A mold is a tool that makes a blank into a part of a specific shape and size under the action of an external force. Widely used in blanking, die forging, cold heading, extrusion, powder metallurgy parts pressing, pressure casting, as well as compression molding or injection molding of engineering plastics, rubber, ceramics and other products. The mold has a specific contour or cavity shape, and the application of the contour shape with the cutting edge allows the blank to be separated (punched) in the shape of the contour. Applying the inner cavity shape allows the blank to obtain a corresponding three-dimensional shape. The mold generally includes two parts, a movable mold and a fixed mold (or a convex mold and a female mold), which can be divided and combined. When the parts are separated, the parts are taken out, and when they are closed, the blanks are injected into the mold cavity to form. The mold is a precision tool with complex shape and bearing the expansion force of the blank. It has high requirements on structural strength, stiffness, surface hardness, surface roughness and processing accuracy. The development level of mold production is one of the important signs of mechanical manufacturing level. The so-called mold opening is the manufacture of molds.
Mold production and inspection:
The control of the raw materials of the mold is carried out in the following aspects:
1. Macro inspection
The chemical composition is decisive for ensuring the performance of the steel, but the composition is qualified, and the steel properties cannot be fully explained. Due to the uneven organization and composition of the steel, the macroscopic inspection largely complements this deficiency.
Macroscopic inspection can observe the crystallization of steel, the destruction of steel continuity and the inhomogeneity of certain components.
Standard "Low-Structure Defect Rating Chart for Structural Steel" GB1979
There are 8 common defects in macroscopic: segregation, looseness, inclusions, shrinkage cavities, bubbles, white spots, cracks, and folds.
2.1. Evaluation of annealed tissue
The purpose of annealing is to reduce the hardness of the steel, to facilitate machining, and to prepare the tissue for subsequent heat treatment.
The annealed structure of carbon tool steel is evaluated according to the GB1298* rating chart.
2.2, carbide non-uniformity
Cr12 type Leysite steel contains a large amount of eutectic carbides in the structure. Carbide inhomogeneity has a very important influence on the performance of use, so the distribution of carbides must be strictly controlled.
All in all, because the production objects of the mold production plant and the workshop are relatively cumbersome, and the number is one-piece and small-quantity, which brings certain difficulties to the formulation and management of the mold production quota, plus the production methods of the factories and workshops. The equipment and technical quality are not the same. Therefore, when formulating the quota, it is necessary to find out the appropriate method according to the actual situation of the factory and the workshop to formulate an advanced and reasonable working hour quota to improve the labor productivity.
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