Red Hot

Reduced operating costs, better part quality and energy savings are just three of the benefits Pacific Energy has experienced with the introduction of fiber laser cutting technology.

Electricity is expensive on Vancouver Island. This was a large part of the reason why Pacific Energy Fireplace Products Ltd. had long steered clear of CO2 lasers, opting instead to stick with its tried and true CNC turret punches.

Yet fabricators have been successful with lasers for over three decades. Compared to punching, laser cutters are faster to set up, and require far less maintenance. And in Pacific Energy’s case, cutting complex part profiles was becoming increasingly difficult with its aging equipment, a task that’s far simpler on a laser than
on a turret punch.

General manager Shannon Sears knew all this, and says the company took a hard look at CO2 several years ago. “We found the operating costs represented a significant increase over our existing equipment. And we knew the utility companies were projecting a 30 per cent rate increase over the next few years, so lasers were eliminated from consideration at that point.”

Pacific Energy is an independently owned producer of fireplace heating solutions. It offers a wide variety of wood and gas burning stoves, fireplaces and inserts, and prides itself on manufacturing clean, efficient energy products. Located in Duncan, BC, the company employs 200 people, and has customers in Australia, Russia, and all points in between. Says Sears, “we’re a metal fabricator at heart. Aside from a few purchased components, we manufacture everything in house—that means we cut, bend, form, paint and finish roughly 20 different grades of steel into finished products.”

With 35 years in the hearth appliance business, Pacific Energy has gone through several generations of fabricating technology. Like many companies, it started with hand-operated shears, ironworkers and forming presses, then evolved to CNC turret punches and eventually to automated material handling. Through it all, laser technology was kept at arm’s length.

Read the rest:

Mini Mills

Haimer's shrinkfit holder, which president Brendt Holden says are the best option for micromilling.

Nineteen minutes into the second period and the University of Ottawa’s women’s hockey team, the Gee-Gees, trails by one. Out of nowhere, the Montreal Carabins’ left wing bruiser Helga Lefèvre smashes Gee-Gees centre Holly McDuff into the boards, fracturing her cheekbone and leaving a ragged gash above Holly’s hairline. Blood turns the blue line red, but the crowd roars as the intrepid junior shrugs off the pain; she pulls a third period hat-trick and leads the team to victory.

At the hospital, the doctor repairs Holly’s cheek with a tiny metal plate, then uses staples to reattach the flap of skin to her forehead. Because he’s worried about an infection, several blood tests are needed. With Holly safely in recovery, her boyfriend uses his smart phone to snap a photo for Facebook. “Gnarly scar, Holly,” he says. “It looks like a maple leaf.”

Bone plates, surgical staples, blood testing equipment, even smart phones and their ever more capable cameras—none would be possible without miniature cutting tools. Yet as Cory Cetkovic points out, a host of things must go right before cutting tools smaller than a human hair can be used successfully, including the right toolholder and the right feeds and speeds.

Cetkovic is an application engineer for BIG Kaiser Precision Tooling Inc., Hoffman Estates, IL, and product manager for the company’s Sphinx brand of cutting tools. He explains that micromachining produces that realm of parts and part features measuring less than 0.5 mm (0.020 in.), with feature sizes smaller than 100 microns (0.004 in.) becoming more common every day.

Cetkovic will tell you microcutters are not simply smaller versions of that 12 mm (0.472 in.) endmill you loaded into the machining centre this morning. As cutters become smaller, web thickness relative to tool diameter increases, making chip evacuation vs. cutter strength a delicate balance. Edge sharpness, too, becomes more difficult to achieve as cutters shrink in size—the slight edge prep used on a roughing end mill may be larger than the entire flute depth on a microtool. This makes rubbing a real concern with Lilliputian cutters, since depth of cut during machining is often a fraction of the tool’s edge radius. Lastly, Cetkovic says to ditch the coating. Its benefits are marginal, and may even be detrimental on tool diameters smaller than 0.2 mm (0.0078 in.).

Built-up edge, rapid tool wear, unexpected tool breakage—all the problems seen in macro milling are magnified exponentially as tools become smaller. However, there’s a straightforward way to alleviate many of these microcutter challenges, Cetkovic says: crank up the speed. “It’s very common that customers are using micro-sized endmills without the appropriate surface footage.”

Read the rest:

5 X 5

The Kipp clamping system from distributor Mittmann.
Tooling up a vertical machining centre is easy. Just bolt a pair of 6 in. machinist vises on the table and call ‘er done. And while this path-of-least-resistance approach may be limited, it’s also fast, easy and cheap. Unfortunately for the owners of five axis vertical machining centres, machinist vises don’t cut the mustard.

Five axis machining can be broken down into two distinct processes. The first involves simultaneous movement of up to three linear axes (X, Y and Z) together with the machine’s two rotary axes, typically labeled A and B. This process is used to produce sculpted, three dimensional surfaces such as knee replacements, pump impellers, mag wheels or a mould for the next greatest motorcycle helmet.

The other type is called 3+2, where the rotary axes are used to index and position the workpiece, enabling five-sided machining of manifold blocks, valve bodies, and a host of other parts that, prior to five axis machines, would have been “tumbled” through multiple operations on a three axis machining centere. Today, five axis machines eliminate the handling and need for multiple fixtures, greatly reducing part lead-time while improving accuracy.

There’s more to five axis machining than spinning a part. Programming, process planning, and the machine tool itself are all more complicated than what’s needed for traditional three axis work. One aspect of this is how to best grip the workpiece. No matter what you’re making on a five axis machine, the parts must be positioned farther from the table, sometimes much farther, than on a three axis machine. That’s because, when the part is tipped on its side or rotated at some extreme angle, the cutters and toolholders need room to clear the machine table. If the part is snugged down close to the table, as with a machinist vise, interference is as sure as a February snowstorm in Winnipeg.

Workholding providers have responded with a variety of solutions. Mittmann Industrial Equipment, Rigaud, QC, distributes the Kipp five axis compact clamping system from German manufacturer Heinrich Kipp Werk KG. President Thomas Mittmann says five axis machining is prevalent in the aerospace, automotive and die/mould industries. “It’s especially useful for machining low volume, complex parts. You can do the whole part in a single clamping on these machines.”

Read the rest:

Tough Tubes

A high strength steel forming mill from Yoder. Note the progressive forming stations. Image: Formtek Group.

Ever wonder about the legs on a folding chair? How about the exhaust pipe on your car? Tubing is everywhere, but most of us don’t give it a second thought. The technology used to make this important product is quite amazing, however, requiring equipment longer than a football field and more expensive than a mansion on Vancouver Island.

Someone who knows all about tube rolling is Brian Kopack, senior sales engineer at Formtek Inc., Warrensville Heights, OH. The Formtek Group represents a number of metal forming equipment manufacturers, including Cooper Weymouth, Tishken, Hill Engineering, Dahlstrom, Rowe Machinery and the Yoder brand of tube and pipe mills.

Roll forming is a broad topic. It’s used to manufacture everything from bicycle rims and auto bumpers, rain gutters to aircraft fuselage. In fact, almost any shape—angles, channels, S, T, U, V, W and Z-shapes—can be roll formed, and done so quickly and accurately. Tube manufacturing is a small part of the roll forming process (see sidebar page 83).

Kopack explains that tube mills are just another type of roll forming machine, but one with a critical difference: these monstrous systems weld the rolled form shut partway through the manufacturing process, then trim and smooth the weld bead to create a strong, precise and mechanically stable product.

Almost any aluminum, steel or stainless steel, is a candidate for tube making, but as Kopack points out, high strength steel is being called for with increasing frequency. Automakers in particular have their eye on weight reduction, and this means maintaining or in some cases increasing the structural integrity of their products, and doing so with less material.

“The term high strength is relative,” Kopack says. “The generic, low carbon steel tubing that’s been around since the 50s is typically 40,000 to 50,000 psi yield strength material. By comparison, we have ultra high strength, low
alloy (HSLA) steels today that offer yield strengths of 150,000 to 180,000 psi. Those materials form much differently than do commodity grade materials, and may require additional forming passes, different tooling and even modifications to the machine configuration.”

As material becomes stronger, manufacturers can reduce tubing wall thickness with no loss of product strength. This provides for a lighter weight product, and allows manufacturers to cut costs. For example, the ratio of tubing diameter to wall thickness runs between 10:1 up to 50:1 in the “plain Jane” materials mentioned in the chair leg and exhaust pipe examples cited earlier, whereas high performance tubing like that used in a modern automobile could easily be 80:1 or higher.

Read the rest:

Shop Floor Evolution

Renishaw and its associated company MSP, support Tier 1 aerospace suppliers on a variety of setup problems, such as automating the alignment of Airbus A330 ribs prior to machining.

When I started in the shop, machine tools were dumber than fence rails. Load the paper tape, adjust the rheostats for feedrate and spindle speed, click, click, click the offset thumbwheels, push cycle start and pray. Programs were keyed into a Teletype machine; when changes were needed, the printout was redlined and sent back to the programming office for laborious corrections. CAD/CAM systems and the mainframes to run them cost more than a new house. Probes were something they sent into space, and the only thing high speed was the steel we used to cut parts.

What a difference a few decades make. Today, the combination of complex software, inline probing systems, and increasingly intelligent machine controls give machine tools uncanny decision-making abilities, anything from stopping the machine a split second before one of us error-prone humans crashes it, to automatically adjusting cutting tools and part programs based on the in-process inspection information.

Perhaps the best known of these technologies is in-machine probing, although Dafydd Williams, general manager of Renishaw (Canada) Ltd., Mississauga, ON, hesitates to call it adaptive. “In process measurement using a touch probe or inline CMM is more along the lines of process control,” Williams says. “It’s about checking tool wear and managing temperature fluctuations that may affect part size. Adaptive machining is when the actual part program is automatically modified based on in-process measurement.”

In Renishaw’s definition of adaptive machining, a touch probe is used to validate part location and condition, and the resultant information is sent to some “really deep and very clever software.” This software analyzes part features to determine whether the NC program must be adjusted or “morphed” in to bring part dimensions into spec, or to compensate for certain material conditions. “Let’s say that a customer has an expensive casting, and they need to discover what state the workpiece is in before machining,” Williams explains. “For example, is there too much material, or is the casting warped or oriented incorrectly?. Those arequite complicated problems to deal with on a machine tool.”

That’s where NC-PerfectPart comes in. Metrology Software Products Ltd. (MSP), an associate company of Renishaw located in Northumberland, England, has developed a software program that assesses current part conditions based on data collected via a probing system, and then rotates or shifts the machine coordinate system to suit.

Read the rest:

Choosing wire EDM workholders


There comes a time when some chipmaking shops add wire EDMing to their repertoire. This is often done to reduce costs, because bringing what were once subcontracted, secondary EDMing operations in-house often makes good financial and logistical sense. It can also be due to demands from medical and aerospace customers, who ask their suppliers to control the entire manufacturing process under one roof. In either case, merging these disparate machining operations can be a workholding challenge.

Substantial differences exist between workholders for conventional CNC machines and those for wire EDMs, starting with the material. Pull a cast iron vise off a machining center and submerge it in a tank of deionized water dielectric and you’ll soon have a rusty mess. For this reason, virtually all EDM workholders are made from hardened 400 series stainless steel.

There are exceptions. For example, some high-end wire machines use oil dielectric, so it might be possible to use a conventional vise in these instances. However, dedicated EDM workholding is often a necessity due to machine considerations.

EDM tooling can seem like alien Tinker Toys to those familiar only with conventional machine tools. Much of the confusion about what to order can be avoided by understanding the terminology.

For example, reference elements are rails that mount on pedestals inside the EDM work area. Together with reference stops, they provide a zero point to locate fixtures and other workholding components. Chucks are available in pneumatic and manually actuated versions and accept pallets that in turn accept workpieces and fixtures. Mounting heads are used as the “middleman ” between the chuck and a vise or universal holder. Add to that a plethora of adapters, f rames, blocks and clamping heads, and a phone call to an EDM workholding expert might be in order.

Some of these experts work at System 3R USA LLC, Elk Grove Village, Ill. John Roskos, vice president of sales, said many shops ease into EDM workholding with a starter kit. For example, a basic system containing a vise, mounting head and adapter might cost $2,000, whereas a full-blown package with reference rails and pneumatic clamps could easily cost 10 times that amount.

Read the rest: Wire EDM Workholding

Leaning towards lean


I’m not wired for lean. My garage is a disaster, I take too many steps when making coffee in the morning and I have no problem stocking up on paper towels if there’s a sale. Some of this antilean thinking may stem from my early years in a machine shop, where half-day setups and that’s-the-way-we’ve-always-done-it attitudes were the norm.

Back then, most shop owners felt that, once the machine was set up, it was best to make 6 months’ worth of parts and put them on the shelf. The customer would eventually buy them. They took a pass on just-in-time for just- in-case, and the only key productivity indicator was who could make it to the lunch truck fastest. Inventory turns took place every few years, when dusty, leftover material was sold to the scrap man.

With this in mind, I posted a question on social media: Does lean manufacturing always make sense? After all, many machine shops are too busy getting parts out the door to worry about a bunch of process flow diagrams and whiteboard fantasies. Like yesterday’s shop owners, many feel there’s nothing wrong with building products in advance or buying material in bulk, as long as there’s space in the warehouse and sales orders on the books.

Boy, did I get an earful.

Consultants galore expostulated on the many reasons why companies should embrace lean. Inventory is the devil. Smaller lot sizes force shops to become more efficient. Messy workplaces impede the elimination of waste. Long setup times cost money and reduce opportunities for productivity improvement. And yes, they said, lean is for everyone, even small shops with only a handful of people—who may see the biggest benefit from lean.

Nonetheless, lean benefits manufacturers of all shapes and sizes. Russ Scaffede, an instructor with the University of Michigan’s Lean Program at the College of Engineering, offered the example of a luxury yacht manufacturer in Holland, Mich., that was struggling to get product out the door.

“The owners felt they could sell 30 percent more yachts but were unable to increase production, at least not without adding to the facility and hiring a bunch of people,” Scaffede said. “They knew there were inefficiencies on the production floor; they just didn’t know where.”

Read the rest: Leaning towards lean | Cutting Tool Engineering | February …

Shops have plenty of choices when gripping small parts


Wedge, cam, square and pull-down clamps, micro vises and chucks, hexagons and rounds. These are just some of the workholding options available to shops that mill small workpieces. Finding the right clamps isn’t a problem, but how they’re utilized may be. This article examines some of the options and provides tips on how to use them.

Consider a job for a few thousand surgical widgets roughly the size of a paper clip. Some shops might try to fall back on the standard 6 ” (152.4mm) vise and a set of machinable, or shallow step, jaws to grab a fingernail’s worth of material along the workpiece bottom. That’s probably not a good idea.

Holding tiny parts in this manner is like pounding penny nails with a sledgehammer. Even with a delicate touch, a 6 ” machinist’s vise exerts hundreds of pounds or more of clamping force, which can quickly distort small workpieces. Big, clunky vises are also inefficient in terms of machine capacity. A typical 20 “×40 ” (508mm × 1,016mm) machining center would be hard pressed to hold half a dozen such vises, and with two workpieces per vise, that’s a paltry 12 parts per cycle.

Better to go with a clamp designed for small workpieces. Many utilize a wedge activated through the turn of a screw, which opens a set of expandable rails, activates a cam or mechanically forces the vise jaw against the workpiece.

Carr-Lane Manufacturing Co.’s Tiny Vise is one such device. The St. Louis-based tooling provider offers the vise in serrated, V-jaw and double-edge configurations, the smallest of which is 0.250 ” (6.35mm) high × 0.562 ” (14.275mm) wide and uses a #8-32 screw to generate 60 ft.-lbs. of clamping force. Colin Frost, chief business development officer, said a pair of opposing wedges provides the vise’s clamping motion by drawing together as the clamping screw is engaged.

“The Tiny Vise not only applies force horizontally against the part but also presses it down,” Frost explained. “Multidirectional clamping such as this is very effective for fixturing small parts, where it’s important to securely grip the sides of the workpiece while keeping the top clear for machining.”

Read the rest: Shops have plenty of choices when gripping small parts …

Collaborative robots lend a helping hand


Joe’s struggling to package a truckload of parts before noon. Mary can’t keep up on the painting line. Jimmy’s in trouble with the boss because he can’t make quota. These are just a few of the challenges faced by workers on the manufacturing floor, problems that, in many cases, can be solved with collaborative robots.

More affectionately known as “cobots,” collaborative robots are opening new possibilities in manufacturing. In this brave new world, cobots and humans work side by side in a common space not segregated by fences or walls. Need to hand deburr a few hundred parts, or insert bushings into thousands of assemblies? Grab a cobot, show it what to do and go back to whatever intelligent task you were doing.

Cobots are perfectly happy getting stuck with the short end of the manufacturing stick and won’t complain about doing the dirty, dull and dangerous tasks we humans grumble about.

But what are cobots, and how are they different from the robotic arms that load material in CNC machine tools and weld car chassis? The complete, mind-numbing details are available in the robotics safety specification ANSI/RIA R15.06-2012, jointly published by the American National Standards Institute and the Robotic Industries Association. Briefly put, the spec describes collaborative operations as ones where the robot monitors its surroundings and slows down or stops in the presence of a human, where force and power are limited in a work space shared by humans and robots, or where the robot is manually guided by a human.

Bob Doyle, director of communications for RIA, pointed out several additional differentiators between cobots and their stronger, faster and more accurate counterparts. The first is safety. Interfere with an assembly line drone as it bolts wheels onto an F-150 and you might be headed to the emergency room. Granted, safety barriers make this an unlikely situation, but unless using sharp or very heavy objects are part of its duties, injury such as this could never happen around a collaborative robot.

Read the rest:

Metrology toolbox includes optical micrometers


It used to be that a well-trained eye was the only noncontact method for inspecting a part. Then came optical comparators, also known as shadowgraphs, which were the popular choice in quality-assurance labs until the advent of lasers and CCD cameras. These technologies opened the door to through-beam and laser-scanning micrometers, both of which use light to measure workpieces in a manner similar to the one used by the venerable shadowgraph.

Typically called optical micrometers, there are several flavors of these noncontact inspection devices. The most mature version is the laser-scan micrometer. Also known as a laser mic, it became a useful machine shop fixture in the 1980s, and has since evolved into the de facto standard for gage calibration.

Another useful “Mike,” sales specialist Michal Grosenbach of metrology provider Mitutoyo America Corp., Aurora, Ill., explained that a laser-scanning micrometer is a gage that uses a ribbon of laser light to measure part features.

“It works by emitting a laser beam at a rotating polygonal mirror, which redirects the laser light through a collimating lens,” Grosenbach said. “The resulting light ribbon passes across the part, and whatever light makes it past the feature being measured passes through a condenser lens and then reaches a photoelectric receiver. As the scan moves across the workpiece, the time differential between the beginning and ending edges is measured and analyzed, which allows the machine to accurately extract the dimensional data.”

Like mechanical micrometers, most laser scanners measure in a single axis only, and are, therefore, best at measuring various facets on round parts—ODs, gaps between parallel surfaces (such as grooves), distances between parallel holes or flats, taper and other cylindrical features. By rotating the object being measured, ovality and other out-of-round conditions can be identified.

Read the rest: