The Cause Of Uneven Wall Thickness During The Processing Of Rotomolded Products

- Nov 24, 2018-

In the process of rotational molding, it is not easy to process plastic products with sudden wall thickness. The average wall thickness of the products depends mainly on the amount of material to be fed. The uniformity of the mold and the structure of the mold itself and the rotational molding process are extremely great. relationship. If the wall thickness is uneven during the rotational molding process, it is very likely that there is a problem in structure, temperature, and rotational speed.


From the rotomolding product and the rotomolding mold structure, generally, the thickness of the concave corner of the rotomoulded product (the convexity of the mold) is small, and the thickness of the convex portion of the product (the concave portion of the mold) is large, but if the product is If the angle of the convex part is too small, the material may not be filled with defects such as holes and holes, so the product should not have sharp corners, and usually a large smooth arc transition is used.


The melting and adhesion capabilities of plastics are primarily related to mold temperature. Where the mold temperature is high, the plastic is easier to melt first and is coated with the rotating layer of the mold, and there are more adhesive resins, and the resin adhered to the lower temperature portion is relatively less, resulting in uneven wall thickness of the product.


The wall thickness of the article is also related to the speed of rotation. The rotation speed is not uniform, it is easy to cause uneven wall thickness, and there is no regularity. Therefore, a constant-torque or constant-speed motor that can be automatically controlled is generally used to ensure the constant rotation of the main and auxiliary shafts. When the wall thickness of a certain part of the product is different from other parts, and the mold cannot be modified, it is necessary to find a solution from the technical point of view.