On the Right Frequency
- August 3, 2021
Why RFID tagging of toolholders is a very smart idea
Radio-frequency identification (RFID) has been around a long time. The British first used it during World War II to identify friendly aircraft. The Soviet Union used it shortly after that to spy on a U.S. ambassador. Research into the technology continued over the next two decades, and in 1973, inventor Mario Cardullo was awarded the first patent for his read-write RFID tag. Additional patents were issued ten years later to Charles Walton.
Decades of development
Today RFID is used for everything from hotel key cards (one of Walton’s inventions) to pet identification chips, toll road tracking, theft-proof poker chips, and checkout-free retail shopping. And yes, it’s used in machine tool toolholders, as indicated in this article’s title. One of the leaders in this area is Kentucky-based Balluff Inc., which according to technical sales specialist Wolfgang Kratzenberg, has provided RFID systems to manufacturers and distributors for more than 30 years.
“The BIS C low-frequency RFID system has been a flagship product of ours for decades,” he says. “It’s used for tool identification in CNC machining applications as well as conveyors and pallet transport systems. As demand increased and RFID became more widely used in the manufacturing process, we developed our BIS M, which has a longer range and larger data capacity. Both, however, can be placed directly on or within a toolholder, and are an excellent way to transfer data from a presetter to the machine tool, and from there to an external software system.”
If your shop doesn’t have an offline presetting system, you might be tempted to skip to the next article. Probably not a good idea. Kratzenberg and many other industry experts will tell you that presetters not only reduce setup times significantly but virtually eliminate the data entry errors that can lead to expensive crashes. And when used in conjunction with an RFID system, they further foolproof the machine setup process while closing the loop on tool life data. Add it all up, and the decision to implement RFID tagging is an easy one to make.
More is better...or is it?
Making that decision doesn’t come without its challenges, however. As Kratzenberg explained, Balluff’s BIS M system boasts a much larger memory—sixteen times larger, to be exact—than the original BIS C system that remains quite popular today. So which one is right for your shop? Where the latter’s 8 kb storage capacity might seem pathetically small by today’s gigabyte and terabyte standards, it is more than sufficient to store a unique tool number which, depending on the implementation strategy, is often all that’s needed.
“Which system to go with comes down in large part to a philosophy of centralized or decentralized storage,” he says. “If the shop plans on keeping all of its tool-related data in a tool management system (TMS) that is more than likely sitting on a server somewhere, and the presetter and machine tools can communicate with that system, then all that’s needed is to read the tool identifier. The software supplies the tool’s dimensional data, elapsed tool life, procurement information, and whatever else the shop wants to manage. But if a TMS is unavailable, then a decentralized approach should be considered, since this stores everything related to that tool locally on the RFID tag.”
Rob Caron, president of Caron Engineering Inc. in Wells, Maine, can play it both ways, although he’s probably more inclined to agree with the “bigger is better” crowd. “The centralized storage approach is becoming less popular,” he says. “That’s because even the most robust network or database server can go down, and all of a sudden, you can’t load tools in the machine. Storing all of the relevant tool data in the RFID chip is a much more robust solution.”
Caron is quick to point out that a decentralized tool data approach such as this does not prevent using a tool management system. Using MTConnect and other protocols, tooling information can be sent in real-time to the presetting system, a server, the cloud, or wherever it’s needed. It can also be shared with Caron Engineering’s TMAC (Tool Monitoring Adaptive Control), a real-time tool wear and breakage detection system that is said to make “automatic and instantaneous corrective adjustments during cutting without the need for human intervention.”
Data storage and software systems aside, Caron is a big fan of RFID. “By going to an offline presetting system and using RFID to bring the data into the machine control, you save a significant amount of time and have far greater visibility besides,” he says. “But more importantly, you eliminate the chance that an operator misses an offset or puts the tool in the wrong pocket. Avoiding even a single crashed spindle can easily recoup the investment in an RFID system.”
Caron lists off several, less obvious benefits. Thanks to some clever behind-the-scenes macro programming, an RFID tag can alert the machine to a “heavy” tool and tell it to reduce the tool changer speed. Similarly, an oversized tool can be directed to a magazine location with open pockets on either side. Depending on the machine tool, he and his team have even made the tool setup and loading process both automatic and random—all the operator has to do is stick the tool into the spindle or an open pocket and push start.
“The RFID tags are just the start of the solution,” he says. “That’s why we developed our ToolConnect system, to address these and other needs. There are many different machine types, brands, and controls out there. Our tools and products are retrofittable to any of these and can be adapted to whatever RFID format the customer is using. Obviously, some machine tool builders offer RFID capabilities, but these only work with that specific equipment brand. With ToolConnect, we can walk into any shop and help them implement RFID in the most productive manner possible, no matter what they’re making.” SMT