Accompanying article enum erates and. describes many, if not most, of the tools and equipm ent— hydraulically, pneum atically, electrically and manually operated— for machine marking of m etals and metal parts. Because the use of crayons, talc, paints, etc., is a simple and long-standing means of identification, it must not be inferred that progress in their m anufacture and use lias halted. Im proved hand-marking media of this type, layout dopes, small scribing and etching tools, steel and nonmetallic stamps, stamping dies, and inks will be discussed in STEEL next week.
By J O H N E. HYLER
P e o ria , 111.
MANY different kinds of printing presses and machines have been de
veloped for printing and marking on metal. Variety of materials to be marked and great disparity in types of sur
face-ranging from flat to globular, in all degrees— constantly are presenting new challenges to makers of such devices, and the refinements incorporated in the new machines signalize the passing of ranparably cruder and less efficient models.
One manufacturer making presses for printing many different kinds of sheet materials has provided presses especially suited for printing galvanized sheets.
Some of these machines have exception
ally large diameter cylinders (like that in Fig. 1) so that printed trademarks can be located accurately on the sheets.
For example, when marking 12-foot sheets which later will be cut up for comigated culvert stock, the trademark can be located so that, it will show at the proper location on the curved culvert surface in each case. Frequently, three trademarks are required across the sheet and lengthwise.
Other sheet-marking processes require a printer with sm all-diameter printing cylinders. These have been used quite extensively not only for marking steel, sheets, but also for aluminum, and from prime stock to scrap in each instance.
They can be used to print any one or two of seven colors or w hite in one oper
ation, and they print in lines only 2J/2- mches apart. One printing operation amplifies the task of segregating and identifying scrap. Different color
com-TTg. 1—Press used by Republic Steel Corp. for printing galvanized sheets.
Manufacturer is Schm utz Mf g. Co., Louisville, Ky., which also produces the gang printer shown in Fig. 7. Insert is a rocker-mount stam p for printing United States Steel C.orp.’s trademark on a special grade of sheets. I t is made
by Pannier Brothers Stamp Co., Pittsburgh
Fig. 2— Universal-type machine arranged for pneumatic pressure and adaptable for many different kinds of work. N ote work-holding cradle w hich permits
work to revolve yet remain centered
Fi". 3— Lithographic proof-type press for use by plants requiring large numbers
°f duplicate templates. Transfers outlines from scribed master to duplicate sheet. Photo courtesy of Chas. W agner Litho. Machinery Co., Hoboken, N. J.
F'g- 4— Pneumatically equipped machine of vertical-dial typ e suited for marking work that can be chute-fed
Fig. 5— Machine for horizontal-dial feeding of work w ith wall thickness to withstand die pressure even though unsupported internally. Hollow parts
shown are rolled between pressure dial and marking die
F'g. 6—Power-driven graduating machine for marking conical fuse rings. Pitch and size of marking die are in agreement with that portion of ring to be marked
binations are used on various alloys.
W ith the printed lines occurring only 2Vi inches apart, even a small piece of scrap is identified instantly. Thus it can be sorted and returned to the mill with all speed. One of these machines appears in Fig. 7.
Other identification also is incorporated in the printing. Block letters are used to indicate a heat-treated sheet, and italics denote annealed sheets. Special fast-drying inks are employed to prevent smearing or offsetting when the sheets are stacked; yet these marks are perm a
nent. In addition to sheet printing, special units have been developed and put into use for printing stainless steel in coils. One company making these various printing presses also has pro
duced machines for marking pipe, tub
ing, and steel shapes.
Lithographic Tem plate Printing Another very interesting aspect of printing sheet metals in a press is found in the reproduction or duplication of sheet m etal templates. These are especial
ly favored in aircraft factories where large numbers of identical units are re
quired. The unit used is a proof-press model, and is of lithographic type.
W here a considerable num ber of standard templates are w anted, they are printed from a single master.
There are two beds on the press, located at a common level. One bed supports a scribed, sheet-metal, master template. On the other bed is held a blank metal sheet, on which the scribed outline is to be duplicated. The
011 the workpiece. The arm then retracts, under continued m anual turning of thé crank, and the process repeats over and over again.
In another machine of small size, de
signed to apply ink to cylindrical work, a synthetic rubber die of rotating style is used. The workpieces in this case have a bore concentric w ith th e outer surface, and are m ounted by hand on a small mandrel for marking. As th e rotating die comes around into marking position, it engages the work on the mandrel, revolving the work in surface-synchronization with it
self, leaving the inked impression on the cylindrical surface. The ink contains just a slight am ount of etching acid (suffi
cient to etch the steel enough that the ink will remain in place, regardless of handling operations and weathering).
It feeds to the rotating die from a reservoir in the machine housing. This machine is a product of Acromark Corp., Elizabeth, N. J.
Interchangeable Type Pieces
operator applies ink to th e m aster tem plate, using a separate inking slab and a hand roller for this purpose.
The press shown in Fig. 3 incorpor
ates a traveling, motor-driven printing roll assembly. W hen actuated, the print
ing roll travels over and takes an impres
sion from the freshly-inked master, then lifts and reverses its direction to transfer the impression on to th e duplicate sheet.
The process can be repeated as many times as desired w ith a given master template. T he duplicate impression ob
tained is black, w ith the scribed lines appearing in white. Various forms of layouts can be m arked on sheet steel in this m anner at a high rate of speed, re
gardless of w hether they are templates or not.
Ink-M arking Cylindrical W ork M achines of relatively simple form can be and have been devised for fast-pro- duction ink-marking of cylindrical steel
parts. Some of these use a straight rubber die, and some use a rotating die of rubber. In either case, the cylindrical parts are revolved while the marking is done. Usually, the p art is revolved by frictional contact w ith the rubber die itself. In the case of one machine, made by Adolph Gottscho, New York, an arm of overhanging design, carrying a flat, inverted die w ith rubber type on it travels back and forth, actuated by a hand crank mechanism. At the beginning of its forw ard movement, the die travels over an inking roller. T he inking roller rides upon a fountain roller beneath, and th e latter dips into a supply of ink in the m achine housing. A fter th e inverted rubber die is carried over the inking roller, it continues forw ard to a point where it engages the top tangent of a cylindrical piece of work. By frictional action, it rolls the work on a perfectly smooth and level bed. By this means, the impression is left with perfect truth
Various kinds of composite hand and machine stamps feature interchangeable type pieces, so the same tool can be used for m aking a wide variety of differ
ent marks, as the occasion may demand.
However, the idea of using
interchange-Fig. 7— Special printer widely used on steel and aluminum can print a series of lines only 2% inches apart entirely across sheets. In addition to m aking colors avail
able for different alloys, block letters indicate heat-treated sheets and italics signify annealed sheets Fig. S— Production marking equip
m ent for impressing trademark and typ e num ber into outer races of bearings before finish grinding.
Inscription is 0.020-inch deep.
Supporting mandrels are of dis
appearing type, rising and falling during revolution of horizontal dial, so that pieces can be automatically
loaded and ejected.
Fig. 9— An im proved machine with interchangeable fixtures for mark
ing gage handles, ring dies, holders, etc. Known as Acromarker Model 7, machine's marking die wheels carry characters easily removed for substitution of special dies. Marks
in curved or straight line