US3341329A

US3341329A - Photomechanical method for producing cutting dies

Info

Publication number: US3341329A
Application number: US311788A
Authority: US
Inventors: Trevor H Blake
Original assignee: American Can Co
Current assignee: ATLAS STEEL RULE DIE Inc
Priority date: 1963-09-26
Filing date: 1963-09-26
Publication date: 1967-09-12
Anticipated expiration: 1984-09-12

Description

Filed Sept. 26, 1963 Sept. 12, 1967 .T. H. BLAKE 3,341,329

PHOTOMECHANICAL METHOD FOR PRODUCING CUTTING DIES 2 Sheets-Sheet l INVENTOR. TREVOR H4 BLAKE ll... max/IQ;

Sept. 12, 1967 T. H. BLAKE 3,341,329 I PHOTOMECHANICAL METHOD FOR PRODUCING CUTTING DIES Filed se t. 26, 1963 2 SheetsSheet 2 INVENTOR TREVOR H. BLAKE United States Patent Jersey Filed Sept. 26, 1963, Ser. No. 311,788

8 Claims. (Cl. 96-36) This invention relates to a new and improved method for the formation of cutting, scoring and/or embossing dies, which are of particular value in the formation of paperboard carton blanks.

It has been found that the many costly and laborious hand operations necessary for producing conventional dies, which consist of a male die member made up of metal knivesmounted in wooden furniture and a female die consisting of impressions cut in a paper member, can be eliminated by the use of coacting, opposed dies formed from unitary metal plates having the working elements of the dies as an integral part thereof standing in shallow relief above the background areas of the die plates. Such dies may be formed economically by removing portions of a thin, metal plate by chemical means to form the background or depressed areas of the plate, leaving the scoring and cutting edges standing above the background areas so formed. A further disadvantage of conventional dies is the fact that since the cutting knives must be made up from many small pieces, a great number of discontinuous cuts are produced. The dies produced by my method, have the advantage that the cutting and scoring lines thereon maybe continuous.

It is of critical importance that the working edges or elements on the opposed die members be aligned precisely with respect to each other in order that the desired cutting, scoring or embossing operations will occur when the dies are used. One method for producing dies having the necessary alignment involves the use of a complete drawing for each of the die plates to be produced. However the cost of preparing such drawings having the necessary precision renders this method uneconomical. It is an object of the present invention to accomplish the manufacture of precisely aligned opposed die plates thru the use of only a single drawing of the desired cutting, embossing and/or scoring pattern.

The principles of the present invention may be best understood from the following specification and accompanying drawings, in which:

FIGURE 1 is a plan view of an example of the type of drawing used in the preparation of aligned working elements on opposed die members,

FIGURE la is a magnified view of a portion of the drawing of FIGURE 1,

FIGURE 2 represents the optical transmission of a desired image from a drawing onto a photosensitive film or plate;

FIGURE 3 represents the optical transmission of a defrom a photographic film negative onto a metal plate having a photosensitive coating, and

FIGURE 4 is a cross-sectional view of a portion of a pair of opposed coacting die plates in register, showing matched cutting and scoring working areas thereon.

My new and improved method for making dies having precisely aligned working areas involves the use of only a single drawing of a carton blank or other desired cutting, creasing or embossing pattern. This drawing will generally represent the composite working areas oneach of the opposed die plates, a desired portion of the composite drawing being separated out and imposed on a plate, the surface of which has been photosensitized by known procedures. Another portion of the composite image is separated out and imposed on a second plate to form a matchplied to metals, such modifications of which bears the imposed 3,341,329 Patented Sept. 12, 1967 ing opposed die member image. The plates subsequently are etched after removal of the photosensitive resist from those areas of the respective plate not bearing images of the cutting and scoring elements.

The die plates may be made of any of a variety of etchable metals such as magnesium, copper, steel, bronze and the like, the choice of the particular metal to be utilized in a given case being determined by the relative importance of various factors such as durability, rapidity and ease of etching, flexibility, economy and other factors. The etching medium used will depend on the particular metal which is to be etched, satisfactory etchants for each of the metals listed as well as other etchable metals being well known in the art. In general, magnesium is most often etched in a bath composition based primarily on nitric acid while copper, steel, and bronze are customarily etched with ferric chloride etchant compositions, although ammonium persulfate and other oxidizing etchants may also be used. Similarly, the die plate may be of a photopolymerizab'le plastic composition, such as photosensitized nylon or a photopolymerizable composition of a divinyl ester of a polyethylene glycol or the like. The utilization of photopolymerizable plastic materials for the preparation of the die plates for my invention involves certain modifications of the basic processes as apbeing obvious to those skilled in the art.

Referring first to FIGURE 1, a sheet of material 1, of a composition of the type described below, bears line drawing 2 of the composite working areas of the opposed die members to be produced. On this drawing the working surfaces of one of the die plates plus an amount sufficient to allow for undercutting of the resist coating by the etching solution are indicated by an indicating medium 3 (see also FIGURE 1a), while those of the opposed die member are indicated by a second indicating medium 4. Areas at which the working surfaces of the two die plates overlie each other or overlap to form areas common to the plan images of both plates are indicated by yet another indicating medium 5. Theseindicating media are selected such that

media

3 and 4 are separable from each other by theuse of color filters or the use of sets of different colored lights to illuminate sheet 1 at the time when images therefrom are imposed on a colorsensitive photographic surface, or by the use of photographic films sensitized to some wave lengths, but insensitive to others. Indicating medium 5 is such that the optical-photographic techniques used to selectively separate out

media

3 and 4 do not separate out medium 5. Thus two photographic negatives 6 may be formed, one image of the areas indicated "by media 3 and 5 (the image of medium 4 being eliminated by the use of a particular optical-photographic technique), and the second of which bears the imposed image of the areas indicated by media 4 and 5 (the image of medium 3 being eliminated by an appropriate opticalphotographic technique), Creasing lines are indicated on FIGURES 1 and 1a by the letter a, while cuttting lines are indicated by the letter 17.

In the preferred mode of carrying out the method,

media

3 and 4 are of complementary colors which easily can be separated from each other by the use of color filters. These colors are indicated in FIGURE 1 as being red and blue. However, many other combinations of complementary colors will immediately be obvious to those skilled in the art, such as .red and green, yellow and blue, and orange and purple. The media need not be colors, but one of the media could instead be a composition which fluoresces under given lighting conditions, whereas the other medium might be a particular shade of gray, which could easily be separated by lighting techniques from the fluorescing composition.

Medium is shown in FIGURE 1 to be black. However, it should be obvious that many other colors would also be suitable, particularly, in this instance, purple, which is a combination of the red and blue shown in FIG- URE 1. It will be understood from the following description that in many cases the third medium will be unnecessary since no overlapping of theworking surfaces on the line drawing 2 may be needed, for example, if only scoring is to be performed by the dies.

Drawing 1 may be prepared on any suitable material such as paper or plastic film. Since, however, a high degree of precision is necessary in the dies produced, it is desirable that the material be one having high dimensional stability. One example of an appropriate material is polyethylene terephthalate sheet. The lines of drawing 1 may be laid down accurately with ink or may be carefully laid down with colored tapes of a preselected width and color. As seen in FIGURE 2 the image of the desired portion of line drawing 2 is imposed upon photosensitive film or plate 6. The exposure is readily accomplished by the use of camera 7. It will be apparent that in order to increase the accuracy of the positioning of the working surfaces 7 on the die plates to be produced, line drawing 2 should be made on an enlarged scale and then reduced photographically. Then, for example, if the accuracy attainable in the drafting method is 10.005 inch, and the size of the image is reduced by a factor of 5, the maximum error in the photographically imposed image will be only 10.001 inch.

In the preferred embodiment of my invention, two photographic negatives, each of which bears the image of the working surfaces of one of the die plates, as described above, are produced on films 6. As shown in FIGURE 3, each negative 6 is then placed in direct contact with the surface of a metal plate 8 coated with a photosensitive resist 9. Coating 9 is then exposed to light from a light source 10 passing through the negative 6. Since the negative is transparent only at the portions corresponding to image 2, this same image is imposed on coating 9. The exposed metal sheets or plates are then developed and fixed in conventional manner and the resulting sheets, bearing a protective resist coating only in those areas corresponding to the cutting and scoring elements, are etched in a suitable etchant bath to a depth ranging from 0.005 to 0.035 inch, depending on the stock to be cut and creased. The finished opposed coacting die plates consisting of thin flexible metallic plates will then bear the cutting and scoring elements in shallow relief.

If the basic material constituting the die plate is a photopolymerized plastic such as nylon or a polyethylene glycol divinyl ester composition, for example, the image of the cutting and scoring elements is transfersed through the medium of the suitable negatives directly onto the surface of the photosensitive plastic sheet, which is then developed and hardened by conventional processes for treating the particular photopolymerizable plastic material utilized. As represented in FIGURE 4, which shows cooperating sections of finished die plates in register, the plate 20 bears paired

female scoring elements

22a and 22b in register with male scoring element 23 of plate 21. Also shown are

cutting elements

24 and 25 on

plates

20 and 21 respectively.

The height h of the male scoring element, the width w of the male scoring element, the width k of the groove in the female scoring element and the depth d of the female groove are all factors which influence the quality of the score which is formed in a paperboard sheet impressed between the dies. Also these factors are related to the particular type and caliper of the paperboard being processed. To obtain satisfactory score lines in paperboard, the height h (FIGURE 4) should range from about 0.005 inch to 0.035 inch above the die plate background, depending on the caliper of the paperboard being processed, and preferably the height h should be between 0.5 and 2 times the paperboard stock thickness. The optimum height h of the male scoring element is approximately 0.8 times the thickness of the paperboard stock. For example, the optimum height h of the male scoring element, for scoring paperboard of 0.010 inch thickness, was found to be 0.008 inch, for 0.017 inch thick paperboard about 0.015 inch and for 0.026 inch thick paperboard about 0.022 inch.

The width w of the male scoring element 23 may range from about 0.5 to 2.0 times the paperboard thickness, the optimum being about 0.8 to 1.2 times the paperboard thickness. Satisfactory results have been obtained when the width k of the groove between the paired raised por.

tions 22a and 22b of the female scoring element ranges from about 2.0 to about 4.0 times the thickness of the paperboard being processed, 2.5 to 3.5 times such thickness being optimum. This groove width k preferably equals the width w plus 1.5 to 2.5 times the paper stock thickness. The depth d of the groove between the raised portions 22a and 225 may suitably range between about 0.5 and 1.5 times the paperboard stock thickness or even slightly deeper, although greater depth presents no substantial advantage. The depth d preferably should be at least substantially equal to the height h.

The amount of vertical gap v between the plates (that is, the closest vertical distance between the working elements of the plate when the press is on impression) substantially affects the operation of the cutting elements. A further factor, closely related, is the amount of horizontal overlap g of the co -acting

cutting elements

24 and 25, one of which is integral with each of the opposed die members. Optimum cutting conditions obtain if the cutting members overlap to a small degree, which should not normally exceed about 50% of the paperboard stock thickness. If there is too much overlap the paperboard stock may merely be compressed, and not cut. Satisfactory cut lines may also be obtained if the cutting members do not overlap but rather have a gap therebetween of not more than about 20% of the paperboard stock thickness. The gap v between the cutting elements when the press is on impression may be up to about 50% of the thickness of the paperboard stock being cut. The preferred combination of horizontal and vertical relationships between cutting members for producing cleanly cut paperboard of a variety of thicknesses combines a vertical gap v of 0.003 to 0.005 inch with a horizontal overlap g of 0.002 to 0.004 inch. That is, when the press is on impression, the vertical distance v between the cutting members of the die is between 0.003 and 0.005 inch, and the overlap g of the cutting members is 0.002 and 0.004 inch, each cutting element overlapping the actual desired line of cut by 0.001 to 0.002 inch.

My invention is further illustrated by the following examples which are given for purposes of illustration only, the invention not being limited thereto. 1

Example I Steel dies are prepared for use in cutting out and scoring paperboard carton blanks. Creasing elements are provided on the opposed die plates to cooperate to crease the sheet material where it is to be folded and cutting elements are provided to cut an outline of the carton blank and provide the carton blank with the desired slits and notches. The carton blank is drawn on a sheet of polyethylene terephthalate, on a scale of five times the desired final size of the carton. The basic layout and the line width layout are made with pencil. Black ink then is applied at the portions where the working elements will overlap one another, allowance also being made for undercutting of the resist coating by the etching solution. It is known that for etching steel, and etching solution containing 20% nitric acid will undercut the coating approximately 0.010 inch per edge for an etching depth of 0.015 inch. Each of the cutting elements is toextend 0.001 inch beyond the cutting line, i.e., the cutting elements will overlap a distance of 0.002 inch, and the final width of the working surfaces is to be 0.030 inch. The overlapping areas of the working surfaces are to be represented in black. The width of the black lines 5 (FIG- URE 1a) will then be 0.002 inch overlap plus 0.020 inch to allow for the anticipated undercut for a total width of 0.022 inch. The black area will, then, overlie the lines of the pencilled drawing which are to be the cut lines in the finished carton blank, and will extend an equal distance (0.011 in.) on each side of the pencilled center line. The working surfaces of the cutting elements of one of the dies exclusive of the overlap area are indicated by red ink while the corresponding portions of the working surfaces of the cutting elements on the other die are indicated by a complementary color, blue. The distance from the center line to the edge of the working surface is 0.029 inch (0.030 inch less 0.001 inch overlap). To this dimension is added 0.010 inch to allow for undercut at the outside edge, making a total distance of 0.039 inch from the center line to the edge of the red or blue lines. Scoring surfaces having a width of 0.020 inch are formed by the use of a blue line 0.040 inch wide centered over the score line. A red line 0.040 inch wide is placed on each side of the blue line. Sufiicient clearance between the coacting elements is provided by the undercutting effect of the etching solution. All of the above dimensions are multiplied by a sizing factor of five and the drawing is inked in using the appropriate colors. The drawing is illuminated by conventional tungsten lamps. A camera is then set for size reduction by a factor of five and two exposures are made on separate photographic plates, the first with a red filter and the second with a blue filter. Two photographic negatives. are produced from the two exposures. One will contain the photographic representations of the blue and black areas, the other will record the red and black areas. Each negative after being developed in accordance with conventional procedures is then placed in contact with the surface of a steel plate coated with photosensitive resist composition. The coated steel plates are then exposed to light through the photographic negatives to impose images of the line widths, including the allowances for undercutting, onto the resist composition which becomes insoluble to the etching solution at the areas where it has been so exposed. After washing away the unexposed resist coating with water, the exposed resist portions are baked to increase their resistance to the etching solution and the steel plates are etched to a depth of 0.015 in. by treatment with 20% nitric acid solution for approximately 15 minutes.

Example 11 'Die plates are constructed from thin sheets of magnesium. Since the amount of undercutting in using the etching solution mentioned below on magnesium is negligible; no allowance for undercutting need be added to the line widths on the line drawing of the carton blank. The steps are carried out as in Example I above, and the magnesium plates are etched to a depth of 0.015 inch, using an etching solution containing 11% nitric acid, 7% diethylbenzene, 0.4 dioctyl sodium sulfosuccinate and 0.0001% gelatin, the latter additives being used to eliminate undercutting of the resist coating by the acids.

Example 111 The procedure of Example I is repeated except that the use of color filters is eliminated, and separation of the indicating media is instead achieved by making a first exposure-on a photosensitive plate which is sensitive only to the red and black colored portions of the drawing and a second exposure on a photosensitive plate which is sensitive only to the blue and black colored portions of the drawing.

The die plates of the present invention are effective in the cutting and scoring both of uncoated paperboard and paperboard coated with a variety of protective and decorative coatings, including lacquers, varnishes, polymeric materials, such as the polyolefins and various polymerized vinyl compounds and the like. The combined cutting and scoring die plates. produced by my method may be of varying thickness, depending on the particular type of press on which they are to be used and the caliper and character of the paper stock that is to be cut and scored. The minimum practical thickness of the die plates is about 0.005 inch greater than the height of the scoring and cutting elements above the etched background. Thus, for use in cutting and creasing of 0.010" paperboard, the overall die plate thickness may be as little as about 0.013 inch. For cutting and scoring of 0.017" paperboard, the overall die plate thickness may range upward from about 0.020 inch, and plate thicknesses of about 0.026 inch are satisfactory for preparation of dies for cutting and scoring of 0.026 inch thick paperboard, assuming in each case an etched depth of about 0.8 times the thickness of the paperboard being processed. Similar relationships exist for paperboard of other thicknesses. The dies produced by my method have been found to successfully cut sheet metal of thin gauge as well as paperboard.

It will be noted that the cutting and scoring dies may very much thinner and consequently more flexible than conventional cutting and scoring dies made from an assembly of individual rules and furniture block, maximum plate thickness of 0.04 inch being ample to provide cutting and scoring elements of optimum dimensions for all normal operations on even very heavy paperboard stock. In general, it is desirable from the standpoint of economy and utility to use die plates of near minimum thickness. The very thin plates of the invention are sufficiently light in weight to be adhesively secured to either fiat or cylindrical press members without the necessity of clamps or screws. A preferred operation is to clamp each of the die plates to the outer surface of a cylindrical press member.

It is often desirable also to provide holes through the plates for accurately registering the plates on the press members. This can conveniently be done by indicating the location of the holes on the drawing with an indicating means which will be imposed upon each of the photographic negative produced. The holes may then be accurately drilled at the same point on each of the plates, using the photographically-imposed marks on the plates for locating the positions thereof.

If desired, die elements may be etched directly on the surfaces of a pair of metal cylinders of the same diameter instead of on thin fiexi'bleplates.

My method can be used to produce dies which will form reverse score lines, i.e., dies which have male scoring elements on each of the die plates in registry with corresponding female elements on the other die plate. This result is unfeasible with conventional dies on which one of the die members contains all of'the working elements and the corresponding female elements are in the form of indentations on a sheet of backing paper or a grooved metal plate except by passing the sheet material through two successive different dies the first of which presses on one surface and the second presses on the other. Scoring elements for producing reverse scores can be produced by my method simply by indicating the respective male scoring elements in the form of lines centered on the desired score lines, some of such lines being laid down in one and some in the other of a selected pair of mutually separable indicating'media. On each side of these lines is then placed a line in the other medium. The image imposed on each of the die plates will then include some male and some female elements.

It is obvious from the foregoing description that the method of this invention will result in the production of cooperating die elements, the working surfaces of which are very precisely aligned with respect to each other. Since the working surfaces on each of the opposed members are produced from the same drawing, any errors which occur in the drafting of the carton blank will show up to the same extent in the working surfaces of each of the cooperating die plates and thus will not affect the registry of the plates with respect to each other.

Various other modifications of the die forming process herein described will suggest themselves to those skilled in the art, and it is not intended, therefore, that the scope of the invention be limited except as specifically set forth in the appended claims.

I claim:

1. In a method for producing a cutting and scoring die for working a sheet material along a preselected pattern of cut lines and score lines, said die comprising a pair of opposed, coacting die members, each member being all of one homogeneous piece and including as working elements on its working surface in shallow relief one of a coacting pair of cutting elements and one of a pair of coacting scoring elements, said paired cutting elements having their longitudinal axes slightly displaced on opposite sides of a desired cut line to be formed in said sheet material and said scoring elements including a male scoring element the longitudinal axis of which is centered on a desired score line to be formed in said sheet material and a female scoring element comprising two raised areas parallel to and having their longitudinal axes slightly and equally displaced on opposite sides of said desired score line, which method comprises the steps of forming a plan image of each of said cutting and scoring elements, optically transferring the plan image of a first member of each of said pairs of elements onto a first photosensitive surface and the plan image of the second member of each of said pairs of elements onto a second photosensitive surface, removing by chemical means material from said surfaces except in the regions bearing said images to produce a pair of matched opposed coacting cutting and scoring dies having said cutting and scoring elements as integral portions thereof in shallow relief above the background areas of said surfaces, the improvement which comprises:

forming a single drawing including the plan images of both members of each pair of working elements, the plan image of the working elements of the first of said pair of die members being marked on said drawing in the combination of a first indicating medium and a second indicating medium, the plan image of the working elements of the other of said pair of die members being marked on said drawing in the combination of the second indicating medium and a third indicating medium, the second indicating medium comprising an area common to the plan images of certain working elements of both die members, said common area being aligned with and substantially equivalent in length to a line of working in said sheet material to be worked and having a critical width precisely related to the displacement of the longitudinal axes of the working elements from the desired line of working and to the degree of undercutting resulting from chemical removal of material in forming said die,

said first and third indicating media being optically separable from each other and said second indicating medium being optically combinable with either of said first and third indicating media under conditions which exclude the other of said first and third media.

2. The method of claim 1 wherein said first and third indicating media are complementary colors and said exclusion is effected by passing said optical transmissions through color filters.

3. The method of claim 2 wherein said complementary colors are red and blue.

4. The method of claim 3 wherein said second indicating medium is black.

5. The method according to claim 1, including the steps of:

(a) optically transmitting the image of said first and second indicating media onto a photosensitive plate While substantially excluding the image of said third medium,

(b) optically transmitting the image of said second and third indicating media onto a second photosensitive plate while substantially excluding the image of said first medium,

(c) removing by chemical means material from said plates except in the regions bearing said imposed images to produce a pair of matched coacting die plates having the working surfaces as integral parts thereof in shallow relief above the plate background areas of said plates.

6. The method according to claim 1, including the steps of:

(a) optically transmitting the image of said first and second indicating media onto a photosensitive film while substantially excluding the image of said third indicating medium,

(b) developing said first film to produce a first photographic negative,

(c) optically transmitting the images of said second and third indicating media onto a second photosensitive film while substantially excluding the image of said first medium,

((1) developing said second photographic negative,

(e) exposing a first photosensitive metal plate to light through said first negative to impose an image on said plate,

(f) exposing a second photosensitive metal plate to light through said second negative to impose an image on said plate, 7

(g) removing by chemical means material from said plates except in the regions bearing said imposed images to produce a pair of matched coacting die plates having the working surfaces as integral parts thereof in shallow relief above the plate background areas of said plates.

7. The method of claim 1 wherein the surfaces marked with said first medium described both male scoring elements and female scoring elements at desired positions, and the surfaces marked with said third medium describe corresponding female and male scoring elements whereby one of the die plates produced will have both male and female scoring elements thereon and the coacting die plate will have the corresponding coacting female and male scoring elements thereon.

8. In a method for producing a die for forming a line of severance in a sheet material, said die comprising a pair of opposed, coacting die members, each member being all of one homogeneous piece and including on its working surface in shallow relief one of a coacting pair of cutting elements, said cutting elements having their longitudinal axes slightly displaced on opposite sides of the desired line of severance to be formed in the sheet material, which method comprises the steps of forming a plan image of each of said cutting elements, optically transferring the plan image of the first of said elements onto a first photosensitive surface and the plan image of the second of said elements onto a second photosensitive surface, removing by chemical means material from said surfaces except in the regions bearing said images to produce a pair of matched opposed coacting cutting dies having said cutting elements as integral portions thereof in shallow relief above the background areas of said surfaces, the improvement which comprises:

forming a single drawing including the plan images of both of said cutting elements, said drawing having an area common to the plan images of both cutting elements, said common area being centered on and substantially coincident in length to the desired line of severance to be formed in the sheet material and having a critical width precisely related to the displacement of the longitudinal axes of the cutting elefilm to produce a second ments from the desired line of severance and to the degree of undercutting resulting from said chemical removal of material in forming said dies, said plan image of said first cutting element being marked on said drawing in the combination of a first indicating medium and a second indicating medium, said plan image of said second cutting element being marked on said drawing in the combination of the second indicating medium and a third indicating medium, the second indicating medium comprising said common area in said drawing, said first and third indicating media being optically separable from each other and said second indicating medium being optically combinable with either of said first and third indicating media under conditions which exclude the other of said first and third media.

References Cited 5 UNITED STATES PATENTS NORMAN G. TORCHIN, Primary Examiner. J. TRAVIS BROWN, Examiner. 15 R. H. SMITH, Assistant Examiner.

Claims

1. IN A METHOD FOR PRODUCING A CUTTING AND SCORING DIE FOR WORKING A SHEET MATERIAL ALONG A PRESELECTED PATTERN OF CUT LINES AND SCORE LINES, SAID DIE COMPRISING A PAIR OF OPPOSED, COACTING DIE MEMBERS, EACH MEMBER BEING ALL OF ONE HOMOGENEOUS PIECE AND INCLUDING AS WORKING ELEMENTS ON ITS WORKING SURFACE IN SHALLOW RELIEF ONE OF A COACTING PAIR OF CUTTING ELEMENTS AND ONE OF A PAIR OF COACTING SCORING ELEMENTS, SAID PAIRED CUTTING ELEMENTS HAVING THEIR LONGITUDINAL AXES SLIGHTLY DISPLACE ON OPPOSITE SIDES OF A DESIRED CUT LINE TO BE FORMED IN SAID SHEET MATERIAL AND SAID SCORING ELEMENTS INCLUDING A MALE SCORING ELEMENT THE LONGITUDINAL AXIS OF WHICH IS CENTERED ON A DESIRED SCORE LINE TO BE FORMED IN SAID SHEET MATERIAL AND A FEMALE SCORING ELEMENT COMPRISING TWO RAISED AREAS PARALLEL TO AND HAVING THEIR LONGITUDINAL AXES SLIGHTLY AND EQUALLY DISPLACED ON OPPOSITE SIDES OF SAID DESIRED SCORE LINE, WHICH METHOD COPRISES THE STEPS OF FORMING A PLAN IMAGE OF EACH OF SAID CUTTING AND SCORING ELEMENTS, OPTICALLY TRANSSFERRING THE PLAN IMAGE OF A FIRST MEMBER OF EACH OF SAID PARIS OF ELEMENTS ONTO A FIRST PHOTOSENSITIVE SURFACE AND THE PLAN IMAGE OF THE SECOND MEMBER OF EACH OF SAID PAIRS OFELEMENTS ONO A SECOND POHOTSENSITIVE SURFACE, REMOVING BY CHEMICAL MEANS MATERIAL FROM SAID SURFACES EXCEPT IN THE REGIONS BEARING SAID IMAGES TO PRODUCE A PAIR OF MATCHED OPPOSED COACTING CUTTING AND SCORING DIES HAVING SAID CUTTING AND SCORING ELEMENTS AS INTEGRAL PORTIONS THEREOF IN SHALLOW RELIEF ABOVE THE BACKGROUND AREAS OF SAID SURFACES, THE IMPROVEMENT WHICH COMPRISES: FORMING A SINGLE DRAWING INCLUDING THE PALN IMAGES OF BOTH MEMBERS OF EACH PAIR OF WORKING ELEMENTS OF THE FIRST OF PLAN IMAGE F THE WORKING ELEMENTS OF THE FIRST OF SAID PAIR OF DIE MEMBERS BEING MARKED ON SAID DRAWING IN THE COMBINATION OF A FIRST INDICATING MEDIUM AND A SECOND INDICATING MEDIUM, THE PLAN IMAGE OF THE WORKING ELEMENTS OF THE OTHER OF SAID PAIR OF DIE MEMBERS BEING MARKED ON SAID DRAWING IN THE COMBINATION OF THE SECOND INDICATING MEDIUM AND A THIRD INDICATING MEDIUM, THE SECOND INDICATING MEDIUM COMPRISING AN AREA COMMON TO THE PLAN IMAGES OF CERTAIN WORKING ELEMENTS OF BOTH DIE MEMBERS, SAID COMMON AREA BEING ALIGNED WITH AND SUBSTANTIALLY EQUIVALENT IN LENGTH TO A LINE OF WORKING IN SAID SHEET MATERIAL TO BE WORKED AND HAVING A CRITICAL WIDTH PRECISELY RELATED TO THE DISPLACEMENT OF THE LONGITUDINAL AXES OF THE WORKING ELEMENTS FROM THE DESIRED LINE OF WORKING AND TO THE DEGREE OF UNDERCUTTING RESULTING FROM CHEMICAL REMOVL OF MATERIAL IN FORMING SAID DIE, SAID FIRST AND THIRD INDICATING MEDIA BEING OPTICALLY SEPARABLE FROM EACH OTHER AND SAID SECOND INDICATING MEDIUM BEING OPTICALY COMBINABLE WITH EITHER OF SAID FIRST AND THIRD INDICATING MEDIA UNDER CONDITIONS WHICH EXCLUDE THE OTHER OF SAID FIRST AND THIRD MEDIA.