ShopSolutions Case Histories of Manufacturing Problem Solving Wolcott Design Pitches a Competitive Shutout Ask Bob Wolcott what matters, and he ll excitedly talk three vertical machining centers to produce its parts, but as about his passion for doing jobs he finds interesting, business grew, Wolcott found himself in a situation where he challenging and rewarding; he has always followed needed to add more capacity and flexibility without adding that credo in his work. As the president and owner of Wolcott more floor space. Design Services (Newburg, OR), he oversees the design, analysis and fabrication that his shop provides for racing, technology, outdoor equipment and other industries. From concept to creation, this small shop prides itself on having all of these capabilities under one roof, creating a fluid transition between design and production while offering increased part quality at a reduced cost and lead time. This is Wolcott s second time at bat in what has been a doubleheader career. He started out as a Major League pitcher for the Seattle Mariners. After retiring from baseball, he studied mechanical engineering at Bob Wolcott knows what it takes to be a Major Leaguer and has built his company on high-performance Makino vertical and horizontal machining Oregon State while working an internship centers, first for precision prototype work and now for production. at Intel. Running a milling machine initially began as a hobby for Wolcott, but he soon learned that the We needed more speed than our vertical machining work he enjoyed doing on his manual machine could be the centers could provide faster processing, quicker changeovers and improved workflow management, said Wolcott. start of a lucrative business opportunity. He opened Wolcott Design Services while handling contract work for Intel. As the It was too time-consuming to take down a big production business began to grow, he found himself manufacturing the job in order to squeeze in a smaller prototype job. We knew very parts he was designing for customers like Gerber, PCC that a horizontal machining center could offer more parts Structurals, Bridge City Tool Works and Rothsport Racing. per fixture, offline setups, higher-volume tool magazines and Today the company has hit its stride making prototype and consolidated operations with multiface machining. By employing these capabilities, we would be able to run produc- production parts using both vertical and horizontal machining centers and competing easily with larger shops. For a tion parts and prototypes in the same setup while preventing small-size company like us to offer the kind of robust manufacturing capabilities and high-performance horizontal and Wolcott chose the a51nx horizontal machining center from spindle downtime. vertical machining centers that you may not even see in some Makino Inc. (Mason, OH) for his operation. The 40-taper mid-size manufacturing facilities, it shows our dedication in spindle is extremely rigid and robust and has allowed us to emphasizing quality, said Wolcott. expand our versatility and the variety of parts that we produce. Wolcott operates his shop on his own land, which means The 14,000-rpm spindle gives us the range of speed necessary to machine a variety of materials and features. Whether he has low overhead and routinely passes that cost saving along to his customers. The company had been using we are hogging out material or producing a pristine finish, the August 2013 ManufacturingEngineeringMedia.com 41
a51nx provides the power and torque we need to produce parts from start to finish in a single setup and the expanded axis travels that can accommodate larger parts, Wolcott said. Because the machine can handle more parts per fixture and doesn t need frequent changeovers, it is always cutting. Its automatic pallet changer and high-capacity tool magazine help Wolcott boost spindle utilization by loading parts and tools outside of the work zone without interrupting the machining process. The company has also improved its manual labor efficiency by allowing one person to operate both the a51nx and a neighboring vertical machining center a task that was not previously possible with two verticals. Vertical and horizontal machining centers produce parts like these at Wolcott Design Services. We appreciate that we don t have to interrupt the machining process on the a51nx, said Wolcott. We get up to 85% spindle utilization, allowing us to move lots of work through the machine. Producing batches of 10,000 parts is easy for us now and, because of that, we are pursuing more high-volume jobs. When we first began to offer production capabilities, 80% of our business was in prototype parts, said Wolcott. Today none of that work has left the shop floor; however, prototype parts now only make up 30% of our business. The company needed a cost-effective solution that would provide a much closer level of quality to that of the a51nx. Wolcott chose to replace one of his previous vertical machining centers with the Makino PS95. Business is booming, and to meet these demands, we needed something economical that could take some of the load off of the a51nx, and that would produce the same parts quickly without any loss of quality, said Wolcott. 42 ManufacturingEngineeringMedia.com August 2013
Wolcott ran a comparison between his current equipment and the PS95 with its 14,000-rpm, 33.5-hp (25-kW) CAT spindle. On the first run, with no changes to the program, the new machine beat the existing machine by eight minutes. The next time the part was run, feeds and speeds were increased to an optimal level for the PS95, and the part was completed 30 minutes faster. On a separate part, Wolcott achieved metal removal rates that were four times faster than those accomplished on his previous machine. That speed makes a real difference. For instance, the extra 30 minutes saved allows me to complete one more part per day, said Wolcott. On a $200 part, with the same number of employees using the same floor space, time savings can produce an extra $1000 more profit per week. That kind of savings quickly justifies the investment in a high-performance machine. Besides enjoying the increased speeds, Wolcott has experienced improved quality with repeatability as tight as 0.0001" (0.003 mm) on the PS95. When doing work on the previous vertical machining centers, the company had to manually polish the parts to achieve desired finishes doubling cycle time. On the Makino machines, parts come out in half the time as on the previous machines and require minimal hand work. ME For more information from Makino Inc., go to www.makino.com, or phone 513-573-7200; for more information from Wolcott Design Services, go to www.wolcottdesignservices.com, or phone 541-231-7479. producer of progressive stamping dies used in manufacturing rotor and stator cores for electric motors. Because the high quality of these tools results in improved core motor manufacturing precision and productivity, reduced waste, and Dynamic Toolpaths Double Die Making Progressive stamping die manufacturer LH Carbide (Fort Wayne, IN), a division of L.H. Industries, is a leading August 2013 ManufacturingEngineeringMedia.com 43
ultimately better electric motor performance, they are used by OEMs in a broad range of industries throughout the world. Like most manufacturers, our company experienced a severe downturn in orders post 9-11. As a result, staff levels declined and they still have not returned to pre 9-11 levels in some departments, said Tom Neuenschwander, L.H. Industries vice president-technology. Gradually, the company has recovered and in 2013 is experiencing record sales. CNC manufacturing productivity is keeping pace with demand by using Mastercam s dynamic toolpaths to get more done with fewer people and at higher levels of quality. Progressive dies are sophisticated tools manufactured to a motor OEM s specifications. They are assembled from 100 or more high-precision parts, mostly 2D, made from extremely hard materials like carbide or tool steel. The Rotor and stator cores for electric motors are manufactured with progressive dies from LH Carbide. With each down stroke of the press one, two, or three rows of 0.010 0.035" (0.25 0.89-mm) thick lamination steel are successively die cut, stacked, compressed and interlocked into unique rotor and stator cores that could be from 18 to 80 laminations high. CNC department cuts the parts to near net shape so that they can be efficiently shuttled through a series of critical-precision downstream processes including heat treating, wire EDM, precision jig and surface grinding, and finally assembly. During the course of the week, programmers receive hundreds of unique part designs detailed in SolidWorks. They use Mastercam X6 Mill from Mastercam/CNC Software Inc. (Tolland, CT) 44 ManufacturingEngineeringMedia.com August 2013
to create programs for the machining department s nine Haas Automation VF2-VF9 mills, a CNC lathe and a Mazak Integrex seven-axis machining center. Parts destined for subsequent processes with long lead times must go to the head of the line to assure that they all arrive at assembly in time to meet the customer s delivery requirements. At the customer s plant, the progressive die will be installed in a large stamping press (e.g., 350 ton) that operates at up to 400+ strokes per minute. With each down stroke of the press one, two, or three rows of 0.010 0.035" (0.25 0.89-mm) thick lamination steel are successively die cut, stacked, compressed and interlocked into unique rotor and stator cores that could be from 18 to 80 laminations high. In spite of the incredible pounding these tools take, they will endure for well over a million stamping cycles before requiring maintenance. As the economy was heating up in 2011, it was becoming difficult to keep up with the volume of work that was being pushed through the manufacturing department. Neuenschwander said that early in 2011, two things changed that made a big difference. Up until that time, 10 machine operators did most of their own CNC programming. The company decided CNC programming should be a separate function, making it a full-time responsibility of their two most experienced programmers. This gave the dedicated programmers more time to focus directly on optimizing Mastercam programs for improved manufacturing productivity. Operators on the shop floor still have access to Mastercam for making some program adjustments and off-loading work from the primary programmers when work volumes spike. Dynamic toolpaths in Mastercam X6 CAM program like the ones shown next to this lower half die model use minimal stepovers and as much of the tool s flute length as possible. While cutting, the program automatically adjust feeds and speeds to avoid excessive stress and heat buildup on the tool. About the same time, CAD/CAM Technologies (LH Carbide s Mastercam reseller) introduced the company to a new kind of dynamic toolpath strategy that was developed by Mastercam to address the types of throughput and tool-wear problems that LH Carbide was facing. The dynamic toolpath strategy goes against the conventional wisdom of aggressively hogging out parts with high stepover cuts using a very small portion of the tool s flute length. Instead, stepovers are very slight but use as much of the flute as possible, often at spindle speeds as high as the particular 46 ManufacturingEngineeringMedia.com August 2013
machine can generate safely. To improve the precision of these cuts, the company is now using shrink-fit toolholders which keep the total runout of carbide tools to within a few tenths, which is very important for assuring clearance tolerances for precision punches within the die system. Excessive forces on the tool are eliminated because the software thinks ahead to detect conditions that will result in the tool getting buried in the material (e.g. hitting a corner) and causing it to break or damage the part. Based on this foresight, the program automatically adjusts feeds and speeds to avoid these overloads. The dynamic toolpath algorithms are continually looking ahead and comparing options to decide such things as where to enter the part, where to go for the next cut and when to lift ever so slightly from the part during a dwell so that heat buildups are avoided. The dynamic toolpaths allow CNC equipment to run safely while cutting the hardest steel. They have helped reduce tool wear and tooling costs. The cost of prematurely worn and broken tools is always a concern. However, the more important advantage of this approach has been the ability to reduce the number of tool changes required for better equipment up-time. LH has been introducing lighter duty CNC equipment with higher spindle speeds to its manufacturing operations. Some of these operate at spindle speeds up to 30,000 rpm. Dynamic toolpaths have improved productivity by as much as 100%. However, when the company began using dynamic toolpaths, there were a significant number of older 40-taper machines only capable of spindle speeds up to 7500 rpm. The dynamic paths allowed these mills to run smaller diameter tools at the highest feeds and speeds possible without placing excessive stress on tools and the less rigid spindles. Productivity on these machines went up substantially. This advanced computer-aided manufacturing technology is allowing us to get a higher volume of work done faster. Until the last few years, if we could complete the detail parts for a die in a week or a week and a half, we would be doing well. Recently, there have been times when we have produced two or three dies in a single week. Our customers have very tight delivery expectations and we are finding ways to give them what they need, Neuenschwander said. ME For more information from Mastercam/CNC Software, go to www.mastercam.com, or phone 860-875-5006. Contour Measurement of Brake Parts Faster, Easier At Advics Manufacturing Ohio Inc., a CNC setup has dramatically transformed contour measurement of automotive brake components from a 45-minute specialist s task to a 3 1/2-minute generalist s job. Founded in 1987 and located about 40 miles northeast of Cincinnati, Advics Manufacturing Ohio employs more than 500 people dedicated solely to production of disc brake calipers and ABS units. These are supplied to automakers around the world for installation in more than 20 different vehicle models by the company, which has a reputation for being a quality-leader for brake products made in North America. August 2013 ManufacturingEngineeringMedia.com 47
Advics mission is to add value to society by creating products to improve safety, comfort and environmental responsibility. Evidence of this pursuit is the implementation of a program of continuous improvement, which impacts every operation. One area targeted for development was caliper bore measurement and inspection. The objective was to increase both the types of calipers that underwent bore inspection as well as the frequency of those inspections with the net result of dramatically increasing caliper bore measurement/ inspection throughput. A brake caliper straddles a brake rotor and houses pistons to which brake pads are affixed. When hydraulic pressure is applied by the foot pedal via a brake master cylinder (augmented, if so equipped, by power brake-assist), the pistons squeeze the pads against the rotor to generate stopping friction. The caliper includes cylinder bores into which the pistons fit. A seal must be maintained between the cylinder and the bore to maintain integrity of the hydraulic circuit. This sealing is provided by a piston seal which fits into a groove machined into the cylinder bore. The piston seal itself is a gasket with a square profile on both its ID and OD. The interaction of the seal s OD against the geometry of the groove in the bore, as well as of its ID against the piston wall is critical both from the perspective of sealing fluid and also because it is responsible for providing what is called rollback. Rollback occurs when the seal deflects as friction with the piston draws the seal in the direction of piston movement (a minute amount); seal edges are designed with chamfers and other details to facilitate this action. The result is that when braking pedal pressure is released, the seal rolls back to its original position, helping to pull the piston with it. This phenomenon is very important to brake function in terms of noise-related issues attributable to pad-to-rotor contact. The Advics Quality Group determined that there are several critical caliper bore groove features that need to be Continued on page 86 48 ManufacturingEngineeringMedia.com August 2013
Continued from page 48 measured, inspected, and monitored. Advics Manufacturing Ohio s caliper bore measurement frequency was established by their continuous improvement program and requires sampling at every tool change. The frequency requirement also takes into account extra measurements between tool changes to monitor bore changes as predicted by tool wear experience and other factors. And with 15 machining centers producing millions of differing types of brake calipers per year, the total number of caliper bore measurements at Advics Manufacturing Ohio is extremely high. Mitutoyo s CV-3000CNC Contracer has taken measuring brake caliper bore grooves out of the hands of a specialist, put the task into the hands of generalist and cut measurement time from 45 minutes to 3 minutes for Advics Manufacturing Inc. Advics uses contour measurement machines to inspect caliper bore grooves. In 2004, the company first installed a manual Mitutoyo CV-3000 Contracer to measure bore grooves. These instruments offer fast traverse speeds (X axis [drive unit]; 80 mm/s MAX; Z2 axis [column; 30 mm/s MAX) and included a precision arc-scale built into the Z1 axis (detector) allowing the arc trajectory of the stylus tip to be read directly, thus minimizing error. The machine s arms are also equipped with collision auto-stop to assure measurement safety during high-speed movement. Depending on the operator, manually measuring all bore parameters with the Contracer averaged about 45 minutes each. A way had to be found to avoid overwhelming Advics capacity for taking these measurements. As a result of the installation of the manual CV-3000, Advics enjoyed a relationship with Mitutoyo s M 3 Solution Center. Advics sup- 86 ManufacturingEngineeringMedia.com August 2013
plied the M 3 Solution Center with sample parts and asked for a recommendation that would achieve the required bore measurement throughput. Within weeks, the center came back with an approach based on use of a CNC Contracer model CV-3000CNC. This machine has a maximum drive speed of 200 mm/s and a linear displacement accuracy of ±(1+4L/200) µm. Control is via an easyto-operate remote box. The M 3 Solution Center proposed combining the CV-3000CNC together with an innovative parts-handling system that included bar coding, advanced part programming, and a highly capable analysis/reporting and data archiving/ networking routine. Advics deemed the solution on-target. Final development was undertaken jointly by Advics and Mitutoyo, and the system was installed. Advics developed a modular fixturing system with each fixture designed specifically for a type of caliper. Each of the different fixtures, however, fits into the same type of base plate, which fits the CV-3000CNC. Bar codes matching the caliper type are affixed to each fixture. All the operator has to do is load the fixture/part combination into the CV-3000CNC and then, using a scanner gun, scan the bar code. The code automatically tells the CV-3000CNC which part program to run. Finally, the operator confirms proper part loading, and everything that follows is automatic. Part programming is via Formtracepak, Mitutoyo s proprietary contour analysis software. Formtracepak offers total support for measurement system control, surface roughness analysis, contour analysis, contour tolerancing, and generation of inspection reports. Both the Contracer and Formtracepak communicate with MeasurLink, Mitutoyo s proprietary statistical-processing and process-control program, which performs statistical analysis and provides real-time display of measurement results for SPC applications. ME For more information from Mitutoyo America Corp., go to www.mitutoyo.com, or phone 888-648-8869. August 2013 ManufacturingEngineeringMedia.com 87