Requirements for mold design and manufacture


The requirements of mold design and production are: acc […]

The requirements of mold design and production are: accurate size, smooth surface; reasonable structure, high production efficiency, easy automation; easy manufacturing, high life, low cost; design in line with the process needs, economic and reasonable.
The design of die structure and the selection of parameters must take into account the factors of rigidity, guidance, unloading mechanism, positioning method, gap size and so on. The wearing parts on the mould shall be easy to replace. For plastic mold and die-casting mold, it is also necessary to consider the reasonable pouring system, molten plastic or metal flow state, and the position and direction of entering the cavity. In order to increase productivity and reduce runner casting loss, multi cavity mold can be used to complete multiple identical or different products in a mold. High efficiency, high precision and long life mould should be used in mass production.
The stamping die shall be multi position progressive die, and the carbide insert progressive die can be used to improve the service life. In small batch production and trial production of new products, simple dies with simple structure, fast manufacturing and low cost should be used, such as combined die, sheet die, polyurethane rubber die, low melting point alloy die, zinc alloy die, superplastic alloy die, etc. The computer-aided design (CAD) has been adopted in the mould design, that is, the optimum design of the mould is carried out by a whole set of system centered on the computer. This is the development direction of mold design.
According to the structural characteristics, the die manufacturing can be divided into flat blanking die and cavity die with space. Blanking die uses the size of punch and die to fit accurately, some of them even fit without gap. Other forging dies, such as cold extrusion die, die-casting die, powder metallurgy die, plastic die, rubber die, etc., belong to cavity die and are used to form solid shaped workpiece. The cavity mould has dimension requirements in three directions: length, width and height. The shape is complex and it is difficult to manufacture. Mold production is generally single piece, small batch production, the manufacturing requirements are strict, accurate, and the use of precision processing equipment and measuring devices.
The plane blanking die can be formed initially by EDM, and further improved by the methods of form grinding and coordinate grinding. The shape grinding can be carried out by the optical projection curve grinder, or the plane grinder with the mechanism of reducing and repairing grinding wheel, or by the special shape grinding tool on the precision plane grinder. Coordinate grinder can be used for precise positioning of mould to ensure precise hole diameter and hole distance. It can also be used to grind the punch and die of any curve shape with CNC continuous locus coordinate grinder. The cavity mould is mainly processed by profile milling machine, EDM and ECM. The machining quality of the cavity can be improved by combining profiling milling with numerical control and adding a three-way translation head device in EDM. The production efficiency can be improved by adding gas charging electrolysis in ECM.