Rubber rings, often referred to as O-rings, are typically manufactured using processes that involve shaping elastomer materials under heat and pressure. The primary methods utilized for this production are compression molding and injection molding.
Main Manufacturing Processes
According to manufacturing standards, two main processes are commonly used to create elastomer O-rings:
- Compression Molding: This is a widely used method, particularly suitable for lower production volumes or larger rings.
- Injection Molding: This process is generally faster and more automated, often preferred for high-volume production.
While both processes achieve the final circular shape, they differ in their initial steps and how the material is introduced into the mold.
Compression Molding Explained
The compression molding process, as highlighted in manufacturing descriptions, follows several key stages:
- Blank Production (Extrusion): The process begins with the production of a blank using the extrusion process. This involves pushing the rubber compound through a die to create a continuous strip with a specific cross-section. This strip is then cut to the appropriate length to form the raw "blank" for the ring.
- Placing in Mold: The cut rubber blank is then carefully placed into a pre-heated mold cavity, which is shaped like the final O-ring.
- Pressing and Curing: In the next step, this is placed in a mold and pressed at high temperature to form a circular O-ring. The mold is closed under pressure, and the heat activates curing agents in the rubber compound, causing it to vulcanize or harden into its final, resilient form.
After the pressing and curing cycle is complete, the mold is opened, and the newly formed O-rings are removed. Excess rubber, known as flash, is typically trimmed off in a secondary finishing step.
Compression molding is valued for its relative simplicity and cost-effectiveness for certain production needs, directly utilizing a pre-shaped blank to achieve the final product.
