Shop Solutions: Software Sharpens Laser Cutting
When it comes to unique knives with a broad selection of available styles and models, it's hard to beat US knife manufacturer Kershaw Knives (Tualatin, OR), a company with an unusual history.
In 1974, Pete Kershaw, a sales manager for Gerber Knives, struck out on his own and began importing knives from a Japanese company called Kai Cutlery Center Co. Ltd., a one hundred-yearold manufacturer of large knives and disposable razors. Kershaw's company, originally located in Lake Oswego, OR, was so successful that Kai purchased it in 1977.
Kai continued to import knives from Japan until about 1995. At that time the US dollar was weakening, making it costly to import knives. To eliminate exchange rate issues, Kai decided it needed to make knives in the country where they were being sold, and opened a factory in Tualatin, OR. It took about a year to ramp up production, with actual knife manufacturing beginning in 1996. Today, the company remains Japanese-owned but offers American-made products.
Knives are usually thought of as utilitarian products, but they can also be considered collectable products. Collectable models might have a very short life span, and designers are constantly developing new models with special features and designs to stay ahead of the competition. Some of the company's knives are custom-made for the military, and not offered to the general public.
Distinctive products such Kershaw's short product-cycle knives can be a challenge to manufacturing. "A typical lifespan of a knife design is perhaps three years," explains Craigg Green, factory manager. "Obviously there's a huge turnover in the actual manufacturing; therefore, we have to be flexible just to make our production. We have about 220 employees and run three shifts, making between 70,000 and 100,000 knives a month from this factory. That's a lot of pocket knives—about 80% of our pocket knife production."
For its milling machines, Kershaw began using Mastercam from CNC Software Inc. (Tolland, CT), Version 6, in 1996. Today, the company's three programmers are using Mastercam X.
"What we're doing with Mastercam is machining knife handles. Mostly these handles can be aluminum or 410-stainless, or even titanium on some of our higher-end knives. We do a lot of 3-D surface machining now. Mastercam X is very good at that. That's one of the most powerful tools that it offers us."
Kershaw programs its lasers with Mastercam. "We have a year-old Mazak laser, and we use Mastercam to program the cutting sequence. We only had to create a custom post processor to create the code. The laser beam is 0.012" [0.3-mm] wide, so we just program it like an end mill with that diameter," Green explains.
This may seem like an unusual use for Mastercam, which is primarily used for machine toolpaths, but Green felt it was an economical choice and one that allowed his programmers to work with software they already knew.
His reasoning: "If a shop starts with a piece of software, it's hard to get them out of it because you have that legacy, and we decided Mastercam could easily be used for our laser. The people at MCAM Northwest (Milwaukie, OR), who sell Mastercam locally, were very good at writing the post processor for the laser. They had it written for us within a week."
Surfacing is one of the important capabilities that Mastercam offers. For example, the handle for one of Kershaw's knives, the Specbump 1596, is contoured to give it a unique look. Green explains that most knives have flat handles and aren't contoured. "If you looked at the top view of them, they're just flat. That works for probably 75% of our products, because it keeps the price down. We have a lot of price-point knives, between $50 and $100 each. Those are our meat and potato products. But we have many products that cost $200 each that have a 3-D handle. They actually have a contour to them," Green says.
"We typically use a 0.25" [6.3-mm] ball end mill, and we're surfacing with it and creating grooves. We're stepping over perhaps 0.080–0.100" [2–2.54 mm] and creating another machined surface. We get a very unique look. I think we were probably the first company in our industry to do that mainstream, to actually offer products that were 3-D machined."
Knife blades, whether a blade in a folding knife or a blade with a tang that has an integral handle, may be either stamped using a fine blanking method or, for the lower quantity specialty knives, laser-cut from sheetmetal. Fine blanking produces a very precise part that doesn't need additional processing to finish the edges.
The Mazak laser, driven by Mastercam, gives the company greater flexibility to produce the lower-volume knives. "When we have items that cost $200 each, you might sell maybe 250 a month. Well, that's not enough to justify buying fine-blank tooling, which is very expensive. So we'll laser-cut the part. Typically we'll laser-cut them leaving a little bit of material around the profile. Then we'll put them on a CNC milling machine to finish them. So we're profile-milling the edges, which is duck soup for Mastercam's capabilities," Green explains.
"We're not even that concerned about the part tolerance or dimensional stability. Within a thousandth tolerance is plenty for us. What we're really looking for is aesthetics. One huge improvement from Mastercam 9 to X is its Verify capability. The new Verify in Mastercam X is far superior to Version 9 and all the other ones. I can look at that part in Verify, and that's what I'm actually going to see when I machine the part, which in the old days was not exactly true," says Green.
Green adds that when they're using the surface-machining capabilities of Mastercam, the product has to look a certain way and it has to work. They have to balance surfacing the handles quickly with giving customers a unique knife handle.
"We might have to machine a part 18 times within the Mastercam program, re-verifying it different ways until we come up with a cool look. Now we can actually print it, show our sales department, and say this is what it's going to look like, before we've ever machined it. We don't waste time machining 15 samples and then showing them to our sales department. We just print the Verify and show them that," adds Green.
After the surface machining is complete, most knife handles are vibratory deburred or smoothed over, and then either anodized using several colors or left uncoated, depending on the handle material.
Kershaw Knives created a new brand about a year ago, called Zero Tolerance, for military and law enforcement only. Some of the military knives are manufactured from titanium, making them lightweight and very tough. These specialty knives are also surface-machined, taking about five minutes per handle. They have a very distinct grip pattern on the back that Kershaw developed using Mastercam's Verify in Mastercam X.
"The Verify feature is the biggest thing that has given us an advantage as a result of using the software. When we're surface machining, what we see when we Verify is what we're going to get. It allows us to change the stepover amount, or the way we're cutting the part so that we can get a certain look," Green concludes.
Big Shafts Machined in One Setup
Production time for large shafts to 6.5-m long weighing 8 tonnes has been reduced by about 50% for VEM Sachsenwerk GmbH (Dresden) using the M120 Millturn 6500 from WFL Millturn Technologies (Linz, Austria; Novi, MI).
VEM is no unproductive relic of the one-time planned economy in eastern Germany. The company has earned a reputation for the highest technology standards in the production of electric generation machines.
Products of the company ensure that both space stations in orbit and mining equipment many miles underground at the extremes of human activities are working safely and reliably. Its shafts are to be found on drive units operating in steel plants, power plants, petrochemical, cement making, and transportation industries.
The scope of VEM's product applications is seen in one recent on-going project. For a continuous-casting plant and plate mill being engineered and built by SMS Demag for the Magnitogorsk Metallurgical Combine, a major Russian steel producer, VEM will provide two 1250-kW edger drives, comprising two synchronous machines with outputs of 12 MW each. Units will be shipped in 2008.
VEM Sachsenwerk is a member of an association of companies that includes VEM motors GmbH (Wernigerode), VEM motors Thurm GmbH (Zwickau), and Keulahutte GmbH (Krauschwitz). It employs 440 on staff plus 24 apprentices. The VEM brand is found on product lines that include asynchronous machines (140–28,000 kW); synchronous machines (400–35,500 kW), traction motors to 1600 kW, traction generators to 3000 kWA, standby generators to 1000 kVA, synchronous generators (250–45,000 kVA), and wind-driven generators (1.5–5.4 MW).
The European electric motor industry has quite a tradition of manufacturing in Dresden. This city is where the company's headquarters is located, and where electric motors have been designed and built for 120 years. It is also where, in the mid-1930s, the first series of modular motors were designed and built that became the standard for production of today's motors.
More recently, the increase in orders for large-size motors has challenged the work capacity of motor builders like VEM. Components such as large shafts stretch the capacity of gantry cranes to handle workpieces with dimensions that match the size of the large machining centers, horizontal boring mills, turning systems, and grinding machines.
Precision manufacturing requirements are essential to ensure that assembly cycles for large electricity-generating equipment can be carried out to ensure maximum availability of the units. To meet these requirements, VEM has acquired the WFL M120 Millturn 6500, a machine that combines turning, boring, milling, and drilling with a full array of B, C, X, Y, Z axes. The multifunctional setup allows one-setup machining of high-precision complex parts.
Engineer Peter Sperling, who is in charge of technical job scheduling in the mechanical construction department of VEM, explains the considerations that led to the purchase of the M120 Millturn: "When a major order for wind-energy generators was in the offing, we had to think of a way to guarantee not only the requisite top precision, but also to improve the economics of production. Our own capacities were not up this challenge; while farming out the shaft production proved unattractive from a financial point of view."
After contacting several machine producers and visiting reference plants, the machine and technology concept from Austrian machine tool builder WFL was judged to be most attractive for the job. It allows machining shafts, including butt ends, with a maximum length of 6.5 m and a unit weight of 8 metric tons, with the required accuracy and cost efficiency.
The figures bear out Sperling's assessment. Before buying the WFL Millturn machine, it took more than 100 hr to manufacture a spider shaft; with the WFL Millturn that time has been cut almost in half.
The project wasn't just about the new machinery, says Sperling, it was also about the implementation of a technology concept tailored to the needs of the Dresden operation regarding the manufacture of high-precision shafts.
This is where the modular design of the Millturn machine generation comes in, according to Manfred Baumgartner, WFL application engineer, who worked on the project both in the WFL Technology Testing Center at Linz and at the VEM facility. "The use of roller-burnishing tools completely eliminates the lengthy grinding process that was formerly required, while still achieving a grinding accuracy in the area of a few microns," he says.
To ensure that necessary tolerances are met in all machining steps, a special high-precision package is incorporated in the machine configuration. The package provides a 3-D in-process measuring system; at the same time, steady-rest positions and temperature gradients inside the machine are taken into account.
In turning, milling, or boring, the sequence "semifinish cut-probe-finish cut" is designed to produce high accuracy in size and position even with complex workpieces. The probe, which is stored in the standard tool magazine, is used for fully automatic length and circumferential orientation of workpieces after clamping by means of premachined or cast features.
In addition, the Millturn machine is designed for gundrilling to 850 mm and diam to 110 mm. Steadyrests guarantee the requisite stability and concentricity for exceptionally long workpieces.
Sperling points to the capability of the M120 Millturn to handle extra-long shafts, and the fact that it doesn't take operators long before they are able to finish-turn every component to the high standards expected.
Filtration Handles Cast-Iron Fines
Machining big cast-iron components for the oil and gas industry requires special attention to handling the iron fines that can clog machining centers, leading to excessive downtime and loss of production.
Paul Precision Machine Inc. (Tulsa) is a contract manufacturer that specializes in heavy machining of cast-iron components for oil and gas equipment. Founded in 1978, Paul Precision targets large-diam parts, usually ranging from 10–30" (254–762-mm) mm) diam, for production on their CNC machining centers. Tool steels, stainless, cast iron, and aluminum are all processed at the company.
A particular specialty of this shop is the machining of ductile-iron cylinder castings, steeple cylinders, and crosshead guides for natural-gas compressors. Very high-pressure coolant flushing is required, as the Paul machining centers accommodate large work envelopes.
As company founder and president, Chuck Paul, explains, the company was experiencing a recurring and costly problem, "Every 80–100 hr, our big machining centers were going down, due to filter clogging from cast-iron fines. The clogging that occurred created immediate problems in coolant delivery to the large workpieces. We'd need to stop production, completely break down the system, clean and replace parts, reassemble, and get back to business. This process usually took anywhere from 8–12 hr, and that represented substantial loss of revenue, in addition to pushing back our production scheduling, every two weeks or so."
Then, his son Kevin Paul took a trip to Chicago for the machine tool show and made a discovery. He'd gone to the show looking for an answer to this challenge and found a magnetic chip disc filtration system specifically designed to handle the fines from cast-iron machining. Kevin returned to Tulsa and began the process of investigating the system further, using the Web site of the manufacturer, Hennig Inc. (Machesney Park, IL).
Within 60 days of conversation and drawing exchanges, the decision was made and the first CICDF (Cast Iron Chip Disc Filter) was installed on one of Paul's 600-mm Okuma machining centers. Through the first four months of operation, not a single instance of machining center downtime occurred as a result of filter clogging.
Machining of cast iron, as Chuck Paul explains, causes a large volume of small particles, known as fines, to be produced. These particles are often in the 25–100-µm range, well below the capabilities of typical machine-tool filter systems. This results in sludge accumulating on the chip conveyor as well as the filter vessel. When clogging occurs, the machine requires substantial downtime resulting in loss of production, as the sludge is literally shoveled out of the system.
On the CICDF from Hennig, the flushing coolant is channeled through the conveyor, where the big chips and larger particles fall off. Next, smaller particles are collected by a magnetic rotating drum that indexes across a stainless-steel blade. As the sludge accumulates on the blade, it also drops onto the conveyor for delivery to the chip hopper. Finally, the smallest particles that escape the magnetic field of the drum migrate to a disc filter media, made from a micronic weave of stainless steel mesh, to intercept particles as small as 25µm.
A continuous backwash of coolant blasts the particles collected on the disc back to the magnetic drum, where they are likewise scraped off as sludge, eventually dropping onto the conveyor. An inverted lip seal protects the rotating bearings from contamination by the fines.
Longer coolant life and less heat buildup are said to be other important benefits of the CICDF system. Only clean coolant returns to the reservoir for continuing duty on the machine tool or is diverted to the system's self-cleaning spray cycle.
Chuck Paul admits he experienced some sticker shock at the cost of the first system, until he calculated the payback time to be 14–16 months on a machining center running one ten-hour shift per work day. And, that calculation only took the billing rate for the machine tool into account. With the additional uptime and better predictability on his work schedule, Paul was able to improve turnaround time on jobs and not make the almost biweekly adjustments caused by the former system's excessive and costly downtime. Chuck Paul notes the CICDF system performs equally well on all materials, even the nonferrous.
As a result, an additional CICDF has been installed and a third is scheduled soon for installation on the shop's Daewoo machining center. Compared to the alternatives of a vacuum-cleaning system or the changeover and HAZMAT disposal problems of conventional paper media, Paul notes there are substantial cost and other benefits to the magnetic drum system selected at his shop.
Installation of the CICDF was a relatively low-impact process for Paul, as the system utilizes the machine-tool controls, interconnected to a manual autoswitch, so the system runs whenever the machine tool is in operation.
In addition to son Kevin, Chuck Paul's wife, Lou, and daughter, Lisa, are among the dozen employees at this truly family-run company.
Chuck Paul cited Jeff Nau and Susan Block at Hennig for their particular assistance in the engineering, delivery, installation, set-up and training on the CICDF systems at his shop. "They made the entire process a satisfying experience for Paul Precision, especially as we began to see the benefits of the system on our shop floor were exactly what they promised," Paul concludes.
Software Helps Shop Earn ISO Fast
NSA Industries Inc. (Lyndonville, VT) is a sheetmetal and metal fabrication shop that manufactures, assembles, and distributes sheetmetal fabrications and products manufactured from steel, aluminum, brass, and copper. NSA employs almost 400 people and, as such, plays a big part in the community.
In April 2002, NSA purchased the E2 Shop System from Shoptech Software (Glastonbury, CT), replacing an antiquated shop management system that wasn't providing the information necessary to grow the business effectively.
NSA was able to get up and running, using 90% of the E2 Shop System within a very short time. With the help of George Wells, senior E2 consultant, the E2 system was implemented for quoting jobs, scheduling the shop floor, managing material, job costing and tracking, real-time data collection off the floor, and shipping, all the way through to accounting.
The net result was that NSA was able to run more efficiently and effectively than ever before. "Over the past four years we were able to grow our business over 35% with the help of E2," says Neil Austin, president and owner of NSA Industries.
It wasn't until the fall of 2006, however, that NSA took a stab at the integration of its Quality Management System (QMS) and the E2 Shop System. NSA was interested in getting registered to the ISO 9001:2000 standard due to increased customer demand. "ISO companies like working with other ISO companies," says Howard Spencer, manufacturing manager for NSA. "Being ISO-registered provides our customers a known level of quality products and services."
In September 2006 NSA took on the daunting task of becoming ISO certified. The horror stories from other shops prepared them for a worst case scenario of many months of hard work documenting procedures along with tens of thousands of dollars being invested just to "get the banner."
The quality management system of most shops is separate from their ERP system. Many shops have an outside firm develop and maintain their quality system. The QMS and ERP systems co-exist in two separate worlds, operating independently of each other, creating double the work and double the money without being very efficient.
NSA decided that, with the help of Shoptech lead ISO auditor Ed Parsons, they would buck the trend and develop their QMS and ERP system into one truly integrated quality management system. The goal of this transformation was to develop a QMS system that would guide them, empower them, and help them grow efficiently.
Parsons immediately went to work performing a gap analysis. This consisted of conducting an onsite visit to determine and document the gap that exists between the ISO 9001:2000 requirements and the existing process at the company. "The gap analysis will tell you where your company is at in relation to registration, and what you need to do to achieve it," says Parsons.
He conducted interviews, mapped all of the processes within the company, and put the process maps into an electronic format using the Microsoft Visio program. Quality Management System training sessions were conducted, one for management, and another session for all other employees. The management training session was longer and more comprehensive, due to the fact that management is responsible for driving the ISO program.
All of the required ISO documentation was developed for NSA, comprising about 50 documents. This included—but was not limited to—a quality manual, all of the procedures needed for a robust QMS, forms, and all of the documentation needed to establish an internal auditing program.
A pre-assessment audit was conducted to ascertain readiness for the registration audit and ensure a successful outcome. The audit was conducted as if it were a registration audit. All facets of the Quality Management System were covered during the audit. Parsons provided recommended solutions to any nonconformances or system weaknesses found during the audit. He also provided guidance and help with the selection of the registrar and the logistical planning of the registration audit. The registration audit is described by all hands as a complete success.
There are 44 major requirements specified by the ISO 9001:2000 standard. In conjunction with the Quality Module, the E2 Shop System satisfies 27 of the 44 requirements specified by the ISO 9001:2000 standard. This means that 61% of all of the ISO requirements were covered by using E2 with the Quality Module.
Based on industry research, a typical ISO 9001:2000 implementation without a quality management system in place, or a very minimal one, should require 10–12 months. This will, of course, depend upon available resources applied to the implementation.
NSA was able to go from start to finish in 100 days. This streamlined approach was developed by the consulting organization at Shoptech Software, and was completely dependent on using the E2 Shop System and its ISO-ready features and functionality.
ISO registration has proven valuable to NSA Industries in retaining its client base and gaining new clients. Beyond that, NSA now has in place a comprehensive business management system. The system is based on providing and enhancing customer satisfaction and continual improvement of the system, and requires the gathering and analysis of data in order to make business decisions based on facts. The integrity of the system must be maintained and improved, ensured via audits, to retain the ISO registration.
This article was first published in the November 2007 edition of Manufacturing Engineering magazine.
Published Date : 11/1/2007