In fine blanking presses, various processing steps can […]
In fine blanking presses, various processing steps can be combined using subsequent compounding tools.
Compared to punching, this tool kit is more sophisticated for fine blanking, and also includes a registration stamp and a pressing device, which press firmly before and during the cutting process. This causes a stress state during shearing, which should be as close as possible to the compressive stress range. This increases the formability of the material and the cut surface of the part does not show any cracks or fractured surfaces.
During punching, the punch moves from bottom to top.
For this purpose, the raw material is held along the cutting contour by means of a so-called ring clamp.
Only then can a stamper with the desired shape cut metal.
Combined with a greatly reduced cutting gap (approximately 0.5% of the sheet thickness), a cylindrical cutting part can be achieved up to 100% of the sheet thickness and a right-angle cutting edge, but for thin plates, the cutting gap Will become small. Guidance is required using complex post stands.
The workpiece material is plastically deformed until the punch has completely penetrated the sheet-without suddenly tearing the material. These tear-free cut surfaces can be used as functional surfaces without further finishing.
Today, fine blanking presses can reach 100 strokes or more per minute
In the fine blanking process, before the workpiece is ejected by a so-called reaction force, the workpiece is pushed back into the mold by an ejector, and finally blown out or taken out.
For example, stamped flanges for exhaust systems can be produced on presses in required quantities with a functional profile inside and a secondary profile on the outside. The flange is 20 mm thick. The inner contour is a functional contour and is produced in the form of a smooth cut. The outer contour and the holes for the fastening screws are stamped in the usual way. Even for metal parts below 20 mm, the stroke speed will not be lower than 80 min -1
Can also be punched at high speed now
Thanks to the servo-controlled hydraulic drive, the precise control speed in each power stroke can be adapted to each process. Fast moving strokes reduce cycle times, and when cutting thin parts, opening strokes are shortened.
In addition, for sheet thicknesses of 17 to 20 mm, the fine blanking limit (fine blanking tolerance) has been reached. Alternatively, use a more powerful punch or a completely different cutting process.
Several factors are important for fine blanking or stamping
When deciding on stamping or fine blanking, factors such as material type and thickness, number of pieces, application, and required cutting surface quality determine whether investment should be made on a stamping machine or on a more expensive and slower fine blanking machine.
Compared with stamping, the disadvantage of fine blanking is obviously that the investment amount of fine blanking press is much larger and the speed is slower.
Through the intelligent design of the punching tool, the design of the feed, smooth cut and cut is different. In this way, a quality similar to that of a fine blank can be obtained at a desired point.
If a large number of serially delivered parts are required, fine blanking usually lags due to speed. For example, stamped flanges used in the automotive industry are often mass-produced. It is not uncommon for batches of up to 1,600,000 pieces per year or 12,000 pieces per day.