Understanding SMC Moulding and BMC Moulding:

SMC Moulding: SMC is a composite material composed of thermosetting resins, chopped glass fibers, and fillers. SMC moulding is widely used to create complex and durable parts with high strength-to-weight ratios, making it suitable for automotive, electrical, and construction industries.

BMC Moulding: BMC consists of a thermosetting resin, fillers, reinforcements, and additives. BMC moulding enables the production of intricate parts with excellent electrical insulation properties, flame resistance, and dimensional stability. It finds applications in electrical components, automotive parts, and more.

Benefits of Compression Moulding:

Compression moulding offers several advantages for SMC and BMC moulding processes, including:

High Precision: Compression moulding ensures accurate replication of intricate designs, resulting in consistent part dimensions and minimal post-processing requirements.

Material Flexibility: It allows the use of various composite materials, reinforcing fibers, and additives, providing versatility in achieving desired mechanical and electrical properties.

Cost-Effectiveness: Compression moulding offers efficient material usage, reduced scrap, and lower tooling costs compared to other moulding techniques.

Enhanced Mechanical Properties: The applied pressure during compression moulding ensures excellent fiber wet-out, leading to improved strength and structural integrity of the final parts.

Advanced Techniques in Compression Moulding:

MDC Mould utilizes advanced techniques to further enhance the quality and efficiency of compression moulding processes, such as:

Precision Tooling: MDC Mould employs state-of-the-art tooling technologies to create precise and durable SMC moulds, BMC moulds, and related tooling solutions.

Automated Production Systems: Leveraging automation and robotics, MDC Mould optimizes production processes, reduces cycle times, and ensures consistent part quality.

Simulation and Analysis: By employing simulation software and analysis tools, MDC Mould can optimize mould designs, material flow, and cooling systems to improve overall moulding efficiency.

Applications of Compression Moulded SMC and BMC Components:

Compression moulding finds widespread applications in various industries. Some common applications include:

Automotive: Bumpers, body panels, interior trims, and structural components.

Electrical and Electronics: Insulators, connectors, switches, and enclosures for electrical devices.

Construction: Composite building materials, electrical distribution boxes, and infrastructure components.

Consumer Goods: Appliance parts, bathroom fixtures, and furniture components.

MDC Mould stands at the forefront of compression moulding technology, offering exceptional expertise in SMC moulds, BMC moulds, and related applications. With their advancements in precision tooling, automation, and simulation techniques, they continue to drive innovation in the field. The versatility, precision, and cost-effectiveness of compression moulding make it a preferred choice for manufacturing high-quality components in various industries.

The rapid development of the automotive industry has led to an ever-increasing demand for automotive components. In order to meet market demands, MDC Mould, as a leading mould manufacturer, has continuously invested in the development of BMC moulds and has demonstrated excellent capabilities in the field of automotive component manufacturing. BMC moulds bring new vitality to the automotive industry with their outstanding mechanical performance, weather resistance and precision moulding capabilities.

As a glass fibre reinforced unsaturated polyester material, BMC moulds offer unique advantages in the manufacture of automotive components. Compared to traditional metal materials, BMC moulds are lighter, stronger and more corrosion resistant, effectively reducing the weight of automobiles and improving fuel economy and driving safety.

MDC Mould has made significant achievements in the development of BMC moulds. Through continuous innovation and technological breakthroughs, the company has successfully developed a range of efficient and precise BMC moulds that are widely used in various areas of the automotive industry.  BMC moulds can accurately mould products to meet design requirements, providing new solutions for the appearance and performance of automobiles.

BMC moulds also have excellent production efficiency and cost control capabilities. With excellent flow and moulding performance, BMC moulds can produce large quantities of automotive components quickly and efficiently through processes such as injection moulding. At the same time, the production process of BMC moulds is relatively simple, without the need for additional processing steps, which can effectively reduce production costs and improve the competitiveness of companies.

In addition to the advantages in performance and production efficiency, BMC moulds also have green and environmental characteristics. The company is committed to environmental awareness, and BMC moulds do not contain harmful substances. They have good weather and chemical resistance, effectively resisting harsh weather conditions and chemical corrosion, extending the service life of automotive components and reducing the negative impact on the environment.

BMC moulds have revolutionised the manufacture of automotive components. Their outstanding physical performance, precision moulding capabilities and green and environmental credentials make them the material of choice in the automotive industry.

MDC Mould is a renowned mould manufacturer both domestically and internationally. The moulds developed by our company have the characteristics of high difficulty, long service life, short cycle, reasonable price, timely delivery and attentive service, and have been favoured by customers at home and abroad in the field of BMC moulds. If you have any requirements, please feel free to contact us.

Thermoset materials such as SMC, BMC, etc have excellent physical properties when getting compression molding. Structural parts molded from BMC or SMC can be replaced for metal products at the condition of weight reduction without lowering strength. Excellent heat resistance, compression strength, and dimensional stability are all advantages of compression molding materials.

Difference Between SMC and BMC Materials

Before the introduction begins, there are a few more proper nouns you need to know:

• Polyester resin: an adhesive that provides three-dimensional crosslinking during processing, connects individual components, and plays an important role in achieving desired thermomechanical properties;
• Mineral fillers: ensuring the transport of glass fibers during the flow of the material, can significantly reduce its cost and, in the case of aluminum hydroxide, significantly improve the refractoriness of the material;
• Glass fiber: provides the mechanical strength of the product;
• Catalyst: Provides initiation of three-dimensional cross-linking chemical reactions. The correct choice of catalyst is the most important condition for obtaining high-quality parts without underpressure, cracks and voids.

SMC material

SMC (Sheet Molding Compound) – Sheet material containing resins, fillers, reinforcing fibers. SMC is a material that can be pressed and processed at a high temperature of 120-160 SMC °C. The SMC is protected by a polymer film on both sides. Thickening agent, inorganic filler, initiator, additive, and pigment were added to the unsaturated polyester resin to make a mixture of resin, impregnated with short-cut fiber or felt piece, covered with PE film on both sides, after thickening, a thin sheet molded plastics were prepared. Unlike woven glass materials, SMC is not reinforced with bonded glass fibers. Because the glass fiber length is significantly longer than that of BMC, SMC has lower flow properties but higher strength properties. By using a chemical-resistant resin, a pressed material with high weather resistance can be obtained.

Typical SMC structure:

• Fiberglass (15-50mm) – 27%;
• Filler (talc) – 40%;
• Resins (polyester, vinylester) – 28%;
• Other additives – 5%.

Usually fibers in SMC products have two orientations. SMC also has the following varieties:

• SMC LP is a thin material that can get products with high surface quality;
• SMC LS – low shrinkage material;
• HSSMC is a high strength material.

Depending on the specific product, different types of SMC can be used, each with different characteristics. The common denominator is minimal technical shrinkage and high impact strength. The significant advantages of SMC products compared to steel are high corrosion resistance and low specific gravity. SMC is processed into large-sized body parts by direct compression. During the pressing process, the pre-cut material is placed into the mold. The clamping time is 2-3 minutes, and the heating temperature is about 150 ℃.

The main application areas of SMC are: automotive industry, traffic engineering, lighting engineering, electrical network. The most notable achievement is the use of oil pans and valve covers made of SMC by car companies in production truck models. The following is a list of auto parts that can be manufactured with compression molds.

• Automotive exterior parts: bumper linings, mudguards, wheel covers, spoilers and rear doors.
• Automotive interior parts: instrument panel, door panel, glove box, car seat and various protection panels.
• Structural and functional components: fuel tank, coolant tank, air filter cover, fan blades, intake pipe and cylinder head.

In addition to auto parts, SMC molding is also used to produce bathroom accessories, water tank accessories, motorcycle accessories, fitness equipment parts and meter housings.

BMC material

BMC (Bulk Molding Compound) – A special paste-like material containing resin BMC, fillers, and reinforcing fibers. It mixes a variety of inert fillers, fiber-reinforced materials, catalysts, stabilizers and pigments in thermosetting plastics to form a gluey “putty like” composite material for pressing or injection molding. The glass fibers in BMC are shorter than those in SMC, so the BMC material flows even better than SMC, and can be made into a better finish or more complex materials. BMC features light weight, electrical insulation, fire resistance, corrosion resistance, heat resistance, weather resistance, low shrinkage, stable dimensional control, good fluidity, and a variety of special properties combined into one, making bulk molding compound (BMC) the most ideal of materials to manufacture smaller but more complex and precise products used in various industries.

Typical BMC structure:

• Fiberglass (5-20mm) – 20%;
• Filler (talc) – 45%;
• Resins (polyester, vinylester) – 30%;
• Other additives – 5%.

BMC is a material that can be processed by pressing or injection. During pressing, metal is used to heat the substrate. Pressures from 30 to 100 atmospheres. The heating temperature is 100-160°C. The mold closing time is 2-3 minutes, during which heating occurs and polymerization is initiated. Injection molding uses a screw injection molding machine to feed material into a closed mold cavity.

BMC technology has also been widely used in the production of complex-shaped parts, such as pump casings, electrical components, etc.

Although there are differences between the two forms of material, both are suitable options for compression molding. In both cases, MDC mould offers SMC and BMC mould options that accompany MDC mould’s commitment to excellence.

SMC VS BMC

MDC mould has been designing and manufacturing moulds for Sheet Moulding Compound (SMC) and Bulk Moulding Compound (BMC) materials since the 1990s. MDC Mould is one of well-known mold makers in china. With the most advanced production equipment and technology, it enables us to manufacture the best quality molds. MDC has a long history in the glass fiber compression molding industry. We are committed to the design, development and production of stampers, as well as provide technical support to customers worldwide, Our aim is to become the best supplier of stable, high-performance SMC mould and BMC mould.

They are both a kind of resin mixture, which will be made into semi-finished products before molding. But at this time, BMC is made into clumps, while SMC is made into matte flakes, which are then cut to size.

The production process of SMC mold and BMC mold is also different. SMC molds are usually formed by compression molding, while BMC molds can be formed by different forming ways like injection, compression molding or transfer molding. These methods can all meet the production needs of medium and high volume.

Although the raw materials of SMC and BMC are roughly the same, there are differences in the use of glass fiber between the two materials. Glass fiber reinforced materials added to SMC generally account for up to 30%, and the fiber length is usually 25~50mm. In BMC, glass fiber reinforced materials generally account for 10%~30%, and the fiber length is usually 6~24mm. In comparison, the length of glass fiber used in SMC is longer than that used in BMC. Therefore, there are some differences in performance between these two. In general, SMC mold is stronger than BMC mold. In BMC molds, mineral fillers have a higher specific gravity and thus lower cost.

The advantages of SMC mold:

●Lightweight and high strength: With the same volume of materials, SMC is lighter than steel and aluminum, and its relative density is generally 1.3~2.0g/cm3, only 1/4~1/6 of ordinary steel, and 1/3 lighter than aluminum alloy. It can achieve the goal of lightweight, and has good impact resistance and energy absorption, and has high tensile strength, bending strength and impact toughness.

●High degree of integration and large degree of design freedom: The flow characteristics and molding process of SMC materials determine that many parts can be molded at one time, which can reduce the number of molds, tooling and the number of steps in the welding, assembly and other processes, thereby significantly reducing costs and realizing low-cost actions for low-volume components.

●Strong corrosion resistance: SMC material itself is a corrosion-resistant material, so it does not need phosphating treatment for anti-corrosion and improved bonding performance. Compared with metal, the application of SMC mold can reduce cost and save energy.

●Excellent heat resistance and paintability: SMC products have good heat resistance. After demoulding, SMC products can maintain dimensional stability at -50-200°C. Excellent heat resistance makes it suitable for use in auto parts. In addition, SMC material is the most suitable material for steel plate spraying technology. SMC has a thermal expansion coefficient and heat resistance similar to steel, and the sprayed SMC products can be cured at the same oven temperature as steel.

●Easy molding process: The molding of SMC molds mainly adopts metal-to-mold compression molding at present. The process is relatively simple. Cut the SMC sheet into the required shape and determine the number of layers to be added, then remove the protective film on both sides, stack it according to certain requirements, and place it on the appropriate position of the mold. Then it can be heated and pressurized according to the specified process parameters.

The advantages of BMC mold:

●Dimensional stability: The coefficient of linear expansion of BMC is smaller than that of ordinary thermoplastics, which makes BMC mold have high dimensional stability and dimensional accuracy.

●Good resistance to water and solvents: BMC has good corrosion resistance to water, ethanol, aliphatic hydrocarbons, grease and oil. Meanwhile, BMC has low water absorption, and its insulation performance is still good after soaking for one day.

●High heat resistance: The heat distortion temperature HDT of BMC is 200~280°C, and it can be used at 130°C for a long time.

●Aging resistance: BMC mold has very good aging resistance. It can be used indoors for 15-20 years, and its strength retention rate keeps above 60% after 10 years of outdoor exposure.

●Excellent electrical performance: Excellent arc resistance is the most outstanding advantage of BMC, which can reach about 190s.

In general, when the requirements for the mechanical properties of the products, including tensile strength, bending strength and impact strength, etc. are higher; when the requirements for the surface area of the products is larger, and when the requirements for the lightweight of the products is higher, SMC will be selected.

In general, the requirements for the mechanical strength are lower than SMC but the cost need to stay low; when the requirements for the electrical properties and flame retardant properties of the products are higher; or when the requirements for the surface area of the product itself is small, people usually choose BMC.

MDC mould is a professional supplier of SMC and BMC materials. Based on the concept of taking technology as the guide and quality as the core, we will provide the best material for your project and provide the most reasonable solution. If your project needs to use SMC material or BMC material, please contact us. We can meet your need.

Points for attention in BMC moulding

1) Barrel temperature and mould temperature. During processing, BMC is required to maintain low viscosity flow for a long time at the temperature of the barrel. Generally, the temperature of the barrel should meet the low limit of BMC. The temperature of the barrel is generally divided into two or three stages of control. The temperature near the hopper is lower and the temperature near the nozzle is higher. Generally, the difference is 20~60?, and the mould temperature is generally controlled at 135~185?.

2) Injection pressure. Due to the poor fluidity of BMC, fast curing, and complicated mould structure, the injection pressure should be selected to be higher, generally 80~160MPa.

3) Injection speed. The increase in injection speed helps to improve the surface quality of the plastic parts, shorten the curing time but is not conducive to exhaust and increase the degree of orientation of the glass fiber. Therefore, lower injection speed should be adopted under the premise of ensuring the surface quality of plastic parts, usually 1.8~3.5m/min.

4) Screw speed and backpressure. If a screw-type injection moulding machine is used, the screw damages the glass fiber greatly when injecting BMC. In order to minimize the damage of the glass fiber, the screw speed should be selected at a low value, generally 20-50r/min. According to the viscosity of BMC, the use of low back pressure is appropriate, generally 1.4 ~ 2.0MPa.

5) Moulding cycle. Due to the different size and complexity of plastic parts, the processing time of each section is also different. The general injection time is 2~20s and the holding time is 10~20.
Please keep us in touch as below info, if you required.
Taizhou Huangyan MDC Mould&Plastic Co.,ltd
No.35-1 Qingfeng Rd, Huangyan North Industrial estate, Taizhou, Zhejiang, china 318020
E-mail:[email protected];
Website: compression mould

BMC mold is a thermosetting mold. Compared with thermoplastic mold, bmc mold is irreversible. Products processed by thermoplastic molds can be recycled, reprocessed and reinjected, while products processed by thermoset molds cannot be processed once formed. There is no difference in the structure of the two molds. The difference lies in the processed material: one is a thermosetting material and the other is a thermoplastic material.

BMC is a thermosetting plastic, which is mixed with various inert fillers, fiber reinforcements, catalysts, stabilizers and pigments to form a sticky “putty” composite material for compression molding or injection molding. BMC plastics are highly filled and reinforced with short fibers. Glass fiber reinforced materials account for 10% to 30%, and the length is usually between 1/32 inches and 1/2 inches (12.5 mm).

According to different final application fields, the formulated composite material can accurately control the size, good flame retardancy and tracking resistance, has high dielectric strength, corrosion resistance and stain resistance, excellent mechanical properties, low shrinkage and Stable color. BMC plastic has excellent flow characteristics, insulation and flame retardancy, and is very suitable for various applications requiring precise details and dimensions.

Please keep us in touch as below info, if you required.
Taizhou Huangyan MDC Mould&Plastic Co.,ltd
No.35-1 Qingfeng Rd, Huangyan North Industrial estate, Taizhou, Zhejiang, china 318020
E-mail:[email protected];
Website: compression mould

1. Preparation before molding
(1) The quality of SMC sheet has a great influence on the molding process and SMC part quality. Therefore, it is necessary to understand the formulation of resin paste, glass fiber content, etc. before molding.
(2) Determine the shape and size of the sheet material cutting according to the structural shape of the SMC part, the feeding position, and the process. In order to prevent contamination by external impurities, the upper and lower films are only removed before loading.
(3) Familiar with the various operating parameters of the press, especially to adjust the working pressure and the running speed of the press and the parallelism of the table. The mold installation must be level, and ensure that the installation position is in the center of the press table. Before molding, the mold must be thoroughly cleaned and coated with mold release agent. Before feeding, wipe the release agent with clean gauze to avoid affecting the appearance of the SMC part.

2. Feeding
(1) Determine the feeding amount and feeding area. The size of the feeding area directly affects the compactness of the SMC part and the surface quality of the SMC part. It is related to the flow and curing characteristics of SMC, SMC part performance requirements, mold structure, etc.
(2) Feeding position and method. The feeding position and method directly affect the appearance, strength and directionality of the SMC part. Normally, the feeding position of the material should be in the middle of the cavity. For asymmetric and complex SMC parts, the feeding position must ensure that the material flow reaches the ends of the molding cavity at the same time during molding. The feeding method must be conducive to exhaust. When stacking multiple layers of sheets, it is best to stack the materials up and down.

3. After the material enters the mold cavity, the press goes down quickly. When the upper and lower molds coincide, slowly apply the required molding pressure. After a certain amount of curing, the molding of the SMC part ends. During the molding process, various molding process parameters and press operating conditions should be selected reasonably.
(1) The molding temperature depends on the type of resin, SMC part thickness, SMC partion efficiency and SMC part structure. Generally speaking, the forming temperature of thick SMC parts should be lower than that of thin-walled SMC parts. For example, if the thickness of the SMC part is 25-32mm, the forming temperature is 135-145 ?. And thinner SMC parts can be formed at 171 ?. It is generally believed that the SMC molding temperature is between 120-155 ° C.
(2) Molding pressure varies with SMC part structure, shape and size. SMC parts with simple shapes only need a forming pressure of 5-7MPa; SMC parts with a complicated shape can have a forming pressure of 7-15MPa. The size of the molding pressure is also related to the mold structure. The molding pressure required by the vertical parting structure mold is lower than that of the horizontal parting structure mold. In short, the determination of molding pressure should consider many factors. Generally speaking, SMC molding pressure is between 3-7MPa.
(3) The curing time is related to factors such as material type, molding temperature, SMC part thickness and color. The curing time is generally calculated at 40s / mm. For thick SMC parts above 3mm, each additional 4mm increases the curing time by 1min.

SMC Mould process produces high strength, complex parts in a wide variety of sizes. The SMC material charge is manually or robotically placed in SMC mould; the heated mold halves are closed, pressure can be available applied from 500T till 4000T at MDC workshop, cycle time ranges from one to five minutes, depending on part size and thickness. Features such as ribs, bosses and inserts can be molded in.

In-mold coating(IMC) and vacuum system in SMC mould are available to improve surface paint ability, eliminating the need for primer. Color compounds can be customized.

if anybody has urgent SMC mold or SMC Molding projects or delivery time pressure, MDC team will give them support, as all of our milling machines are working at 24 hours with 2 shifts.
Please don’t forget that we’re a professional compression mold maker and foaming tool maker. We will stay at your disposal. Please keep us informed, when any questions or requirements.

Depending on the end-use application, compounds are formulated to achieve tight dimensional control, flame resistance, high dielectric strength, corrosion and stain resistance and color stability. Its excellent flow characteristics make BMC mold well suited to a wide variety of applications requiring precision in detail and dimensions. The material is available in a wide variety of colors.

In addition, BMC mold is suitable for either compression molding or injection molding. BMC compressing molding is used to produce complex components such as electrical equipment, car components, housings for electrical appliances and tools, in large industrial volumes.

MDC Mould, as a professional BMC mold maker, is able to make BMC compression mold, as well as BMC injection mold with gate cutting.

If you’re interesting, please contact us as follows:

Taizhou Huangyan MDC Mould&Plastic Co.,ltd

No.35-1 Qingfeng Rd, Huangyan North industrial estate, Taizhou City, ZheJiang Province, china 318020

E-mail:[email protected]

BMC mould, Compression mould