2014年5月30日星期五

How to Calculate Molding Machine Sizes


How to Calculate Molding Machine Sizes

Producing quality plastic products requires a molding machine that has been properly sized.
Molding machines come in a wide variety of clamp tonnages. The clamp tonnage refers to the amount of force that the machine can exert on a mold while the molten plastic is being injected. The plastic is injected into the mold at high pressure in order to ensure that the mold is completely filled before the plastic hardens. The pressure of the injection when coupled with the surface area of the mold creates a force that must be counteracted by the molding machine. The molding machine must be sized to handle this force to produce acceptable products.

Instructions

1.                            Sizing a Molding Machine

1
Determine the surface area of the part that is being molded in square inches. If it is a multiple cavity mold, the surface area associated with each cavity along with the runners that feed each cavity should be included in the total surface area.
2
Determine the planned injection pressure in pounds per square inch (psi). The injection pressure will be a function of the material that you are using and the part wall thickness. A material supplier can help determine the injection pressure.
3
Determine the pressintensification ratio for the molding machine. This is a function of the machine's screw and the hydraulic piston that acts upon it. The machine supplier can provide this information if it is not already known.
4
Multiply the injection pressure by the intensification ratio. This provides the plastic packing pressure in psi.
5
Multiply the plastic packing pressure by the part surface area. This results in the total pounds of force that will be exerted on the mold in pounds.
6
Divide the pounds of force by 2,000 (2,000 pounds = 1 ton). This provides the tons of force required to be offset by the molding machine's clamp tonnage. This gives the minimum clamp tonnage size needed for a molding machine for the specific product in question.
http://www.freetech-mould.com

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