DD225068B1 - METHOD FOR THE CONTINUOUS FREE DEPOSIT OF A METALLIC TAPE - Google Patents

Description

Field of application of the invention

The invention relates to a method for continuous burr-free trimming of a metallic strip, which must meet high requirements and is processed and processed, for example, for profiling and / or longitudinal welding of pipes in sheathing systems.

Characteristic of the known technical solutions

For TIG welding of thin-walled, tube-shaped material an oxide-free, undamaged band edge is required. For this purpose, the material is trimmed before welding by means of a circular knife shear on the strip edges.

Thus, in technological lines, where a slotted tube is formed from a metallic strip and then welded to the strip edges, a circular knife shear is used for trimming the strip edges. The object of the circular knife shears is to eliminate the oxides located at the strip edges, which reduce the quality of the weld, by removing cut edge ripples at the strip edges or damages caused by transport of the strips.

In the previously known production facilities for the production of longitudinally welded pipes and clad wires, the circular knife shear is usually involved in a towed version in the technological line. However, the possibility of optionally driven circular knife scissors is also known.

The embodiment of the conventional circular knife shears is such that the knife shafts are arranged one above the other and the material to be trimmed material is pulled or driven horizontally by the circular knives. The circumcised and trimmed ribbon and the hem scrap run in a plane and in the same direction through the area of the knives. Despite optimum knife gap adjustment, a wafer-thin ridge is formed, which adheres in places to the strip edges and leads to welding defects in the subsequent welding process.

Another disadvantage of such a cutting technology is the increasing cutting burr by cutting gap change due to the wear of the circular blade. At the same time, by bad cutting edge ripples can again arise.

Another embodiment is set forth in DE-OS 2445725. There, the circular blades are also one above the other, but offset from each other. The center distance is smaller than the sum of the knife radii minus the strip thickness. With this pair of scissors, it should be possible to achieve a virtually burr-free trimming of the strip edges. Even by the staggered arrangement of the knife, the material is squeezed by the upper blade on the lower blade, whereby a burr-free cutting is not possible. With increasing wear of the knife edges, the burr formation increases.

Object of the invention

The aim of the invention is to produce a band with high quality cut, which in subsequent processing stages, such as profiling, but in particular pipe profiling with subsequent longitudinal welding process, can be processed without errors.

Explanation of the essence of the invention

The invention has for its object to continuously cut bands in the longitudinal direction without squeezing and thus burr-free. According to the invention the object is achieved in that behind the cutting zone, the trimmed band subdivision wrapping the fixed circular blade and the edge strips are subdivided part by turn wrap the engagable circular blade.

embodiment

An embodiment of the invention will be described in more detail. The drawing shows the arrangement of the rotating circular knives and the tape guide before and after the cut.

The circular blades 4, 5 are now, as seen in the tape running direction, no longer arranged one above the other, but in a plane next to each other. The incoming and to be circumcised band 1 is fed to the fixed circular blade 4 via a preferably off-axis pulley 6, wherein on the fixed circular blade 4, a wrap angle a _B of almost 180 ° is formed. The edge strips 3 are removed with the wrap angle a _s around the adjustable circular blade 5. By the S-shaped band guide in the scissors area, generated by guide roller 6 and circular blade 4, the opposite directions of curvature of trimmed band 2 and edge strips 3. The result is an acting in the direction of the running edge strip 3 tensile stress in the cutting zone 7 and through the fixed circular blade 4 and the engagable circular blade 5 caused notch effect on the material to be cut. The direction of the notch effect points from the surface to the interior of the material. Thus, the material is not squeezed by the upper blade on the lower blade, as in a conventional cutting process, but it is generated by the opposing curvatures in the region of the cutting zone 7 in addition to the strip a three-dimensional field of stress in the material. Transverse to the belt direction thus acts a tensile force that prevents the flow of material into the kerf. By wrapping a _{B of} the trimmed strip 2 around the fixed circular blade 4, a tensile stress superposition is achieved independently of the actual strip tension at the top and bottom band. By these conditions, a burr-free cutting is possible. The otherwise problematic adjustment of the kerf is likewise facilitated by the stress superposition, ie the cutting patch does not have to be set so precisely and tightly tolerated, which in turn leads to an increase in the tool life. Furthermore, the wrap around the fixed circular blade 4 brings no cut deterioration in existing differences in quality and sameness of uncircumcised band.

By the invention it is also possible to produce open profiles, which no longer have to be subjected to further processing (deburring).

Claims (1)

A process for the continuous burr-free trimming of a metallic strip in the dry section of a circular knife scissors with fixed and engageable cylindrical knives, wherein the untrimmed strip is fed to the cut zone by means of a diverting pulley of the fixed knives, characterized in that behind the cutting zone (7) the trimmed strip (2 ) Partially wrapping the fixed circular blade (4) and the tape strips (3) and partial wrapping the engageable circular blade (5) are discharged. For this 1 page drawing