Analysis of Selection and Design of Stretch
(1) the manufacture of tensile parts as far as possible the use of standard mold base, and the standard mold base on the type and size to determine the upper and lower mold base type and specifications. If you need to design their own mold base, the diameter of the circular die base should be 30 ~ 70mm larger than the diameter of the concave formwork. The length of the rectangular mold base should be 40 ~ 70mm larger than the concave formwork. Its width may be slightly larger or equal to the width of the concave formwork . The thickness of the mold base can be determined by reference to the standard mold base, generally 1.0 to 1.5 times the thickness of the concave formwork to ensure sufficient strength and rigidity. For large non-standard mold base, must also be based on actual needs, according to the casting process requirements and design specifications for the design of castings. (2) The die holder selected or designed must be adapted to the relevant dimensions of the table and slide of the selected press and must be checked as necessary. For example, the minimum profile size of the lower die should be at least 40 to 50 mm larger than the size of the leak hole on the press table. (3) mold base material generally used HT200, HT250, can also be used Q235, Q255 structural steel, mold for large-scale precision mold selection of cast steel ZG35, ZG45. (4) Die Block, the parallelism of the upper and lower surface should meet the requirements, the parallel tolerance is generally 4. (5) Upper and lower die sets of guide sleeve, guide post installation hole center distance must be consistent with the general requirements of precision ± 0.02mm below; die seat guide post, guide sleeve mounting hole axis should die with the upper and lower Vertical plane, the installation of sliding guide pin and guide sleeve, the vertical tolerance is generally 4. (6) Die surface of the upper and lower surface roughness Ra1.6 ~ 0.8μm, to ensure the parallelism of the premise, may be allowed to reduce the Ra3.2 ~ 1.6μm. Plate: The role of the plate is directly under pressure to withstand and spread the convex touch to reduce the pressure on the mold seat unit to prevent the local block is depressed, pad size and the same die, the fixation method Also fixed with screws and pins.
Previous article：Improve the stability of the mold have know-how
Next article：Design Considerations for Stretch