How to Deal With the Wave Marks Generated by Injection Molded Parts?

As an ABS Plastic Tube Core Supplier, let's share with you how to deal with the flow marks generated by injection molded parts.

(1) Poor flow of the melt causes an annual ring-shaped wave flow mark centered on the gate on the surface of the injection molded part. When the low-temperature and high-viscosity melt with poor flow performance is injected into the cavity in the injection port and the flow path in a semi-curing wave state, the melt flows along the surface of the cavity and is squeezed by the continuously injected subsequent melt to form reflux and a stagnant flow. Thus, an annual ring-shaped wave flow mark centered on the gate is generated on the surface of the injection molded part.

For the cause of this failure, the mold and nozzle temperatures can be increased to increase the injection rate and filling speed. Increase injection pressure and hold pressure and increase the time. It is also possible to provide a heater at the gate to increase the local temperature of the gate portion. It is also possible to appropriately enlarge the gate and runner cross-sectional area.

(2) The flow of the melt in the flow path is not smooth, resulting in spiral wave flow marks on the surface of the injection molded part. When the melt flows from the narrow section of the flow passage into the cavity of the larger section or the flow path of the mold is narrow, and the finish is poor, the flow material easily forms turbulence, which causes spiral wave flow marks to be formed on the surface of the injection molded part.

In this regard, the injection speed can be appropriately reduced or the injection speed can be slow, fast, and slow. The gate of the mold should be placed in a thick wall or directly on the wall side. The gate form is preferably shank, fan or diaphragm. It is also possible to appropriately enlarge the flow passage and the gate cross section to reduce the flow resistance of the flow material.

(3) Volatile gases cause cloud-like wave flow marks on the surface of the injection molded part. When using ABS or other copolymer resin raw materials, if the processing temperature is high, the volatile gases generated by the resin and the lubricant will cause cloud-like wave flow marks on the surface of ABS Plastic Tube Core for Film.

In this regard, the mold and barrel temperature should be appropriately reduced, the exhaust condition of the mold should be improved, the material temperature and filling rate should be lowered, and the gate cross section should be appropriately enlarged. It should also be considered to replace the lubricant type or reduce the quantity.