The service life of bending machine molds or other molds is generally composed of five factors:
(1) Mold structure. The rationalization of mold structure is the reason for increasing the upper limit of mold load-bearing capacity and reducing the level of thermal-mechanical load that the mold bears. For example, the design of mold guidance is helpful in avoiding mutual abrasion between the punch and die. Also, for cold heading and cold extrusion molds that bear high-strength loads, stress concentration is very sensitive when the cross-sectional dimensions of the load-bearing parts change, making them most prone to cracking due to stress concentration. Therefore, whether the treatment of changes in cross-sectional dimensions is reasonable will directly affect the service life of the mold.
(2) Mold material. Paying attention to the quality of mold materials may cause defects in processing technology and affect the load-bearing capacity during operation. Necessary measures should be taken to compensate for the shortcomings in metallurgical quality to improve mold life.
(3) Mold processing quality. Defects in parts during processing, as well as pretreatment, forging, quenching and tempering, and surface treatment, significantly affect the wear resistance, anti-biting capacity, and anti-fracture capacity of the mold. For example, defects such as surface roughness of the mold, residual tool marks, microcracks from electrical discharge machining, surface carburization and decarburization during heat treatment will affect the load-bearing capacity and life of the mold.
(4) Mold working condition. The precision and rigidity of the equipment used during mold operation, lubrication conditions, pretreatment status of the processed material, preheating and cooling conditions of the mold, etc., all have an impact on the mold life. For example, precision blanking of thin materials is particularly sensitive to the accuracy and rigidity of the press, requiring the selection of a high-precision and high-rigidity press to achieve good results.
(5) Condition of product parts. The surface quality status of the processed part material, material hardness, elongation, and mechanical properties, as well as the dimensional accuracy of the processed part, all have a direct relationship with the mold life. For example, when forming a special alloy with a nickel mass fraction of 80%, it is prone to strong biting with the working surface of the mold, causing the working surface to bite and pull, directly affecting whether the mold can work normally.
In conclusion, the economic and technical indicators of molds are interrelated, and the influencing factors are diverse. In the actual production process, it is necessary to comprehensively balance based on the product parts and objective needs, grasp the main contradictions, achieve the best economic benefits, and meet the production requirements.
