Touchscreen technology, breakthrough for hardness testing

Citation

Sidaway, T. (1999), "Touchscreen technology, breakthrough for hardness testing", Aircraft Engineering and Aerospace Technology, Vol. 71 No. 2. https://doi.org/10.1108/aeat.1999.12771baf.002

Touchscreen technology, breakthrough for hardness testing

Touchscreen technology ­ breakthrough for hardness testing

Trevor Sidaway

Keywords Hardness testing, Quality control, Touchscreen

The adoption of touchscreen technology could well prove to be the most important advance in hardness testing for years.

While it may not quite match the quantum leap from mechanical dial to digital electronics, posterity will surely judge it as the breakthrough that lifted any final constraints on the direct use of hardness testing in analysis and control.

At one level, the new technology has aligned the hardness tester with the growing trend towards touchscreen integration of production and quality monitoring processes. It has freed the machine to deliver the test data needed for statistical process control, in real-time if need be.

At a second level, the touchscreen enables a machine to be operated to display and record a wealth of test, control and stored data without the added cost of ancillary software and computer power. It also makes it easier to program the machine to render information customised to the user, application, specimen, etc.

Viable technique

Although far from widespread, the technology is demonstrably viable, and Rockwell and Vickers testing machines with touchscreens have been available in standard specifications (Plate 1).

Their development stemmed from the search for an economic way of addressing (or customising) reports of hardness-test procedures and results. Ordinarily, this would entail linking a conventional testing machine to a PC with printer and appropriately dedicated software. Most users see this as an expensive and technically inelegant solution.

Plate 1 Rockwell hardness tester with a touch-sensitive graphics screen for operational, display and monitoring functions

The arrival of the touchscreen means that the vast majority of functions required can be performed by the machine itself. There is, in fact, hardly a limit to the test information that can be generated and displayed (Plate 2).

Touchscreen tactility

In these new machines, there are no pushbuttons or presskeys. All functions are selected by a transparent tactile overlay in front of a dot-matrix backlit LCD test display.

The overlay is, in effect, a pair of clear plastic membranes sandwiching an 8 × 8 matrix of 64 contact points. Light finger pressure on any contact or contacts is transmitted as a signal by conductive ink tracks to the machine's software.

The 64 contacts are redefinable. They can operate singly or in various multiples up to one contact covering the full area of the screen. All command, monitoring and memory functions are menu-selected through the screen. As well as test cycle, load, scale and results, the display can include date, time, indenter and data such as specimen details, tolerance settings, conversion to other scales, etc.

Plate 2 Vickers measurement screen, displaying hardness number, scale and diagonals together with tolerance bargraph, statistics, file handling, etc.

Further touchscreen selection produces an X and R chart and distribution histogram, together with the full range of statistical data such as standard deviation, capability indices, max/min readings, etc. Data on earlier tests can also be recalled.

Both histogram and X and R chart can be printed on demand through one of the machine's serial ports, if required.

Alphanumeric addressing

A significant advantage of the technology is that it enables parts files for specimens tested regularly to be stored in the on-board software. Up to 12 component files can be addressed by names and numbers through the touchscreen keypad with its 45 alphanumeric functions (Plate 3).

When a file is subsequently selected for testing, the software automatically presents the test parameters. This shortens set-up times and ensures that test specifications are met properly with minimum involvement by the operator, a useful safeguard against errors and mis-use.

Plate 3 The touchscreen includes an alpha-numeric keypad for addressing 12 component files by name and number

The same keypad allows the printout of the test report to be headed with details specific to the user or customer, batch number, part number, etc.

Further details from Indentec Hardness Testing Machines Limited, Lye, Stourbridge, West Midlands, UK. Tel: +44 (0) 1384 896949.