Electroplating upon a metallized surface
United States Patent 2018471

435,694. Electrodeposition of metal. ELECTRICAL RESEARCH PRODUCTS, Inc., 195, Broadway, New York, U.S.A.-(Assignees of Russell, A. G. ; 47, Rector Place, Red Bank, New Jersey, U.S.A.) June 18, 1935, No. 17480. Convention date, June 20, 1934. [Class 41] In the deposition of separable deposits on a metallized non- conducting surface such as a wax master sound record, metal clips are applied to the edges of the mould to prevent curling away of the deposit. In the apparatus shown, U-shaped phosphor-bronze wire clips 16 are pushed at uniform intervals round the edge over a recessed metal disc 13 supporting the metallized wax layer 10. A rubber edge shield 11 and a back shield 12 are then applied. The ends 18 of the clips are turned up to avoid tearing the wax. After deposition, the shields are removed and the clips bent up at 20 to permit removal of the deposit 14. The deposit is then centre-drilled and the edge cut off at X. Tne invention is particularly applicable in the deposition of nickel. The wax may be metallized by sputtering.

Russell, Alexander G.
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205/68, 369/272.1
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This invention relates to the art of electrodeposition and particularly to the art of depositing a metal upon a metallized non-conducting surface.

For the purpose of illustration this invention . will be described as applied to the art of electrodepositing a nickel master upon a metallized wax original of a phonograph recording.

It has been observed that when it is attempted to electrodeposit nickel directly upon the surface 1; of a wax master record which has been rendered conductive by a suitable coating such, for example, as sputtered gold or silver, the edges of the nickel deposit tend to curl away from the surface during the early stages of the deposition and this curl becomes permanent as the thickness of the coating increases. If the curl extends across a portion of the recorded matter the entire master is rendered worthless.

The direct cause of the curl appears to be a tension in the thin deposit of nickel which pulls it away from the wax surface and with it the sputtered metal or other conductive coating. The proximate cause of the curl may be various impurities which appear in the average commercial nickel-plating bath and the removal of which requires unusual care and attention.

The object of this invention is an improved article upon which nickel metal can be deposited directly without unusual care and unaccompanied by curling.

In general, this invention consists in securing metal to the edges of the non-conducting material and in contact with the bath so that as the deposit forms, it forms also upon the metal, to which it readily adheres. Since the metal is firmly secured to the edges of the non-conducting material the deposit will exhibit no tendency to curl.

The metal may be trimmed off when the electroplate is finished.

The invention may best be described with reference to the accompanying drawing in which Fig. 1 is a plan view of a wax master record ready for plating; Fig. 2 is an elevation in section of a portion of a master record plated with nickel in the usual manner; Fig. 3 is an elevation in section of a portion of a master record made and plated with nickel in accordance with this invention; and Fig. 4 is an elevation in section of a portion of a master record made and plated with nickel in accordance with a modification of this Invention.

The wax master chosen to illustrate this invention is of a composite type comprising a recessed metal disc on which is melted a thin layer of wax.

The invention, however, is not limited to this form of disc and can be applied not only to any form of wax recording but to insulators gen. erally, which are to be plated directly with a nickel metal.

Referring now to Fig. 1, 10 is a wax surface of a master record which is to be plated, I is a portion of a rubber shield used to limit the surface to be plated and 12 is the upturned edge of the remainder of the shield which covers the back of the record.

In the elevation of Fig. 2, the wax surface 10 is seen supported by a recessed metal disc 13 and plated with a substantial deposit of nickel 14 in the usual manner. The wax surface is coated, for example, by the sputtering process by which a thin layer of metal, probably of the order of a millionth of an inch in thickness, is deposited on the wax surface to render it electro-conductive.

Such a deposit has practically no resistance to 2, bending and consequently, when the nickel deposited thereon begins to curl, the deposit is drawn away from the wax surface. Such a curl is shown at 15 in Fig. 2. The curl usually extends inward across several of the grooves containing recorded matter, and consequently the nickel master so formed is not a true negative of the wax and is worthless.

In order to prevent the curl from forming, or at least, to prevent it from extending over the grooved portion of the disc, some metal must be provided for the deposit to adhere to, and the metal must be capable of resisting the bending stresses induced therein'by the nickel as it is deposited. This metal can be supplied in the form .S of spring clips 16 as shown in Fig. 3. The clips may be U-shaped, phosphor-bronze wire slipped over the edge of the wax master record and adapted to contact the electro-conductive coating on the wax surface over a portion of the uncut margin 17. The end 18 of each clip may be bent upward slightly to avoid tearing out portions of the wax as the clip is placed on the disc and to insure a sliding contact between the clip and electro-conducting coating. The clips may be spaced equidistantly around the periphery of disc 17 and preferably not more than two inches apart.

The metal can also take the form of a ring 19 (Fig. 4) embedded in the wax 10 near the periphery thereof and extending inward beyond the edge of rubber shield 1; or instead of a ring, the metal can be supplied as small arcs spaced equidistantly about the edge of the disc as in the case of the clips. The ring or arcs need not be embedded in the wax, but may be merely laid thereon and held 65 in place by shield II. Numerous other forms may suggest themselves to those skilled in the art, the only limitations to be considered being the resistance to bending required of the metal, and the proper spacing of the discontinuous forms about the edge of the record. It is desirable, however, to have the metal and disc, or other material to be plated, united to form a 'single unit for" ease of handling.

After the clips or the equivalent are properly located on the wax master record, shields II and 12 are placed over the portions of disc 13 which are not to be plated and the whole is placed in an ordinary nickel-plating bath with adequate means provided therein for agitating the bath to obtain a uniform deposit on the record. After the required thickness of nickel is deposited, the record is taken from the bath and shields II and 12 are removed from the record. The deposit will be found to be substantially flat over the entire periphery of the disc and adhering firmly to the clips. To separate the deposit from the wax, clips 16 may be bent at 20 to permit the deposit to be lifted vertically from disc 13 and such wax as may come off with the deposit is removed either by melting or with the aid of a solvent, or by a combination of both means. The deposit is then center-drilled, placed in a trimming machine and the edge, with clips 16 adhering thereto, cut off at some point X (Pig. 3) leaving a perfectly fiat nickel master suitable for further processing or for use as a die in a press to form reproducible records.

Although this invention has been described with reference to a phonograph record, it is not limited in its application thereto, but it may be used generally whenever it is desired to deposit nickel by ordinary means upon an insulator rendered conductive by a thin layer of electro-conductive material.

What is claimed is: 1. As an article of manufacture, a wax master record with a metal coated surface and clips secured to the metal coated surface and spaced about the periphery of the record.

2. As an article of manufacture, a record with a metal coated surface and U-shaped clips frictionally engaging the surface and uniformly spaced about the periphery of the record to prevent a subsequent electroplate from curling away from the coated surface. ALEXANDER G. RUSSELL.