COMPRESSION MOLDING FOR LOW VOLUME and MASS production
What role Compression Molding process act in soft plastic low volume to mass production ?
Compression molding is an old press forming process under heating for soft material parts like silicone and rubber, hardness ranges from 15 shore A to 85 shore A. the compression molding parts are applied in a lot of industrial areas like car parts soft pipe, keypad parts, electronic protected shells, camera lens covers, soft toys and sealing gaskets .
Material options for compression molding are in large varieties, beside the silicone , rubber and silicone rubber blend material, there are also other kinds of soft material like EPDM, NBR, SBR, Neoprene, IIR, FKM, PU, TPU, TPR, TPE, LSR and so on.
COMPRESSION MOLDING PROCESS works UNDER heatING CONDICTION
How Compression Molding process works?
Compression molding process works like press molding, getting the geometrical shape from the mold cavity by press the material, the different is compression molding process needs to make a Steel mold as it works under heating condition. The Production starts firstly to place a pieces of pre-weighed solid material in the preheated steel mold and secondly close the mold with high pressure and high temperature to get the solid material melt, formed and cured as per cavity structure.
Compression molding process allows any color options in Pantone color C as per client required. The solid material reflects the product color directly before molding so that client will no need to wait till the product ready, color sample confirmation happens all in advance by the material color. this will save time and cost for color unmatch issues.
Besides, the compression molding product is coming out without any sprue gates, obvious parting line or big flashes. All the process flashes are easy to tear off by hand and all the parts are without defeats and marks.
advantages AND DISADVANTAGES of COMPRESSION MOLDING PROCESS
What is the advantages of Compression Molding process ?
There many advantages of compression molding process compared to Injection molding and even rapid tooling. First of all, the steel mold design for compression molding is easier, it is as simple as two plates with cavities , some dowel pins and handles. Secondly, unlike injection molding, the shrinkage for compression molding material is small so that there is no need get the T1 or T2, production is ok to go on directly. Thirdly, becasue of the above two advantages, the cost for compression molding is cheaper than Injection molding, and the lead time to T1 is less than 2 weeks, it is even faster than rapid tooling. These are the biggest benefits of compression molding.
In Sandi Rapid made, we are using this process for most of the silicone, rubber and soft PVC low volume to high volume productions.
What is the disadvantages of Compression Molding process ?
There are also two disadvantages for the compression molding process, first, it is the preheating and reheating process during production, the working temperature is high but the production line is manumotive, each production shot is slow. Second, it is the size limited, the icompression molding is suitable for small to middium size products but not suitable for the big size products for machine size limited.
However, in the other hand, the compression molding process is the best choice for the simple or complicate structure of soft parts as the process is press and filled the cavity.