Патент USA US3058207код для вставки
Oct. 16, 1962 .1. M. KELLY ETAL 3,058,197 DIIIIE SHAVING WROUGHT COPPER AND ITS ALLOYS Filed June 14, .1960v 2 Sheets-Sheet l :2o_ -so no- -70 Z % I00 _ - [D g 90- RC 6 o 2 S -50 u z I 3 so- O -40 6| Lu 0 2 0 7o_ 0: 4 I -30 *2 LL! U 60- -2o 35 50- -|o 0. 40 | .020 | | l I l .025 l I l l .030 DIE RADIUS-R WITNESSES Fig. 3. INVENTORS James M. Kelly, Edward P. Kelly and Herman H. Schmi?. Mam ATTORNEY waited grates Fatent fire 1 3,058,197 Patented Oct. 16, 1962 2 This indicated that the basic factors that contributed to 3,058,197 DIE SHAVENG ‘WRUUGHT COPPER AND ITS ALLOYS .larnes M. Keily, Tra?crd, Edward P. Kelly, Irwin, and Herman H. Schmitt, Parker, Pa, assignors to Westing the results were not fully understood, and that no con sistent reliable results can be obtained as long as the meth od of attack is one of trial and error. The inventors have made exhaustive studies to get at house Electric Corporation, East Pittsburgh, Pa, a the basic factors involved to obtain consistent reliable re corporation of Pennsylvania Fiied June 14, 1960, Ser. No. 36,083 6 Qiaims. (Cl. 29-953) shaving and shaving die design concerns itself with, (1) sults. Their studies reveal the basic key to successful the radius on the cutting, or shaving, edge of the die, (2) 10 the relation of the hardness of the material to be shaved This invention relates to apparatus and the technique, to this radius, (3) the die clearance and the method of or process, of shaving wrought metals, particularly copper providing this clearance, (4) and the support and the and its alloys. alignment of the material to be shaved. Wrought copper products used in the electrical indusa In the drawings: tries are, in general, formed to desired size and shaped by: 15 FIG. 1 shows a very much enlarged sectional view of the cutting edge of the shave die; (1) Casting wire bar; FIG. 2 is a showing helpful in disclosing the cutting, (2) Hot rolling; and or shaving, edge of the shaving die; (3) Cold rolling. FIG. 3 shows a curve helpful in disclosing this inven 20 tion; and Subsequently as a fourth step the ?nished product is drawn through dies to dimension. Also certain modi ?cations of the mentioned procedures are known as ex trusion instead of hot rolling. FIG. 4 shows a longitudinal sectional view of a com~ plete shaving die. FIG. 1 shows an insert AC of tool steel, tungsten carbide, or other suitable hard and tough cutting material, The mentioned procedures lend themselves to produc 25 in the body of the die. The importance of the radius tion line use and have for years produced reasonably of curvature at the cutting edge cannot be overstressed satisfactory copper products that have been accepted in or overemphasized, because the proper grinding and form the electrical industry and allied applications. ing of this radius, its location in respect to the cutting Recent trends in the electrical industry have raised the edge CE and its physical size are important to successful standard of acceptance and now a much improved 30 shaving operation. Wrought copper product, particularly with reference to FIG. 2, drawn to a smaller scale than FIG. 1, will per surface ?nish, dimension, general appearance, and re haps be helpful in disclosing the radius in question. Two liability in use, must be provided. lines x-—x and y—y are drawn as shown. The circle is Further, new type insulations, new designs of electrical added from the center 0, the intersection of the lines. The apparatus, increased current loading per unit of weight 35 radius of this circle is chosen to be the radius giving the and higher current ratings, demand wrought copper prod best performance of the cutting tool, or die, in relation ucts free from slivers, surface inclusions, copper dust, to the hardness of the wrought copper to be shaved. In rolled in and drawn oxides, and stain, etc., inherently other words, this radius is R shown in FIG. 1 and the cut common to a variable degree in most copper processed ing edge of the shave die is the point A, the intersection by the techniques hereinabove mentioned. 40 between the circle and line x-—x. One broad object of this invention is proper die shav The physical size of this radius in inches has been ing of the bars, rods, or wires of copper and its alloys and found to be directly related to the hardness of the wrought similar metals. copper to be shaved. The curve shown in FIG. 3 shows The process of die shaving is the removal of surface this relation. blemishes and material from one, or more, or all the sur 45 For unworked copper, that is, copper having no cold faces of the wrought copper product thus yielding a prod reduction and having a hardness of 40 as seen in FIG. 3, uct of excellent surface ?nish, close dimensional tolerance the length of the radius has to be .0302 of an inch and no and high metal lustre. This is so because the very nature greater ‘radius R will do. From FIG. 3, it is apparent that of forming the bars and rods places the ‘blemishes in the surface. Rolling or drawing through a die tends to in 50 the amount of cold reduction also determines the hardness. To show this relation the percent cold reduction is shown crease rather than decrease the surface blemish. at the right and the hardness scale at the left. Unusually It has been known for some time that the removal the copper has received some cold reduction in area before of the surface layer from a copper rod, or bar, would im it gets to the mill for shaving. In fact, this reduction in prove its appearance, and reliability in use. Surface area may be well over the 50%. grinding had been tried but such a procedure is rather ex 55 Assuming that the reduction in area from the cold Work pensive. ing is 60%. This corresponds to a hardness number of Die shaving has been tried in the past with some meas 100. The very best radius R for the cutting edge CE is one ure of suceess, but never with a consistent reliable result. At one time it was thought a blunt-nosed die for sur of .0225 inch. This is, however, not too critical. What FIG. 3 actually shows that in no case should the radius R face shaving was desired. This type of die pushed and 60 be less than .02 of an inch nor more than .0302 of an inch. rubbed the copper rod surface rather than shaved off a Within this range there is thus some choice. The best selected layer as was intended. At other times a die with a sharp cutting edge was used and still no consistent reliable results were obtained. radius to use for a copper of a particular hardness is the radius indicated by curve RC, but as long as the radius falls within the range .02 of an inch and .0302 of an inch 3,053,197 3 coppers of a fairly wide range of hardness can be properly We claim as our invention: . 1. A cutting die for shaving a surface layer off of a metal bar, a cutting edge on the die conforming generally to the transverse peripheral shape of the said metal bar that is to be shaved by moving said metal bar perpendic shaved. Now the die must also have a clearance so that no parts of it act as a wire die, that is, a cold reduction die. From FIG. 1 it will be apparent that the radius R emanates from a center that is the same distance from the axis of the die ularly toward the cutting edge of the die, said cutting edge being shaped at the front thereof to a curvature deter as the cutting edge CE, considering a die for a cylindrical mined by a circle whose center lies less than .0302 of an rod CR, is from the axis of the die. Or in other words inch from the cutting edge and the radius of the center it emanates from the surface of the shaved rod CR. From the front of the cutting edge toward the rear, the die has 10 of the circle determining the curvature lies substantially in the intersection line of the shaved surface of the metal a small but increasing clearance C. This clearance, while being shaved and a plane perpendicular to the shaved sur not too critical, cannot be chosen at random, and for face of the metal being shaved. proper consistent results increases from Zero at the cutting 2. In a die for shaving a surface layer off of a metal edge to from .025 of an inch per inch distance from the bar, a cutting edge on the die conforming generally to cutting edge toward the rear to .032 of an inch per inch the transverse peripheral shape of the said metal bar that distance toward the rear from the Cutting edge. This means is to be shaved by moving said metal bar perpendicularly the inner surface of a circular die is in the shape of a toward the cutting edge of the die, said cutting edge being frustum of a cone with the angle between the axis of the shaped at the front thereof to a curvature determined by cone and a straight line in the surface of the cone and intersecting the axis, having an average angle of 1° 38', 20 a circle whose center lies less than .0302 of an inch from the cutting edge and the radius of the center of the circle and a range of about twelve minutes of an are above or determining the curvature lies substantially in the inter below this average angle. section line of the shaved surface of the metal being The die D has the annular cutting insert AC and the curvature at region CU above, or removed, from the cutting edge CE, is so shaped by suitable grinding to pro shaved and a plane perpendicular to the shaved surface 25 of the metal being shaved, said die having an increasing clearance from the cutting edge toward the rear between the die and the material being shaved that increases per inch distance toward the rear from the cutting edge no vide a reverse curve for the proper breaking of the shaved material into small chips, CH. In operation the die, shown complete in axial section less than a selected relatively small distance. 3. In a die for shaving a surface layer off of a metal in FIG. 4, is rigidly mounted in a suitable wire, rod or bar drawing machine and the part to be shaved, as cylin drical rod CR is drawn through the die with the axis of the rod in coincidence with the axis of the die. The relationship the radius should have to the hardness of the copper above described may be ampli?ed by con bar, a cutting edge on the die conforming generally to the transverse peripheral shape of the said metal bar that is to be shaved by moving said metal bar perpendicularly toward the cutting edge of the die, said cutting edge being shaped at the front thereof to a curvature determined by sideriug for soft copper, substantially unworked copper, 35 a circle Whose center lies less than .0302 of an inch from the cutting edge and the radius of the center of the circle determining the curvature lies substantially in the inter Vickers Hardness Number__ 40 Radius “0302:1323 For hard copper, Vickers Hardness Number__ 120 z 6000 Radius section line of the shaved surface of the metal being 40 shaved and a plane perpendicular to the shaved surface — .020 of the metal being shaved, said die having an increasing clearance from the cutting edge toward the rear between the die and the material being shaved that increases from no less than .025 of an inch to no more than .032 of an Thus, it can be stated that, so long as the ratio of the Vickers hardness number to the shaving die radius is 45 inch per inch distance from the cutting edge toward the rear. within the numerical range of 1323 to 6000 successful shaving results are achieved. 4. In a die for shaving a surface layer off of a metal Since :the radius is rather small and the insert AC is of bar, a cutting edge on the die conforming generally to extremely hard and tough material the radius is formed the transverse shape of the said metal bar that is to be by the use of diamond dust and a suitable lapping shaved by moving said metal bar perpendicularly toward technique. the cutting edge of the die, said die being shaped at the The technique hereinabove described is not limited to the simple shape shown in FIG. 4, nor is the procedure con?ned to basic copper. A variety of metals as alumi front of the cutting edge to a curvature determined by a circle whose center lies less than .0302 of an inch from In practice bars, as rods and wires circular in transverse section need shaving most frequently. Also often bars having a transverse section that is either square, oval, or rectangular need to be shaved. The invention is, of course, 60 shaved and a plane perpendicular to the shaved surface of the metal being shaved, said die having an increasing clearance from the cutting edge toward the rear between the die and the material being shaved that increases per the cutting edge and the radius of the center of the circle num, nickel, etc., and their alloys could be processed in 55 determining the curvature lies substantially in the inter section line of the shaved surface of the metal being the manner herein disclosed. not limited to a bar having a particular transverse section. The die properly shaped at the cutting edge and the proper clearance of the rear of the cutting edge, lends itself to inch distance toward the rear from the cutting edge no less than a distance of .025 of an inch. 5. An annular die for shaving a surface layer off of a metal rod, said die having a front circular cutting edge the shaving of one or more surfaces of bars that have any one of the following transverse cross sections: 65 of a selected radial dimension with the inner surface being that of a frustum of a cone with the portion with the ‘C-shaped, D-shaped, H-shaped, T-shaped, etc. Extruded shapes where ?nish and dimension tolerance is not su?iciently exacting are ideal applications for direct larger diameter ?aring outwardly by a relatively small angle, as from a fraction of a degree to no more than a very few degrees, and the cutting edge in any longitudinal subsequent shaving procedure. Soft coppers may, with the die herein disclosed, be shaped to precision tolerance 70 sectional plane including the axis of the frustum of the and provided with excellent surface finish without hot cone has a curvature at the front away from the cutting rolling, cold rolling and subsequent draw-anneal proce that is determined by a radius no greater than .0302 of an inch and Whose center, or rear end, falls at‘ a point away from the axis of the cone a distance equal to the dures. ’ All these suggested dies and alternate procedures fall within the scope of this invention. radius of the circular cutting edge. 3,058,197 5 6. A shaving die for shaving a surface layer of a selected thickness 011° of the surface of a bar of metal, said die having a cutting edge which at its front curves away from the metal being shaved on a radius parallel to the shaved metal surface and whose length may be 5 selectively varied from .020 of an inch for relatively hard 6 References Cited in the ?le of this patent UNITED STATES PATENTS 2,392,481 Kaplan et a1 ____________ __ Jan. 8, 1946 2,679,680 Hanks _______________ __ June 1, 1954 505,442 Great Britain _________ __ May 10, 1939 FOREIGN PATENTS and well cold worked metal to .0302 of an inch for sub stantially unworked metal, said die having a clearance between the die and the shaved metal that may be selec tively varied from .025 of an inch to .032 of an inch per 10 inch distance toward the rear from the cutting edge. OTHER REFERENCES American Machinist, pages 190-494, March 12, 1956.