Having addressed the measurement challenge, the next logical automation step is to dispense with operator handling of the microscope entirely, by acquiring a tester with an integrated one. The automatic microscope described in my previous post is available as a built-in feature on several hardness testing machines. In these configurations, the heavy-duty indenter holder pivots away from its normal line of thrust at the end of the indentation cycle, allowing an internally mounted camera to view the indentation directly. The advantages are considerable: no separate apparatus in the vicinity of the test machine, significantly reduced handling time, and therefore much faster testing overall. Results are displayed next to the control panel and can be uploaded to company quality systems immediately.
A further option is to replace the traditional hand-cranked anvil capstan with a tester featuring a fixed anvil and movable test head. In this arrangement, the operator is no longer required to manually raise and lower the anvil to accommodate variations in sample size. Instead, the test head automatically takes up the space and clamps the test piece securely in position throughout the test cycle.
The fourth — and most dramatic — step is the incorporation of a custom-designed hardness tester directly into the production line. Large billets and forgings simply cannot be lifted into the jaws of a bench-top or floor-standing Brinell tester, so accurate testing of such items demands something altogether larger. The second image shows one such machine, now operating in Texas — the entire gantry moves on one axis of travel while the test head moves perpendicular to that and vertically, providing full x, y, z movement. Large samples are manoeuvred on and off by crane. The test head assembly incorporates the automatic microscope; results are displayed on a screen beside the control panel and can be uploaded to factory quality systems. The head assembly can also incorporate a milling tool for surface preparation.
With any significant capital purchase, a cost-benefit analysis is worthwhile. If a substantial volume of business with a customer is at risk because hardness measurements are being disputed too frequently, the decision to invest in an automatic microscope is not a difficult one. If staff are working overtime because mandatory hardness testing is adding unacceptable time to production schedules, a heavy-duty production machine with automatic microscope, movable test head, and sample clamp will pay for itself readily. As a practical illustration: one such machine runs almost continuously, testing every link of every track used by the tanks and other tracked vehicles of the British Army.
Whatever the scale of the operation or the nature of the application, every automation option in Brinell testing increases accuracy and saves time.
