When designing head expanders or fixtures 3D Models are produced using the complete moving system to ensure that all resonances that might be excited are investigated. At least 20 mode types are usually considered. Head expanders are available as round or square shapes, made from cast magnesium or aluminum or as weldments, depending on the required size, operating frequency and budget.
Slip tables can be supplied in monobases or in stand-alone structures for mating with any existing shaker. The slip table assembly consists of a steel moat structure, a magnesium slip plate, a precision ground granite block and (usually) a set of guidance bearings. The steel moat acts as an oil reservoir, where oil flows from the slip plate and guidance assembly. The granite slip surface is enclosed within this structure and is ground and lapped to a tool room grade B finish to provide minimum friction during vibration testing. Data Physics Corporation manufactures a variety of head expanders, fixtures, and slip tables.