Do you remember when the only thing a cell phone did was make telephone calls and you had to dial them yourself? Today of course that “phone” is actually a pocket-sized computer with gigabytes of memory and enough processing power to recognize your voice commands, play your favorite movies in HD, and do your banking, all while keeping you in constant touch with the world.
While all that was happening in the world of communications, a similar explosion of technology was taking place in the world of metrology, particularly handheld metrology. Today’s handheld gages bear as much resemblance to their “dumb” predecessors as a vintage “bag-phone” does to the latest smart phone, and for many of the same reasons.
A Bit of History
The immediate predecessors to today’s “smart” handheld gages were the early wired handhelds that came on the scene a couple decades ago. These delivered the accuracy and flexibility of electronic gaging technology in a package that was rugged enough to withstand the rigors of the production environment in the hands of a human operator.
They were, in many ways, analogous to the last generation of wired telephones, excellent devices that ultimately were hampered by the fact that they were permanently tethered to a cable. In the manufacturing environment, though, cables and metalworking processes simply do not play well together. Still, it was the best solution contemporary technology could offer.
Then, along came cordless phones and a bit later the first generation of wireless handheld gages using similar technology. They shared some common traits including communication speed and short battery life. However, they were very convenient and cut the cable tether once and for all.
That’s when things really started to change.
Where We Are Today
The industry is well into the second generation of handheld smart gages built around reliable Bluetooth 4.0 smart-low-energy-consumption communication; inductive charging of light, power-dense batteries; and computer assisted inspection processes known as “guided sequence” technology. The cumulative impact of those three technologies has driven a real revolution in the capabilities and applications of handheld gages.
Physically, a modern wireless gage is smaller, lighter and has better ergonomics than its first generation predecessor.
It is environmentally sealed to IP67 standards with magnetic buttons and a seamless plastic shell so it can live comfortably with coolants, oils and other contaminants found in a machining environment.
It has an integrated display that allows both the gage and the remote gaging computer to communicate with the operator before, during and after the gaging operation.
It has enough internal processing power and memory to operate effectively inside a machine tool enclosure that temporarily interrupts wireless communication, and store and deliver the measurement information when communication is restored.
It has an internal accelerometer that turns it on when it’s moved to extend battery life and an automatic circuit to optimize inductive battery charging when it’s in the cradle waiting to be used.
It’s available in either a fixed “direct head mounting” configuration with a dedicated nosepiece, or a “star lock mounting” configuration with interchangeable nosepieces to meet user preferences for one system or the other.
It is equally suited for measuring both inside and outside diameters.
Finally, it is supported by very sophisticated software, both internally and on the remote gaging computer, that collects and interprets the data generated by the gage.
How It Works In Practice
Like everything else in modern manufacturing, development of wireless handheld gages has been driven by the need for continuous improvement in process efficiency and product quality. In particular, manufacturers want to minimize the amount of skill and training required for operators while simultaneously reducing the human errors they inevitably introduce.
Wireless gages immediately eliminate the problems associated with wires and cables, which minimizes maintenance and cable-related production “accidents.” More importantly, however, they also help eliminate human errors.
In a typical application, several handheld gages will be housed on a “gage table” or some similar arrangement. Using a software-controlled “guided sequence” ensures that the measurements are made and made accurately. The software will “turn on” the display of the appropriate gage for the required measurement and then guide the operator through the process using prompts on the built-in display. When that measurement is complete, the software will “turn on” the next gage to indicate the next operation to be performed, and does so sequentially until the inspection is completed.
In this way, an in-process inspection of multiple features on a complex product like an engine block or cylinder head can be accomplished efficiently with a high degree of reliability, even by a relatively unskilled operator. Moreover, that operator can be effective with only a minimal amount of training.
Even on a complex machine with automatic gaging, there are frequently features that cannot be reached mechanically, but can be accessed by a human operator with a handheld gage.
All of those considerations directly impact quality, but in practice wireless gages also are a lower cost solution than wired gages. Direct comparisons in applications where wireless gages have replaced wired gages clearly show that the reduction in maintenance and related downtime over the life of the application more than compensates for the slightly higher initial cost of the wireless solution.
Remember, cables and metalworking processes simply do not play well together. They never have and they never will.
Where Do We Go From Here
To be perfectly honest, the mechanical, electrical and electronic aspects of today’s wireless gages are not likely to see any real “game changing” breakthroughs in the next few years. There will, of course, be incremental improvements, but the technology almost certainly will remain recognizable well into the future.
What will change, however, is the power of the software that underlies the performance of today’s wireless gages. Today we have driver libraries to integrate wireless handheld gages into virtually any process using common CNC or PLC controllers. We also can implement SPC directly through the gaging computer or supply the necessary data to another system.
Tomorrow the range of possibilities is virtually endless. Perhaps, for example, the software could detect and learn the idiosyncratic characteristics that make one operator more effective than another and then duplicate them to make every operator a “master” of the process.
If that sounds farfetched, just think back to the first time you saw someone talking on a “bag phone” and consider how you would have reacted to that person describing the capabilities of the smart phone in your pocket today. Yes, that’s where wireless handheld gaging technology is going, and it’s happening right before our eyes.