Mold (m ú J ù), various molds and tools used in industrial production to obtain required products by injection molding, blow molding, extrusion, die casting or forging molding, smelting, stamping and other methods. In short, mold is a tool used to make molded articles. This tool is composed of various parts, and different molds are composed of different parts. It mainly realizes the processing of object shape through the change of the physical state of the formed material. Known as the "mother of industry".

A tool for making a blank into a piece with a specific shape and size under the action of external force. It is widely used in blanking, die forging, cold heading, extrusion, pressing of powder metallurgy parts, pressure casting, and molding or injection molding of engineering plastics, rubber, ceramics and other products. The die has a specific contour or cavity shape. The application of the contour shape with cutting edge can make the blank separate (blanking) according to the contour shape. The application of the inner cavity shape can make the blank obtain the corresponding three-dimensional shape. The mold generally includes two parts: moving mold and fixed mold (or male mold and female mold), which can be divided or combined. When separating, take out the parts, and when closing, inject the blank into the mold cavity for forming. Mold is a precision tool with complex shape, bearing the expansion force of blank, and has high requirements for structural strength, stiffness, surface hardness, surface roughness and machining accuracy. The development level of mold production is one of the important symbols of mechanical manufacturing level.