Gradient Coil Sub-Assemblies

A method of manufacturing a gradient coil sub-assembly, the gradient coil sub-assembly comprising:

• a first coil layer comprising a first punched sheet metal conductive saddle coil portion having a higher incidence of burrs, left by the punching process, on one face than the opposing face,
• a second coil layer comprising a second punched sheet metal conductive saddle coil portion having a higher incidence of burrs, left by the punching process, on one face than the opposing face,
• wherein in that the first and second conductive saddle coil portions are connected electrically to one another in parallel so that the first and second conductive coil portions act together as one saddle coil, and
• a B-stage material insulation layer is sandwiched between the first and second coil layers, with the first conductive saddle coil portion bonded to a first side of the insulation layer and the second conductive saddle coil portion bonded to a second, opposite, side of the insulation layer and the respective face of each of the first and second coil portions having the higher incidence of burrs facing and bonded to the insulation layer, such that the B-stage material and burrs are located in a region of minimised electric field strength when the subassembly is used in a gradient coil assembly of an MRI machine helping minimise partial discharge,
• and the method comprising steps of:
• a) laminating the first and second conductive coil portions together by bonding the first and second conductive coil portions on opposing sides of the insulation layer;
• and
• b) electrically connecting the first conductive coil portion to the second conductive coil portion.