IMS with vacuum chamber removed

The IMS preceded the HSX machine. IMS was designed and built at PSL for the Electrical and Computer Engineering Department of the College of Engineering, University of Wisconsin-Madison. For a description of the importance of research and training performed on machines like this, see David Anderson's summary.

IMS Chamber

The vacuum chamber of IMS is 1.2 meters (47 inches) in diameter, and of much simpler geometry than that of HSX, because of the placement of the coils and their holders in vacuum.

IMS Coils

The coils were designed to be placed in vacuum, and cooled by their holders. Each coil consists of 4 turns, and includes features for accurate mounting, and installation of current feed pins. The coil shape approximates a sine wave wrapped around a doughnut (in the short direction). Twenty one coils of two different types made a complete set. The tolerances of ± 0.25mm (0.010) inch on coil profile required a construction method different from the usual winding approach. Special tooling was built to aid in the construction of the coils. The coils were cut from a solid piece of aluminum by drilling reference points into the blanks, machining toroidal (doughnut shaped) surfaces and holes for electrical connections, then electrical discharge machining (wire EDM) to separate the turns. The coils were hard coated and then shimmed with insulating plastic.

The IMS was constructed prior to PSL's acquisition of CNC machine tools. The toroidal surfaces were machined on a large lathe by building hard tooling to support and swing the workpiece in an arc while the headstock spun a boring bar. A DEC minicomputer with custom programs controlled the EDM process by driving stepper motors on a custom built toroidal EDM setup. Time lapse photos were taken with still cameras over the 40-hour EDM process for each coil to produce a movie of the process.

Compare the toroidal blank to the uncoated coil along with all the drop pieces. Click any image to go to a larger image. Each coil is about 20.5cm (8.1 inches) minor outside diameter.