Shop Solutions: Video Measurement Cuts Costs, Boosts Data Integrity
Parmatech Corp. (Petaluma, CA) needed a flexible and precise platform for collecting measurement data for a key customer part. The small surgical component featured intricate details and close tolerances, and the inspection system the company was using simply wasn't getting the job done.
"We had a vision system here on loan from one of our customers," recalls quality assurance manager Lyle Hilfigure Jr. "It wasn't user friendly, and it had poor repeatability and reproducibility. Our backup system was a toolmaker's microscope. Both systems were inefficient and ineffective for our needs."
Parmatech, a subsidiary of ATW Cos., manufactures components for customers such as Motorola, Johnson & Johnson, and Smith & Wesson in its 30,000 ft2 (2790 m2) facility. Specific products include hinge assemblies for cell phones, components for minimally invasive surgical procedures, and handgun and rifle components. The majority of the parts are stainless, low-carbon, and alloy steels. Regular production rates exceed 1 million units/month.
Parmatech began searching for a video inspection system that would not only measure its parts, but also capture data and facilitate process improvement. After an extensive search, the company selected a SmartScope video measurement system from Optical Gaging Products (OGP; Rochester, NY).
"We produce small components with intricate details and close tolerances, and our measuring datums are often difficult to define," Hilfigure explains. "We have a couple of customer projects that we could not have developed without the SmartScope system in place.
"We've been able to manage these accounts at a higher quality level and lower cost," he continues. "Our data are now over 50% more reliable than our previous methods based on gage repeatability and reproducibility [GR&R] studies. Product development cost is down by an average of $1500 per project, because we've reduced the outsourcing of critical data acquisition. And, standard inspection time for parts is reduced by more than 30% compared with previous methods."
In 2002, a four-component project that made extensive use of the system was awarded Grand Prize in an annual industry competition for use of metal injection molding (MIM) technology. MIM is a low-cost, high-volume manufacturing process that can produce small parts to near-net shape, resulting in fewer secondary operations.
The system's ease of use allowed Parmatech to quickly bring inspectors up to speed, improved measurement reliability, and helped engineers isolate operator and measurement error from process variation. Resulting improvements have significantly streamlined and improved processes. And, data collected from the video inspection system are entered into either a spreadsheet or part tracking software for statistical analysis.
Located in the Parmatech QA Lab, the system is used for in-process and final inspection, as well as product development and engineering design of experiments (DOE) studies. "The SmartScope is the most-used piece of high-tech equipment in the lab," notes Hilfigure. "We use it to measure a wide range of features from lengths and widths to profiles of complex surfaces. We check a number of geometric tolerances on difficult-to-measure features."
According to Hilfigure, the system's flexible design lets Parmatech use both fixtures and open setups and reduces inspection time for a variety of jobs. "We're doing first-article inspections with 100 dimensions or more, as well as production samples," he says. "Our MIM process is batch-based using molds with one to eight cavities, and we use an acceptable quality level [AQL] system for sampling up to 35 pieces per cavity per lot."
Hilfigure says the system's combination of magnification and lighting control is especially useful. "We are able to clearly identify edges in spite of component feature aberrations," he notes. "We control how and where we see and obtain features. This puts the feature designation decision in the hands of the inspector and not in the interpretation of the gage."
System benefits have also extended into Hilfigure's role as a QA manager. "I have less training to do, so I can focus on other issues," he says. "With more reliable data to make decisions, I don't have to re-measure to have confidence in those decisions. I now have customer respect when it comes to measurement disputes. Although there are times when a customer checks parts and gets different data, we usually prevail. And, I have improved inspection throughput--we can now do more with less."
Lean Thinking, Online Training Help Revive Shop
Miltronics & Skye (Painesville, OH) is no stranger to the ups and downs of contract manufacturing. Founded in 1984, the medical manufacturer at one time employed more than 100 people before falling on hard times. A late-2002 acquisition by Trust Technologies, another northeastern Ohio precision contract manufacturer, marked the beginning of a turnaround for Miltronics & Skye.
"We are not the same old company," says site manager Jack Hostutler. He ticks off the changes that have occurred at the company since the end of 2002: new owner, new president, new sales staff, new continuous improvement programs, new training methods, new customer focus.
Miltronics & Skye uses CNC turning and milling, laser marking, electropolishing, and passivation processes to produce components for orthopedic implant manufacturers from titanium alloys and other materials. After training key employees in lean principles, Miltronics launched lean implementation teams that reconfigured the plant layout, creating cells around part families. Other initiatives included a 5S program.
And, Hostutler adds, all shop employees now receive in-house Certified Operator Training based on online training courses from Tooling University (www.toolingu.com; Cleveland, OH). "Online training classes are the main body of knowledge used," he says. "We looked into several different training options, such as local tech schools and colleges, but Tooling U gave us the biggest bang for the buck. It's also the most flexible as far as when the employees could train."
Miltronics & Skye requires five Tooling U classes plus other training as a base of knowledge for operator certification. Training is ongoing, and Hostutler says online learning fits in well with the company's overall training philosophy as well as employees' busy schedules. "With Tooling U, any computer with Internet access becomes a training center," he says. "At work or at home, employees have access to training 24/7."
Results from operator training have been impressive, according to Hostutler. Internal quality, measured in defects per million, has improved almost 92% from a year ago. "Our largest customers are medical device OEMs, which means we must conform to the U.S. Food & Drug Administration's Good Manufacturing Practices [GMP] regulations," Hostutler says. "The GMP requires manufacturers to establish procedures for identifying training needs, to ensure that all personnel are trained to adequately perform their assigned responsibilities, and to document the training.
"Our training files used to be a weak point during ISO 9002 or GMP audits, but with Tooling U and our Operator Certification program our training files are impressive," he concludes. Training files are generated from the Tooling U Administration Center, where managers can quickly set trainee schedules and monitor employee progress and performance.
Miltronics & Skye will soon consolidate in a new 67,000 ft2 (6200 m2 facility, essentially doubling its current space. Hostutler says Tooling U training has been a key component in the company's revitalization. "Online training has been instrumental in developing a lean approach on the manufacturing floor as well as in the continuous improvement of both quality and delivery metrics," he concludes.
Lower Costs in Motion
Bayside Motion Group (Port Washington, NY) is a supplier and integrator of precision gears, servomotors, and linear technology. The company employs true cellular manufacturing, where each cell or team is responsible for a product from start to finish. Lean manufacturing principles continually lead Bayside to seek ways of reducing cost and optimizing processes.
In the spring of 2003, CNC programmer and assistant process engineer Saf Samad was given the task of cutting costs and standardizing cutting tools throughout the entire factory. It was around this time that he received a phone call from his Seco-Carboloy distributor, who offered to bring in some tools for evaluation.
The test tools included a cemented carbide turning grade, TP1000. Designed to minimize all common wear patterns, the grade features a cobalt-enriched substrate with a hard interior and a tough, wear-resistant surface region. These combined properties offer both deformation resistance needed for high cutting speeds and excellent edge toughness for high reliability.
With tests showing an average increase of 77% more parts per insert corner, Bayside agreed to try out a TP1000 CNMG432 roughing insert in a gear-cutting operation currently being run on a Wasino lathe with a competitor's cutting tool.
Bayside produces two fundamental styles of gear - helical and spur. Each gear style has seven different frame sizes ranging from PS40 to PS300, and each frame size has a different ratio. Add to that the fact that the number of teeth per gear varies from 10 to 48, and the result is a large number of machining variables for each gearbox produced.
Gears are machined from a specialized stainless material, and 90% of machining operations are performed on the Wasino lathe. The TP1000 roughing insert is used at a depth of cut of about 0.0400" (10 mm) per pass. For finishing, a TP1000 DNMG insert is run at a depth of cut of 0.010" (0.25 mm). The remaining work is performed on a gear cutting machine.
Since implementing the Carboloy tools, Bayside has seen productivity gains in a number of areas, including longer tool life, increased feeds and speeds, reduced cycle times, and improved chipbreaking.
"When we saw the capabilities of the TP1000, we modified a few programs to take advantage of the tool," says Samad. Where we were getting 400 sfm (122 m/min) on the competitive insert, we're now getting 590 sfm (180 m/min).
"In addition, we're gaining 25 - 35% in tool life," he continues. "With the old insert, we were producing about six to seven pieces per edge. With TP1000, we get at least 10 pieces per edge."
Bayside soon began using the inserts on other components, including pinions and housings produced on Mori Seiki turning machines. Similar to the gears, the stainless steel pinions also require extensive roughing and finishing. The housings arrive at the manufacturing cell in near-net shape.
"We have modeled our manufacturing process on the Toyota Production System, delivering JIT products through a one-piece manufacturing flow," Samad explains. "That means we have to meet short lead times, whether on standard or special products. The responsiveness of our cellular manufacturing operation has been hugely important, but the gains we are making with TP1000 have also been significant."
How significant? Samad says the company has achieved an overall 30% increase in part production, a 50% reduction in shop-wide tool costs, and a 20% decrease in cycle time. The processes require fewer tool compensations and fewer tool changes.
Technology Tackles Global Competition
With the recent rise in competition from low-cost manufacturers around the globe, many machine shops in the United States have found themselves struggling to find ways to remain profitable.
Managers at Liberty Machine Inc. (Arab, AL) responded to the challenge by identifying and concentrating on areas in which they held a clear advantage over foreign rivals. Over the past year, both the shop and its sales volume have grown.
Robert and Kenny Cleveland founded Liberty Machine in 1984. Initially, the father and son duo were the shop's entire workforce. Five years later, the company moved to a new building and hired its first employee. Over the next decade, the shop continued to expand, Its customer base grew to include such clients as Boeing, NASA, Southeastern Technology, and Wright Medical Technology.
As Liberty Machine gained experience, it also gained a reputation as a shop willing to try new things and make them work. "We've really worked hard to make sure that our employees have a broad variety of capabilities," says company president Kenny Cleveland. "It's given us the ability to go after the difficult and complicated jobs in addition to more standard work."
This ability to perform more specialized work has helped Liberty stay afloat as more standard work is shipped overseas. Despite this, the shop had to lay off employees for the first time in its history in 2002.
The downturn prompted the Clevelands to identify areas in which they excelled that were unlikely to be sent overseas. "Medical parts have made up an increasing percentage of our workload," explains Kenny. "They require tight tolerances and extreme accuracy and need to look good as well, which means they take a little more time. The quality levels required make them unlikely to go to a shop overseas, and time constraints make them undesirable for a lot of shops here."
Liberty began to pursue more medical work, and in early 2003 earned a contract to manufacture a large quantity of orthopedic femoral cutting blocks. The parts feature a series of six 0.060" (1.52-mm) slots. At the time, the shop did not have a wire EDM capable of performing the work as efficiently or accurately as required. After reviewing possible options, Liberty purchased three Robofil 240 wire EDM machines from Charmilles Technologies (Lincolnshire, IL).
Liberty established an EDM cell with two slots being produced at each machine. The shop was able to use a single operator to run all three machines and inspect the final parts. Taking full advantage of the machines' capabilities, the shop added weekend and night shifts and has had no trouble finding work.
"The work's still out there if you can do a quality job and have a fast turnaround time," says Kenny Cleveland. "There's been a movement toward reduced inventories by a lot of our customers. Now we might run 20 or 25 parts for a customer that used to order lots of 100. The fact that our Charmilles machines are around 40% faster than our old wire EDM has helped us adapt to this shift."
All of this translated into an improved business outlook for Liberty. A 20% increase in sales allowed the shop to rehire all of the workers laid off in 2002, and also add five new positions to their workforce. As the shop continues to grow, the Clevelands are contemplating an expansion of their EDM capability.
Drills Improve Holemaking Efficiency
Wood Group Pressure Control (WPG; Shawnee, OK) manufactures wellhead and gate valve equipment for both domestic and international markets.
The company produces large quantities of holes for bolt-circles in flanges and lockscrew preps around the periphery of flanges. WPG's products also require large-diameter holes, which were previously machined with insert drills, spade drills, and twist drills on both machining centers and lathes. Components are machined from carbon and alloy steels; several stainless materials, including 17-4PH and types 316 and 410; and Inconel 718.
With all those holes, holemaking productivity is a must. According to VP of Manufacturing Dave Cermak, the company's conventional drills were accurate but cycle times needed improvement. After a meeting with a sales engineer, WPG engineers decided to try Trigon-style insert drills from Komet of America (Schaumburg, IL). The deep-hole piloted drills are used in bolt-circle operations, lockscrew prep holemaking, and for production of large-diameter holes.
"In the larger-diameter drills [>1 1/2", or 38 mm, diam] with a high depth-to-diameter ratio, the piloted insert drills have been an improvement over a regular insert drill or spade and twist drills," Cermak says. "They require less horsepower and have through coolant. They provide a better surface finish and are more stable in the drilling process due to the pilot and the wear pads."
According to Cermak, some deep holes with smaller diameters are more difficult to drill consistently, efficiently, and safely due to the higher spindle speeds used, reduced chip clearance, and relative lack of tool rigidity. Komet piloted drills provided a solution for these problems, and WPG has experienced significant manufacturing benefits as a result.
On the machining centers, valve bodies, which require flat bottom holes 3 - 7" (76 - 178 mm) in diameter and 13 - 21" (330 - 533 mm) deep, previously required a spade bit and multiple boring bars to finish. Since the larger-diameter Komet piloted inserted drills are adjustable on diameter, these holes are now drilled to size with one tool and have the same surface finish or better as that obtained using a boring bar.
"Also, on the machining centers that perform the lockscrew preps, we've gone from using three or four tools to produce the holes to just two," Cermak says. "This change has saved us as much as 2 1/2 hr per part.
On the horizontal lathes, WPG is now able to produce a rough hole in solid material that is very close to the finish dimensions. This saves time and money over the previous process of pre-machining on a manual lathe.
WPG also employs a bridge mill for some operations. Here, the Komet Trigon drills are used to produce bolt holes with depths 3 - 4 X diameter in large-diameter flanges. The holes range from 1 to 2 1/8" (25 - 54 mm) diameter, and each flange requires 8 to 24 holes. Before the switch to this machine, flange bolt circles were produced on a radial drill with twist drills that took anywhere from 1 1/2 to 7 hr depending on the flange. That time is now 45 minutes to 2 hr.
Vacuum Clamping Speeds Deburring
Airbus Industries' Varel, Germany, plant machines airframe components for the company's A318-A321, A330/A340, and A380 commercial aircraft as well as the Eurofighter project. Holding the large aluminum workpieces for deburring proved to be a challenge until the plant switched to vacuum workholding.
Part sizes at the Varel plant start at 1.2 m and go up to 7 m. Most of the parts are milled from solid aluminum alloy plates. Sharp edges have to be removed, and for this Airbus engineers have used skid-grinding methods as well as an automatic Fladder 400/GYRO deburring machine.
Workpieces are fed to the Fladder machine on a rail-guided vehicle. The variety of workpiece shapes and sizes and the possibility of edge interference eliminated conventional clamps as a potential workholding solution. Engineers found what they were looking for in the Flip Pod vacuum workholding system from Horst Witte (Bleckede, Germany; represented in North America by IBAG North America, North Haven, CT).
The system uses a pump to create a vacuum between workpiece and chuck. Hold-down force increases in proportion to the workpiece surface area and is evenly applied, making vacuum workholding especially useful for large aluminum workpieces with thin walls. Most jobs, though, require fast clamping with relatively low forces.
To handle a variety of workpiece geometries--including many with deep pockets, ribs, and other features that reduce vacuum clamping efficiency--the system uses a grid of standard and custom "pods." These are the points to which the workpiece is clamped. Pods not in use are flipped over and stored in hollows in the pod plate.
Before a new workpiece is deburred for the first time, tests determine optimal pod position. The clamping plan is then entered into a personal computer. But the machine's software really comes into its own when a workpiece has been previously set up, according to operator Uwe Hentschel. "There is a bar code on each workpiece, which we enter into the PC. The relevant clamping plan appears, according to which we set the pods," he explains.
Clamping takes place at the press of a button. The deburring machine's worktable consists of five separate elements, each with its own pressure station. This minimizes deformation or damage of thin-walled workpieces.
Making a Muscle Car
Ford Motor Co. is using programmable peen marking technology to place critical identification marks on aluminum cylinder heads for the 2005 Ford GT engine.
The Unigrav special marking machine designed and built by Columbia Marking Tools (Harrison Township, MI) marks numbers on the cylinder head bearing caps to correspond with those of the matching cylinder head position. These are critical marks to ensure that quality and proper assembly sequence is maintained. Improper assembly of bearing caps can ultimately cause an engine to seize up.
The machine is built with a heavy-duty, welded steel, free-standing base. A steel plate table mounted to the base has a mechanical 180º rotating turntable fixture that locates and presents the marking surface of the cylinder heads to the peen marker. A gantry framework bolted to the table supports the axis movements and the marker stylus head. Palm buttons mounted to the top plate surface provide safe actuation.
In operation, the aluminum cylinder heads for the 500-hp engine are manually loaded onto the rotating fixture plate over locators that fit into holes on the bottom of the cylinder head. The fixture is locked in place, and the marking head automatically peen marks the numbers 1 through 6 on the bearing cap exterior surfaces. The head is then rotated and the sequence performed again on the opposite side.
Cylinder heads on the 2005 Ford GT engine are numbered using a programmable peen marking system from Columbia Marking Tools.
Marking head movement is controlled by an X-Y slide arrangement driven through linear ballscrews. The system lets users switch between a servomotor drive that provides high-speed marking capability up to 10 characters per second with 0.005-mm positioning accuracy or a stepper motor drive that gives 0.02-mm repeatability at 5 characters per second. The system marks each cylinder head, on both sides, in 24 seconds.
This article was first published in the May 2004 edition of Manufacturing Engineering magazine.