US2332003A - Process of engraving - Google Patents

Description

Patented Oct. 19, 1943 UNITED STATES PATENT GFFICE PROCESS F ENGRAVING Francis H. M. New, Taylors, S. C.

Application June 28, 1941, Serial No. 90,199

3 Claims.

This invention relates to the art of printing and has more particular reference to improvements in processes and methods of etching, engraving, or otherwise removing materials from selected portions of an object, printing cylinder or the like, either by means of chemical or electro-chemical means. Y

It is an object of this invention to provide a simplified, economical process for removing material from an object with the use of an electroplated protective coating on said object, in place of using lacquers or asphaltum or other paints as have been used generally in the past for chemical and electro-chemical etching resists.

Another object of this invention is to supply a means of quickly polishing, plating, scriblng or otherwise marking through the electroplate on the surface of an article, etching and thereby removing material from the scribed, or otherwise marked through, electroplate, and using the object without further treatment.

It is a further object of this invention to provide an acid proof coating for any metallic or metallic covered article upon which it is desired to engrave or shape by etching, said coating oeing of electroplated metal and an effective acid or alkali resist even though the heat of etching may rise to a much higher temperature and result in greater rapidity of the etching but without breaking through as was the case with the old methods of using paints and varnishes for acid resists which lifted or melted at comparatively low temperatures.

A further object of this invention is to provide a process whereby engraving for intaglio or surface printing may be done and the finished surface have a protective coating of electroplated wear or chemical resisting metal and at the same time avoid having the edges of the engraving rounded or damaged in preparation for plating as was the case with old methods.

A further object of this invention is to provide a means of chromium plating copper printing rollers for intaglio or surface printing before the engraving is accomplished in order to avoid numerous ne holes which so often occurred in the unengraved portions where old type acid resists were applied before etching, and to avoid low places near to and bordering upon the edges of engraved portions by reason of abrasive actions of cleaners used in preparing the rollers for chromium plating as was formerly done after the engraving operation.

A further object of this invention is to provide means for producing an ornamental two-tone defil ' electroplated chromium or other metal on the well polished surface of the printing roller or object before the engraving is done, then cut or drill through the thin chromium or other electroplated coating with any suitable tool, and etch to the desired depth the bare base metal with any suitable chemical or electrochemical action which will leave the electroplated metal unaltered on unattacked portions as a protective coating* for the surface of the engraved object.

Another object of this invention is to preclude the possibility of vrough points or projections forming at the edges of the engravings which is the usual result when electroplating is done after the engraving of the article.

The process of this invention is described as used in the preparation of engraved copper rollers for use in printing but I do not wish to be limited to this particular use or embodiment of the process since many of the advantages of the process will be apparent particularly in its use in the graphic arts such as in fiat plate and roller preparation for use in stamping or printing upon paper, textiles, rubber, plastics, metals, leather, wood, celluloid, stone, earthenware, and resinous substance.

It is also apparent that where multitudinous copies are to be stamped, printed, embossed. pressed, or otherwise formed by means of a substantially irregular surface, an electroplated surface for first contacting the material to be stamped upon, printed, embossed or pressed would be of tremendous value in such operations since in using chromium metal for coating such surfaces much wear and abrasion of the object doing the forming or printing would be prevented. This invention provides a process for accomplishing this desired result.

In order that the advantages of the process of this invention may be more fully understood the preparation and engraving of a copper printing roller as used in printing textiles will be described as it was done by the old method.

The roller is first turned off in a turning lathe, then it is revolved on a. mandrel of a polishing .lathe in a trough of water where a polisher passes a coarse stone from one of its ends to the other by hand in a continuous swinging motion until he has thus removed all of the turning tool marks or ridges. Then a iiner stone scratches to and fro over the roller until all of the coarser stone scratches have been cut away. Next a still finer stone is used to finish the surface to the desired smoothness.

After the polishing is nished the roller is carefully dried off, the trough of water having been lowered out of the way, and an acid resisting asphaltum varnish is evenly spread over the revolving roller by means of ak composition topper which is a printers inking roller mounted to revolve in a frame that is manipulated by hand while the topping roller revolves in contact with the polished roller. The varnished or topped roller is then baked or heated for a period of approximately three or four minutes at a temperature of' about 200 F., which operation causes the ne particles of varnish to all unite to form a smooth coating. The roller is next cooled to room temperature.

'I'he design to be engraved on the topped roller is then cut by means of diamond points through the topping of varnish. After the design has been scratched or cut'through the acid resisting coating the roller is placed on a mandrel and revolved in a trough of acid, usually either nitric acid or perchloride of iron solutipn is used until the exposed lines of the copper have been etched to the desired depth.

The roller is then heated, placed in a trough of kerosene or other solvent and scrubbed with a brush until the varnish has been all removed after which it is cooled with water to the room temperature.

After the etching operation the roller is proofed, that is, an impression is made to see that the pattern is correct and any corrections are made by hand. Y

The roller is then placed again on a polishing lathe where fine scratches and any damages are repaired or removed by further polishing, the roller dried and polished by use of a solvent fluid and a buillng compound rubbed on a rag which is passed under pressure by hand from end to end of the roller until the desired finish is obtained. Washing with solvent and drying is the next operation which may be further supplemented by chemical or electro-chemical cleaning after which the roller is electroplated with chromium metal and is then ready for use.

In preparing the roller surface for topping with the asphaltum varnish it was formerly maintained by those engaged in the art that a tooth or grain, consisting of a form of roughness of very fine parallel scratches on the surface had to be left in order that the varnish remain firmly and securely anchored to and not chip or peel or crack from the roller in the cutting, scratching or punching of the design through the varnish. With the use of the process of this disclosure I have provided a means permitting the polishing to a mirror-like finish of the surface before it is engraved, thus eliminating the possibility of any damaging of the engraving resulting by a second polishing operation upon the etched roller as was formerly necessary for preventing the fine scratches of toothedsurface from retaining color and printing in on undesired places on the goods.

It has been found in practicing the old method and process of engraving as above described that after the roller is engraved the edges of the engraved lines are considerably rounded off by the action of the abrasive material which may be used to further improve and clean the surface and work prior to chromium plating. With the use of the process of this invention such rounded edges or areas cannot occur because all the polishing is done ona smooth unbroken surface prior to the engraving itself.

The features of this invention will be more readily understood by referring to the accompanying drawing, in which there is illustrated embodiments of this invention which will hereafter be described in greater detail.

In the drawing:

Figure 1 is an elevational view of the apparatus used to prepare the roller for engraving;

Figure 2 is a cross sectional view of the roller being cut by an electric punch or similar tool;

Figure 3 is a cross-sectional view of the roller being cut or engraved by a diamond point;

Figure 4 is another cross-sectional view of the roller shown in Figure 5, partly engraved; and

Figure 5 is a cross sectional view of a printing roller prepared and engraved in accordance with this invention.

In Figure 1 of the drawing, I0 is a roller being turned, I I is the cutting tool engaging the surface I0, I2 is the tool post for rigidly holding tool-holder I3, and tool II is in fixed relation to roller I0. 'I'he spindle I4 of the polishing head or motor (not shown) carries flange I5 and a polishing wheel I6. The periphery of said wheel may be adjusted with respect to roller III by means of adjusting screws (not shown). Also a carriage or other movable means upon which the polishing head or motor may be'mounted controls thel contact of the same with the surface of roller Il.

In one use of the invention as described herein the roller is revolved at a suitable speed and direction for turning and polishing as shown by the arrow in Figure 1. As on a turning lathe. tool bit II is engaged with and rigidly held to a predetermined cutting depth with respect to the revolving roller I0. A carriage (not shown) carrying tool post I2. holder I3, and tool II is slidable on the bed of the machine and is fed lengthwise of the roller by conventional screw mechanism for the purpose of exposing the engaged cutting tool to each andevery part of the surface area of roller III.V The carriage feed screw is driven by positive chain or gear drive by a spindle which is also supported by suitable bearing mountings on the machine bed, and also drives the roller I0. This arrangement may be that of an engine lathe.

Polishing head spindle I 4 may have two wheels, a polishing wheel I6, and a buiilng wheel of approximately the same diameter mounted thereon and rotating in unison therewith and following but separated therefrom by some space. 'Ihe polishing head assembly also is supported on and carried parallel to the roller by the same carriage which supports the tool post and tool.

Instead of polishing the printing rollers by hand the arrangement as just described may be used as an automatic or semi-automatic machine for polishing them, by the following procedure.

Roller I0, which is mounted either on a mandrel or on cones, or on bearings between a driving spindle and a tail stock, 1s revolved by the headstock spindle in the direction of the arrow. as shown in Figure 1, which shows the roller in cross section and facing toward the headstock. Tool I I is next brought up into engagement with roller I0 to the proper depth for turning the roller to the desired diameter or circumference size. The polishing wheel I6, which trails or follows the turning tool, is caused to rotate in the direction of the arrow and is next engaged with the newly turned surface of the roller I with sufficient pressure to remove all traces of the turning tool marks caused by tool Il. The buiiing wheel, which is not shown, may be slightly larger in diameter and softer than the polishing wheel, and as the same follows the polishing wheel the surface of the roller is buffed to a bright mirrorlike finish.

The roller is next cleaned of any grease or other foreign substances which might interfere in any way with the electrical deposition of a metal coating upon its surface. Such a cleaning may consist of immersion and scrubbing ina hot bath of an alkali solution of suitable strength, and rinsing the roller.

After being suitably rigged as cathode the roller is next given a smooth bright coating of chromium metal 24 in a chromium plating bath which is relatively free of impurities and dirt which might cause incomplete coverage of the base metal by the electro-deposited chromium.

When the roller I0 has been rinsed and dried after electroplating, the design or pattern is cut through the coating of chromium metal 24 by means 0f a hard sharp tool such as diamond point Il in holder i8 in Figure 3, which is suitably held by member I9 and weighted down by a weight2l, or the design may be drilled by a diamond or other hard pointed drill or a plurality of such, or by an electric punch apparatus 26, as shown in Figure 2. 'Ihe tool or tools which cut, drill, or punch the design need do no more than pentetrate through the chromium coating 24, but it is contemplated that lines or holes of varying characters may be engraved or etched by subsequent operations, as a result of variations in these cutting, punching or drilling depths into the base metal.

The surface of the roller is next exposed to the action of an etching fluid such as a solution of nitric acid and water, perchloride of iron and water or any other etching reagent which is not chemically active to chromium metal but which does attack the base metal. As the lines or areas deepen and Widenv the work is brushed with a stiff brush to keep the over-hanging chromium metal broken off for observation of the depth of the work. In Figure 4 2|) indicates points at which the etched chromium plate should be broken off in brushing. After the exposed unprotected lines, dots, or other areas are etched to the desired depth, the roller is washed free of any remaining etching reagent or broken particles of chromium metal and is ready for use in printing. The electroplated chromium metal 24 which remains on the surface of the roller is comparatively unaffected by the etching reagent and offers the same resistance to abrasion and abrading action as if the roller had been first etched and then chromium plated.

In Figure 5 roller Ill is shown with engraved line 22 produced according to the process of this invention. Edges 23 of this cut disclose the sharpness of the lines s0 produced.

It is contemplated that other metals than chromium may be electroplated on metal or metal coated articles, designs cut through said electroplated metal, and suitable reagents, which do not affect said electroplated metals, used to etch out the designs. For instance, lead may be plated on an object of iron or steel, a design cut through the electrodeposited lead, the iron or steel object exposed to the action of dilute sulphuric acid which etches away the exposed areas of the base metal and leaves the lead covered areas unaffected. Likewise, electroplated gold is an effective resist when it is used for resisting the action of nitric acid.

Thus the process may be put to use for preparing many serviceable and ornamental objects or articles.

It is also contemplated that the process of this invention be used in conjunction with other methods of resisting the action of etching fluids, as, for example, in a case where it is desired to cover a large area of or a major portion of the surface of a roller with given pattern repeats. In this case the roller could be polished and chromium plated, coated with an etching resist such as an asphaltum varnish coating. dried or baked, and the varnish etching resist penetrated by pressing through or cutting so as to expose lines or areas of the chromium plate. Such exposed lines or areas may be removed with muriatic acid or an alkali solution vand an electric current, and the base metal may then be etched out with an etching fluid, leaving the remaining plated parts of the original surface intact but coated with the acid resist which may be removed by use of a solvent.

In the preparation of signs, name plates, scroll Work, thin metal cut-outs, and other ornamental and useful articles, the chromium plated sheet or object may have a design stencilled or otherwise printed 0r painted or hand drawn on its surface with an etching resist, the unprotected areas stripped of chromium, and etched or painted a different color and the resist then removed, leaving a design in chromium plate and base metal or chromium plate and paint, or, if desired, before the resist is removed another electroplate of a different metal may be applied to the base metal where exposed and unprotected.

It is also possible in accordance with the present invention to etch articles wherein the base is formed of a synthetic resin more generally termed a plastic. In this instance the base does not conduct electricity and accordingly before the surface of the plastic base can be electroplated with a metal such as chromium it is necessary totreat the surface thereof to render it conductive. One conventional method which has been found satisfactory for the present purpose is to coat the surface of the plastic base with a binder such as cellulose dissolved in amylacetate having finely divided copper mixed therein, or copper, or bronze powder may be dusted onto the surface of the freshly coated plastic material. After the binder has dried the metallized coating is rubber or buried to give a smooth conducting coating of clean copper. Should the copper coated surface contain oxides on the particles of' copper said surface may be treated for a short time with a reducing agent such as hydrogen chloride to thereby increase its conductivity to an electrical current. The surface is then rinsed and chromium plated in a manner as described with respect to articles having a metal base. The electroplating process may include chromium alone or may consist of copper followed by chromium.

For etching the article wherein the base is of l until the exposedlines or areas are of proper depth.

Another method for etching a plastic article having a chromium surfacing or other metal surfacing consists in coating the said surface with an asphaltum or with an acid or alkali resistant varnish or paint. The design is then cut through the asphaltum or other resistant coating and the chromium metal which is thus exposed and also the plastic base material is then etched to the desired depth by a solution of chromic acid in water. One formula that has been satisfactory consists of iifty-three ounces of chromic acid per gallon of water with 0.53 ounce of sulphuric acid (H2SO4) per gallon of water. 'I'his formula gives very ne lines when used at or near room temperatures. Of course, other concentrations of chromic acid may be used to advantage and it has been found practicable to work the solution at a temperature as high as 110 F. Solutions of sodium hydroxide or other Abasic solutions may be used to etch the articles where the scratched or cut lines extend through the electroplated coating so as to expose the plastic base.

The invention is not to be limited to or by details of construction of the particular embodiment thereof illustrated by the drawing as various other forms of the device will of course be apparent to those skilled in the art without departing from the spirit of the invention or the scope of the claims.

What is claimed is:

1. The method of producing a member adapted for use in printing or like operations, which comprises the steps of providing a base, smoothing the working surface of said base, applying on the smooth surface of said base a coating of metal which is resistant to certain etching iiuids which will attack said base, removing in accordance with a predetermined design or configuration portions o'f said coating to a depth suicient to expose the underlying portions of said base, subjecting said coated base to the action of an etching fluid which will attack said base but which will not attack the metal of said coating, continuing the action of said etching fluid until said predetermined design or configuration has been etched in said member, and finally removing portions of said coating adjacent the upper edges of said etched portions which may overhang or be left substantially unsupported as a result of said etching treatment, and thereby producing said member in condition for immediate use.

2. The method of producing a member adapted for use in printing and like operations, which comprises the steps of providing a metal base, smoothing the working surface of said metal base. electroplating the smooth surface of said metal base to provide a coating of chromium thereon, cutting through said chromium coating in accordance with a predetermined design or configuration, subjectingsaid coated base to the action of an etching iluid which will attack said metal base but will not attack the chromium constituting said coating, and continuing such action until said predetermined design or coniiguration is etched in said member, and nally removing portionsof said chromium coating adjacent the upper edges of said etched 'portion which may overhang or beleft substantially unsupported as a result of said'etching treatment, and thereby producing said member'in condition for immediate use.

3. The method of producing a member having etched, ink-retaining grooves therein adapted for use in printing and like operations, which comprises the steps of providing a metal base, smoothing the working surface of said metal base, electroplating the smooth surface of said metal base to provide a coating of chromium thereon, cutting through said chromium coating in accordance with a. predetermined design or conguration, subjecting said coated base to the action of an etching fluid which will attack said metal base but will not attack the chromium constituting said coating, and continuing such action until inkretaining grooves are formed in said member, and iinally removing portions of said chromium coating adjacent the upper edges of said ink-retaining grooves which may overhang said grooves or be left substantially unsupported as a result of said etching treatment, and thereby producing said member in condition for immediate use.

CERTIFICATE 0F' CORRECTION. patent No, 2,352,005. october 19, 191g.

FRANCIS H. N. NEw. i

Int is hereby certified that error appears inthe printed specification of the above numbered patent requiring correction as follows: Page 2, first colmnn, line 67, for "in" read it; page 5, second column, line 5 7, for I 'rubber' read -rubbed; and that the said Letters Patent should be read with this correction therein that the same may coniom to the record of the case 1n the Patent office.

simd and sealed this 11th day of January, A. ,1). 19151;.

Henry Van Arsdale, (Seal) Acting Commissioner of Patents.

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