Metalcasters that maintain machining operations — and those thinking about adding or expanding machining capabilities — must recognize that productivity is just as important in those types of operations as it is in a core shop, melt deck, grinding operation, and so forth. Product quality and dimensional accuracy make the machined castings saleable — but “uptime” is always the critical measurement of machine shop productivity. For dedicated machine shops, in recent years that productivity factor has been dependent on improvements that amount to a very few minutes or even seconds.
In high-volume shops operating with long runs of parts, the time involved in making tool changes can add up to hundreds of thousands of dollars annually.
One of the milestones in improving machining uptime happened in the 1990s when Sandvik Coromant — one of the world’s top developers of tools for metal cutting, drilling, milling, turning, and machining — introduced the Coromant Capto® quick-change system. That ISO-certified, integrated and modular tool face method resulted in productivity increases up to a 25% thanks to reductions in tooling change-over times.
Now, more modern tooling designs are taking those gains and reducing change time even further, from minutes down to seconds.
“One of the major factors behind our decision to incorporate the quick-change system is our goal of improving set-up time,” explained Jimmy Lytle, president of Daystar Machining Technologies Inc., a North Carolina job shop with CNC turning and milling capabilities. Daystar focuses on precision machining and fabrication, with quick turnaround for short-run, prototype, and specialty-part production. “Now, our set-up time has been reduced from minutes to seconds,” Lytle said.
Making Quick-Change Faster
In addition to changing tools faster, improving tooling life is a priority for production machine shops (i.e, operations dedicated to supporting a larger manufacturing enterprise.) Not only is the saving of set-up and change-over time increasingly valuable to them, so too are the flexibility and stability of the quick-change system, and the potential for reduced capital investments in tooling.
One noteworthy development is the introduction recently of Benz Solidfix, a versatile, modular quick-change collet system that allows machine operators to perform set-ups and change-overs in speeds of 15 seconds or less.
Daystar recently installed the system on two new lathes, live tooling Y-axis machines.
“We have quick-change adapters on all the live tooling for those lathes,” Lytle said. “We can set the adapters out on the work bench and get everything ready for a set-up. Then we are in and out of the machine very quickly.”
The adapters to which Lytle refers are a central advantage of the Benz Solidfix quick-change system. Adapters are attached to individual tools and are quickly and easily inserted into a head via a bayonet-type mount that is then secured by using an Allen wrench to simply turn a single nut. Various popular soft tools, such as live turrets, angle heads and static tools, can be interchanged with different size adapters. The system will fit older machining equipment as well as newer models.
Developed and manufactured by Benz Inc., a specialty tooling system developer for turning and milling machines, this modular quick-change system saves production machine shops and job shops like Daystar several for each set-up. It also reduces their investment in tooling.
When a machine shop finishes a run using its conventional tooling set-up, the driven tools have to be removed in order to clean the collet – a relatively cumbersome task requiring the use of two hands and multiple tools. Then, the new tooling must be installed and offset measurements must be made. All this can easily take two or three minutes.
Using the Benz Solidfix system, operators don’t have to remove the main tooling unit itself; they simply change the adapter, which holds the pre-measured tool. This also means that the machine shop doesn’t have to buy as many live tools, which are expensive by themselves. All they have to do is buy quick-change adapters.
“We are able to switch from a collet chuck to a shell mill adapter to a solid end-mill holder without having to change to a different live tool holder for every application,” Lytle explained. “Using this quick-change system, we have one somewhat expensive tool holder and everything else is fairly inexpensive, which gives us a great deal of versatility without a major capital investment.”
Large and small shops are able to use the Solidfix system to reduce the number of live tools or angle heads as the spindles can be changed from ER collet to mill arbor adapter, weldon or whistle-notch adapter, shrink fit, and various special tooling types.
In developing its new modular system, Benz simplified the original quick-change technology. Instead of requiring operators to spin on and tighten tooling in the holder using a wrench, this system requires them only to turn an Allen wrench.
Also, in a standard quick-change system the operator has to remove the tool, install a new tool, and then to touch-off their tool to ensure the offset is correct. With the Benz Solidfix, they can preset tools on a granite surface plate. When their tool starts wearing or another type is required, they simply insert and secure the new tool.
“Essentially, they’re putting the whole tool aggregate back in, and the repeatability is so accurate they can program in what they just measured off their height gauge so they don’t have to go through that scenario of touching-off the tool, and then programming the offset,” explained Mike Starnes, Benz sales application engineer. “So, it is really a plug-and-play system. Operators just switch out the soft tooling, and they’re all set.”
When operators try to work quickly on a traditional set-up, they can be exposed to injury,” according to Starnes. “Normally, the cutting tool they are removing is very sharp. Even if it’s too dull to machine a part accurately, it’s still very sharp to the human touch. If the operator gets cut while handling one of those tools, the wound could be deep enough to require stitches.
“So, even experienced operators have to be very careful when handling cutting tools. When mishaps occur, they have to go a nursing station to have the wound cleaned up. In more serious cases, they may have to go offsite to a doctor or even the hospital. Of course when those injuries occur, even more production time may be lost.”
Starnes added that the Benz Solidfix system simplifies operators’ task significantly, in most cases allowing them to perform using one hand. Because of the ease of mounting and securing the adapter and tooling, exposure to potential injuries – and more lost productivity — is reduced, too.