Holding a metallographic sample both steady and level during hardness testing is essential to ensure accurate and repeatable results. To make this mount both convenient to use, versatile and effective can be a challenge. An innovative fixturing method was developed by Buehler’s Wilson Hardness Testing Group over 10 years ago. This fixture is not widely known, but deserves a spot why it is considered an innovation.
Many are familiar with the Universal Mount Fixture, which is typically used to fixture a metallurgical mount for hardness testing. This fixture has a conical-point threaded post that adjust upwards to push the mount up against the top tabs. The top tabs adjust with a hex-key wrench to accommodate various mount diameters. For all testers with a stage, the fixture is fastened to the stage with four mounting screws to avoid slippage or movement. If slippage or movement occurs during testing, then indents may not remain at the same place or will require replacement for measurement. Once the fixture is fastened to the stage, due to limited space, it can be difficult to load or unload the mount into the fixture as well as being difficult to adjust the mount orientation. The typical process may take a couple of minutes when loading and unloading the same diameter specimen, and longer when adjusting to accommodate different diameter mounts. Also, care must be taken to align top tabs along the Y-axis to avoid turret rotation or indent collision.
The EZ Clamp accommodates different mount diameters with different top plates. For high volume work, most users would have a fixture dedicated to each mount size. With the EZ Clamp fixture design, a pair of neodymium magnets are permanently mounted to the stage, such that the EZ Clamp fixture can be placed and firmly held in one quick movement. There’s no further need to use fasteners, only sliding the EZ Clamp to and from the magnets. This allows the loading and unloading of the mounted specimen away from stage and avoids the restriction of working in a tight space. Since design has no protrusion (tabs) above the top mounting plate, turret or indenter collision will not come into play. In addition, this round fixture may be easily rotated to a preferred orientation making indent placement quicker and easier. The typical process takes approximately 15 seconds to load a mounted specimen and align to the desired orientation.