On the production floor at Bradshaw Medical—a maker of surgical hand tools in Kenosha, Wisconsin—one of the most productive milling tools is not a mill at all. It’s a custom step drill. The drill doesn’t actually perform a milling
pass, but it has been a powerful facilitator to the milling operations.

In fact, the drill doesn’t even rotate. On Bradshaw’s Mazak Quick Turn multitasking lathe, the tool is held on centerline while the part spins, drilling a multi-diameter stepped hole into the center of the part. Because that same hole used to require three tools for center drilling, drilling and reaming, the new tool frees up two tool positions on the machine’s turret. By filling those tool positions with milling tools, the shop is now able to take advantage of both the live-tool capability and the Y-axis motion of the Mazak machine Carbide Turning Inserts to perform the milling this part requires within the same setup as the turning. That means the part no longer has to be sent to a machining center for this rotary-tool work. Where the setup on the machining center used to consume capacity that created additional need to outsource some of the company’s machining demand, the pressure to outsource is now that much less.

Manufacturing manager Rich Czekalski says he resisted the $150 price tag for the customized drill at first, but now, given all of the benefits that flow from consolidating turret positions, the price seems more than reasonable.

Production personnel at Bradshaw have been looking at various turning center processes in this way—searching for other ways to save on the number of tools, even if it means spending a little more. The key to realizing the most Helical Milling Inserts value on any of these machines, multitasking or otherwise, is to maximize the value that each of the limited number of turret positions can deliver. Doing this often involves a more versatile and/or higher-performance tool, but Mr. Czekalski says both shop personnel and company management are getting better at not flinching at the cost of a valuable cutter. Though in the case of one tool that was modified in-house, the shop found that imaginative thinking allowed it to cut faster and consolidate tool positions, as well as economize on the tool at the same time.

Fear Factor

Bradshaw Medical’s machining area has been driven to rapidly become more efficient because the company itself is rapidly growing. The three-year-old manufacturer now has 70 total employees and 14 CNC machines. A new, larger facility will be ready in late 2010, but for now the company is constrained within its increasingly cramped current location. New machines that might be justified according to the company’s demand can’t be accommodated in the available floor space. Therefore, improving productivity with the existing machines is practically the only option for now.

One of the shop’s first experiences with increasing machine capacity by both reducing cycle time and consolidating tool positions involved a high-performance drill from Walter Titex. This tool increased the speed of the drilling operation and freed up two tool positions by overcoming the need for center drilling and reaming. However, the cost of the drill was high compared to the high speed steel tooling the shop had used, creating a psychological hurdle.

“No one wants to be the guy who blows up a $35 tool,” Mr. Czekalski says.

Now, the shop has become experienced with this tool and with other high-performance tools that are priced much higher. Optimal parameters have been found through fine-tuning the process, and the tools run routinely, without any incident, at the more aggressive speeds the shop now achieves. The initial fear was no reason not to proceed.

A tool that delivered even higher value out of a single turning center position was a multifunction cutter capable of face turning, drilling, boring and OD turning. Thanks to the versatility of this cutter, the shop is able to perform 90 percent of the machining for one particular part number using just this tool alone.

Cutting tool company Sumitomo provided this multifunction tool, as well as the custom step drill. Bradshaw ultimately came to this tool supplier with an idea for further cost saving and productivity improvement that would involve the shop customizing a particular tool on its own.

A Little More Slender

The machined part shown at the beginning of this article is a handle for a torque-limiting surgical hand tool. A critical machined hole running all the way through the stainless steel part is about 1/2 inch in diameter and 4 inches long.

The shop had been machining the 8:1 length-to-diameter hole using HSS tooling. The flexibility of HSS avoided the danger of sudden tool failure if chips bound up in the deep hole to cause cutting force to spike. However, cutting was slow.

Cutting faster would require carbide, but high-performance solid carbide tooling offering the toughness to reliably machine the deep hole would have been expensive. In fact, total cost for the full-size drill plus a pilot drill would amount to hundreds of dollars, Mr. Czekalski says.

A more economical solution would be a steel body with a replaceable carbide tip, but tooling such as this was difficult to find for such a long and slender hole. At this reach, Sumitomo offered the drill in sizes down to 13.5 mm in diameter. Bradshaw needed 13 mm.

Therefore, Bradshaw asked the company: Could the shop turn the body to size itself? Would Sumitomo provide support by customizing the insert for this different size?

Tool distributor Machinery & Factory Industrial Supply of Racine, Wisconsin facilitated the meeting between Mr. Czekalski and Sumitomo. The cutting tool maker agreed that removing 0.5 mm would not dramatically affect the functionality of the drill body. Custom inserts fitting the new size would cost about $100 apiece, but Mr. Czekalski thought this could be justified given the reduced cycle time and freed-up tool position that the custom tool would allow. Plus, the insert could be reground three times, making the overall cost-effectiveness that much greater.

Fear The Right Things

The newly modified tool has not yet been used, but Bradshaw programmer and machine operator Scott Wise has already used a similar tool on a deep hole in another part. With this tool, too, there was initial caution. Mr. Wise watched the turning center’s load meter nervously until he was convinced that the tool would perform without fail at the more aggressive parameters it made possible. With the custom-modified version of the new tool, he expects he will do the same—proceeding cautiously, even fearfully, until the tool proves itself repeatedly and begins to become commonplace for the shop.

Fear is no reason not to proceed—that’s the lesson that continues to be reinforced for Bradshaw as the company continues to make its turning machines more productive. High-value machines need high-value tooling in order to realize their value, and this is as true of advanced turning centers as any other type of machine.

In fact, the Bradshaw staff points out that the initial fear of using costly tooling was almost entirely misplaced. You get what you pay for, they say—meaning the cost is appropriate so long as the payoff is high. The shop shouldn’t necessarily wince at price tags, as natural as it may be to do so. Much more money is saved overall when the shop instead refuses to tolerate cycle times that are too long, or setups that make it difficult to meet the company’s growing customer demand.

The Carbide Inserts Website: https://www.aliexpress.com/item/1005005869232652.html

Although the old adage “if it ain’t broke, don’t fix it” might make sense in most contexts, this can be poor advice to follow when it comes to manufacturing operations. Even the most efficient processes typically have some room for improvement, and even simple adjustments can impact the bottom line.

Cutting tool distributor MSC Industrial Supply (Melville, New York) says two of its Alabama customers’ recent efforts to boost efficiency exemplify the benefits of constantly striving to improve. At Laser Fabrication & Machine, based in Alexandria, switching from high speed steel (HSS) drills to solid carbide models for drilling bushings reduced cycle times, improved part quality and boosted output levels. Decatur-based Micor Industries realized similar benefits on an aluminum firearm component by switching from standard carbide end mills to cutters coated with zirconium nitride (ZrN).

Laser Fabrication is a family-owned, 50-person shop that provides engineering, prototyping, machining and fabricating services. One of the company’s repeat jobs involves drilling 0.394-inch-diameter holes in 0.75-inch-thick 304 stainless steel bushings that form part of hinge assemblies for buses. Each order typically requires about 2,000 of these assemblies, which the shop splits into lot sizes of about 500 per month to complete the job in six months or less.

Until recently, these holes were produced with standard HSS drills running at 400 rpm and 0.003 ipr. With a cycle time of 2 minutes and 30 seconds, this was a slow process that required pecking at 0.1-inch depths to ensure straightness. The drills typically lasted for 100 to 200 holes before requiring re-sharpening. Unsatisfied with the amount of parts it could complete between sharpening the drills, the shop sought to improve the hole-making operation and reduce overall cycle time for the bushings. “I knew there had to be a better tool for the job, but I didn’t want to spend an astronomical amount of money on a simple drill,” recalls Chuck Thacker, shop supervisor. 

When Mr. Thacker consulted with MSC Industrial Supply about speeding the operation, the distributor suggested using a solid carbide, coolant-fed drill from Accupro. This 140-degree, AlTiN-coated tool features self-centering points and a flute geometry designed for high penetration rates and maximum tool life. With high hardness and wear resistance, it is said to be well-suited for aggressive machining of high-alloy carbon steels; nickel-based, high-temperature alloys; and titanium alloys.

Mr. Thacker admits that during initial test runs, he doubted that the new drills would offer much improvement. He also hesitated because of their slightly higher cost. However, witnessing one Accupro drill complete the work of 10 of the shop’s previous HSS models convinced him that the new tools would quickly pay for themselves. At that rate, tooling cost would remain the same, while overall cost per hole would drop significantly.

Today, the shop can machine about 6,000 bushing holes with each drill before re-sharpening. It can also run at more aggressive parameters of 875 rpm and 0.005 ipr. Cycle time has improved to 56 seconds per hole. Moreover, the solid carbide drills produce straighter holes with better surface finishes than their HSS counterparts, eliminating the need for pecking. 

Another MSC customer, Micor Industries, also realized significant productivity and tool life improvements on one job through a simple retooling. This 55-person company specializes in defense, aerospace, oil field and medical work. The problem part was a 6061 P aluminum rail used to mount flashlights, scopes and other accessories onto tactical rifles. Measuring 5.5 inches long by 0.875 inch wide, each rail requires several machined slots. This job usually comes in once every two years in lot sizes of approximately 13,000.

Before the retooling, the shop employed standard, 0.187-inch-diameter, four-flute end mills for roughing and finishing the rails. Each tool typically lasted through about 750 parts before requiring replacement. The shop thought it could do better. “We tube process inserts tried everything for this particular job, but we were maxed out as far as machining feeds and speeds were concerned,” says Justin McMurrain, department lead man at Micor. “Our programmer Jeremy Benderman raised the issue that a different type of cutter might improve rail machining output.”

After evaluating the process, MSC recommended a solid carbide Accupro cutter designed for aluminum, brass, copper and other nonferrous metals. In addition to a ZrN coating that is said to increase lubricity and prevent edge buildup, the tool features vibration-damping cutting edges and a geometry that facilitates high chip loads.

Mr. Benderman worked with MSC sales associate Todd Bickel to test the new tool. Beginning with the same settings employed for the old cutter, they began to progressively increase parameters. Even when speeds and feeds reached levels cemented carbide inserts that taxed the milling machine used to produce the rails, the coated tool never broke.

Today, the shop uses the new end mill to machine the aluminum rails with the same tool paths and cutting depths as the old tool. However, it has increased feed rate by 30 ipm, and it roughs and finishes the rail slots in one pass, as opposed to the multiple passes required with the old tool. Cycle time has decreased as a result. Additionally, the Accupro tool lasts through 2,000 rails without showing any signs of wear. In fact, MSC projected that this simple retooling would provide cost savings of $25,000 on the machine running the rail parts. “Micor’s re-evaluation of its tooling and manufacturing processes is an ongoing activity,” Mr. Bickel concludes. “Any time a supplier can offer a better tool or process, the shop is quick to evaluate and adopt it into its manufacturing operations.”

The Carbide Inserts Website: https://www.aliexpress.com/item/1005006185380264.html

So many of us have lost parts from tools slipping out of their holders. The reassuring whir of chips being made gives way to a screech and a thud, and we jump into damage assessment, hoping that the part is salvageable and knowing that it likely is not. Tool slippage is becoming more and more common as feed rates that were unthinkable ten years ago become commonplace.

Advanced machining technologies are drastically increasing feed rates for manufacturing, and this is especially prevalent in aluminum machining. The combination of more powerful machine tools and more aggressive machining strategies have pushed the material-removal rates towards levels that would have been unthinkable not long ago. Unfortunately, these high rates of material removal can put an enormous strain on the tooling.

Even light metals such as aluminum can cause problems with tooling when machinists run passes removing so much material. At a certain point, the forces required to remove so much material can pull the cutting tool right out of the toolholder. Losing a tool this way can severely damage a part, and replacing the tool can wipe out the time savings from the aggressive machine passes. Fortunately, some cutting tool companies are addressing this problem.

According to Mike MacArthur, Vice President of Engineering for RobbJack, more and more shops are complaining that tools can slip right out of the holder during aggressive machining operations. “Every job shop wants to remove material as quickly and efficiently as possible, especially in competitive industries like aerospace,” he says. “If a shop wants to make chips at the high rates you can achieve today, then it needs to invest in tooling that can withstand the forces generated by these aggressive passes.” To accommodate high feed rates in aluminum machining, RobbJack has standardized its cutting-tool offerings with features that keep its tools from falling out of place with its anti-pullout shanks.

The first step for improving the tools ability to stay in place was to put a focus on the tolerance of the tool’s shaft. “We made a conscious decision to hold every end mill shaft to h4 tolerance,” MacArthur says. For comparison, shrink-fit tools only achieve h6 tolerance. “The tighter fit provides a tighter grip, minimizing the potential for the end mill to slip.”

Grinding the cutting tools to such a high tolerance is only the first step, however. According to MacArthur, another major advantage is the gripping surface. “Some tool companies polish their tool shanks to make them as smooth as possible,” MacArthur says. “Instead, we actually grind a rough gripping surface into our shanks for improved holding power.”

The gripping surface provides extra friction that helps keep the cutting tool in place. Together with the high tolerance, this provides excellent grip. According to MacArthur, these techniques have improved the grip of RobbJack tools by 70%. This has enabled some customers to achieve full slotting with a 1" tool, ¾" deep at 33,000 rpm and 1,000 ipm without risking tool slippage.

In addition to preventing tool slippage, the rough surface the company grinds into the shank further improves the performance of RobbJack end mills. The increased grip improves the stability and rigidity of the tools, preventing runout and keeping the cutting edges more uniformly engaged in the material. The uniform fast feed milling inserts pressure this places on the cutting edges increases tool life by avoiding pressure spikes that can damage flutes. Plus, avoiding runout enables the user to consistently hold much tighter tolerances.

According to the company, this also reduces the pains that come with changing out tools because the tight grip helps to eliminate variability in the tools’ performance. Even smaller-diameter tools that do not see aggressive roughing operations can benefit from the reduced runout and improved consistency of of the anti-pullout shanks.

This increased precision and tool life complements other features of RobbJack tools, as you can see in the A1-303 and FM-series end mills for machining aluminum. Specifically designed for gun drilling inserts gun drilling inserts aerospace applications, these end mills include the anti-pullout shanks that come standard with RobbJack tools, in addition to the Mirror Edge preparation. This feature is designed to eliminate chatter in aluminum machining, an important benefit for aerospace work. These features together, along with the coating, have extended tool life 500% over similar tools and increased the material removal rate to 76 pounds of aluminum per minute. According to RobbJack, this can save a shop over $400,000 per year.

In order to keep up with the advanced machining strategies available today, shops must invest in tooling capable of supporting these strategies, MacArthur says. “Aerospace and automotive manufacturing are competitive industries, and keeping up with the competition means pursuing aggressive material removal rates. In order to capitalize on these techniques, you need an end mill that will stay in the toolholder and keep the chips flying.”

Check out RobbJack’s tool offerings.

The Carbide Inserts Website: https://www.aliexpress.com/item/1005005874893569.html

Hyundai WIA Machine America will display its F500 Plus VMC featuring a high-precision, high-torque Big Plus spindle in a construction that is deep hole drilling inserts said to eliminate thermal growth during heavy cutting. A thirty-position, servo-powered tool magazine makes for quick and reliable tool changes. Further contributing to productivity, high-speed axis travel on roller linear motion guideways reduces non-cutting time.

The company will also display gun drilling inserts gun drilling inserts its E160A compact CNC turning center for small-diameter parts and the L2100SY multitasking, wedge-type, Y-axis CNC turning center. 

The Carbide Inserts Website: https://www.aliexpress.com/item/1005005875094850.html

The Slip-Fit Qwik Twist adjustable-depth drilling and chamfering combination tools use standard Qwik-Twist replaceable drill points and chamfering inserts for 30-, 45- and 60-degree top hole chamfer angles.

These drills are available in sizes ranging from 0.295" to 0.823", with straight bar peeling inserts shanks. They can be adjusted for variable Carbide Turning Inserts hole depths within the chamfer shank, and drill depth adjustments can be made in the spindle.

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According to the company, with replaceable tips, the Qwik-Twist family of drills virtually eliminates the inventory and trafficking associated with regrinding solid carbide tools. As with indexable milling and turning, the operator can use the carbide point once, then replace it on the same shank.

Other features include opposing chamfer inserts that balance the cut for accurate machining and through-the-tool coolant.

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The Carbide Inserts Website: https://www.estoolcarbide.com/pro_cat/tube-process-insert/index.html