Rubber injection molding is an advanced manufacturing process in which uncured rubber is transformed into a finished product by injecting rubber material into a mold cavity. Due to the pressure in the process, the raw rubber material undergoes a chemical reaction that causes it to cure and hold the shape of the mold when completed. This simple concept is used to create a wide variety of different products across numerous industries, but the precision required to avoid flaws means companies will need to utilize experts for their rubber injection molding needs. Take a closer look at how rubber injection molding works and how Dalin Mold puts our expertise to use for a variety of different businesses.

How Rubber Injection Molding Works

The rubber injection molding process allows raw rubber material to be shaped and cured into products that can be applied to a range of different industries. The primary benefit of this process is how much more efficient it is compared to shaping parts by hand. It begins by injecting raw rubber into a mold after the material is heated to a liquid state. Then, the liquid rubber is injected into the tightly clamped mold through a barrel and nozzle assembly until the mold is filled by the rubber. It packs tightly to the dimensions of the mold and is cured to create the final shape. The curing process typically involves applying heat and pressure to the material.

The Rubber Injection Mold Design Process

To get the most out of any rubber part, you will need to make sure that the mold is properly designed. To prevent mistakes, the design process has several considerations. The finalized part’s function needs to be the top priority. If you need a container seal, for example, then it is imperative that the mold design allows for the creation of a rubber part that cannot be bypassed by fluids or whatever the container is going to store.

Corners are commonly required in rubber parts, but the design should consider the fact that sharp corners are generally not the most efficient solution. Sharp corners require a lot more effort to mold and fill properly, so they drastically reduce the efficiency of the process. Rounded corners with a radius of something greater than 0.05 inches is typically standard since it makes the mold design substantially easier. Keep in mind, however, that this is a contrast to how rubber part edges are designed, since sharp edges are standard. Sharp edges, unlike corners, increase the efficiency of the design and molding process for the rubber part.

Designing Molds with Undercuts

Some rubber parts utilize undercuts or features that project into the main body of the part itself. While this is essential for some rubber parts, it can make the part difficult to remove from the mold under normal production conditions. When undercuts are involved in a rubber part, the mold design should allow it to be opened both vertically and horizontally. This makes it significantly easier to remove the completed part from the mold without damaging it. Just keep in mind that this kind of functionality for the mold typically means the mold is more expensive.

Features of the Design

Rubber injection mold designs come with several features to keep in mind when considering the most efficient solution for your rubber part needs. With rubber injection molding, several advantages are included in the basic process including the following.

• High efficiency
• Process can be automated
• Rubber parts can be produced with precision and tight tolerances
• Complex geometry can be molded
• Eliminates the need for preforming and its associated costs
• Cavities fill rapidly cutting down on cycle time
• Minimizes material waste

Multi-Cavity Molds

Multi-cavity molds are an available solution to rubber injection molding that allows for a significantly higher output in production runs. They are particularly useful for high volume production runs of a rubber part that is needed in mass quantities. As the name suggests, multi-cavity molds are rubber injection molds that have multiple cavities. This allows more than one rubber part to be created at a time. This comes with notable advantages like faster production runs, shorter lead times, and less wasted material.

High-Efficiency Rubber Molds

While multi-cavity molds play a major role in increasing the efficiency of high volume rubber injection mold production runs, several other factors can contribute to overall efficiency as well. The more automated the process is, the less labor is required to get the job done right, and that kind of automation is only possible with advanced technology that allows for constant monitoring and data collection. Additionally, flash and waste will need to be reduced as much as possible. Multi-cavity molds already reduce flash and material waste, but other factors like material choice and the size of the mold can affect efficiency as well.

Common Applications of Rubber Injection Molding

Rubber injection molding produces rubber parts with tight tolerances that are applicable to a range of different industries considering the sheer variety of forms and configurations that are moldable with this process. Note that these applications include products made from both natural rubber and synthetic rubber.

• Construction Industry
  • Gaskets
  • Seals
  • Vibration control
  • Tubing
  • Grommets
• Automotive Industry
  • Engine parts
  • Valves
  • Transmission components
• Defense Industry
  • Vibration control
  • Noise control
  • Seals
  • Weapon parts
• Medical Industry
  • Ventilation masks
  • Seals
  • Tubing
• Agriculture Industry
  • Vibration control
  • Suspension
  • Noise control
  • Bushings
• Transit Industry
  • Steering
  • Brake systems
  • Tubing
  • Engine parts
  • Covers for electrical wiring

Rubber Injection Mold Tooling from Dalin Mold

Dalin Mold & Machine offers custom rubber injection mold tooling with an in-house designer and experience serving rubber part manufacturers. Our molds are designed for precision and can hold up to multiple repeated uses. Additionally, we offer rubber injection mold design support for custom molds with a focus on precision and efficiency. Our high quality equipment allows us to create multi-cavity molds and other designs to streamline the production process and reduce costs and lead times without compromising quality. Get a quote from our team today for your custom rubber injection mold design.