Shop Solutions: Connectors Test Parts Cleaning
Machining tiny electrical connectors and contacts instead of stamping or forming them enables Positronic Industries Inc. (Springfield, MO) to achieve a high level of precision for use primarily in circuit boards for avionics, military, and even space-bound applications like the Mars Rover.
Positronic produces ten families of parts made of various materials, including brass, bronze, tellurium copper, beryllium copper, lead nickel copper, mild steel, stainless steel, and thermocouple materials. They are produced at Positronic’s four Missouri facilities, as well as manufacturing facilities in Puerto Rico, France, Singapore, and India.
Though machining produces a high-quality product, any chips left behind by the machining can damage the delicate electronics. Parts washing is essential. Unfortunately, the cleaning solution Positronic had used for years collected in tiny holes in the parts, causing vapor lock that trapped chips inside.
"If you can’t get the chips out, you have to scrap the parts," explains Tony Didia, Positronic shop superintendent. "You can’t risk something coming loose and getting into a circuit board. So after washing we’d go to an ultrasonic cleaning station. And cleaning everything twice doubled our production time."
Complicating the process is the fact that there are thousands of variations in the connectors (lengths, press-fit etc.). All are very small and most have blind holes. The holes are typically 0.3 (7.64 mm) with a typical diameter of 0.02–0.04 (0.5–1.0 mm). Few cleaning systems are designed to clean parts with holes that small.
"Water-soluble is the most environmentally-friendly process, but has the same problems," Didia says. "We also looked at different additives for better cleaning. But more additives add residue to the parts. The scum traps the chips, and you’re worse off than before."
As a result, Positronic had to put up with high scrap and rework to ensure the quality of their high-performance electrical connectors.
The solution came when Didia and his team looked at a number of alternative cleaning processes. After narrowing the field of potential processes, Positronic invited manufacturers to clean batches of sample parts.
They found that the Dürr Ecoclean 81C system, using non-halogenated hydrocarbons, cleaned as well as a solvent washer without the environmental and safety concerns. What impressed Didia most was that the 81C eliminated the vapor lock that had been trapping the chips.
The parts-cleaning machine submerges the baskets of parts into a solvent bath. Once the parts are completely submerged, the cleaning media cleans outer surfaces as well as holes and cavities.
During the heated immersion process, parts in baskets, under vacuum, are agitated within the solvent bath through internal automation. Operators select one of eight pre-programmed processes and movement patterns via a control panel. The movement of parts within the cleaning solution dislodges debris that may not have been removed by the solvent bath alone. Vacuum drying thoroughly dries the parts following the solvent bath and rust prevention.
"The whole system is under vacuum at all times," he explains. "It pulls down to 4 mbar or less, takes out the air, and releases the chips. It works. It’s well-engineered and well-built."
The 81C has a footprint of approximately 17.5 × 6' (5.3 × 1.8 m) and is about 8.5' (2.6-m) high. It features a cleaning chamber (with turning and rotation capabilities), flood tank, vacuum distillation, and PLC controls. The system can be ordered with automatic conveyors, ultrasonics, a second flood tank, and other options.
Positronic runs 342 lots per day, up to 2000 parts each, through the 81C, which adds up to nearly 300,000 parts a day. Each of the standard baskets holds 20 pans, each containing a different part. All 2000 parts are cleaned in about 7 min. The system runs Monday through Friday, two shifts, and requires very little attention. Maintenance consists of changing the oil and filters every 400 hr, which takes about 20 min, and changing the caustic soda.
The installation and start-up went smoothly, according to Didia, and very little operator training was needed. The cleaning cycle (wash time, whether to turn or oscillate, etc.) is programmed by following simple screen prompts.
The Dürr cleaning system has played an important part in improving Positronic’s scrap rate—not only in its own production, but in other ways. Recently, for example, a vendor delivered 800,000 parts that appeared to be clean, but after flame-annealing were bubbled and heavily oxidized. Running them through the hydrocarbon cleaning process quickly made them usable.
"The Dürr system pulled off stuff you couldn’t even see," he recalls. "It has surpassed what I expected it to do," Didia concludes.
Ego Tripp Wheels Rolls With VMCs
Wheels have become intricately designed accessories in just about every price range for cars and motorcycles. Producing new designs can be an expensive proposition and, sometimes, wheel manufacturers run into manufacturability issues.
To make products that its competitors have been unable to produce, Ego Tripp Wheels and Accessories (Lubbock, TX) purchased two Fadal VMC 4020s. According to Greg Hoeve, Ego Tripp general manager, the accuracy and repeatability of the machines have allowed the company to offer better and more intricate designs, reduce machining cycle time 15%, and realize substantial savings in wheel-polishing operations.
"The Fadals are reducing our cycle times, but they have a bigger advantage. We can do things now that were possible before, but not economically practical. Even though we are doing more elaborate work, we are not dramatically increasing our run times. Because of that, we have a competitive edge," Hoeve explains.
Ego Tripp Wheels is an 18-year-old manufacturer of custom and off-the-shelf show motorcycle wheels, pulleys, sprockets, and brakes for Harley-Davidson and other motorcycles. Because the wheels are made to show-quality standards, highly polished finishes and smooth surface finishes are critical.
Historically, show wheels have gone through several polishing processes. Pre-polish operations are done before machining. The wheels are then machined and finish-machined with scroll patterns or designs that incorporate stepover and scroll marks into the design. When the wheels are finish-machined, they go through a final polishing operation. It’s during this final polishing operation that patterns may be literally polished off, and so much material removed that features of the wheel may be distorted or no longer visible.
"Every company gives its wheels a show polish, but it’s only a Band-Aid solution," says Hoeve. "The finishes are beautiful as they come off the Fadal without burrs or scroll marks where the machinist forgot to pull the tool tip off the part before the next stroke."
Ego Tripp’s wheels begin as blanks forged from aluminum and heat-treated. They go through a pre-polish process before mounting in the VMC. Essentially, it’s a finished wheel, but there is no pattern work on it. The center is an inch thick all the way down to where a modular hub is attached to the wheel.
"Primarily we are using the Fadals for finishing, like engraving and fine pattern work," says Hoeve. "However, we do use them for roughing out the windows and hogging material out of the way. We need a reasonable amount of rpms and torque to get these things done."
One Fadal VMC has a 15,000-rpm spindle and the other a 10,000-rpm spindle. They were purchased with the Siemens Sinumerik 840D digital control, which provides fully interpolated four-axis capability and fast program execution speeds for high-speed machining.
"The 840D control is a die-making control," says Hoeve. "It was designed to interpolates curvature, particularly through X, Y, and Z axes at an enhanced level. This allows the contours we are machining to turn out smoother. For the nature of our work, these controls are probably overkill, unless you look farther down the line. The labor to get the level of polish quality we offer costs every bit as much as the CNC, manhour per manhour. So spending an extra 10 minutes in the CNC to save an hour in the polish department is easily justified."
With the new machines, wheels are pre-polished before machining operations. After machining patterns, final polishing is a one-step process, which requires the use of rouge to achieve a very high luster polish. Polishing with the coarser grit Tripoli Emery cloth to remove machine marks has been eliminated.
"When they are finished, the wheels are much closer to how we idealized the pattern," says Hoeve. "We don’t do all this precision machine work and then watch the polish department wipe them out because they have a large amount of stock to remove. The VMCs have improved the surface finish that much."
Typically, engraving routines have a very narrow step-over, usually between 0.01 and 0.005 (0.25 and 0.13 mm). This causes engraving to be a very slow and costly process. However, a 15,000-rpm spindle significantly speeds up the engraving process. "Engraving was too slow to be profitable. This is where the 15,000-rpm spindle helps," Hoeve says.
"The speed and accuracy of the new machines allow us to be more elaborate with pattern work without affecting prices at the retail level," says Hoeve. "The Fadals are reducing cycle time, but the bigger advantage is to develop new products faster, competitively, and different from those made by competitors. We are able to create industrial art with the Fadals."
Outboard’s Performance Depends On Cutting Quality
Mercury Marine, a division of Brunswick Corp. (Lake Forest, IL), is well-known to watersports and leisure enthusiasts because of its famous brand names.
They include Mercury and Mariner outboard motors, Mercury MerCruiser sterndrives and inboards, Mercury Racing products, Mercury and Typhoon propellers, and Mercury Jet Drives, as well as precision parts and accessories.
In 2004, Mercury Marine introduced the Verado, a four-stroke supercharged outboard propulsion system, to meet pending and future guidelines for requirements for low emissions while improving top performance in high-horsepower outboards. Combining the best qualities of two-stroke and four-stroke technology, the Verado features supercharger technology with the latest innovations in power steering, digital throttle and controls, and sound-dampening technology.
"The image processing technology we now use permits fully automatic cutting edge measurement of tool length, diam, corner radius, and two cutting edge angles." The Verado is an inline six-cylinder production outboard with 158.5 in.3 (2.6L) displacement and four valves per cylinder. It’s available in four horsepower configurations: 200, 225, 250, and 275 (149, 168,186, and 205 kW).
Mercury outboards are produced in a 1 million ft2 (92,903 m2) facility at Mercury Marine’s world headquarters in Fond du Lac, WI. To handle production of the Verado, a state-of-the-art assembly area was custom-designed around the unique needs of the product. (See Rev Up Outboard Production in Manufacturing Engineering, April 2005, pp. 55–66.) Computers monitor every step of assembly via in-process validation points. Hot and cold tests are run on the line to ensure 100% performance.
For the Verado, Mercury Marine set and met many new tolerances to ensure its performance. One of the trickier tooling tolerances has to do with the valve-seat boring tools. Fifteen of the long, narrow, multi-insert tools are used on Mazak Corp. (Florence, KY) machining centers to finish-machine the 24 valve seats, intake, and exhaust, in the one-piece aluminum cylinder head.
Because valve clearances are factory-adjusted and intended to remain within tolerance for several thousand hours of operation, very close machining tolerances are essential. Checking the valve-seat tools manually was a complex and time-consuming task, and results were not always as accurate or reliable as possible.
At the Mercury Marine plant, there are more than 6700 tools in the databases of the tool department, with two to five backup tools for each. A total of 35,000 tools are in-house. The department sets each one and returns them back to the shop floor where they are needed. They are not stored in a toolcrib.
Mercury Marine selected the Saturn vision system from Zoller Inc. (Ann Arbor, MI) for fully automatic measuring and inspection of each tool in the plant’s complement in combination with a Zoller Venturion automatic three-axis CNC vertical tool presetter and measuring machine. "With the help of our Zoller Venturion tool measuring and presetting system, we were able to improve tool accuracy from ±0.0002 [±0.01 mm] to 2 µm," says Dale Kutchek, supervisor cutter grind/tool preset.
Turnaround time was reduced dramatically. "Because we had to calculate all settings manually, we were putting a lot of time into setting the tool, taking from 30 to 45 min to set each. It is now down to 5–10 min, a 70–90% time savings for us, plus we have the assurance of consistency," Kutchek says.
"There are three separate inserts positioned in the tool," Kutchek explains. "It is very critical the way they flow into one another as the cutter rotates in the cut and creates the valve seats in the heads for the new engine." The Zoller system has the ability to measure the location of each insert on the tool, and show the width of the intersection between the three inserts.
"With that information, we know that we will be cutting to a certain depth and diam on the valve seat. This has a direct impact on the cutting accuracy on the machining centers," he says.
The measuring machine features a Z-axis measuring range of 600 mm and diam of 400 mm. Two CNC linear-driven slides, vertical and horizontal, position the optic carrier, and the CNC spindle rotation permits focusing on the tool
"The image processing technology we use now permits fully automatic cutting edge measurement of tool length, diam, corner radius, and two cutting edge angles," says Kutchek. "The software automatically detects cutting edges for any shape, location, and orientation in the measuring screen. A manual measuring mode for length, radius, and angles helps us determine the dimensions of chips and breaks on cutting edges."
The camera in the optic carrier transmits the image of the tool edge to the control and screen. High-resolution digital CCD Sony cameras with fixed focus and fixed enlargement transmit the image of the tool edge, displaying a cutting edge image on the screen.
The presetter includes a high-precision spindle system with power-operated tool clamping for taper, HSK, KM, and Capto-style tooling adapters, allowing the group to handle any tool in the plant. An adapter toolpost system is lightweight, and adapters can reportedly be exchanged in less than 10 sec with 1µm changeover repeatability in length and diam and 2µm in concentricity.
Once the tool is located in the spindle, the CNC autofocus provides fully automatic tool positioning independent of the user. Different focus modes are available for any style of cutting-edge geometry. After tool focusing, measurement of the cutting edge is automatic.
Zoller software measures the cutting contour when rotating the cutting edge through the camera system. This is helpful when measuring milling cutters and form tools, as is the case at Mercury Marine, to assure proper machining results before a single workpiece is cut. That’s why the first-pass yield at the motor maker has improved.
RP, Laser Scanning Cut Auto Fixture Time 80%
Hyundai Mobis, which was established in 1977 under the name of Hyundai Precision Industries, is a leading Tier-1 supplier of automobile components.
The company focuses on modules and systems such as chassis modules, cockpit modules, automatic braking systems (ABS), air-bag systems, telematics, and electronics, and has increased the integration of its products to help its customers reduce weight, part count, assembly time, and inventory.
Hyundai Mobis has built a 400,000-ft2 (36,000 m2) plant in Montgomery, AL, to supply instrument panels and front and rear chassis assemblies to Hyundai Motors’ $1-billion, 2000-worker plant, which is located in the area.
Designing and building fixtures is a critical task for any automotive manufacturer. The principal function of the fixture is to control and manage dimensional accuracy at the point of production. Fixtures are especially important in inspecting components that could be deformed by their own weight, for example.
With many parts coming together from different sources for assembly, the manufacturer must be able to quickly identify any problems associated with components being out-of-tolerance.
With its former process, it cost Hyundai Mobis $25,000 and took 20 days to design and build a typical fixture using traditional metalworking and manufacturing and inspection methods. Company engineers took a solid model that contained the geometric definition of the part and converted it into a design concept for the fixture, including applying the gap needed to account for manufacturing variation in the production components. After the design was approved, the model was then converted to a CNC program used to produce the fixture on a machining center.
Key dimensions of the fixture were inspected with a CMM, which could be a time-consuming process, depending on part complexity. Once the part was digitized, the point cloud generated by the CMM needed to be converted, first into a surface model, and then into a solid model. This was another difficult task that could take a few days for fairly complex fixtures, and as much as two weeks for the most challenging.
Using a combination of rapid prototyping and laser scanning, Hyundai Mobis has significantly reduced the time required to produce its precision fixtures for inspecting its automotive parts. The company has switched to software that automates the design process. Features are built using fused deposition modeling (FDM), and the body of the fixture is assembled from a modular system.
The fixtures are then inspected with a laser scanner that captures tens of thousands of points per second, quickly generating a highly accurate surface model of the fixture that can be compared to the original design.
The new method makes it possible to produce fixtures in only seven days at a cost of $5000 per fixture. The company estimates that it has saved $2 million per year by adopting these new methods. The new fixtures are said to be accurate to 0.1 mm, reportedly last at least one year, and support parts weighing as much as 40 kg.
The new process begins by using RapidFit software from Materialise (Leuven, Belgium) to automate the fixture-design process. Engineers first define the support system with base plates and beams, indicate the contact points where fixture elements are needed, and define the type of contact. The RapidFit software designs the fixture, fitting the contacts to the part automatically. The fixtures have a well-defined geometry so they will fit to the part only on the specific spots that have been defined by the user.
The features that provide the measuring function in the fixture are built using an FDM machine from Stratasys Inc. (Eden Prairie, MN). Features used in larger fixtures are extended using Alufix beams that provide a flexible fixturing system made of high-tensile aerospace aluminum. The Alufix system, developed by Horst Witte Gerätebau Barskamp e.K. (Bleckede, Germany), and sold in the US by Paul W. Marino Gages Inc. (Warren, MI), in conjunction with Stellar Engineering Inc. (Madison Heights, MI), uses open bores that allow combinations in any direction while maintaining the horizontal and vertical grid.
The system is made of pre-machined modular components that can be assembled according to an inspector’s needs. Modularity makes it possible to inspect products as they evolve in size and shape. Once the manufacturing process is complete, the fixture can be disassembled, and rebuilt into new configurations for future use.
Accuracy of the fixtures must be maintained within ±0.2% over 200 mm, which translates into 1.5 mm as the overall allowable tolerance after final assembly. Fixture inspection has been improved through the use of laser scanning.
Laser scanners are able to measure large parts while generating far greater numbers of data points than probes without the need for templates or fixtures. Since there is no contact tip on a laser scanner that must physically touch the object, problems such as depressing soft objects, measuring small details, and capturing complex free-form surfaces are eliminated.
Hyundai Mobis selected the Surveyor DS Series 3-D laser scanning system from Laser Design Inc. (Minneapolis) for scanning the rapid prototype fixtured parts. Laser Design’s Rapid Profile Scanning (RPS) Model 150 laser scanning probe captures up to 14,400 points per second and features digital (ASCII) coordinate output, a visible beam, a Class II rating, and a long standoff to prevent crashes during dynamic part scanning.
In the inspection process, the fixtures are set up for laser scanning using various jigs. Once the laser scanner is calibrated and set up, the operator scans the fixture with the probe almost as if he were spraying the fixture with paint. The resulting point cloud is then imported into color error-mapping inspection software that compares the scan data with the original CAD model. Discrepancies show up as a color variation to highlight out-of-tolerance conditions.
This allows everyone interested in quality of the body-positioned part to see where the shape of the part varies from its original design intent. Such process transparency speeds the analysis of any problems, and allows all involved to understand what needs to be changed in either the tooling or the manufacturing process.
Flying Optic Laser Helps Shop Soar
There is no doubt that attending the biennial International Manufacturing Technology Show (IMTS) is good for manufacturers of all sizes who want to find and adopt the latest in advanced manufacturing technology.
For Janco Industries (Sully, IA), the 2004 version of IMTS proved to be a turning point for the company. Founded in 1993, Janco Industries numbers laser cutting, welding, fabrication, and contract machining among its process capabilities for the agricultural, food processing, sporting goods, trucking, and construction industries. All of these processes are available in its 1393.5-m2 facility.
What owner Joel Jansen saw at IMTS 2004 changed his view of his company’s potential and its future. That something was the Echo III flying optic laser from Han Kwang USA (Mt. Prospect, IL).
Jansen admits he had looked into laser cutting in the past, but the Echo III had some noticeable advantages over other units he had seen. The Panasonic resonator, which generates the laser beam, had significant upsides in operating and maintenance costs, always critical areas in evaluating the competitiveness of laser operations.
Another major plus was the Sinumerik 840D CNC control from Siemens Energy & Automation (Elk Grove Village, IL). The 840D features a user-friendly design for PC interface, 10-GB hard drive, 2-MB memory, and a network-based remote diagnostic support.
In the flying optic-laser design, the optics move in the X and Y axes while the material remains stationary. In addition to the flying optics design, twin linear-drive motors enable it to make more complex metal parts with holes and cutouts in less time than conventional machines. The shuttle-table system runs at 30.5 m/min for saving time in loading and unloading workpieces.
The 840D CNC and dual linear-motor drives produce positioning on the order of 170 m/min with 0.10-mm accuracy. Acceleration is 10 m/sec2 with constant inertial dynamics, and therefore minimal wear on the rack and pinion assembly.
The CNC controls all the laser power settings, as well as axis movement and feed rates. With DNC and LAN interface, the remote diagnostic capabilities allow Janco operators, or even Siemens’ personnel, to interact with production control over the Internet for assistance and direct real-time troubleshooting.
Another consideration in Jansen’s decision to buy the Echo III laser was that training and local support would be readily available as both Han Kwang and Siemens have offices and training facilities in the Chicago area.
The Echo III laser provides auto focus control with 9.5-mm maximum focal length variation, achieved through air pressure deformation of a hard gold-coated mirror. In the 4-kW unit, material thicknesses over a wide range can be cut, making it well-suited for a contract manufacturer such as Janco.
Janco regularly processes mild steels from 1 to 20 mm, and stainless from 0.8 to12 mm to fabricate the various components the shop produces. The Echo III laser at Janco can handle workpieces that weigh as much as 800 kg.
When programming the laser, Janco utilizes its own software as well as the onboard ProDesign program. Programming of sheetmetal cutting machines is automated from CAD to the nesting function, Jansen explains. Because the program allows various lead-in/lead-out settings for differing contours, more diverse parts can run simultaneously.
Software updates can also be made by direct uploading from the manufacturer, thus keeping Janco equipped with the latest versions of all applicable programs.
Homespun With CNC In The Heartland
The challenge for today’s production shop is to be versatile enough to manufacture everything from limited quantities of a variety of intricate specialized parts to high volumes of the same part.
For one contract manufacturer, Iowa Metal Spinners (IMS: Cedar Falls, IA), its metal-spinning capability has provided the agility to consistently meet the changing needs of the market and exceed its customers’ expectations.
Founded in 1980 by President Kevin Harberts, the company is a manufacturer of spun-metal components used by assemblers and fabricators throughout the US. The company fabricates a variety of products from ferrous and nonferrous metals, aluminum alloys, precious metals, common steels, copper, brass, stainless, and specialty and coated steels.
Metals come in many forms from cold-rolled steel to aluminized or galvanized steel, ranging in thickness from 0.010 to 0.250 (0.25–6.35 mm), depending on the alloy and part configuration. In the course of one year, for example, the company will process more than 1.5 million lb (680,388 kg) of aluminum for use in HVAC, fan housings, and products for the lighting industry.
In 2000, Iowa Metal Spinners moved into a new facility located in an industrial park in Cedar Falls, IA. It was designed to provide a workflow that allowed IMS to meet production requirements more quickly and with more efficiency than most companies of similar size and range of products.
During facility planning, Harberts recognized that remaining competitive required IMS to commit to a program of long-term improvement through adopting advanced automation systems.
"Our industry is totally changing," says Harberts. "Ten years ago, everything was spun by hand. Now forming is computerized. And the processes are being continually upgraded so that manufacturing is more transparent and more automated. Customers can place their orders and the follow them right through to delivery by going online to check job status and the stage of production," Harberts points out.
"Our customers dictate our designs. Projects turn around in as little as a few weeks depending upon the complexity of the parts we’re making. The more complex parts may take up to six months," he says.
In his search for the expertise to enhance and automate his metal-spinning operations, Harberts turned to MJC Engineering and Technology Inc. (Huntington Beach, CA). MJC manufactures high-tech metal-spinning equipment, and specializes in CNC retrofit, machine rebuilding, and support for leading manufacturers worldwide.
"Our relationship with MJC goes back over 20 years," Harberts explains. "About 15 years ago, we bought four retrofit specialty machines from MJC. They came in and set everything up. It was painless," he says.
IMS retrofit the older machines, including a spinning lathe and a specialty machine for venturi panels, which are special frames used in HVAC applications. "MJC helped us do what we wanted to do with the specialty machine. They figured it out. It was a risk we took together," Harberts says.
Avoiding downtime is critical to the company’s operational efficiency. "We had a problem once with one of the retrofit machines," he explains. "MJC knew the machine was down and that we couldn’t fix it, so they jumped on a plane the next day and were here on site to solve the problem. For them, it was maybe a 10-min fix. They never charged us for a ‘house call.’
"In our fabrication process, we take a sheet of steel and laser-cut blanks, which go into the spin machine. They are formed on a lathe and then undergo secondary operations, such as drilling, welding, trimming, beading, rolling, and finishing," Harberts explains.
"To stay competitive and profitable, we purchased a new SP-3230 two-axis CNC metal-spinning machine about a year and a half ago. The machine allows us to be more efficient and hold quality better. We’ve experienced an overall improvement in quality of 25%. The machine takes a circular blank piece of metal, spins it, cuts the part, and it’s done. It’s that simple," he says.
The only learning curve with the new CNC machine was the training, which took about a month. As far as operating the machine, IMS moved one person from the shop to program the CNC. MJC standard, custom-built, and retrofitted spinning machines are shipped with the Siemens 840D CNC control and proprietary SpinCAD software.
Harberts says, "We change the oil every so often. That’s about it."
Harberts credits MJC’s engineering with improving machining processes and reducing programming, setup, and cycle times. "The specialty machines allow us to produce more precision stainless steel work, and that has opened up a variety of new markets for us, such as aerospace, medical technology products, among others. Plus, it has an added bonus that I like. MJC’s equipment and parts are made in the US."
This article was first published in the April 2006 edition of Manufacturing Engineering magazine.