Refrigerator Door Seal Production Process

Most sealing strips used on refrigerators are made of silicone rubber. Silicone rubber offers superior oil resistance and low‑temperature performance compared with other types of rubber, which is why it is commonly chosen for seals and rubber tubing in food‑related applications. During production, silicone rubber sealing strips are extruded into the desired shape using an extruder, with the profile formed at the feed port of the machine. The extruded strip then undergoes vulcanization in a hot‑air curing oven to yield the finished silicone product. In the manufacturing process, the extruder serves as the primary equipment for shaping the seal; because silicone rubber has distinct physical properties from conventional rubbers, the extruders designed for this material are specially engineered. Typically, these machines feature a relatively short L/D ratio for the screw and are equipped with significantly lower‑power drive systems than standard general‑purpose extruders. Moreover, silicone rubber is highly prone to vulcanization, so the hot‑air curing ovens used in this process usually measure 8 to 20 meters in length—considerably shorter than the traditional 30‑meter ovens. Consequently, producing silicone rubber sealing strips with dedicated equipment results in substantially lower production costs than using generic sealing‑strip machinery. It should be noted that the sealing strips installed on refrigerator doors cannot be directly mounted after extrusion; they must first be processed on an edge‑joining machine to bond the four corners before the final product is considered complete.

Purpose

It is suitable for the efficient extrusion of profiled silicone products such as silicone strips. The design of the silicone extruder and its feeding system have been successfully implemented, ensuring excellent production stability and reducing the workload on operators. A screw with a high compression ratio and a high length-to-diameter ratio delivers superior extrusion density and mixing performance, resulting in products with smooth inner and outer surfaces, no bubbles, and consistent dimensional stability.

Performance Characteristics of Silicone Strip Extruders

1. This machine is equipped with an AC motor and a variable-frequency drive, offering a wide speed-regulation range, excellent adaptability to the production of silicone rubber products in various specifications, and convenient operation.

2. This machine is equipped with a hardened‑tooth‑surface rubber extruder reducer, which features low noise, high transmission torque, smooth operation, and convenient maintenance.

3. This machine employs pneumatic cylinder‑driven forced feeding, enabling the processing of multi‑layer rubber strips with dense extrusion and excellent product quality.

4. This machine is equipped with a dual-channel automatic temperature controller, ensuring minimal temperature fluctuations during heating. It allows for optimal selection of the heating temperature based on different processing requirements and automatically maintains the set temperatures of the heated barrel and die head.

5. This machine employs electric heating for the barrel and a circulating cooling system, enabling rapid cooling of the material to prevent thermal degradation.

Hebei Shuangda Rubber and Plastics Machinery Co., Ltd. is a modern enterprise integrating research and development, manufacturing, and sales of complete sets of extrusion equipment for rubber, silicone, and plastics. The company’s main products include rubber extruders, rubber hose extrusion lines, three‑layer composite sealing strip extrusion lines, silicone sealing strip production lines, plastic sealing strip production lines, plastic profile extrusion lines, plastic pipe extrusion lines, elastomer extruders, and other extrusion equipment, as well as production machinery for engineering seals, automotive seals, wire and cable applications, air‑conditioning hoses, braided hoses, automotive hoses, waterstop strips, and related products.