Patent GB-980244-A (GB)
Title: Method of bonding hard abrasive particles to a support structure
IPC: B24D18/00
Filed: 1963-10-14
Abstract: A process of bonding hard abrasive particles to a supporting structure comprises applying a paint containing a pigment of an electrically conductive material on to a forming body, applying said abrasive particles to said paint while it is still tacky, electrodepositing metal over said paint and particles to grip said particles, casting a hardenable supporting material on to said electrodeposited metal, and separating said forming body from said paint.  A suitable composition of paint is: - ..by weight .Finely divided silver.60-65% .Organic resin binder, e.g. polybutyl. .methacrylate.2- 6% .Solvent, e.g. ethylene glycol monobutyl. .ether or diethylene glycol. .monobutyl ether acetate.29-38%ALSO:<PICT:0980244/C6-C7/1> <PICT:0980244/C6-C7/2> <PICT:0980244/C6-C7/3> <PICT:0980244/C6-C7/4> <PICT:0980244/C6-C7/5> A process of bonding hard abrasiv particles to a supporting structure comprises applying a paint containing a pigment of an electrically conductive material on to a forming body, applying said abrasive particles to said paint while it is still tacky, electrodepositing metal over said paint and particles to grip said particles, casting a hardenable supporting material on to said electrodeposited metal, and separting said forming body from said paint. The manufacture of a tool for dressing a grinding wheel comprises the following steps: Step 1. A metal (e.g. aluminium) blank 12 is ground by a grinding wheel 10 which has been contoured to give the desired shape of finished workpiece.  Step 2. The blank 12 is placed in a container 14 and material cast around the blank to form a body 16.  For an aluminium blank, the material may be an epoxy resin with a filler, e.g. of metal.  Step 3. The blank 12 is decomposed within the cast body 16.  For an aluminium blank and an epoxy resin cast body, the decomposition is effected by sodium hydroxide solution, e.g. of 20% strength.  Step 4. The internal surface in the body 16 exposed by the decomposition of the blank 12 is sprayed with an electrically conductive paint, those portions of the surface which are not to be coated with abrasive particles being masked by tape which is removed after the paint has dried. The paint may comprise finely divided silver, organic resin binder and a solvent.  Preferred thicknesses of paint, after drying, for various abrasive particles sizes are given. Step 5. While the paint is still tacky abrasive particles, e.g. diamond, are poured into the interior of the body 16.  The body is laid on its side and slowly rotated and the particles are pressed into the paint, e.g. by a rubber finger, so that their apices contact the internal surface in the body 16.  The surplus particles are poured out of the body, which is then shaken to remove any remaining loose particles.  Step 6. When the paint has dried, metal is electrodeposited around the abrasive particles to hold them in place. Electrolyte from a tank 30 containing filter means and a thermostatically controlled heater is circulated through the interior of the body 16 by a pump 28.  An anode 26 is placed centrally in the interior of the body 16 and contact with the conductive paint layer is made by a screw 38.  An initial current density of 3-10 amperes per sq.ft. on the cathode is increased after several hours to approximately 80 amperes per sq.ft.  The metal deposited may be nickel, copper, iron &c., the thickness of the layer being 1/32 -\ba1/4 inch.  Final deposition at high current density without special precautions develops greater metal build-up at ridges, with the development of tree-like growths radially inward from higher current density regions closer to the anode, these growths providing a desirable interlocking bond with the subsequent cast core material. Step 7. The interior of the body 16 is washed and dried and filled with material serving as an adequate support for the electrodeposited layer. The material may be a low melting point metal or an epoxy resin, e.g. the same as that used in Step. 2.  Step 8. The body 16 is removed by sawing it at a number of peripherally spaced regions and breaking off the sections with a hammer and chisel.  The paint acts as a parting agent.  Step 9. The dressing tool body 42 is drilled to receive a shaft 48.  Modifications are described.ALSO:A process of bonding hard abrasive particles to a supporting structure comprises applying a paint containing a pigment of an electrically conductive material on to a forming body, applying said abrasive particles to said paint while it is still tacky, electrodepositing metal over said paint and particles to grip said particles, casting a hardenable supporting material on to said electrodeposited metal, and separating said forming body from said paint.  As one step in the manufacture of a tool for dressing a grinding wheel the internal surface of a body is sprayed with a paint containing finely divided silver, organic resin binder and solvent.  Those portions of the surface which are not to be coated with abrasive particles are masked by tape which is removed after the paint has dried.  Preferred thicknesses of paint, after drying, for various abrasive particle sizes are given.