The Pros and Cons of the 3 Primary Rubber Molding Production Methods

Custom rubber molding products have many uses across a wide range of applications. In fact, it is difficult to imagine an industrial or manufacturing setting that doesn’t employ these items in some capacity. For example, the automobile industry utilizes many customized rubber components in the production of new vehicles. How each of those components is produced depends largely on a number of factors, including how it will be used and the costs associated with its production.

There are 3 Primary Methods of Producing Rubber Molding Products:

1. Compression molding is the oldest and most simple rubber molding process available. With this process, an uncured “slug” of rubber is placed in a cavity between two plates that are then pressed together. (The cavity between the two plates is in the desired shape of the final product). Pressure is applied to both plates which forces the uncured rubber to conform to the shape of cavity. The mold remains closed until the rubber is cured and the process is complete.

Compression molds are the most simple to create and are therefore the most economical to use. However, producing rubber molding products in this manner is a manual process which requires more time and effort to perform. Of the 3 production methods, compression molding also yields the most inconsistent results and takes the longest time for the rubber to cure.

2. With transfer molding, an uncured slug of rubber is placed in a chamber above the mold’s customized cavity. Pressure is then applied directly to this chamber in an effort to force the rubber through small openings called “sprues.” The rubber then passes through (“transfers”) those openings to fill the mold’s cavity. Once complete, the rubber remains in the mold until it is fully cured.

Transfer molding offers faster curing times than the compression method because of the heat produced during the transfer process. Also, because the mold remains closed throughout the process, less excess material is able to seep out, which results in less waste material. In terms of consistency, this process offers better results than compression molding. On the other hand, these molds have a more complex design and carry a correspondingly higher price tag to produce.

3. Injection molding is the most sophisticated method of producing rubber molding products and produces the most consistent results. With this method, the uncured rubber is softened prior to being injected into the mold through a series of small openings. This method is entirely automated and uses a precise amount of raw materials. With injection molding, the cavity plates remain closed throughout the process, thereby limiting the amount of excess rubber that can escape the cavity. This, in turn, limits the amount of excess flash that is produced. However, injection molds are the most complicated to create and represents the most expensive option.

Each rubber molding production method is better suited for some applications than others. This is due to the inherent advantages and disadvantages associated with each process. As with most things, there is a clear relationship between cost and quality, with the highest-priced alternative (injection molding) yielding the most consistent and uniform results. However, not all jobs require this level of sophistication and precision. In those cases, less precise but more cost-effective options are worth exploring.

Post time: 01-31-2017