A. Confirm and prepare the parameters before setting them
⑴ Confirm whether the material dryness, mold temperature and heating barrel temperature are properly set and can be processed.
⑵ Check the posture and spacing settings of opening and closing the mold and injection.
⑶ Set the injection pressure (P1) to 60% of the maximum value.
⑷ Set the holding pressure (PH) to 30% of the maximum value.
⑸ Set the injection rate (V1) to 40% of the maximum value.
⑹ Set the extruder screw speed ratio (VS) to about 60RPM.
⑺ Set the condensing type (PB) to about 10kg/cm2.
⑻ Set the release to about 3mm.
⑼ Set the position of the pressure holding conversion to 30% of the extruder screw diameter. For example, for an extruder screw of φ100mm, set it to 30mm. ⑽ Set the measurement and verification stroke shorter than the calculated value. ⑾ Set the total injection time to be shorter and the cooling time to be longer.
B. Manual operation parameter adjustment
⑴ Lock the mold (confirm the increase of high pressure), and the injection seat moves forward.
⑵ Manually inject until the extruder screw stops completely, and pay attention to the stop position.
⑶ The extruder screw rotates back to feed the material.
⑷ After cooling, remove the molded product.
⑸ Repeat the process of ⑴~⑷, the extruder screw finally stops at 10%~20% of the extruder screw diameter, and the molded product has no short shot, burr, whitening, or cracking.
C. Adjustment of automatic operation parameters
⑴ Adjustment of the measurement and verification stroke [measurement and verification end point] Increase the injection pressure to 99%, and temporarily adjust the holding pressure to 0, adjust the measurement and verification end point S0 forward to produce short shots, and then adjust it backward to produce burrs, with the midpoint as the selected position.
⑵ Adjustment of the injection rate Restore the PH to the original level, change the injection rate, find a certain rate that produces short shots and burrs, and use the midpoint as the appropriate rate [This step can also enter the parameter setting of matching the appearance problem with two speeds.
⑶ Adjustment of the holding pressure Change the holding pressure, find a certain pressure that produces surface dents and burrs, and use the midpoint as the selected holding pressure.
⑷ Adjustment of the holding time [or injection time] Gradually increase the holding time until the net weight of the molded product is significantly stable for a clear selection.
⑸ Adjustment of cooling time Gradually reduce the cooling time and confirm that the following conditions can be met: 1. The molded product is not easy to be whitened, cracked or deformed when ejected, clamped, trimmed, or packaged. 2. The mold temperature can be balanced and stable. Simple optimization algorithm for cooling time of products with a thickness of more than 4mm: ① Theoretical cooling time = S (1 2S) .... Mold temperature below 60 degrees. ② Theoretical cooling time = 1.3S (1 2S) .... Mold temperature above 60 degrees [S indicates the maximum thickness of the molded product].
⑹ Adjustment of melting parameters
a. Confirm whether the condensation type needs to be adjusted; b, adjust the extruder screw speed ratio to make the metering time shorter than the cooling time; c. Confirm whether the metering time is stable, and try to adjust the gradient direction of the electric heating coil temperature. d. Confirm whether there is dripping on the nozzle, whether the flow channel has pigtails or sticking to the mold, whether the finished product has air marks, etc., and adjust the nozzle head temperature or loosening distance appropriately.
⑺Use of stage holding pressure and two-stage spring speed
a. Generally speaking, injection should be carried out at high speed without affecting the appearance, but it should be carried out at a lower speed before passing through the injection port and before switching to holding pressure
;b. Holding pressure should be gradually reduced to prevent the residual thermal stress of the molded product from being too high, making the molded product easy to deform.
