How to decide molding pressure for SMC Molding

(1) Decision of Molding Area

Method 1 : Decide by projected area of molded product (Product size(Width(M) x Length(M)) 

For example : 

Product outer dimension : 1M(Width) x 1M(Length) 

Projected Area : 1m(W) * 1m(L) = 1 M2

Method 2 : Decide by developed area of molded product

Developed Area : Projected area + side steep area x steep coefficient(1/3 or 1/4) 

If product steep is high, steep coefficient : 1/3

     product steep is low, steep coefficient : 1/4 

For example : 

Product outer dimension : 1M(Width) x 1M(Length) 

profile area : 0.8M(Width) x 0.8M(Length)

Projected Area : 1m(W) * 1m(L) = 1 M2 

Development Area : 0.8M* 0.8M * 1/4 =  0.16 M2

Total Area : 1.16 M2

(2) Decision of Molding Pressure/SQM for SMC

LoreDDD

To be practical, SMC must be non-tacky so that it can be handled at the press. Some compounds can be formulated to be non-tacky at 2-12 million centipoises, but most go to 30 million and up.
Please check your SMC viscosity from your SMC supplier.
For example) Our current using SMC viscosity : 40,000,000 cps (400,000 ps)
According to upper graph(Molding pressure versus SMC viscosity), 850 psi(=597 TON/SQM)

(3) Final molding pressure for SMC

= MOLDING AREA X MOLDING PRESSURE/SQM
For example)
method 1) 1 sqm * 597 ton/sqm = 597 ton

method 2) 1.16 sqm * 597 ton/sqm = 692.52 ton

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