A shop makes its money when the chips are flying. For jobs that require multiple milling operations, changing tools can take time away from the cutting process. This is where multifunctional, single tools can make all the difference. Combining multiple milling operations into one tool enables a shop to purchase fewer tools, improve production efficiency by reducing cycle time, and get products to market faster, all impacting the bottom line.
Today's multifunctional tool options can combine operations such as drilling, slot milling, side milling, plunge milling, ramping, helical interpolation, and facing on a single tool. A popular option is the drill mill, which can drill, ramp, helically interpolate, slot, plunge, and shoulder mill. Another is a high-feed cutter that can often face, slot, ramp, helical interpolate, and plunge mill.
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“If a multifunctional tool proves to be the best tool for an application, it is the best tool,” said John Mitchell, general manager, Tungaloy Canada, Brantford, Ont. “Many customers have purchased multifunctional tools for one specific application, simply because it was the best tool for that application, even though they don't use many of the other functions.”
Yet Mitchell noted that having multifunctional tools in a shop's arsenal makes it much more agile and able to turn a job around quicker and for less cost than conventional tools, making more profit.
One of the most obvious benefits of a multifunctional tool is in inventory management. Replacing multiple tools with a single tool that can perform all operations is not only a smart option, but also an economically advantageous one. These tools are great for limiting inventory carrying costs.
“Many machines currently used still have a relatively small number of tool pockets (30 or less), so tools like drill mills and high-feed cutters that can perform multiple functions open up positions for dedicated tools such as taps, thread mills, finishing end mills, reamers, and more,” said Brian Wilshire, technical center manager, Kyocera Precision Tools, Hendersonville, NC “They also limit the number of tools and inserts a shop needs to keep on hand for production.”
For example, high-feed cutters with their ramping capabilities are able to helically interpolate larger-diameter holes, Wilshire explained. While these tools are not as efficient as a large-diameter drill, they eliminate the need for a number of different drills to produce various hole sizes.
“The obvious advantage to using a multifunctional tool is reduced inventory carrying costs,” said Mitchell.
He explained that there are many multifunctional tools on the market. For example, choosing a face mill that can accommodate a square insert capable of a large depth of cut with eight cutting edges or a hexagonal insert with 16 cutting edges capable of a lighter depth of cut offers greater flexibility. Using the same body, the cutter can accommodate a round insert that can perform high-feed milling or extreme cutting conditions such as flame cutting.
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“If you are a job shop, this tool is great,” said Mitchell, “given the nature of the job shop environment and not knowing what job tomorrow will bring. By having a multifunctional tool on the shelf you can simply select the insert for the job and you're up and running.”
He added that every shop should have a multifunctional face milling tool. Some face mills offer high-feed roughing, large depth-of-cut face milling, economical multi-edge inserts, and even inserts to fit the same body to machine gummy materials and reduce spindle load. Depending on the application, one tool can provide multiple options.
Reduced Cycle Time
CNC machines use tool changers, and depending on the style of tool changer, it can take anywhere from 20 to 30 seconds from cut stop to cut start to change over tools. And depending on the number of changeovers needed, this can add up. That's valuable cycle time that is wasted, and in today's manufacturing environment, every second counts.
“A multifunctional tool tool changes and machining time needed for a sequence of conventional tools it replaces,” said Cory Cetkovic, product manager, Sphinx, Big Kaiser Precision Tooling Inc., Hoffman Estates, Ill. “For example, a multifunctional chamfer drill is capable of reducing cycle time needed for a drill and chamfer mill by up to 50 per cent.”
Beyond changeover times, cycle times can be reduced with tools such as multifunctional, replaceable-head end mills. Mitchell noted that once this tool is placed into the machine, either using a mill chuck orfit adapter, the distance is fixed and setups are much quicker, since the home position position (distance from the spindle) is already shrinking.
“If your job calls for a ball-nose end mill, you simply screw one into the shank and you already know the distance from the spindle or home position,” said Mitchell. “The next time the tool is used, you may require a slotting tool. The catalog clearly shows the L dimension of the slotting tool and the home position can simply be calculated. This learning the need to use a height gauge and touch off, making setups much quicker and easier.”
Another advantage of a replaceable-head end mill is the cost. A traditional solid-carbide end mill may be 4 or 5 inches long, yet the depth of cut required may be only 0.100 in. or less, which is a waste of expensive carbide. The replaceable-tip end mill is much shorter and therefore more economical.
Combining operations in a single tool gives shops the ability to hold critical tolerances, improving dimensional control, increasing process reliability and production consistency.
“These tools have the ability to machine detailed features with tight geometric tolerances,” said Cetkovic. “Multifunctional tools often result consistently in tight geometric tolerances in production and low-volume applications.”
Cetkovic added that multifunctional tools also are designed to successfully incorporate the functionality of a sequence of tools into a single operation. Using a sequence of tools, each designed with a singular purpose, often requires a programmer to develop a machining process. Multifunctional tools reduce the possibility of in-process failure caused by a sequence of unrelated tools.
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With a multifunctional tool, the operator doesn't need to program complex information about multiple tools; rather, he or she can focus on the one tool, offering that all tolerances are met. This will help increase and speed up production, while maintaining consistent process reliability.
Opting for a multifunctional tool will depend on a number of factors. With so many options available, a shop needs to consider its priorities, whether that's limiting stock investment or reducing cycle time, and then choose a tool that fits those needs. And, in some cases, it may make more sense for a shop to choose multiple dedicated tools.
“There is generally less flexibility within a manufacturer's programs of standard multifunctional tools when compared with corresponding dedicated tool programs,” said Cetkovic. “Increased availability of dedicated tools allows consumers to make minor alterations to their machining process by changing one of many cutting tools.”
The main disadvantage is that most multifunctional tools compromise performance for versatility. This is not always the case, but it is certainly something to consider when looking at investing in this type of tool. For example, drill mills can drill and mill, but usually can't match the efficiency of a drill for drilling or an end mill for milling.
“The advantage of using a high-feed cutter is its ability to direct cutting forces into the spindle to reduce vibration and chatter and the ability to improve tool life due to better heat dissipation,” said Wilshire. “Also, high-feed cutters are excellent for high metal removal rates when milling but can't match that of a larger drill. If shorter cycle times are the goal, shops may be better off using a dedicated tool instead of a multifunctional tool.”
From an operational standpoint, multifunctional milling tools don't have any different requirements than standard tools. Proper maintenance, of everything from the insert to the retention knob, is important for optimum performance.
Associate Editor Lindsay Luminoso can be reached at [email protected]
Big Kaiser Precision Tooling Inc., www.bigkaiser.com
Kyocera Precision Tools, www.kyoceraprecisiontools.com
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