Swiss Tech Precision, USA
690 S. Clearwater Loop, Post Falls, ID 83854 P: 208.773.4800 F: 208.773.4882
Fineblanking presses are similar to other metal stamping presses, but they have a few critical additional parts. A typical compound fine blanking press includes a hardened die punch (male), the hardened blanking die (female), and a guide plate of similar shape/size to the blanking die. The guide plate is the first applied to the material, impinging the material with a sharp protrusion or stinger around the perimeter of the die opening. Next a counter pressure is applied opposite the punch, and finally the die punch forces the material through the die opening. Since the guide plate holds the material so tightly, and since the counter pressure is applied, the material is cut in a manner more like extrusion than typical punching. Mechanical properties of the cut benefit similarly with a hardened layer at the cut edge of the part. Because the material is so tightly held and controlled in this setup, part flatness remains very true, distortion is nearly eliminated, and edge burr is minimal. Clearances between the die and punch are generally around 1% of the cut material thickness, which typically varies between 0.5–13 mm (0.020–0.512 in). Currently parts as thick as 19 mm (0.75 in) can be cut using fineblanking. Tolerances between ±0.0003–0.002 in (0.0076–0.0508 mm) are possible based on material thickness & tensile strength, and part layout.
The advantages of fineblanking are excellent dimensional control, accuracy, and repeatability through a production run; excellent part flatness is retained; straight, superior finished edges to other metal stamping processes; little need to machine details;multiple features can be added simultaneously in 1 operation; more economical for large production runs than traditional operations when additional machining cost and time are factored in (1000–20000 parts minimum, depending on secondary machining operations).
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Fineblanking is a high precision metal forming process used extensively in the automotive, heavy duty, electronics, medical, lawn and garden, and general industrial industries. Materials that can be fineblanked include aluminum, brass, copper, and carbon, alloy, and stainless steels. Fineblanking utilizes three concurrent forces to closely control material flow throughout the process of forming and extruding. Presses incorporate hydraulic cylinders to control the stinger pressure and counter pressure, but main pressure (blanking force) is applied by mechanical force. This unique process creates parts with very tight dimensional tolerances, excellent flatness, and with very little variation from part-to-part throughout long production runs. These characteristics lead designers and manufacturing engineers to specify fineblanked components for their most critical applications.
Fineblanking offers shearing with no fracture zone. This is achieved by compressing the whole part and then an upper and lower punch extract the blank. This allows the process to hold very tight tolerances and perhaps eliminate secondary operations.