The content of mold accuracy includes four aspects: dimensional accuracy, shape accuracy, position accuracy, and appearance accuracy. Since the mold is divided into two parts, the upper mold and the lower mold, the mutual position accuracy between the upper mold and the lower mold is the most important among the four types of precision.
3. Mold accuracy is for product accuracy. High-precision products must be guaranteed by higher-precision molds. Mold accuracy must generally be 2 or more grades higher than the precision of parts.
How to improve mold precision
1. Precision guarantee of mold processing equipment
2. Parts Accuracy Requirements for Mold Manufacturing
①. Mold material accuracy requirements
Die steel processing tolerance restraint Standard template size Fine plate thickness Flatness within 300X300 +0.005-0±0.005300X500 +0.01-0±0.01500X800 +0.01-0.01±0.015800X1200 +0.02-0.02±0.02
②. The accuracy of mold parts requires a. The guide parts that affect the precision of the mold adopt MISUMI guide post and guide bush series, and the ultra-precision tolerance can be restrained within 0.002mm.
b. The cutting edge forming punch adopts MISUMI standard material: SKD-11 hardness: 60-62HRC The cutting edge shape is: DREGTH punching needle is usually used to form the inner hole or cylindrical shape on the product. The punching accuracy can be controlled within ±0.01mm, and it can be about 2um for special requirements, and the mirror surface can be maintained.
3. The size of the die gap is the main basis for the precision of die design and manufacturing. To ensure the dimensional accuracy and shape position accuracy of the products produced by the die, as well as the product quality (such as the quality of the punching section and the height of the burr), the gap between the die and the concave die must be guaranteed.
4. The structural accuracy of the mold is required
①. Guarantee of the accuracy of the mold base Luo Baihui said that from the perspective of processing and assembly, the accuracy of the mold base mainly includes the following aspects: a. Consistency of the plane dimensions of the upper and lower templates and the position of the guide holes; b. The flatness and parallelism of the large plane of the template; c. The verticality of the guide hole to the large plane; d. The verticality between adjacent sides of the formwork; e. The matching accuracy between the guide post and the guide sleeve.
The main methods to ensure the accuracy of the mold base are as follows:
a. The one-time processing method means that after the large plane of the template is processed, the upper and lower templates are clamped together, and the plane dimensions and guide holes of the two templates are processed at one time.
b. One of the four pilot holes is offset from the symmetrical position to ensure the assembly orientation of the mold.
c. Machining datum (Datum), used for calibration processing.
d. Adopt high-precision guide post and guide sleeve.
e. Improve the machining accuracy of parts.
②. Guarantee of punch accuracy It is believed that from the perspective of processing and assembly, punch accuracy mainly includes: a. The shape and dimension accuracy of the punch; b. The perpendicularity between adjacent sides of the punch.
③. The accuracy of the die is guaranteed from the perspective of processing and assembly, the accuracy of the die mainly includes: a. The shape and dimensional accuracy of the die; b. The verticality between the adjacent sides of the die; c. The verticality of the side of the die facing the large plane; d. The position of the die.
5. The accuracy of the forming process is guaranteed. When processing the forming structure, whether it is processed by computer gongs, EDM, wire cutting or ordinary milling machines, the coordinate processing method is used. The guarantee of this accuracy mainly depends on the accuracy of the machine tool and the accuracy of the operator’s calibration and scoring. It is believed that, like the guidelines and guiding ideology for establishing enterprise product quality assurance and management system, the concept of mold precision should also run through the entire process of mold design and manufacturing. In order to ensure the precision requirements of the closed loop of the mold assembly dimension chain, all processes involving mold manufacturing, outsourcing (including materials, standard parts) and the entire process of mold assembly, mold trial, acceptance, packaging and transportation, affecting the mold. The key links and key factors of precision must be strictly restrained and managed.