Patent GB-1385473-A (GB)
Title: Bonding
IPC: C09J5/02
Filed: 1971-03-09
Abstract: 1385473 Welding by pressure P J VESEY LUC 2 March 1972 6344/71 Addition to 1224891 Heading B3R In a process for bonding two or more metal parts together the parts are held in intimate contact in the bond area and relative movement provided between the parts and a frictional tool applied to a surface in closely spaced relation to the joint surfaces parameters of the treatment being selected so as to produce a wide range of sonic and ultrasonic vibrations multidirectionally in the parts and thereby to form a join at the interface without substantial distortion of the interface. The frictional tool may be a rotating wheel, roll or cup-shaped member or even, in the case of rapidly fed thin films, a stationary foot or horn. The rotary friction wheel is usually from 4 to 10 cms. in diameter and rotates at a speed in the range 3000-50,000 r.p.m. or above and may be of hardened or alloy steel, tungsten carbide, chrome-nickel alloy, Vespel (Registered Trade Mark) or Tufnol (Registered Trade Mark). An interlayer between the tool and workpiece or lubricant may be used to prevent surface damage. Two opposed or slightly staggered frictional tools may be applied on opposite sides of the parts to be joined. Metals that may be joined include iron, steel, tin-coated steel, tin-free steel (chromechrome oxide coated steel), tin, aluminium, titanium, magnesium, silver, gold, platinum, copper, zinc, nickel and alloys thereof. The same or dissimilar metals may be bonded and the parts may be in the form of sheets, webs, foils, rods, tubes or a metallized layer on a sheet, film or fibre. Several layers may be bonded simultaneously and a layer of solder or aluminium may be bonded between two sheets, e.g. of steel. Seam or spot welds may be made and reference is made to welding a foil to a honeycomb structure. The parts to be welded are preferably held together by means which apply pressure in addition to the pressure on the parts due to the frictional tool. Thus mechanical clamps, vacuum, air pressure or magnetic means may be used. The backing material i.e. on which the parts rest during bonding may be resilient or hard, heat-conductive or insulating and may take the form of a wheel, roller or travelling band. Auxiliary excitation may be applied simultaneously with the frictional treatment; thus the frictional tool itself or a backing member may be used to apply ultrasonic vibrations at the same time as the frictional treatment. Reference is also made to the use of electric currents or fields, magnetic fields, or preheating to augment the process. It is stated that the operation of the frictional tool generates a very brief but intense rise in temperature of the parts being bonded in the region of the tool. The resultant bonds however show no sign of gross fusion of the parts. Four different embodiments of apparatus are shown: (i) Fig. 1, for producing a seam weld between overlapped sheets by relative traverse of the clamped sheets under a rotary friction wheel 5; (ii) Fig. 2 for affixing an opening device 6 to the end 8 of a drum using a cup-shaped rotary tool 4c and magnetic clamping means 7; (iii) Fig. 3 for joining two webs 10, 11 by means of a rotary drum 13 and (iv) Fig. 4 for producing a butt joint between tubular members 31, e.g. of aluminium by means of a rotary tool 37, the tubes being supported for rotation in the opposite direction to the tool 37 and being loaded axially throughout the bonding process.