Title of Invention

"METHOD FOR MAKING SEMI FINISHED PRODUCT MADE OUT OF A DUCTILE MATERIAL WITH BREAKING AREAS"

Abstract

The semi-finished product features burr-free separated edges, a defined geometry of the parting planes and very less surface ruptures. As compared to conventionally divided semi-finished products, e.g. with roll cutting technology, the p A band-shaped semi-finished product is made out of a ductile material and is configured to be separated into at least two sections. At least one pair of wedge-shaped, non-cuttingly formed longitudinal notches are formed, between the tips of which there remains a thin web of material, which can be torn easily with little force. The semi-finished product is distinguished by burr-free separated edges, defined geometry of the separating surfaces, and extremely reduced breaking-surface portions. It shows improved resistance during static and dynamic stress, in particular for alternating bending loads, in comparison to conventional, for example via the rolling-cutting technique, separated semi-finished products.

Full Text

BACKGROUND Field of the invention The present invention relates to a method for making semi finished product from a ductile material, preferably metal and having regions of reduced thickness to facilitate separation thereof. Description of the related Art Ductile materials, like metallic materials, are manufactured as semi-finished products in large quantities and sizes. During the manufacturing process, it is necessary to attain the required geometries by isolating the blanks manufactured in multiple widths or lengths. Thus, for example, band-shaped semi-finished products are manufactured with the width and/or length required for the respective use through lengthwise and crosswise separation. In large scale production, cutting methods designed according to the roll cutting principle are mostly used for this. Fig. 1 shows the procedure in accordance with the current technological status. Sheet metal band wound to a coil is thereby mostly separated into several narrow bands or strips of bands by longitudinal separating systems. The strips are separated by a waste free cutting with circular rotating knives. The circular knife cutters with a continuous operating shaft are fitted with circular knives, ring like rollers and spacer sleeves. A typical circular knife cutter for the non cutting longitudinal separation according to the roll-cutting principle thus consist essentially of symmetrical rotating which are fastened on one upper and one lower cutter bar in the space adapted to the thickness of the material to be cut or are clamped axially on the knife shafts above and below the belt. The knives are adjusted to one another and are set axially to a particular cutting pressure and vertically to an insertion depth of the tools. These values are determined on the basis of the quality of the material, its thickness and the desired shape of the cut edge. During the cutting process, the arched cutter of the upper knife rolls towards the cutter of the lower knife. A part of the material is sheered by the cooperating knives, the remaining material thickness breaks to complete separation. For several materials, this ruptured part contributes approximately 20 - 40 % of the strip thickness, depending upon its thickness, hardness and quality. The ruptured area develops an extremely rough forced rupture surface and its shape is determined by the rupture process, which mostly takes place freely. As shown in Figure 2, the shape and dimensions of the ruptured zone clearly differ from those of the cut zone formed under the direct effect of the tools and the ruptured zone necessarily extends to the original surface as cutting burr. The cutting burr is a highly hardened, sharp-edged material, which extends beyond the contours of the ideally separated material. The shape and size of burr are again strongly influenced by method parameters. In any case, burr is an unwanted material. They may cause injury during manual handling. In further processing, burr may result in increased unwanted abrasion and development of tinsel or the surrounding material may be damaged due to the cutting effect of the burr. During the application, the burr found on the outer edge of the material is the weakest point. Often, the tear formation begins here in cases of dynamic and static loads. An unfavourable shape of the band edges in the shearing zone area, the rough breaking zone and cutting burr affect the fatigue strength to a large extent. Thus, efforts are being made to minimise the burr formation and the low cost finishing of separate, burr containing bands is of great interest. The undefined shape of the ruptured part of the parting plane is another defect in the otherwise economical roller knife technology. Thus, several applications demand strips that are re-processed by seaming the edges instead of the economical separated strip-like semi-finished products. Alternatively, pressed or drawn products in the form of wires are used. These have defined geometries in the entire cross-section right from the beginning. This invention aims at doing away with the disadvantages of roller cutting technology, without incurring high costs or reducing the productivity. SUMMARY It is an object of the present invention to overcome the disadvantages of separating via the roller cutting technique according to the state of art without thereby causing high expenses or lower productivity. In particular the object is to manufacture a defined position of the breaking zone, avoiding the formation of burrs, reducing the wear and filter formation and drastic reduction of the breaking portion. Another object of the present invention is to provide for a semi-finished product for manufacturing flexible flat strip cable for the transmission of electrical signals or electrical energy. Another object of the present invention is to avoid the mechanical weak points of the separated goods, which weak point is caused by the breaking portion and outside position of the burr. Another object of the present invention is to provide for the semi-finished product for the manufacturing wielded structures, particularly pipes. Yet another object of the present invention is to provide for semi-finished product for manufacturing electro-mechanical components such as pin-and socket connector, relay, contact spring, etc. BRIEF DESCRIPTION OF THE DRAWINGS The preferred embodiments of the invention will hereinafter be described in conjunction with the appended drawings provided to illustrate and not to limit the invention, wherein like designations denote like elements, and in which: Fig. 1 is longitudinal cutting of a strip-like semi-finished product in accordance with the current technological status; Fig. 2 is burr formation in accordance with the current technological status; Fig. 3 is a schema of a band shaped semi-finished product with longitudinal notches as described by the invention; Fig. 4 is schematic presentation of the process of manufacture of the semi-finished product described by the invention and the separation / cutting of a section of the product; Fig. 5 is schematic presentation of a section of the semi-finished product moulded into an open seam tube before welding it to a pipe with a longitudinal seam ; Fig. 6 is detailed manufacturing process of the semi-finished product described by the invention along with a numerical example, and Fig, 7 is schematic presentation of the influence of rolling steps on the formation of a pair of notches while forming the breaking area DESCRIPTION OF PREFERRED EMBODIMENTS The present invention is directed to executing the following individual tasks; 1) establishing a definite position of the breaking zone; 2) avoiding burr formation; 3) reducing abrasion and tinsel formation; 3) drastic reduction of the breaking zone; 4) avoiding the formation of mechanical weak points in the separated/ cut product resulting from the breaking part and external position of burr. According to the invention, this task is resolved by making a band shaped semi-finished product from ductile material, particularly metal wherein by band shaped semi finished product we mean a flat strip like sheet/bar made of metals with specific areas of reduced thickness. The invention is to make band shaped semi finished product made from ductile material having on oppositely lying sides of the semi finished product at least one pair of aligned wedge-shaped notches, the thickness d of which web of material is so thin in comparison to the thickness D of the semi-finished product that it can be easily separated off with little force by deflecting the areas of the semi-finished product defined by the notch pair, thus avoiding any deformation caused by metaS cutting. The notches are in particular non cutting formed. The semi-finished product is preferably band-shaped material. However, the invention can also be used, for example, for wires or profiled wires. An advantage in case of coated strips, for example having tin-, silver or nickel-coated surface, is that the coating of the notched flanks is retained to a large extent. The invention clearly uncouples the cutting and breaking on the basis of the operation of circular knife cutters. It is recommended to form semi finished product made out of ductile material which is to be separated through plastic, non chip creating forming along an axis that is perpendicular at the same time to the surface of the semi finished product, advantageously on both sides and symmetrically by wedge shaped notches so that a very thin web of material to be separated remains between the tips of the two notches, which are exactly as possible directly opposite to one another. Symmetrically rotating tools arranged according to the machine design are used, as is already known from the conventional process of circular knife cutting. For example, roller plates with the corresponding profiles are used as a tool for the wedge-shaped longitudinal notches. A typical geometry of the wedge profile shows a wedge angle of 10 - 80". The axial and vertical offset of the disc wedge tips should be kept at a minimum so that the smallest existing tolerance realisable information for the common toots of the precision cutting can be applied. The thickness of the remaining web of material is in the case of a band-shaped semi-finished product below 0.5 mm thickness, preferably 5% to 40% of the material thickness of the material to be separated. The material flow in length and width of the semi-finished product, which material flow is caused by the removal of the material from the notches, can result in changes of the cross-sectional contour of the semifinished product to be separated so that, depending on the situation, advantageously a bound cold shaping of the surfaces affected in the exactness of their shape is to follow. This process can be used with a specific purpose in order to achieve an almost perpendicular edge design in at least one forming step on the notch pair In addition, this cold shaping makes it possible in the cases of the thinnest bands with D.ltoreq.0.2 mm and foils, where a defined notching is, based on the question of tolerance, difficult or not reliably possible, to start out from a pre-manufactured band, the notches of which are indeed-almost rolled shut in several steps, however, its breaking area is maintained. The semi-finished product prepared in this manner is separated with little force and with any desired speed in a further step by deflecting or bending out of the plane of the semi-finished product areas relative to one another, which areas are defined by the notches. The separated semi-finished product sections have according to the inventive method defined constructed outer edges. The broken surface lies always completely within the surface of the separating surface without extending beyond the original material surface. The expansion of the breaking surface corresponds with the thickness of the web formed by the respectively two oppositely lying notches. It is thus smaller by a multiple than in the case of the common cutting with rolling knives. A burr is not created during separation of the web when a sufficient directly opposite aligned orientation of the notches exists. As shown in figure 3 and 4, the band-like semi-finished product 1 with thickness D has two pairs of wedge-shaped longitudinal notches 2, 3. These notches 2 and 3 have tips 2a and 3a and flanks 2b and 3b, between which is the wedge angle a. A thin web 4 with thickness d extends between the tips 2a, 3a arranged, as far as possible, with very little or no offset. As shown in Fig 4, the impression of the slots 2, 3 is made with the upper and lower notching disc 5 (shown here is only an upper plate). The material between the notches 2, 3 is hardened by the opposite sided forming operation. The web of material 4 is thin but extremely resistant, however the broken elongation of the material is very low in the narrow localised area of the web 4. Thus, the material is ready for cutting and requires very little force. A section 6 of the semi-finished product is separated by deflecting the areas adjacent to the notches 2, 3 with the required force in the direction of the arrow. As seen in this figure, the section 6 of the semi-finished product shows only a small broken surface (on both sides). This is also clear from Fig. 5, where such a semi-finished product section 6 is formed into an open seam tube in order to longitudinally welded into a tube. Numerical example: Figure 6 shows the numerical example. A strip with thickness D = 0.20 mm made from soft-annealed SE-Cu 58 was cut into strips (sections) 6 having width B = 6 mm with tips of mutually aligned wedge-shaped circular knives, each embedded up to 0.080 mm in the strip. The width of the circular knife plates 5 axially fixed to one upper and one lower operating shaft was same as the width of the flat strip B - with the ground tip of the circular knife in the half plate thickness B/2. The wedge angle of the slot profile is a = 20°. After fixing several circular knives 5 on the (two) operating shafts, these were adjusted in the stand according to the alignment and concentric running of the knife tips 2a and 3a. This adjustment led to a simple rounding off of the wedge-shaped tips 2a/3a to the radius of the plate tip Flat band strips 6 with symmetrical longitudinal slots were formed with the (wedge) circular knife system aligned in the abovementioned manner and by fixing a brake lever aligned to the flat band strips cross-section. The web thickness d was d = 30 to 50 µm, 40 urn in the centre corresponding to 20% of the strip thickness D. The coil thus treated was wound on the reel of a finishing machine. Individual sections 6 of the coil 6 mm wide were then manually separated at a length of approx. 1 m, whereby the outermost section 6 was ripped off with a slight pull by deflection from the strip plane. Specimens tested later showed an almost centrally running rupture zone with a cross-section with thickness approximately 40 + 10 µm. No burr formation was detected in the ground section or the rupture zone. The cross-sections of the separated / cut individual sections 6 did not show any unacceptable permanent plastic deformation of the strip cross-section within the required tolerance, caused by the separating / cutting forces. The individual sections 6 separated / cut in this manner were threaded in the finishing machine and wound together for further processing over guide rollers with less tension and uniform acceleration. The rollers allowed the required mutual deflection of the individual sections 6 for continuous tearing. Fig. 7 finally shows the influence of, for example three rolling steps on the formation of the pair of notches 2, 3, with the help of a strip-like semi-finished product 1 having wedge-shaped notches 2, 3 and residual web 4 as seen in Fig. 7a (see also Fig. 3). In the first rolling step itself (Fig. 7b), an almost perpendicular edge guiding is attained at the notches 2, 3. After the next two rolling steps, the original slots 2, 3 are also nearly rolled (Fig. 7c/7d), however one target rupture point 7 still remains on the slots 2, 3. While the preferred embodiments of the invention have been illustrated and described, it will be clear that the invention is not limited to these embodiments only. Numerous modifications, changes, variations, substitutions and equivalents will be apparent to those skilled in the art without departing from the spirit and scope of the invention as described in the claims. We claim 1. The method for making a band shaped semi-finished product made out of a ductile material, particularly metal, with breaking areas that characterises wherein on oppositely lying sides of the semi-finished product at least one pair of oppositely aligned wedge-shaped notches is provided, and wherein between the tips of the wedge-shaped notches there exists a web of material, the thickness d of which is so thin in comparison to the thickness D of the semi-finished product, that it can be torn off using little force without a cutting deformation through an oppositely directed deflection of the semi-finished product areas defined by the notch pair. 2. The method for making a band shaped semi-finished product as claimed in Claim 1 wherein the notches are non cuttingly formed. 3. The method for making a band shaped semi-finished product as claimed in Claim 3, wherein the band shaped semi finished product is coated with nickel, tin, silver or other metals. 4. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the web of material lies off centre in the expansion of the semi-finished product, which expansion is defined by the notch pair Wherein notch pair are a pair of wedge shaped, non cuttingly formed longitudal slots, between the tips of which there remains a web of material of thickness d. 5. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the web of materials occupies an edge position in the expansion of the semi finished product, which expansion is defined by the notch pair. 6. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the web thickness is d 7. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein only a slight offset of the tips of the notches exist. 8. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the wedge angle is a = 0° to 120°. 9. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the wedge angle is a = 10° to 80°. 10. The method for making a band shaped semi finished product as claimed in Claim 1, wherein the ductile material comprises of copper-based materials or copper composites combined with reinforced agents like fibres, particulates, whiskers and matrix thereto. 11. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the ductile material comprises of aluminium-based materials or aluminium composites combined with reinforced agents like fibres, particulates, whiskers and matrix thereto. 12. The method for making a band shaped semi finished product as claimed in Claim 1, wherein the ductile material comprises of iron-based materials or composites thereto. 13. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the ductile material comprises of zinc-based materials composites with reinforced agents like fibres, particulates, whiskers and matrix thereto . 14. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein the ductile comprises of plastic, ceramic or material composites with reinforced agents like fibres, particulates, whiskers and matrix thereto, 15. The method for making a band shaped semi-finished product as claimed in Claim 1, wherein after at least one cold-forming at the place of the notches in each case an almost squared off edge guide is formed. 16. The method for making the semi finished product as claimed in Claim 1, wherein defined breaking surfaces are formed and wherein the expansion of the breaking surface corresponds to the thickness of the web of material. 17. The method for making the semi finished product as claimed in Claim 16, wherein defined breaking surfaces are formed, and wherein the thickness of the band-shaped semi-finished product is in the range of 10 µm to 300 µm and width in the range of 0.5 to 25 mm. 18. The method for making the semi finished product as claimed in Claim 16, wherein flat band cable for the transmission of electrical signals or electrical energy is formed. 19. The method for making the semi finished product as claimed in Claim 16, wherein electro-mechanical building components such as pin-and-socket connectors, relays, contact springs etc are formed. 20. The method for making the semi finished product as claimed in Claim 16, wherein building industry products, in particular roofing or covers for facades is formed. 21. The method for making the semi finished product as claimed in Claim 16, wherein material for welded structures, in particular of tubes is formed. 22. The band shaped semi finished product made out of ductile material, having a maximum thickness of 0.5 mm wherein on oppositely lying sides of the semi finished product at least one pair of oppositely aligned wedge shaped notches is provided, wherein between tips of the wedge shaped notches there exists a web of material, the thickness of the semi finished product, so that the wedge shaped notches are capable of being torn off using little force and without a cutting deformation through an oppositely directed deflection of the semi finished product areas defined by the notch pair, and wherein flanks of the notches are not flat surfaces. 23. The band shaped semi finished product as claimed in Claim 22, wherein the flanks have arch shaped, wavy or stepped cross sections.

Documents:

1278-del-2002-abstract.pdf

1278-del-2002-claims.pdf

1278-del-2002-correspondence-others.pdf

1278-del-2002-correspondence-po.pdf

1278-del-2002-description (complete).pdf

1278-del-2002-drawings.pdf

1278-del-2002-form-1.pdf

1278-del-2002-form-18.pdf

1278-del-2002-form-2.pdf

1278-del-2002-form-26.pdf

1278-del-2002-form-3.pdf

1278-del-2002-form-4.pdf

1278-del-2002-form-5.pdf

1278-del-2002-petition-137.pdf

1278-del-2002-petition-138.pdf