What is injection molding back pressure?

Back Pressure in an injection molding process is often defined as “the resistance of the screw to recover as the metering section pumps molten plastic through the non-return valve to the front of the screw.” When this position is reached, the screw will stop rotating.

How does injection pressure affect injection molding?

Generally speaking, with the increase of injection pressure, the orientation degree, weight, weld joint strength, material flow length and cooling time of the product increase, while the shrinkage and thermal deformation temperature in the material flow direction decrease.

What is the minimum pressure that can be given to injection molding?

7. What is the minimum pressure allowed to be given to the injection molding process? Explanation: None.

How do you calculate injection Moulding tonnage?

Now you can calculate necessary tonnage based on the projected area times the clamp factor for the material used. T = A x cf. For example, the projected area of the molded part is 150 sq/in times a clamp factor of 3 (tonnage needed/square inch from material data sheet). 150 x 3 = 450 tons needed.

How do you calculate injection molding weight?

Let’s assume we have a shot weight of 40.6 gms. Thus, we can calculate volume as mass/density, which will be (40.6/1.52)= 26.71 cube centimeters. To calculate the injection stroke or shot size, we can put all values in the formula of shot volume, i.e., Shot Volume = π x r2 x Shot Size.

How do you calculate shot size in injection molding?

To calculate the injection stroke or shot size, we can put all values in the formula of shot volume, i.e., Shot Volume = π x r2 x Shot Size. Here, r=1.4 and shot volume is 26.71 cm^3.

How do I lower my injection pressure?

Select a different material with a lower viscosity, which requires less injection pressure to fill the mold. Increase the melt temperature to reduce the viscosity. This reduces the injection pressure required to fill the mold.

How do you increase injection pressure?

The increase of injection pressure is accomplished by increasing the injector opening pressure from 400 up to 1600 bar.

What is the basic formula of clamping force?

Mold Clamping Force Formula (F: tf) The total projection area is the total of the projected areas of the cavities and runners in relation to the parting surface. Therefore, this value varies depending on the number of items molded and on the runner layout. 400 × (16.0 + 5.0) ÷ 1000 = 8.4 (tf).