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Injection Molding Parameter Settings In Mold

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Confirm whether the material drying, mold temperature and heating cylinder temperature are correctly set and reach a processable state.
Check the mold opening and closing and ejection movements and distance settings.
Injection pressure (P1) is set at 60% of the maximum value.
Keep the pressure (PH) set at 30% of the maximum value.
Set the injection speed (V1) at 40% of the maximum value.
Screw speed (VS) is set at about 60RPM.
The back pressure (PB) is set at about 10kg/cm2.
Loose withdrawal is set at 3mm.
The position of pressure maintaining switching is set at 30% of the screw diameter. For example, for a φ100mm screw, set it to 30mm.
Set the metering stroke to be slightly shorter than the calculated value.
Set the total injection time to be slightly shorter and the cooling time to be slightly longer.

Lock the mold (confirm the rise of high pressure) and move the injection base forward.
Inject manually until the screw stops completely, and pay attention to the stop position.
The screw rotates back to feed.
After cooling, open the mold and take out the molded product.
Repeat steps 1-4 until the screw finally stops at 10%~20% of the screw diameter, and the molded product has no short shots, burrs, whitening, or cracking.

Correction of the metering stroke [Measuring end point] Increase the injection pressure to 99%, temporarily adjust the holding pressure to 0, adjust the metering end point S0 forward to the occurrence of short shot, and then adjust it backward to the occurrence of burrs, and then adjust it to the middle point To select a location.
Correction of the injection speed returns the PH to the original level, adjusts the injection speed up and down, finds out the individual speeds where short shots and burrs occur, and uses the midpoint as the appropriate speed. [At this stage, you can also enter the parameters of multiple speeds corresponding to appearance problems. set up].
Correction of the holding pressure. Adjust the holding pressure up or down to find out the individual pressures where surface dents and burrs occur, and use the midpoint as the selected holding pressure.
Correction of the holding time [or injection time] and gradually extending the holding time until the weight of the molded product is obviously stable is an appropriate choice.
Correction of cooling time Gradually reduce the cooling time, and confirm that the following conditions can be met:

a. The molded products will not be whitened, cracked or deformed when they are ejected, clamped, trimmed and packaged.

b. The mold temperature can be balanced and stable.

Simple algorithm for cooling time of products with meat thickness of 4mm or more

Theoretical cooling time = S (1+2S)…… The mold temperature is below 60 degrees.
Theoretical cooling time = 1.3S (1+2S)…… The mold is above 60 degrees [S represents the maximum thickness of the molded product].

6. Correction of plasticizing parameters

Confirm whether the back pressure needs to be adjusted;
Adjust the screw speed so that the metering time is slightly shorter than the cooling time;
Confirm whether the measurement time is stable and try to adjust the gradient of the heating coil temperature.
Check whether there is dripping material from the nozzle, whether there is pig tailing or mold sticking in the main flow channel, whether there are air marks on the finished product, etc., and adjust the nozzle temperature or loosening distance appropriately.

7. Use of stage pressure holding and multi-stage firing rate

Generally speaking, without affecting the appearance, the injection should be at high speed, but it should be done at a lower speed before passing through the gate room and switching between pressure holding;
The holding pressure should be gradually reduced to prevent the residual stress in the molded product from being too high and making the molded product easily deformed.

Contact Person: Alex Chu
WhatsApp/ WeChat: 0086 18968677763
Email: sc10@solidcomould.com
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