During compression moulding of sheet moulding compound (SMC), voids are formed .. “Design for Success – A Design & Technology Manual for SMC/BMC”. Premix manufactures Sheet Molding Compounds (SMC) that are primarily used in compression molding. Premix offers SMC’s that are suitable for molding a. Most compression molding presses require that both the loading of SMC into the metals and even other polyesters such as bulk molding compound (BMC).

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During the cycle the operator would load the jig with slugs. Thermoset Sheet Molding Compound SMC is a mixture of polymer resin, inert fillers, fiber reinforcement, catalysts, pigments and stabilizers, release agents, and thickeners and possesses strong dielectric properties.

The introduction of SMC was justifiably xnd as a revolution in parts manufacturing, heralding the shift away from metals and towards polymers. The operator would then stretch the bottle at the neck over the core to free the bottle.


Compression Molding with SMC | Composite Parts

Bulk Molding Compound Offers Excellent Flow Characteristics Bulk Molding Compresskon BMC is a thermoset plastic resin blend of various inert fillers, fiber reinforcement, catalysts, stabilizers, and pigments that form a viscous, ‘puttylike’ injection molding compound.

The fiber-polyurethane mix is sprayed directly into the mold using a machine; the molding process uses lower pressure than traditional compression molding and is completed within minutes. It is sturdy and durable, capable of resisting impact even at high speeds. The landed plunger type mold must have an accurate charge of plastic, and no flash is produced. Wind and Other Renewable Energy Products. Materials that wmc typically manufactured through compression molding include: Basically the extruder was made part of the molding cycle.

Sheet Molding Compound | Compression Molding Process

All articles with unsourced statements Articles with unsourced statements from March Articles with unsourced statements from August The material charge is manually or robotically placed in the mold, heated mold halves are closed, and up to 2,psi of pressure is applied.

The material is available in a broad selection of colors, and can tolerate powder-coat or water-based paint. Therein the first cycle was complete. Here’s a quick “how-to” for incorporating ribs for optimum manufacturability. While sheet molding compound SMC certainly has its benefits, and may be the way to go for certain parts, in many cases long fiber injection LFI can provide the same quality of product for a lower price and with less waste.


Compression molding is a forming process in which a plastic material is placed directly into a heated metal mold, then is softened by the heat, and forced to conform to the shape of the mold as the mold closes.

Ideal for HVAC components and other applications where non-flammability is crucial. The molding press looked a lot like a ladle filled vertical press used for casting aluminum. Retrieved from ” https: Sheet molding compounds can be molded into complex shapes. Designed-in ribs can add enhanced stiffness to your SMC part. In addition to its light weight, SMC is easy to produce, and can be manufactured in high volume. Chopped glass fibers are randomly deposited onto the paste.

Sheet molding compound is a type of reinforced polyester containing glass or carbon fibers. The flash type mold must have an accurate charge of plastic and produces a horizontal flash excess material protruding from the mold. Retrieved 19 March Compression molding can therefore be used to create even complex, detailed parts with great accuracy. The compound is even approved for use in the outer shells of passenger vehicles, where it regularly receives high scores in crash tests.

This class of Sheet Molding Compound is available in two types of applications: The platens of the presses were steam heated.

Its excellent flow characteristics, dielectric properties, and flame resistance make this thermoset material well-suited to a wide variety of applications requiring precision in detail and dimensions as well as high performance. Fiberglass FRP composite materials and processes are explained in detail.

Since the process was brought to America by Romeo RIM init has gained immense popularity and been used for automotive parts, housing, furniture and more.

Compression molding

No problem — LFI can even mimic fine textures such as stone and wood grain. Compressiob of SMC of is typically done by compression or injection molding. BMC is available in bulk bags as well as slug form. Compression molding is also widely used to produce sandwich structures that incorporate a core material such as a honeycomb or polymer foam.


The start button moved the lower platen back into the press and the cure cycle bagan again. Materials Molding Data Sheets. With the evolution of compression molding, next was injection transfer. These thermosets can be in either preform or granule shapes.

Male and female tools are commonly made from tool-grade steel. When the cycle ended about 3. With the latest of electronic servo motor to high pressure hydraulic pump users save considerable energy and the greatest in speed, distance, pressure, dwell time and burping movements.

Compression molded parts are characterized by net size and shape, two excellent finished surfaces and outstanding part-to-part repeatability. These materials can be found in Underwriters Laboratory file E The process chosen is dependent upon specific product properties, product form and volume. The substance is then squeezed between two films; it is compacted until it reaches the desired thickness and texture. Depending on the end-use application, bulk molding compounds are formulated to achieve close dimensional control, flame and track resistance, electrical insulation, corrosion and stain resistance, superior mechanical properties, low shrink, and color stability.

Materials may be loaded into the mold either in the form of pellets or sheet, or the mold may be loaded from a plasticating extruder.

BMC is suitable for either compression or injection molding. Low shrink composite materials. Three types of molds used are the flash plunger-type, straight plunger-type, and the “landed” plunger-type molds.

Compression molding is the most common choice for high-volume composite parts and often associated snc SMC and BMC materials. Our off-the-shelf SMC can eliminate or reduce development time, translating to cost savings.