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Rapid Prototyping
Precision machining with tight tolerances and advanced finishing capabilities, as quick as 1 day.
Explore versatility and cost-efficiency through flexible application choices.
FDM, SLS, SLA, PolyJet, MJF services.
High-quality parts and low price
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Why Choose 91mns
Our vision is to simplify manufacturing complexities and shorten project cycles for our customers through our rich manufacturing and design experience. Our success is defined by our customers' success
High-Volume Production
High-quality steel tooling for production, delivered in a matter of weeks.
Craft precise and accurate custom mechanicals with top quality
Lower tooling costs, high-quality durable parts
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91mns Industries
Our vision is to simplify manufacturing complexities and shorten project cycles for our customers through our rich manufacturing and design experience. Our success is defined by our customers' success
Compression Molding
Compression molding offers cost-effective, high-quality molding with a wide range of applications, making it an ideal choice in the manufacturing industry.
What Is Compression Molding?
Compression molding is a manufacturing process where compressive force is used to shape a material to fit the contours of a mold composed of two halves, an upper and a lower part. When the mold halves are pressed together, they create a cavity that shapes the material into the desired form. The design of the mold ensures that the product can be easily ejected once the material has set and cured.
Originally developed for synthetic materials, compression molding is the most cost-effective technique for processing thermosetting plastics. For thermoplastics, however, injection molding is generally preferred.Compression molds come in several types, including flash, positive, landed positive, and semi-positive molds, with the flash mold being the most commonly used.
Compression molding processes are categorized into bulk and sheet molding, with bulk molding involving a blend of fillers, catalysts, stabilizers, pigments, and fiber reinforcers. The key advantages of compression molding for thermoset plastics include enhanced strength, reduced weight, and high resistance to corrosion.
The application of compression molding
Density and Durability: Sealing products like O-rings, gaskets, and seals need to have good density and durability to effectively prevent leakage of liquids or gases in various environmental conditions:
High Temperature and Chemical Resistance: Many sealing products must withstand high temperatures or exposure to chemicals. Parts produced through compression molding often use special material formulations to ensure stable performance.
Precise Dimensions and Geometric Shapes: The dimensions and geometric shapes of sealing products are crucial for their functionality. Compression molding can produce parts with precise dimensions and shapes to ensure perfect fit with other components.
Mass Production and Consistency: O-rings, gaskets, and similar products often require mass production and demand consistency in quality and performance for each unit. Compression molding provides an efficient production method to ensure product uniformity.
Compression Molding Materials
Silicone
SBR
Natural Rubber(NR)
Neoprene(CR)
NBR(Buna-N)
FKM(viton)
HNBR
Polyurethane(PU)
EPDM Rubber
Compression Molding Tolerance
| With Drawing | Without Drawing | |
| Linear Dimension | +/- 0.1mm | SPI Commercial |
| +/- 0.004 inch | ||
| Hole Diameters | +/- 0.1 mm | SPI Commercial |
| +/- 0.0004 inch |
Compression Mold Surface Finishes
All finishes meet SPI standards
MoldTech textured finishes and SPI polished finishes
Using an ink-based, 2D design to a flat/3D surface
Compression Molding FAQs
Q What is compression molding and how does it compare to other molding techniques?
Compression molding is a manufacturing process where a preheated material is placed into an open mold cavity and then compressed to take the shape of the mold. It differs from injection molding in that it does not involve injecting material into a mold cavity under high pressure.
Q Which materials are commonly used in compression molding?
Common materials used in compression molding include thermosetting plastics, rubber, composites, and various types of polymer blends.
Q What are the key benefits of opting for compression molding over alternative methods like injection molding?
Compression molding offers cost-effectiveness, suitability for large and intricate parts, minimal waste generation, and the ability to work with a wide range of materials.
Q How can one ensure uniformity and precision in products manufactured through compression molding?
Achieving uniformity and precision in compression molded products involves maintaining consistent mold temperatures, pressures, and cycle times, along with using quality materials and ensuring proper mold design.
Q What are the typical turnaround times for projects involving compression molding?
Turnaround times for compression molding projects can vary based on factors such as the complexity of the part, the type of material being used, and the production volume. Generally, compression molding offers relatively quick cycle times compared to other molding methods.
Q Are there any specific design considerations or constraints to bear in mind when selecting compression molding for a project?
Design considerations for compression molding include draft angles for easy part ejection, uniform wall thickness to prevent defects, and the need for proper venting to release trapped air during the molding process. Additionally, complex shapes may require multiple mold pieces for effective compression molding.
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