The gate is a passage from the split runner to the cavity of the Furniture Mould(FURNITUREMOULD), which is the smallest and shortest section of the gating system. The location, quantity, shape, and size of the gate have a direct impact on the quality of the plastic product and the appearance of the product. Therefore, attention should be paid to the design of the gate during the design process. Common gates include center gates, side gates, lap gates, submerged gates, thin gates, fan gates, ring gates, horn-shaped lurk gates, point gates, and the like. The following principles should be noted in the design:
(1) The gate should be placed at the thick wall of the moulded product to make the plastic flow from the thick wall to the thin wall to reduce the loss of pressure. The plastic melt should be injected into the cavity quickly with the shortest path, minimum heat, and pressure loss to complete the injection.
(2) The gate should be placed where the product is most easily removed, and try not to affect the appearance (if possible, flow marks).
(3) The position of the gate should be such that when the plastic flows into the cavity, it can flow uniformly in the parallel direction of the cavity and facilitate the exhaust of the cavity.
(4) The position of the gate should be set to avoid the occurrence of weld marks and flow marks in important parts of the product and reduce the strength of the product.
(5) When a multi-hole is used, the size and position of the gate shall be based on the distance between the gate and the main channel and the size of the product.
(6) The setting of the gate should avoid the plastic directly impacting the weak core, inserts, row position, etc., to prevent deformation of the product.
(7) The setting of the gate should take into account the different shrinkage of the product in the transverse direction and the longitudinal direction. The temperature and pressure of the melt entering the cavity from each gate should be the same to ensure the same shrinkage of the products in each cavity.
(8) The turning point of the runner should be a circular arc transition, and the joint with the gate should be processed into a slope to facilitate the flow of the melt.
The form and location of the gate not only has a great influence on the moulding speed and quality of the plastic product but also affects the final quality of the entire furniture mould. Gate design is directly related to the quality of plastic moulded products. Therefore, the rational design of the gate is an important part of the design of furniture mould. It should be considered as a whole based on the structure of the plastic product, the characteristics of the material, the fluidity, and the moulding process.