When discussions began nearly a year ago about what car to bring to Today’s Technology Center booth #W-20 for IMTS 2016, Cadillac’s CT6 was a clear favorite. Not as flashy as the Chevrolet Corvette that we brought to McCormick Place in 2014, or as radical as the Buckeye Bullet electric speed racer from 2012, the CT6 represents where automotive manufacturing needs to be by 2025 to meet fuel economy standards.
A mixed-metal vehicle with extensive use of high-strength steels, sheet aluminum, extruded aluminum, and several exotic alloys, the CT6 is forcing its manufacturer to explore new production techniques and develop entirely new systems.
It’s the role that Cadillac has often played for GM – a nameplate that sells expensive vehicles that stretch the limits of what engineers can accomplish. And as Cadillac perfects those techniques, they flow down to Buick, GMC, and Chevrolet. For example, when the Cadillac CTS launched in 2003, it featured never-before-used welding techniques such as laser-brazed steel sheets to connect vehicle side panels to the roof – creating a smooth, flat seam between the two. The 2016 Chevrolet Malibu uses that technology to create a sharply raked rear deck lid, giving the trunk a spoiler-like look without adding plastic trim.
The materials and processes enhancements don’t end at the vehicle body. Two redesigned V-6 engines feature specialty alloyed steel crankshafts, rather than cast iron, and use polymer-coated pistons and sintered connecting rods.
On the following pages, we’ll discuss what makes the CT6 special, and how its manufacturing technologies are a glimpse at where the world is heading.
One of the toughest challenges faced by a leading manufacturer of composite motorsports components is drilling and tapping holes that need to be closely aligned with embedded metal bushings. The complex, freeform shape of the components makes them difficult to accurately align in fixtures, and even a slight misalignment causes cutting tools to crash into bushings, usually breaking tools and requiring three-to-four hours of manual effort to extract them from the part.
Aerodine Composites Corp. overcame this problem by using Delcam’s PowerInspect software to generate numerical control (NC) code that drives a touch probe in the spindle of a CNC router to determine the position of the part in the fixture and recalculate the machining datum prior to cutting the part. The machining process has nearly eliminated tool breakage, reducing the time required to produce each part by about 90%.
Aerodine Composites’ team of repairmen and composite technicians work together to produce highly specialized alterations of existing composite structures and to repair damaged components to original equipment specifications. The company’s experience as a premier supplier of structural assemblies, research and development parts, ancillary support components, and structural repair schemes to the high-performance motorsport industry has enabled the company to build a vast catalog of damage scenarios, repair techniques, and manufacturing methods to ensure that safety is not compromised.
One of Aerodine’s recurring projects is producing about 50 front wing assemblies per year for an Indy car racer. The parts consist of carbon fibers and various metallic components such as bushings, bonded together by epoxy resin. The value of each assembly is about $15,000, and individual components range from $1,000 to $1,500. Many holes need to be drilled through the composite material in perfect alignment with the bushings, and then the bushings need to be threaded. Aerodine employees had produced these parts on manual machine tools, but operators had difficulty aligning the machine spindle with bushings buried in the composite material. Bushings or taps frequently broke off when the tool crashed into the bushing. Part machining time was only 15 minutes, but it took the operators three-to-four hours to manually extract the broken drills and taps. Repairs cost about $150 per hour, including both labor and machine time.
Looking to improve on this operation, Aerodine engineers studied CNCs to produce these and similar parts. Aerodine purchased its first CNC machine, a DMS router with 5ft x 10ft x 4ft travel, and was immediately successful in producing parts with flat surfaces that allowed them to be accurately positioned in a fixture. But every surface in the front wing assemblies is curved, as are other parts produced by Aerodine, so they are much more difficult to accurately align. Machine operators did the best they could, but the inevitable misalignments caused drill bits and taps to continue to crash into the bushings embedded in the composites.
Kyle Castor, patternmaking manager for Aerodine, says engineers were already using Delcam PowerMill to produce CNC programs, so he spoke to Design and Software International, the local systems integrator that recommended and provided PowerMill.
“The reseller recommended Delcam’s PowerInspect part aligner as a tool to help us accurately locate the part prior to machining,” Castor says.
He now opens a CAD model of the part in PowerInspect and uses a mouse to select a series of points that can be used to accurately locate the model in 3D space. PowerInspect then generates a CNC program that runs on the machine tool with a touch probe in the spindle. Each time a new part is loaded onto the fixture, the machine tool control runs the CNC program generated by PowerInspect which determines the actual position of the locator points, compares the results with the CAD model, and performs a best-fit analysis to determine the actual position of the part in the fixture.
“Finally, PowerInspect updates the CNC program to incorporate the actual position of the part,” Castor says. “This approach eliminates the collisions that wasted so much time in the past.”
As Aerodine adopted the PowerInspect location technique, it also switched from using drills and taps for machining the holes to using end mills and threads mills. The new tools increase machining cycle time but reduce the delamination of the composite parts, improving quality. Eliminating the need to accurately position the part in the fixture also saves time. And nearly every part is produced in the specified cycle time of 20 minutes, a reduction of about 90% from the average time required to produce parts in the past.
On another project, a customer asked Aerodine to change three existing patterns used to lay up composite parts. The patterns are about 3f x 2ft x 8ft and weigh more than 900 lb. They consist entirely of curved surfaces without any flat surfaces that can be used to locate them in the fixture. The customer provided a CAD model of an existing pattern that showed the changes they wanted to make, comprising about 30% of the surface of the pattern. The challenge was that the pattern needed to be precisely aligned with the CNC program so that the cuts blended smoothly into the existing curves.
“I estimate that it would have taken about a week using manual methods to position the part in the fixture accurately enough to smoothly blend the needed machining operations into the pattern,” Castor says. “We ran the risk of damaging the part if we made a mistake.”
Using PowerInspect to select points on the CAD model of the pattern to determine its location in 3D space allowed engineers to incorporate position data into the CNC program.
“The result was that we were able to get the patterns located and aligned in only an hour,” Castor says. “This approach made it possible to repurpose the existing patterns at a fraction of the cost that would have been required without this software. We also use PowerInspect to inspect parts and fixtures with complex curves that are very difficult to accurately inspect using conventional measurement methods.
“PowerInspect has dramatically improved our ability to locate and align parts with complex curved surfaces,” Castor concludes. “The result is that we have been able to substantially reduce the time required for part alignment while delivering increasingly accurate products to our customers.”
The 31st edition of the International Manufacturing Technology show will collect more than 2,000 exhibitors, occupying 1.3 million square feet of exhibit space at the McCormick Place complex in Chicago, Illinois.
Today’s Technology Center: Booth #W-20 features automotive, advanced energy, aerospace, and medical exhibits from the publisher of Today’s Motor Vehicles, Today’s Medical Developments, Today’s Energy Solutions, and Aerospace Manufacturing & Design
NHTSA nearly triples fines for missing fuel economy targets
Thanks to a law passed in late 2015, the National Highway Traffic Safety Administration (NHTSA) has dramatically increased fines for companies that fail to meet Corporate Average Fuel Economy (CAFE) standards. Fines jump to $14 per vehicle sold for each 0.1mpg miss of the standard. Set in 1978, the standard of $5 per 0.1mpg miss had not been updated since. For Jaguar Land Rover, one of the most heavily fined companies for missing standards for decades, fines could jump from about $375 per car sold (based on its 2014 CAFE performance) to $1,050 per vehicle with the new fine structure.
Most automakers generate credits from beating standards for cars and apply those credits to their trucks and SUVs. In addition, greener car companies, such as Tesla Motors, can sell credits based on their sales to allow competing automakers to reduce their exposure to fines. The value of those green-car credits could spike in response to the higher cost of paying fines for non-compliance. Since the mid-1980s, NHTSA data show that two automakers – BMW and Daimler (via Mercedes and its sub-brands) have accounted for almost two-thirds of the nearly $1 billion collected with the $5 fine structure.
Officials with the Alliance of Automobile Manufacturers say the new fine structure complicates the relationship between manufacturers and regulators. The sides have been cooperating on working out a single national framework for automotive regulation, but discrepancies remain between U.S. Environmental Protection Agency (EPA) standards, NHTSA standards, and standards used in several states, spearheaded by California.
“Despite commitments made in 2009 and 2011, the troubling reality is that we still do not have One National Program for fuel economy standards,” Alliance officials say. “Automakers were already preparing to face the unfair reality of having to pay significant CAFE fines despite meeting the more aggressive EPA standard. That daunting prospect just nearly tripled due to this draconian fine increase and the corresponding impact to the credit market. These harmonization issues must be addressed in order to ensure consumers are able to afford the cleaner, more fuel efficient, and safer vehicles available on showroom floors.”
In its rule filing with the Federal Register, NHTSA officials said the fee change was mandated by the Federal Civil Penalties Inflation Adjustment Act, a 2015 law that requires old fine levels be increased to match inflation. That law capped increases at 150% of the original fine (with some minor adjustments and rounding). Had it not been for those caps, the fines could have increased to $22, based on the Consumer Price Index. www.nhtsa.gov
US automotive safety lags falling death rates of similar nations
About 90 people die each day from motor vehicle crashes in the United States, resulting in the highest death rate among 19 high-income comparison countries. Crash deaths fell 31% from 2000 to 2013, but other high-income countries reduced crash deaths by an average of 56%, according to the Centers for Disease Control and Prevention (CDC).
The U.S. had the:
Most crash deaths per 100,000 people and per 10,000 vehicles
Second highest percentage of deaths involving alcohol (31%)
Third lowest front seat belt use (87%)
If the U.S. had the same motor vehicle crash death rate as second-highest death rate Belgium, about 12,000 fewer lives would have been lost and $140 million in direct medical costs would have been averted in 2013. If the U.S. matched top-ranked Sweden, about 24,000 fewer lives would have been lost and an estimated $281 million in direct medical costs would have been averted in 2013.
"Seeing that other high-income countries are doing better, we know we can do better too," says Dr. Debra Houry, director of the CDC's National Center for Injury Prevention and Control.
Erin Sauber-Schatz, transportation safety team lead, CDC's National Center for Injury Prevention and Control, adds, “About 3,000 lives could be saved each year by increasing seat belt use to 100%."
Researchers recommend seat belt use in front and rear seats, car seats and booster seats for children, never drinking and driving, obeying speed limits, and avoiding distracted driving. www.cdc.gov
Hyundai, Energy Department extend fuel cell research program
Hyundai and the U.S. Department of Energy (DOE) are extending their fuel cell vehicle confirmation program, originally from 2013 through 2015, to its second phase, from 2016 through 2017. The program involves Hyundai providing a number of Tucson Fuel Cell crossovers for daily use and confirmation by the DOE using existing hydrogen infrastructure. This phase of the program will use a newly-opened hydrogen refueling station in the Washington D.C. region.
Phase 1 of the Hyundai/DOE program focused exclusively on Southern California, where the earliest hydrogen infrastructure existed. Phase 2 further expands the program to Northern California, Washington D.C., Michigan, and Colorado.
The Hyundai/DOE partnership continues preparation for the rollout of fuel cell vehicles nationwide in the near future. Hydrogen fuel cell vehicles promise quick refueling, longer range, more flexible vehicle size scalability, and range performance in colder climates. www.hyundaiusa.com/tucsonfuelcell
Southeast Michigan’s automakers announced a slate of plant investments between April and June, and FCA announced two major upgrades in July. Combined, companies announced more than $5.5 billion in North American spending. www.fcanorthamerica.com, www.ford.com, www.gm.com
London double-decker bus to use Cummins diesel engine
An iconic Routemaster red bus uses the Cummins ISB4.5 clean diesel engine to meet the Ultra-Low Emission Zone standards planned to take effect in congested areas of London, England, from 2018 to 2020. The AEC Routemaster RM1005 double-deck bus, which first entered service in 1962, now has the distinction of being the oldest bus to meet the latest Euro VI emissions standards.
The bus owner, Sir Peter Hendy CBE, former commissioner of transport for London, challenged the Cummins engineers to extend the operating life of RM1005 with a cost-efficient repower package, hoping to enable other Routemasters to continue operating in London.
The Cummins 4.5L ISB clean diesel engine has integrated exhaust after-treatment, ensuring that despite the new technology, the bus will look the same as non-upgraded models. www.cumminsengines.com