by Kip Hanson
Improve machining efficiency and cut costs with specialty tooling
Machinists today enjoy a greater variety of high quality tooling than ever before. Practically any hole, groove, slot, trepan, bore, or other part feature can be machined using off-the-shelf cutting tools and toolholders, so why bother with the hassles and high cost of custom tooling? As it turns out, there are darned good reasons to do just that. In this article, five tooling experts weigh in with some sound advice.
Jason Farthing, technical sales and marketing for Horn USA Inc., Franklin, TN, says custom tooling comes in many shapes and sizes, and may include changes to a standard tool’s geometry, coating, and substrate, or require design of a new tool altogether. In either case, and depending on design complexity, customers can expect to wait weeks or perhaps months for a custom tool to arrive, and pay premium prices to boot. Despite this, Farthing says the investment in time and money is often worthwhile, and can bring cutting performance and cycle time reductions far beyond what’s possible with standard tools.
One excellent example of this is a combi-tool Horn designed for a connecting rod manufacturer. Where machining the 4340 forged steel component once required four separate cutting tools, the multi-purpose tool combined boring, grooving, and chamfering operations into a single tool body. This decreased idle time due to tool changes and positioning from 40 seconds to 14.5, a reduction of 64 per cent.
Farthing admits specialty tooling is primarily used in high production scenarios, but says that even low-volume shops can benefit by going the custom route. “Custom tools are a great solution when you need to maintain a specific distance between two part features—a series of grooves, for example, or a flange thickness. Quite often, shops must pay skilled operators to babysit features such as this, where a custom tool will remove any guesswork. It’s especially useful on final operations, where a customer might have $20,000 or $30,000 tied up in a component; there are no second chances here. By designing a tool that practically guarantees several dimensions are held spot on—say a reamed hole with a counterbore, or some sort of sealing surface—there’s no risk of scrapping an expensive workpiece.”
Shops should look to their tooling partner as an extension of their engineering department, Farthing points out. “It must never be about selling a tool just because it’s capable of machining a part feature. The tool should be optimized for the application, especially in higher volume applications. The customer should be able to hit the production numbers they need to, with tool life and a cost per part that helps makes them competitive.”
Iscar Tools Inc., Oakville, ON, is another company that designs and manufactures custom tooling. Dina Agranovsky, project department and MTB (Machine Tool Builder) manager, offers several examples of solutions that increased productivity, extended tooling life, or allowed the part to be made in the first place. One of these was a step reamer head for a 4140H steel retainer. Iscar modified one of its BN6 solid carbide reaming heads to simultaneously semi-finish and finish a 14 mm hole (0.55 in.) running the length of the retainer, greatly improving predictability of the reaming operation. In another example, a combination drill-counterbore-chamfer tool was developed to increase holem-making efficiency on a Chiron horizontal machining centre producing carbon steel axle components.
In both of these applications, part volumes hovered around 1,000,000 pieces per year, making custom tooling a no-brainer. Yet Agranovsky offers another example, this one a custom slotting tool designed to machine 8620 steel hubs for the power generation industry. In this instance, however, the customer needed to machine just four pieces annually, but because of the slot width, together with tightly controlled radii in each corner, they decided to contact Agranovsky for a custom cutter.
“With any custom tooling request, documentation is very important,” she says. “We ask our customers to supply basic information such as the type of machine, estimated annual production, and a part drawing. Based on that form, we’re usually able to return a quote within a few days, and deliver the tooling together with feed and speed recommendation, time estimates and so on six to eight weeks later.”
Sometimes, machinists and engineers don’t know what they need, only that they have a problem. This was the case with one of Randy McEachern’s customers, a heat exchanger manufacturer that drills “millions of holes each year.” McEachern, a holemaking application specialist for Sandvik Coromant Canada Inc., Mississauga, ON, says this particular customer has a reputation for pushing tools to the limit. While discussing the application, McEachern offered to help with their high volume drilling of SA51670 steel plate, but knew he had his work cut out for him. “They were getting decent tool life with a competitor’s product, but they needed more. In the past we went in with standard drills and were unable to exceed existing performance. That’s when we turned to our Tailor Made program, which is part of our engineered solutions toolbox.”
Since it was unclear at that time what the magic bullet would be, McEachern ordered an assortment of edge preps, corner chamfers, and carbide grades, all of which were modifications to a standard 20 mm (0.787 in.) 870-series CoroDrill with replaceable carbide tip. “This was a field test, so we started with the feeds and speeds recommended by the engineers at Tailor Made, documenting the results as we went,” says McEachern. “By the end of the test though, we were way beyond our initial cutting parameters and the drill was still going strong.”
This is one example of how machine shops large and small can benefit from custom tooling programs, since even small tweaks to standard cutting tools can yield tremendous benefits. Tooling manufacturers have the knowledge and experience to make their cutting tools sing and dance in a variety of machining situations; partnering with them is often the difference between a winner job and one you’d just as soon forget.
Mark Blosser, director of solutions for Komet of America, Schaumburg, IL, agrees. “When a tooling package is quoted, we assign an engineer to stay with that project from cradle to grave. There are also local application engineers that work through the implementation, to make sure that everything is running well without any issues.”
Much of Blosser and his team’s work is automotive-related, where every second of extra cycle time may add up to thousands of hours in lost production. Blosser says much of their effort is focused on reducing the number of tools needed to machine a part, and it’s common practice to combine three or more tools into a single cutter body. “Think about a steering knuckle,” he says. “There are four on every car, so if you’re developing the machining process for a model year production of 300,000 vehicles, you have 1.2 million knuckles to make. It’s pretty obvious you have to machine them very, very quickly. You do that by utilizing specialized tools.”
Like his competitors, Blosser has a program designed to make the custom tool voyage as fast and painless as possible. Most importantly, that program is available even if you don’t work for Ford, General Motors, or Chrysler. True, the engineering expertise that Komet and others bring to bear sounds expensive, but given the right application, it can save any shop a ton of money long-term. “We’re out in the field every day, and get to see everything, from engine blocks to knee joints,” he says. “Quite often we can suggest different approaches to component production, whether it’s a different carbide grade, a better way to fixture something, or a custom cutting tool. It can be very cost effective.”
Dave Cope, manager of technical engineered programs for the Americas at Kennametal Inc., Latrobe, PA, says custom tooling is just one piece of the machining efficiency puzzle, and a robust solution encompasses the right mix of both standard and custom tooling, backed by process knowledge and experience. “The most productive solution reduces cost per part and opens up existing capacity. It makes a complicated manufacturing world less so.”
Cope recently worked with an aerospace supplier on a project aimed at optimizing metal cutting processes in tough alloys such as 6Al4V titanium and its ugly step-sister, “triple nickel three” (5553). During the course of the project, a number of custom end mills and indexable end milling cutters were developed, but that fact is somewhat secondary, Cope says—more important is the collaboration required for successful completion of any such project. Kennametal engineers worked closely with the customer team, beginning with a “Discovery” phase where a site visit was performed to analyze the shop’s current state and determine tooling preferences, budget and timeline. From there, the team entered the Collaborative Engineering phase, identifying improvement opportunities in fixturing and tooling, in turn developing an overall “future state” machining concept. The tooling package supporting that concept was then quoted and, after customer approval, built and delivered.
Soon thereafter, a trial runoff and production ramp-up took place, with Kennametal engineers supporting the implementation throughout. Cope is unable to share specifics on the actual process improvements, but says projects such as these are designed to make the most of the customer’s resources, both in capital equipment and human capital. “Many companies continue to lose internal expertise to attrition and retirement, making collaborative engineering–and building a database of proven solutions–even more vital to
ongoing success.” SMT