BMC(Bulk Molding Compound)
BMC (Bulk Molding Compound)
Short for Bulk Molding Compound, BMC is a thermosetting composite molding material in bulk form with excellent formability. BMC is created by evenly dispersing and kneading glass chopped strands into a compound that is made by adding additives such as low profile agents, internal lubricants, and fillers to unsaturated polyester resin, which serves as a base.
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The Characteristics
of BMC- 1) Since it has excellent fluidity, BMC makes it possible to mold large products as well as products with complex shapes.
- 2) BMC has excellent mechanical and electrical properties.
- 3) Due to its excellent dimensional stability, products molded using BMC have great levels of dimensional accuracy and have smooth surfaces (no sink marks).
- 4) BMC has excellent corrosion resistance and excellent weatherability.
- 5) BMC has high heat deflection temperatures and suffers little thermal aging.
- 6) BMC has an excellent self-extinguishing capability, and there are even high-grade types that have achieved a UL 94 V-0 rating.
- 7) BMC has excellent surface gloss and can be created in various colors.
- 8) BMC has an excellent vibration damping capability (motor encapsulation).
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Handling Precautions
- 1) BMC contains a large amount of volatile styrene monomer. As a result, when volatilized, it becomes stiffened and can cause molding defects.
- 2) BMC comes wrapped in nylon film, and damaged packaging and remaining packing materials must be sealed with nylon film or al-laminated film.
- 3) As the pot life of BMC is less than one hour, it is recommended to use BMC immediately after opening its package.
- 4) It is recommended that BMC be stored in a cold dark place at a temperature of 20℃ or below. If BMC is stored in a place whose temperature is 10℃ or more above/below 20℃, the BMC’s pot life decreases by half. (Normally, BMC stored in a cold dark place at a temperature of 20℃ lasts for about two months.)
- 5) The packaging of BMC is often damaged during loading, so please be sure not to stack BMC in more than five layers.
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Molding Methods
Compression molding, injection molding, or transfer molding is chosen depending on the shape, size, and quantity of the molded product.
| Method | Compression molding | Transfer molding | Injection molding |
|---|---|---|---|
| Use | Common products requiring strength | Products requiring insert-molding | Mass-produced products and areas requiring precision |
| Merits | Small quantity batch production Reduction of molding costs | Insert-molding/encapsulation The cavity can be widened. | Capable of mass production Excellent precision Excellent production processability |
| Molding conditions |
Forming temperatures: 150-170℃ Forming pressure: 100-200㎏/㎠ Clamping time Primary: 2-3 sec. Secondary: 2-3 sec. Tertiary: 5-10 sec. Molding time: 40-60 sec./mm |
Material preheating:40-70℃ Forming pressure: 130∼150℃ Forming pressure: 30-100㎏/㎠ Injection time: 5-15 sec. Molding time: 40-60 sec. |
Forming temperatures: 150-180℃ Forming pressure Primary: 500-1000㎏/㎠ Secondary: 300-500㎏/㎠ Molding time: 1-5 sec. Holding pressure time: 10-20 sec. Molding time: 20-30 sec. Screw RPM: 50-100 |
Introducing Our BMC Products
Our BMC products in this line are used throughout all areas of the heavy electric machinery industry, such as for no fuse breakers and switch box cable supports. They are available in various grades with different types of dimensional stability, appearance, moldability, mechanical strength, electrical properties, and flammability, depending on the use and the molding conditions of the desired product.
Characteristics
- 1) Diverse shrinkage rates have been made available, so you can choose what suits the characteristics of the desired product.
- 2) They have excellent appearances and surface gloss.
- 3) They have high heat deflection temperatures and suffer little thermal aging.
- 4) They have excellent self-extinguishing capabilities, and there are even grades that have achieved a UL 94 V-0 rating.
- 5) Various grades are available in order to suit different types of molding, such as injection molding, transfer molding, and compression molding.
- 6) They have excellent mechanical strength.
- 7) They have excellent electrical properties.
BMC Automotive Product Features Table
Grade
Characteristic
Application
Molding method
Data sheet
SN-250
High strength, non-shrinkage, and good water resistance
High strength heavy electrical equipment parts and marine heavy electrical equipment parts
Compression molding
View technical sheets
Request MSDS’s
SLS-325
General product, UL-certified (HB rated)
Refrigerator handles and oven range door-vents
Injection molding
SL-319
Low shrinkage and HB rated
NFB covers and cases, and various precision part
Compression molding and injection molding
SLS-319
Low shrinkage and flame retardant type
NFB covers and cases, and various precision parts
Compression molding and injection molding
SL-360
General product, HB rated
Wire supports, insulation sheets, and ATS parts
Compression molding
SLS-90
Low shrinkage, excellent electrical properties, and UL-certified
Flame retardant electrical parts and industrial heavy electrical equipment parts
Compression molding and injection molding
Major Customers
| Grade | Characteristic | Application | Molding method | Data sheet |
|---|---|---|---|---|
| SN-250 | High strength, non-shrinkage, and good water resistance | High strength heavy electrical equipment parts and marine heavy electrical equipment parts | Compression molding |
View technical sheets Request MSDS’s |
| SLS-325 | General product, UL-certified (HB rated) | Refrigerator handles and oven range door-vents | Injection molding | |
| SL-319 | Low shrinkage and HB rated | NFB covers and cases, and various precision part | Compression molding and injection molding | |
| SLS-319 | Low shrinkage and flame retardant type | NFB covers and cases, and various precision parts | Compression molding and injection molding | |
| SL-360 | General product, HB rated | Wire supports, insulation sheets, and ATS parts | Compression molding | |
| SLS-90 | Low shrinkage, excellent electrical properties, and UL-certified | Flame retardant electrical parts and industrial heavy electrical equipment parts | Compression molding and injection molding |
Samsung Electronics, LG Electronics, LS Industrial Systems, Fine Platech, Jinwha Precision, Shinheung Chemical. Taeil New Materials, Jinheung Electric, Seoul Industrial Electric, and Dong-A Electric Device
