Hydraulic Press For Rubber Molding

Hydraulic presses are essential tools in the fabrication, assembly and production of parts across a range of industries.

Greenerd Press & Machine Company offers a variety of hydraulic press models to fit any production or assembly requirement. Their models can be configured with various dies, pressures, stroke speeds and process positions for optimal efficiency and productivity.

Compression Molding

Compression molding is a commonly used manufacturing process for rubber, plastic and composite materials. This involves placing an uncured material into a heated mold cavity and then pressing until it takes on its desired shape.

This process is ideal for many parts, from simple shapes to intricate products with strong physical characteristics. It also serves to produce prototypes or evaluate production designs.

Compression molding typically starts with metal tooling composed of two parts (or a mold and core) that replicate the dimensions of the final product. Utilizing a press, these heated pieces are then filled with fiber reinforced resin material to produce an injection-molded part.

Hydraulic presses are ideal for these tasks due to their long dwell times, variable ram speed and consistent force distribution across a wide area. These features make them ideal for compression molding and many other processes.

Transfer Molding

Hydraulic presses for rubber molding are machines that use a plunger to compress uncured rubber into an enclosed mold cavity. This technique has many applications, from small to medium sized products to larger components.

The process begins by placing uncured rubber into a part of the mold called a pot. Next, using a plunger, force the rubber into its designated cavity within the mold cavity which has been heated to an exact temperature.

This process isn't sensitive to the exact weight of material charged into each cavity, making it ideal for producing small and intricate parts. Additionally, it's suitable for molding metal inserts which may produce sharper edges than injection molds.

Injection Molding

Injection molding is a widely-used method for producing plastic parts with tight tolerances.

Molten plastic is poured into a mold and filled with cavities using sprues and runners. After cooling, the part is expelled from its container which has been opened and cooled.

Some injection molded parts may experience warping due to plastic cooling and shrinkage unevenly.

This can cause the material to warp or even break, leaving behind a small recess in its surface known as a sink mark.

Another issue is drag marks, which appear when the walls of a part slide against the mold during ejection. To prevent them, ensure that your part has an appropriate draft angle.

Finally, certain injection molded parts may be prone to undercuts. These can add cost, complexity and maintenance requirements for the mold; however, there are design tricks you can use to completely avoid them.

Customization

Hydraulic presses are versatile production tools that can be tailored to a manufacturer's requirements. They're used for multiple processes like metal stamping and compression molding.

Joseph Bramah invented the hydraulic press in 1795, using Pascal's law of fluid dynamics as its foundation. This machine consists of two cylinders filled with liquid and connected by a pipe.

By applying pressure to two cylinders, fluid can move from one to the other until it builds up enough force to push a piston against an anvil, baseplate or die of a part in order to form it into its desired shape.

Customization of a hydraulic press for rubber molding can include altering the size of cylinders or beds, changing the hydraulic fluid type, increasing or decreasing folding down to 1mm in depth and length to 1 mm, as well as altering die shape among other options.

Hydraulic press manufacturers provide various guiding arrangements, such as adjustable eight-point gib guiding or prismatic temperature-compensated guiding. These features help maintain guide clearances at increased temperatures in compression molding applications.