The plastic paste flow channel is due to the poor contact surface between the injection port and the nozzle arc, the gate material is not demoulded together with the product and the abnormal packing. Generally, the sprue diameter should be large enough that the sprue is not fully solidified when the part is demoulded.
(1) Problems of runner and mould: ① runner and nozzle must match well; ② ensure nozzle orifice is not larger than runner diameter; ③ Polish sprue; ④ increase sprue taper; ⑤ adjust sprue diameter; ⑥ control runner temperature; ⑦ increase sprue pulling force;
(2) Injection conditions: ① cut off the flow channel; ② reduce the injection feeding; ③ reduce the injection pressure; ④ shorten the injection time; ⑤ reduce the total pressure time; ⑥ reduce the material temperature; ⑦ reduce the barrel temperature; ⑧ reduce the nozzle temperature;
(3) Material problems: ① clean up material pollution; ② dry materials.
13、 Nozzle flow
How to prevent the nozzle from flowing
The nozzle salivates mainly because the material is overheated and the viscosity becomes smaller.
(1) Nozzle and mold problems: ① use the spring needle valve nozzle; ② use the inverted nozzle; ③ reduce the nozzle hole; ④ increase the cold material hole.
(2) Injection conditions: ① reduce the nozzle temperature; ② cut off the flow channel; ③ reduce the material temperature; ④ reduce the injection pressure; ⑤ shorten the injection time; ⑥ reduce the total pressure time.
(3) Material problem: ① check whether the material is polluted; ② dry the material