Above: HHA Sports' top-selling bow sight, the Optimizer Lite 5500.

Bow sight manufacturer relies on a saw brand it’s used for two decades

July/August 2015 - An entire day of watching and waiting can be wasted if you’re not ready when the object of prey appears. Often, that means locking in on your target ranging from 20 to 80 yards. To ensure an accurate shot, the archer needs a quality bow sight to make the most of that rare opportunity.

If manufactured by HHA Sports in Wisconsin Rapids, Wisconsin, each bow sight is constructed of CNC machined parts that fit in the palm of your hand. Parts are cut from large custom extrusions and bar stock. To make the most of the material and to increase efficiency, HHA Sports installed a fully automatic Kaltenbach SKL 450 NA aluminum saw from Structural Machinery Solutions (SMS), Columbus, Indiana, with a high-horsepower motor and complete chip exhaust system.

Ninety-nine percent of the material used in HHA’s product line is aluminum. Twenty years ago, HHA had one CNC milling machine but as demand has grown, “we have five CNC machines running at two and three shifts a day,” says Brian Hamm, co-owner and design engineer. In need of an automatic sawing solution to keep pace with production, Hamm hoped to stick with the brand that had served his company so well for over two decades.

“I looked at a fair amount of saws 20 years ago,” he recalls. “I did check out a couple of other brands this time around but I’m just so comfortable with SMS [and] the Kaltenbach never breaks down.” Barring the occasional seal or hydraulic replacement, maintenance over two decades has been minuscule.  

“We knew what we were getting with them,” Hamm continues, which includes the enduring presence of Max Hotz, service manager and Mike Stephens, parts manager. “They were there 20 years ago. When you call, they are both still there today. Add in President Dave McCorry, and you’ve got a heck of a team working with you.” SMS and Kaltenbach have been major players in HHA’s success for so long, there was no need to look elsewhere, he adds. 

Hamm sent SMS a 6-in. piece of a large extrusion that HHA uses before he arrived to view a demonstration. “I took some 4-footers down there as well,” he says. “They didn’t have to cut a quarter of it before I knew it would do what I needed it to do.

Automation upgrade

The biggest benefit seen with the new saw is once the operator inputs the cutoff length, the machine takes that cut and feed information and gets to work, freeing the operator to walk away and work on another task. The automatic feed pushes the blanks out to a small roller or down a chute where they slide into a bin. “We also have an automated, vibratory deburring process, so by the time the parts reach the CNCs, they are dry, free of oil and burr-free,” Hamm says.

Besides freeing up manpower, the Kaltenbach allows HHA to streamline scrap disposal. According to Hamm, when cutting an extrusion on the manual saw, the operator had to stop it in 4 ft. increments to pull the tray out, resulting in “a boatload of chips.”

“We generate a lot of chips so we have this large vacuum system,” Hamm explains. “There’s hardly any down time to clean it out during production.” The older model required operators to wait for the blade to retract before unclamping the material, then reaching in with a stick to remove the sawed part and reposition the bar. Now it’s fully automatic.”

Using the chip exhaust system coupled with the automatic feed, HHA’s productivity in sawing large extrusions has tripled, bar stock saw times have been cut in half, and saw operators have the time to perform other duties. “It’s been an amazing transformation in our shop, and our employees are absolutely thrilled with this move,” Hamm says.

The chip exhaust system helps because a built-in tray collects chips that are disposed of at the end of the shift. “But on heavier sections and on solids, the amount of chips can be a problem, because it necessitates production stops to clean the machine and empty the tray,” says McCorry. “So a chip exhaust system becomes desirable in the interests of uninterrupted production and a clean work environment.”

Feature breakdown

The SKL 450 NA enhances throughput, providing better cutting length tolerances, which was previously determined by the manual movement of the material to a backstop, according to McCorry. The new machine is equipped with a ballscrew-mounted automatic feed carriage and will cut to a tolerance of ± 0.005 in.

The traditional method of controlling a shuttle feed carriage is via a lead screw or a pneumatic cylinder against hard stops—one fixed and one adjustable, explains McCorry. “Which generally means that to change the cut length you need to interrupt production and do a reset.” 

On the SKL 450 NA, the numerically controlled ballscrew allows up to 99 sets of cut length/batch size to be preprogrammed and cut completely automatically out of one length—or several lengths—of the same material, he says. The ballscrew has a shuttle mode, where it acts like a traditional shuttle feed carriage, running back and forth for a given length; or incremental mode, where the gripper runs all the way back to the far end of the feed carriage, then feeds incrementally between cuts without having to let go, return and regrip each time, “effectively acting like a pusher system.” 

The saw can be set up to run faster on light materials and slower on heavier materials. “It then ramps up and ramps down at the beginning and end of its stroke to overcome the effect of inertia,” McCorry says.

Safety is another benefit as the upstroke motion of the saw (where the blade comes up through the table) is in the middle, says McCorry. The upstroking blade does not need to grind through the chip collecting in the bottom of the material during the cut. 

The new saw also affects how HHA Sports can stack bars while sawing. “A lot of times we buy rectangular shapes like 3⁄8 in. by 1.5 in., which are conducive to stacking,” Hamm says. “Before, we stacked the bars vertically like a pile of books on a desk with a c-clamp holding the stack together. Now the clamping/feeding arm grabs the stack with the bars standing vertically, side by side. Each movement of that blade feeding vertically is going to yield more parts per cut.”

NC controls on the SKL 450 NA, an atomizer lubrication system and extensive safety equipment were specified “so, in most cases, no further options are required,” McCorry says. “One exception would be when we have to clamp and feed irregularly shaped material, which may require shaped clamping jaws, or ‘form’ jaws. To make these easier to interchange for various material shapes, we offer quick-change prismatic jaws.”

Any irregular shaped component on HHA’s bow sight line is produced in-house, starting with the Kaltenbach. “Most of our round parts are machined outside, then brought into our shop for secondary machining,” Hamm says. “We do some cutting of round stock on our Kaltenbachs, and they perform beautifully.” FFJ