In the design of handle rubber shell mold, the selection of parting surface is crucial. First of all, the appearance requirements of the product should be considered. If the handle has a specific appearance texture or logo, the parting surface should avoid these areas to avoid leaving parting line marks after molding to affect the appearance. For example, for a handle with fine anti-slip texture on the surface, the parting surface should be selected along the tangent direction of the texture to ensure the continuity of the texture. Secondly, according to the convenience of demolding of the product, try to choose a part with a relatively regular handle contour and a gentle depth change, so that when the mold is opened, the rubber shell can be smoothly separated from the mold, reducing demolding resistance and reducing the risk of product deformation.
The determination of the gate position is closely related to the structure and function of the handle. For parts with concentrated force, such as the connection end of the handle and the operating rod, the gate should be avoided here. Because the molding characteristics of the material near the gate are slightly different from other parts, there may be stress concentration. If it is in the critical force area, it will reduce the strength of the handle. Usually, it is selected in the non-critical functional area of the handle, such as the side or back of the relatively hidden position, which does not affect the appearance and can ensure uniform filling of rubber material.
The size of the gate directly affects the filling speed and molding quality of the rubber. If the gate size is too small, the flow resistance of the rubber melt in the cavity will increase, which may lead to incomplete filling, lack of glue, and affect the integrity of the handle. On the contrary, if the gate is too large, the flow rate of the rubber material is too fast, which is easy to cause turbulence, entrain air, and form bubbles inside the handle, reducing the density and strength of the product. According to the size of the handle, the wall thickness and the fluidity of the rubber material, the appropriate gate size range should be calculated through simulation software or empirical formula. Generally, the gate diameter of a small handle is between 1-3mm, and the gate diameter of a large handle is appropriately increased.
From the perspective of mold processing technology, the parting surface should be as simple and regular as possible, reducing the splicing of complex curved surfaces and reducing the difficulty and cost of mold processing. For example, the use of plane parting or simple step parting facilitates the use of conventional processing equipment such as milling and EDM, thereby improving mold manufacturing efficiency.
Considering the shrinkage characteristics of rubber materials, the gate position and size must also take into account the shrinkage compensation function. Reasonably set the gate near the thicker part of the handle or the area prone to shrinkage marks, and use the rubber material that solidifies last at the gate to compensate for the shrinkage of the product, reduce the surface depression caused by uneven shrinkage, and ensure the dimensional accuracy and appearance flatness of the handle.
For multi-cavity molds, the consistency of gate position and size is particularly important. The gates of each cavity should be distributed as symmetrically as possible to ensure that each handle rubber shell is molded under the same process conditions, avoid dimensional deviation and performance differences caused by uneven filling, and ensure the quality stability of mass production of products.
In short, the selection of the parting surface, gate position and size determination of the handle rubber shell mold need to comprehensively consider many factors such as product appearance, structural function, molding process, material characteristics and processing cost. Only through repeated optimization design can high-quality molds be manufactured and handle rubber shells that meet the requirements can be produced.
