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Productive Times feature Kevin Burns Golf, 408-244-7768, www.kbputters.com. Challenge: Maximize productivity and minimize tool breakage when roughing custom putter heads. Solution: A 5-flute, solid-carbide endmill that minimizes chatter. Solution Provider: Dura-Mill Inc., 800-444-6455, www.duramill.com.
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Kevin Burns is a visionary. Faced with increased competition for custom golf putters, he decided to go a different, more risky route—one-off putters built to each customer’s specifications. To do this, he’s developing a manufacturing system and software for the individualization of putters and to run his 5-axis machine tool.
Burns is president of Kevin Burns Golf, San Jose, Calif., and his love of golf led him to a job early in his career with a business that repaired golf clubs. He eventually opened his own repair shop. Later, he decided that if he was going to be in business permanently, he wanted to produce custom clubs.
Courtesy of Dura-Mill
Kevin Burns, president of Kevin Burns Golf, uses a device (top) to document the angle he holds a putter at and the required shaft length for his stance. That information will be downloaded to a machining center, where a customized putter head is produced to fit an individual’s specifications.
After he designed his first putter, he had a vendor cast, machine, grind and polish a run of them. Although the putter design was unique, it wasn’t fitted to the golfer.
Feeling he could do a better and cheaper job than his vendor, Burns opened a manufacturing plant, hired a part-time plant manager to help him with the machining and programming and bought a milling machine.
Burns learned from his plant manager how to run machine tools, and his business grew to eight employees and eight Haas machining centers.
“Then my plant manager left, and he left me nothing,” Burns said. “The machining information was all in his head, and much of it was [self-taught]. I had to figure it all out. So I bought Mastercam software to help me with it.”
Burns received a contract from Bridgestone, an Asian company, for his putters. He said: “I was building thousands of them for the Asian market. Before this, I was producing 60 putters per day on two shifts. Then I increased production to about 128 by changing the workholding setups. I used modular tooling for the workholding, allowing me to produce more putter heads. It only took me 2 months to produce 5,000 putters.”
Burns eventually realized that having employees and their constant complaints and problems really wasn’t for him. When he didn’t renew his putter contract with Bridgestone, it was an ideal opportunity to start customizing putter heads.
But first he needed a suitable machine. “I looked at many different machine tools,” Burns said. “I could see that a 4-axis mill could do 90 percent of my putter, whereas 5-axis equipment could produce the entire putter head. Along with using tombstones for my workholding and a pallet changer, I would have the perfect manufacturing system.”
He traded in his used machining centers for a new Mazak Variaxis 5-axis horizontal machining center and laid off his employees. He bought a building and installed the machine with a pallet changer and 12 pallets with tombstones held in a tiered rack.
“There was a pretty steep learning curve for the equipment,” Burns said. “The biggest thing was learning the center of rotation to get the parts to be cut properly. We have a rather special program for this.”
While experimenting with the cutting of his putter head from a 303 stainless steel extruded bar, Burns discovered a unique endmill for roughing. He worked with Mark Jacobson, a tooling salesman at Tool Technology Distributors Inc., Fremont, Calif., who informed Burns about the WhisperKut endmill from Dura-Mill Inc., Malta, N.Y.
“I was able to run extremely fast,” Burns said of the ½ "-dia., 5-flute, solid-carbide tool. “Comparatively, it’s light years ahead of anything else I’ve used, as far as the way it cuts and sounds. I ran about 12 parts with it and the edges of the cutter were still like new. It’s given me about a 30 percent increase in cutter life over what I was using.”
The endmills have an asymmetrically designed variable helix. “Because of their patented design, they don’t chatter,” Burns said. “Any time you get chatter, you can break a tool.”
Burns uses a shallow step-over, a 0.100 " radial DOC and a 1.250 " axial DOC for roughing the part. The feed rate is 100 ipm, or 0.0033 ipt, and the spindle speed is 6,000 rpm to achieve a cutting speed of 786 sfm.
Burns noted that companies that customize putters typically only bend the shaft or add or decrease a putter’s weight. “I wanted to make a putter that was designed for its user, which brings me into mass customization,” he said. “But currently, I’m still 2 years away from doing this.”
To develop a unique putter, Burns developed a kiosk using a computer that will capture the customer’s customization information at retail stores. A patented device will capture the angle a golfer holds a putter at and the required shaft length. This information will automatically be sent to Burns after the purchase. It will be downloaded to the machining center and a custom putter will be produced within 2 weeks.
Related Glossary Terms
- centers
centers
Cone-shaped pins that support a workpiece by one or two ends during machining. The centers fit into holes drilled in the workpiece ends. Centers that turn with the workpiece are called “live” centers; those that do not are called “dead” centers.
- chatter
chatter
Condition of vibration involving the machine, workpiece and cutting tool. Once this condition arises, it is often self-sustaining until the problem is corrected. Chatter can be identified when lines or grooves appear at regular intervals in the workpiece. These lines or grooves are caused by the teeth of the cutter as they vibrate in and out of the workpiece and their spacing depends on the frequency of vibration.
- cutting speed
cutting speed
Tangential velocity on the surface of the tool or workpiece at the cutting interface. The formula for cutting speed (sfm) is tool diameter 5 0.26 5 spindle speed (rpm). The formula for feed per tooth (fpt) is table feed (ipm)/number of flutes/spindle speed (rpm). The formula for spindle speed (rpm) is cutting speed (sfm) 5 3.82/tool diameter. The formula for table feed (ipm) is feed per tooth (ftp) 5 number of tool flutes 5 spindle speed (rpm).
- endmill
endmill
Milling cutter held by its shank that cuts on its periphery and, if so configured, on its free end. Takes a variety of shapes (single- and double-end, roughing, ballnose and cup-end) and sizes (stub, medium, long and extra-long). Also comes with differing numbers of flutes.
- feed
feed
Rate of change of position of the tool as a whole, relative to the workpiece while cutting.
- gang cutting ( milling)
gang cutting ( milling)
Machining with several cutters mounted on a single arbor, generally for simultaneous cutting.
- inches per minute ( ipm)
inches per minute ( ipm)
Value that refers to how far the workpiece or cutter advances linearly in 1 minute, defined as: ipm = ipt 5 number of effective teeth 5 rpm. Also known as the table feed or machine feed.
- inches per tooth ( ipt)
inches per tooth ( ipt)
Linear distance traveled by the cutter during the engagement of one tooth. Although the milling cutter is a multi-edge tool, it is the capacity of each individual cutting edge that sets the limit of the tool, defined as: ipt = ipm/number of effective teeth 5 rpm or ipt = ipr/number of effective teeth. Sometimes referred to as the chip load.
- machining center
machining center
CNC machine tool capable of drilling, reaming, tapping, milling and boring. Normally comes with an automatic toolchanger. See automatic toolchanger.
- milling
milling
Machining operation in which metal or other material is removed by applying power to a rotating cutter. In vertical milling, the cutting tool is mounted vertically on the spindle. In horizontal milling, the cutting tool is mounted horizontally, either directly on the spindle or on an arbor. Horizontal milling is further broken down into conventional milling, where the cutter rotates opposite the direction of feed, or “up” into the workpiece; and climb milling, where the cutter rotates in the direction of feed, or “down” into the workpiece. Milling operations include plane or surface milling, endmilling, facemilling, angle milling, form milling and profiling.
- milling machine ( mill)
milling machine ( mill)
Runs endmills and arbor-mounted milling cutters. Features include a head with a spindle that drives the cutters; a column, knee and table that provide motion in the three Cartesian axes; and a base that supports the components and houses the cutting-fluid pump and reservoir. The work is mounted on the table and fed into the rotating cutter or endmill to accomplish the milling steps; vertical milling machines also feed endmills into the work by means of a spindle-mounted quill. Models range from small manual machines to big bed-type and duplex mills. All take one of three basic forms: vertical, horizontal or convertible horizontal/vertical. Vertical machines may be knee-type (the table is mounted on a knee that can be elevated) or bed-type (the table is securely supported and only moves horizontally). In general, horizontal machines are bigger and more powerful, while vertical machines are lighter but more versatile and easier to set up and operate.
- milling machine ( mill)2
milling machine ( mill)
Runs endmills and arbor-mounted milling cutters. Features include a head with a spindle that drives the cutters; a column, knee and table that provide motion in the three Cartesian axes; and a base that supports the components and houses the cutting-fluid pump and reservoir. The work is mounted on the table and fed into the rotating cutter or endmill to accomplish the milling steps; vertical milling machines also feed endmills into the work by means of a spindle-mounted quill. Models range from small manual machines to big bed-type and duplex mills. All take one of three basic forms: vertical, horizontal or convertible horizontal/vertical. Vertical machines may be knee-type (the table is mounted on a knee that can be elevated) or bed-type (the table is securely supported and only moves horizontally). In general, horizontal machines are bigger and more powerful, while vertical machines are lighter but more versatile and easier to set up and operate.
- modular tooling
modular tooling
1. Tooling system comprised of standardized tools and toolholders. 2. Devices that allow rapid mounting and replacement of tools. Commonly used with carousel toolchangers and other computerized machining operations. See toolchanger; toolholder.
- step-over
step-over
Distance between the passes of the toolpath; the path spacing. The distance the tool will move horizontally when making the next pass. Too great of a step-over will cause difficulty machining because there will be too much pressure on the tool as it is trying to cut with too much of its surface area.
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