Disadvantages:
- High mold cost
- Material cannot be recycled for secondary use
- Complex machine cleaning process
Applications of Liquid Silicone Rubber Include:
- Children’s tableware
- Baby products
- Medical devices
- Consumer goods
- Food and beverages
Design and Manufacturing Considerations for LSR Injection Molding:
Mold Material:
In mold manufacturing, you’ll be faced with the decision of choosing different materials such as P20, S136, NAK80. These materials vary in hardness, wear resistance, lifespan, and cost, depending on the quantity of your product and the lifespan requirements for the mold.
Mold Structure:
When designing the mold, it’s crucial to consider factors like parting line positioning, hole locations, and shrinkage for silicone products. This is key for the quality and appearance of the final product.
Cooling System:
The design of the cooling system is also a critical step, especially considering that silicone is a thermosetting material. A well-designed cooling system can play a crucial role in batch production, ensuring stability in the performance of both the mold and the product.
Mold Surface Treatment:
Mold surface treatment typically involves processes like sandblasting and electroplating. Such treatments help ensure smooth demolding of products, enhancing production efficiency, and extending the lifespan of the mold.
Materials Used in Silicone Liquid Injection Molding:
- Clear
- Low hardness
- Wear-resistant
- Food-grade
- Medical-grade
- Flame-retardant-grade
The Selection of Silicone Pigments in Liquid Molding:
In the initial stages, liquid silicone rubber materials were primarily available in transparent and translucent colors, mainly used in the high-end medical industry. With the advancement of industries, there is an increasing demand for higher product quality in consumer goods. With continuous technological progress, we now have the capability to customize liquid silicone rubber materials in various colors. Within the Pantone color range, you can choose any Pantone color, providing a broader spectrum of color combinations for products. This customization ability makes liquid silicone rubber materials more versatile and creative in various application fields.
LSR Vs. Compression Molding: What’s the Difference?
LSR Silicone Molding
1. Injection Process:
LSR silicone molding shares the same process as plastic injection molding, with the only difference being the material. In plastic injection molding, plastic is melted into a liquid state at high temperatures and injected into the mold cavity through a high-pressure screw for cooling and forming. In LSR silicone molding, the liquid material is directly injected into the mold cavity through a high-pressure screw and solidifies into the final product.
2. Characteristics:
The mold structure in LSR silicone molding allows for an automated molding process using robotic arms. The entire molding process with liquid molds is more precise, and the mold framework ensures more accurate dimensional tolerances, making it friendlier for complex and high-precision parts.
Compression Molding
1.Compression Process:
Compression molding involves placing pre-cut solid materials into the mold cavity, compressing the silicone material in the mold through the upper and lower molds, and then curing and forming the product through high-temperature insulation.
2. Characteristics:
Compression molding typically requires more manual operations and is suitable for producing complex silicone products and simpler parts. It offers greater flexibility.
Differences:
1.Automation:
The mold structure in LSR silicone molding inherently supports automation, making it well-suited for automated production. Compression molding requires more manual operations but can also be adapted for large-scale production.
2.Mold Selection:
LSR silicone molding is suitable for high-precision and complex-shaped silicone parts. Compression molding is suitable for environments that require more flexibility and cost control. The choice between the two depends on the added value of your product and the target audience. If the added value is not high, we recommend choosing compression molding.