SMC molds, characterized by their high-strength and high-hardness construction using steel, boast polished surfaces that play a crucial role in ensuring the impeccable surface quality of the resultant SMC molded parts. The primary attribute defining SMC molds is their fabrication through a compression process, where the SMC material undergoes compression to attain its final form.

The distinctive production method involves the utilization of hydraulic presses for compression molding. In this process, the cavity and core of the mold are securely affixed to the upper and lower platens of the machine. The operational sequence initiates with the introduction of the SMC material into the open mold. Following this, the mold is meticulously sealed, subjected to a specific temperature, and the SMC material seamlessly flows throughout the entirety of the mold, driven by the synergistic forces of pressure and temperature.

In essence, the utilization of SMC molds, coupled with the precision of the compression process, ensures the creation of SMC molded parts that exhibit not only high-strength and hardness but also maintain a superior surface quality. The orchestration of these factors, facilitated by the hydraulic press and controlled temperature conditions, encapsulates the efficiency and reliability of the SMC molding technique.


SMC mold design points

The color of the compound can be customized.
In-mold coating and vacuum system can improve the surface paintability without the need of primer.
Parting lines and shear edges for mold design; design of tendons and inserts; mold surface roughness; extraction angle.
SMC compressors typically operate at 140 degrees to 160 degrees.
Both male and female molds are made of high quality steel, except at temperatures below 400 psi.
SMC molds require heating access. Normal heating systems are steam, oil, electricity or high pressure water.

SMC Molding Processes

SMC molding is an advanced method for molding composite materials. The process is continuous, allowing for the production of high-strength, complex parts in various sizes. It takes place in a “compression molding machine,” typically hydraulically driven. During the process, the heated half-mold closes, applying a downforce of up to 2,000 psi. Cycle times vary based on part size and thickness, ranging from one to five minutes. Compression molding enables the formation of intricate parts like ribs, tabs, and inserts with enhanced accuracy.

Operational Procedure:

When initiating the SMC molding process, the SMC tooling is secured on the press platen. The SMC mold is heated, and the SMC material is placed into the open mold. Process parameters such as molding pressure, cure time, and opening/closing speed are set. After closing the mold, the SMC workpiece is demolded, and the finished product is extracted.

Advantages of SMC Finished Products:

SMC parts exhibit precise sizing, shape, excellent surface finish, and remarkable part-to-part repeatability.
In-mold coloring options are available.
Minimal trimming and finishing costs.
Good dimensional stability, heat resistance, and chemical resistance.
Mirror-finished SMC precision molds meet automotive grade A surface requirements.
Variable SMC material ratios allow parts to meet environmental needs effectively.
Nominal weight reductions of approximately 50% compared to metals and 30% compared to other thermoplastics.

Bulk Molding Compound (BMC) and Sheet Molding Compound (SMC) are both fiber-reinforced materials, typically using different lengths of glass filament fibers. SMC uses slightly longer fibers than BMC and typically has a higher percentage of reinforcing fibers than BMC.

Sheet Molding Compound (SMC) is a reinforced polyester containing glass or carbon fibers. These fibers, usually 1 inch or longer in length, are suspended in a bath of resin – usually epoxy, vinyl ester, or polyester.

SMC (Sheet Molding Compound) consists of polyester, glass fibers, mineral fillers, pigments and various additives. It can also be produced in desired colors.Some examples of the various areas of use for SMC include the construction, automotive and electrical industries.

SMC (Sheet Molding Compound) is a compression molding compound that is typically used for large parts that require higher mechanical strength. The glass reinforcement is between 10% and 60% and the glass length is superior to BMC (block molding compound).

SMC molding pressure is determined by the structure, shape and size of the part and the thickness of the SMC. Simple shapes only need 25-30Mpa molding pressure; for complex shapes, the molding pressure can reach 140-210Mpa. the higher the degree of SMC thickening, the higher the required molding pressure.


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