How to solve injection molding parting surface burrs problems

Injection molding-parting surface burrs problems and the influence of injection molding process on the transparency of PP products,do you know how to solve?
Today let us talk about them.
1. Mechanical equipment:
(1) The clamping force of the molding machine is insufficient. When selecting an injection molding machine, the rated clamping force of the machine must be higher than the tension formed by the longitudinal projected area of ​​the injection molded product during injection.Otherwise it will cause mold expansion and parting surface burrs.

(2) The mold clamping device is not well adjusted, the toggle mechanism is not straight, and the left and right or up and down molds are not balanced, and the parallelism of the mold cannot be achieved. The phenomenon that one side of the mold is tightly closed while the other side is not closely attached. , There will be parting surface burrs during injection. Para

(3) The mold itself is not parallel well, or the installation is not parallel, or the template is not parallel, or the tension rod is unevenly distributed and deformed. These will cause the mold clamping to be not tight and the parting surface burrs will appear. Para

(4) The non-return ring is severely worn; the spring nozzle spring fails; the barrel or screw is worn too much; the inlet cooling system fails to cause “bridging” phenomenon; the barrel set injection volume is insufficient, the cushion is too small, etc.. It may cause the parting surface burrs to appear repeatedly, and it must be repaired or replaced in time.

2. Mold aspect
Poor precision of mold parting surface. The poor flatness of the mold core causes gaps when the mold is closed, resulting in burrs on the parting surface. Para

3. Process
(1) The injection pressure is too high or the injection speed is too fast. Due to the high pressure and high speed, the opening force on the mold increases and causes flashing. The injection speed and injection time should be adjusted according to the thickness of the product. The thin product should be filled quickly at high speed, and no injection after it is filled; the thick product should be filled at low speed. Para

(2) Excessive feeding volume causes burrs on the parting surface. It is worth noting that do not inject too much melt in order to prevent the depression, so that the depression may not be “filled”, but the parting surface burrs will appear. This situation should be resolved by extending the injection time or holding time. Para

(3) Too high temperature of the barrel and nozzle or too high mold temperature will reduce the viscosity of the plastic and increase the fluidity.which will cause burrs on the parting surface under the condition of smoothly entering the mold.
4. In terms of raw materials
(1) If the plastic viscosity is too high or too low, there may be parting surface burrs. Plastics with low viscosity, such as nylon, polyethylene, polypropylene, etc., should increase the clamping force;

plastics with strong water absorption or water-sensitive plastics will greatly reduce the flow viscosity at high temperatures and increase the possibility of parting surface burrs For these plastics, they must be thoroughly dried; the viscosity of plastics that are mixed with too much recycled materials will also decrease, and if necessary, replenish the retained components. Plastic

If the viscosity of the material is too high, the flow resistance will increase, and a large back pressure will increase the pressure of the cavity, resulting in insufficient clamping force and producing parting surface burrs. Para

(2) Uneven particle size of plastic raw materials will cause the feeding amount to vary, and parting surface burrs will appear.

The influence of moldaxe por inxección process on the transparency of PP products
The transparency of transparent polypropylene products modified with transparent nucleating agent is not only related to the quality of the plastic raw material itself, but also closely related to the selection of injection molding process conditions.

Finding the best moldaxe por inxección conditions for raw materials is conducive to maximizing the transparency potential of raw materials and obtaining ideal transparent polypropylene products. This has positive significance for plastic products companies.

Influencing factors of PP transparency:

(1) The higher the melting temperature, the higher the haze of the random copolymer polypropylene without the transparent nucleating agent and the worse the transparency.

(2) The influence of melting temperature on the haze of random copolymer polypropylene with different types of transparent nucleating agents is related to the types of nucleating agents.

(3) For products that can fully exhibit the anti-reflection effect of the transparent nucleating agent at a lower melting temperature, the haze will rise slowly with the rise of the melting temperature, but the range of change is greater than that of the non-nucleating agent. The random copolymer polypropylene is much smaller.

(4) The lower the mold temperature, the lower the haze of transparent polypropylene and the higher the transparency.

(5) The faster the injection speed, the higher the haze of the transparent polypropylene and the lower the transparency.

(6) With the extension of the holding time, the haze of transparent polypropylene decreases, and after reaching the limit, it remains unchanged.

(7) As the holding pressure increases, the haze of transparent polypropylene decreases, but if the holding pressure is too large, the product will have flash, and the residual internal stress of the product will also be relatively large.