Combining the length processing advantages of hydraulic bending machines with the single-stroke advantages of stamping dies, a specialized punching processing equipment for profiles is developed. This improves the production efficiency of profile punching, enhances product quality, reduces labor intensity, solves the problem of relying on human factors to improve product quality, and ensures the reliability of profile punching. The subject of developing specialized equipment for profile punching is proposed.
Overview
It is well known that stamping dies can only be used for single-mode operations on stamping/pressing machines, while hydraulic bending machines can only perform length bending processing using bending dies. If we can effectively combine the length processing of bending machines with the single-stroke processing of stamping dies, it means a multiple increase in production efficiency, a significant improvement in product quality, and a substantial reduction in labor intensity for products (such as profiles) that require online stamping. It has an immeasurable impact on reducing production costs.
Feasibility of the Solution
For products processed online, most of them primarily involve punching. If we can make the working mode of the bending machine similar to that of a punch press, it would be ideal. Specifically, the lower die worktable of the bending machine can be designed to accommodate and fix the stamping die, and the waste material can be discharged to the side or rear (rear discharge is more difficult due to the presence of the front plate under the machine). The upper die of the bending machine can be modified to an inverted "T"-shaped pressure plate, and suitable tonnage, slide opening height, and machine length can be selected. Theoretically, the solution is feasible.
Adjustments need to be made to the hydraulic bending machine, dies, and other related factors:
1. Adjustment of the machine tool.
2. Removal of the upper and lower dies and the backgauge device of the bending machine to reduce the cost of machine tool acquisition.
3. Addition of a separate inverted "T"-shaped upper die pressure plate for the bending machine, inverted and leveled. Its main function is to press the upper die, but it needs to press it to the punching center of gravity of the upper die.
4. Removal of the lower die worktable of the bending machine and the addition of a widened and leveled "U"-shaped middle worktable with a "T"-slot. The "U"-shaped worktable mainly serves to limit the forward and backward movement of the die and allows the die to slide along the length direction of the worktable. The "T"-slot is used for fixing the die.
5. Installation of adjustable stroke blocks at both ends of the bending machine worktable. The adjustable stroke blocks serve to limit the working stroke of the die and protect the die.
6. Adjustment of the bending machine stroke switch and time relay to appropriate positions. The bending machine stroke should be slightly greater than or equal to the stroke of the adjustable stroke blocks, and the time relay should be set to a lower value (generally below 1 second) to increase the working frequency and obtain the corresponding working pressure.
7. The idle stroke height of the bending machine should be as short as possible.
8. Selecting the machine length, slide opening height, and machine tonnage according to the requirements of the profiles. The tonnage should generally be equal to or greater than 40 tons, and the length should be equal to or greater than 1500mm.
Die Adjustments
1. The die frame adopts uniformly sized homemade rear die frames, and the width of the lower die plate must match the width of the "U"-shaped worktable, allowing for adjustments of the die according to the requirements of the profiles.
2. The die frame's guide pillar is fitted with compression springs of uniform length, which automatically spring open after stamping (mainly to address the issue of the upper die of the die and the slide block of the bending machine not being connected).
3. Stamping dies are generally used for punching small holes, and the material cannot be dropped due to the presence of the front plate under the machine tool (located in the center of the U-shaped worktable), which poses a significant challenge.
4. Material discharge is usually done through side or rear discharge, and it is essential to ensure smooth material flow throughout the working process.
5. The profile pressure plate should be close to but not cover the guide bushing holes of the upper die. This prevents excessive travel that could damage the die and cause forward tilting of the upper die, leading to damage to the concave die and guide pillar.
6. The height of the lower die must be consistent. It is necessary to grind the cutting edges uniformly, and if uniformity cannot be achieved, copper sheets or paper can be used for approximate leveling. This prevents workpieces from deforming due to stamping on different planes.
7. The opening height must be consistent, and the "T"-shaped pressure plate must always press down on the upper die plate. This prevents the upper and lower dies from quickly separating due to the sudden upward movement of the guide pillar compression spring.
8. Components should be made as standard parts for easy maintenance and replacement.
9. If the hole spacing is too short and the die cannot be installed, multi-hole molding can be used for one die or the holes can be stamped in separate intervals.
10. The arrangement of positions on the worktable should avoid causing the slide block of the machine tool to work with a tilted foot, i.e., the center of gravity of the downward force of the machine tool slide block must align with the punching center of the profile.
Requirements for Profiles and Empty Spaces
1. The straightness of the profiles at the rear needs to be relatively high.
2. The position accuracy needs to be high.
3. Multiple holes should be evenly distributed or symmetrically arranged as much as possible.
Conclusion: The combination of hydraulic bending machines and stamping dies in the stamping process plays an irreplaceable role in improving production efficiency and product quality, as well as meeting the requirements for employees' personal skills, labor intensity, and safety.
