From Italy to Saudi Arabia, the University at Buffalo in New York to the grounds at GoMomentum Station in Contra Costa, California, Local Motors’ Olli autonomous shuttle is popping up everywhere. The brainchild of Local Motors Co-founder and CEO Jay Rogers, this self-driving, co-created, largely 3D-printed vehicle aims to change the way people get from Point A to Point B and promises to change how people think about manufacturing as well.
Developing and building an autonomous vehicle isn’t without its challenges, however. Tim Novikov, advanced manufacturing engineer at Local Motors’ facility in Knoxville, Tennessee, found this out the hard way recently while attempting to machine an Olli chassis on the company’s massive hybrid additive machining center.
“I had to turn the feed rate override to its lowest setting to keep the chatter under control,” he says. “Anything faster than that and it sounded like the chassis was going to self-destruct.”
Olli, meet LSAM
The machine tools used to make the Olli are nearly as unique as the company. Local Motors’ microfactory in Knoxville is home to one of the largest 3D printers in the world, a 40ft long gantry-style Large Scale Additive Manufacturing (LSAM) machine from Thermwood Corp. Like other fused deposition modeling (FDM) 3D printers, LSAM has a deposition head that heats and extrudes plastic feedstock, building parts one layer at a time. What’s different – aside from its enormous size – is the addition of a 5-axis milling head, allowing users to print and mill on the same machine.
This technology mirrors Local Motors’ digital manufacturing strategy, which according to research and development program director Billy Hughes, drastically reduces vehicle development lead times, provides endless customization and collaboration opportunities, and allows the vehicles to be built in community-centric microfactories. It could also enhance those communities by providing good paying manufacturing jobs and easy access to fleets of environmentally friendly vehicles.
“You look at the problems with urban blight, the decline of manufacturing in the U.S., environmental concerns and sustainability, there’s far more to this than producing fleets of high-tech shuttles,” Hughes says.
Those community benefits, however, require a viable way of building Olli. That’s where Sandvik Coromant US was able to help. Faced with the unacceptable chatter and productivity problems with the complex, oftentimes thin-walled Olli chassis, Novikov turned to sales engineer Matt Brazelton to reduce the 80 hours of machine time per vehicle that Olli was taking.
“We’d actually been working with Local Motors for some time on their legacy machining center, providing them with indexable ball-nose and face mill cutters, and because the composite material they’re using is quite abrasive, we also set them up with polycrystalline diamond (PCD) milling inserts,” Brazelton says. “The larger spindle interface on their new LSAM, though, provided us with several new opportunities for improvement, with chatter elimination first and foremost.”
The first change was an adapter that allowed Local Motors to convert the LSAM’s HSK-F spindle taper to use Sandvik Coromant’s quick-change modular tooling system, Coromant Capto. This increased connection rigidity significantly, reducing tool changeover and setup time, while allowing Novikov to increase feed rates. More importantly, it allowed Coromant Silent Tool milling extensions. Those additions and a custom CoroMill 390 indexable shell mill, eliminated the chatter problem, even at full feed rate.
Due to the extreme length needed to reach deep inside the Olli chassis, the weight of a traditional steel milling tool mounted on the end of the Silent Tool extension did not provide the desired results. Brazelton reached out to tooling engineers at Sandvik Coromant, who came back with a novel solution: a custom CoroMill 390 cutter body made of 3D-printed titanium, optimized to achieve the lowest possible moment of inertia.
“It’s funny when you think about it,” Novikov says. “Here we are making the first 3D-printed vehicles, and we’re using the first 3D-printed tools to do it. But what’s even more funny is the tool itself. It’s so lightweight it feels like a toy.”
The titanium CoroMill 390 doesn’t cut like a toy. Novikov was able to crank the feed rate override up to its programmed setting, reducing the 80-hour cycle time to roughly 5 hours, with greatly improved surface finishes and tool life.
“Before, everything vibrated so much there were gouges in the chassis wall from where it bounced back and forth against the cutter,” Novikov remembers. “It sounded like someone plucking guitar strings, only much louder.”
With Sandvik Coromant’s updated tools, he adds, “Now, it’s completely quiet, and there’s no risk of scrapping out a very expensive workpiece. Better yet, we can now reach twice as far as we could with our old tooling, so we’re able to machine more of the chassis in one operation.”
The latest Olli iteration is almost entirely 3D-printed from tough, carbon fiber composite material. With greatly improved machining conditions and the ability to operate PCD milling tools at the recommended cutting parameters, tool life and part quality are no longer a concern. Greater spindle interface rigidity allows Novikov to use larger cutting tools, further increasing productivity.
As Novikov will tell you, the best part of the improvement is the newfound ability to print and machine a complete chassis in a single shift, freeing the LSAM to crank out more Ollis, or work on any of Local Motors’ other manufacturing projects.
“The Coromant Capto system and Silent Tools have also increased the machine’s flexibility, in that we can use pretty much whatever tools are needed to get the job done efficiently, and not be limited to relatively small milling cutters and drills like we were before,” Novikov concludes. “These chassis are quite large, and we needed a way to machine them in a productive manner. That’s what Matt Brazelton and Sandvik Coromant have done for us.”
Maztech Precision Engineering (MPE) regularly produces precision components in ridiculously short turnaround times. For racecar suppliers in the UK’s Motorsport Valley, that’s just an average Tuesday.
So, when the British government began urging motorsports manufacturers to make components for ventilators and other equipment to handle the COVID-19 pandemic, Founder Wayne Bouchier says his crew was ready to do its part. The company won a government order to produce 7,500 aluminum tube manifold components for medical equipment, keeping its four machining centers running 24/7.
“The tube manifold is a relatively simple 3-axis part, but with the significant quantities required, we needed to design new fixturing to conduct multiple setup machining,” Bouchier says.
That, he adds, is where his company’s focus on having the best equipment and best software played a critical role.
MPE uses Open Mind Technologies’ hyperMill CAM software because of its support for multi-axis machining and newer toolpath technologies. When the company started making ventilator components, he says having the right tools helped speed up machining.
“Using the Linear Pattern feature in hyperMill, we have been able to effectively copy and paste the machining cycle from one position to the next on our machining centers. On one of our machines, we now have 16 WNT ZSG4 vises with suitable fixturing set up for non-stop machining,” Bouchier explains. “The hyperMill program for each part is simply copied and pasted, not just across each fixture, but also across all of our machines.”
Maztech has four employees and a prestigious client list. It recently invested in its fourth machine, a 5-axis machine with 32-pallets and tool storage capacity for 145 tools for continuous around-the-clock production. This has proven priceless during the race to produce ventilators.
“My strategy all along has been to invest in the best machinery, the best CAD/CAM software, the best tooling, the best workholding, the best of everything,” Bouchier says. “It all plays a role in producing the highest quality parts. I think the quality of our parts is a reflection of what we’ve got here on the shop floor; the Mazak machining centers, ITC cutting tools, and of course the hyperMILL CAM system.”
Maztech started using 5-axis machining in 2017. Bouchier says, “I had a CAM system, but it couldn’t provide suitable post-processors to communicate confidently with the VariAxis configuration. I also wanted the full machine model, so I could simulate everything – as the machine is a big investment.”
Colleagues recommended hyperMill, and many Formula 1 (F1) engine producers use the software, so Bouchier requested a demonstration.
“We picked out a model of one of my parts and Open Mind showed me how to program and simulate it, demonstrating the complete machine model. As someone with CAM experience, I asked loads of questions,” Bouchier recalls. “Entering 5-axis machining is never easy, but hyperMill simplified it… The 5-axis capabilities and comprehensive machine simulation made the decision for me to invest in hyperMill.”
Bouchier took a 3-day course to familiarize himself with hyperMill before implementing it at MPE. After a few months, he sent team members to training, bought a second seat, and deleted the stored files on his servers from the previous CAM system.
“This prevented us from falling back on the previous system if a difficult challenge arose. This meant we had to reprogram all our previous jobs, and with up to 50% of our work being repeat business, this was a big move,” Bouchier says.
As MPE increased its capabilities to produce complex parts with 5-axis technology, Bouchier became better known in racing circles and began discussing next steps with potential customers. Following advice from numerous motorsport subcontractors, Maztech specified the hyperMill Maxx machining package for high-performance metal removal rates. Other modules specified were the 5-axis Z-level finishing, 5-axis profile finishing, 5-axis freepath, swarf, and 5-axis contouring.
“The main benefits are the sheer number of options in terms of available strategies to machine parts. In the past, we have wanted to do jobs in a particular way and the CAM system has prevented us from taking our chosen strategy. This isn’t the case with hyperMill,” Bouchier says. “It can be the most frustrating thing as an engineer when you know exactly what you want to do, but your CAM package won’t allow you to do what you want.”
The Maxx package supports trochoidal milling and arbitrary stock machining, systems that MPE uses for stainless steel.
“Arbitrary stock machining enables us to maintain a constant load on the spindle and tool to maximize material removal rates. Equally important is the fact that this also prolongs tool life and improves surface finishes by retaining an even chip load,” Bouchier explains.
For Maztech to produce complex components with confidence, its engineers have modeled all workholding accessories, such as all vises, vise jaws, and chucks, and created a template for each. That work proved critical in quickly ramping up ventilator component production.
“With hyperMill, if you put good data in you get good data out. If you set up your tools exactly as they are set up in hyperMill, run a collision check and the software says there is no collision - you’re 99% guaranteed there won’t be a collision,” Bouchier says. “So, when you first program a job, you open the template and select the vise and the jaws and pull that into your job. Straight away, you are collision checking against your vise and jaws as your machine is modeled up.”
While making cars and trucks look great is important, applying the correct amount of coatings onto vehicle bodies is more important for protecting metal substrates from corrosion and ensuring long product lifespans. The automotive industry needs accurate coating thickness measurement when plating, anodizing, powder coating, or spray coating vehicle bodies.
Properly applied coatings, with thickness measured in mils (0.001") or microns (0.001mm) are crucial to avoid coating breaches that lead to corrosion of the underlying substrate. Precise application to specification, along with coating measurement, can also prevent leaks and other safety issues.
However, conducting frequent, laboratory-quality coating thickness tests throughout the manufacturing process has been difficult. Traditionally, this required meticulous sampling and preparation, as well as taking the sample to the lab for evaluation. Portable coating thickness gages are not new, but most fail to provide the accuracy, speed, or simplicity required for quick checks.
Newer handheld devices allow personnel to easily and quickly perform lab-quality coating thickness measurements. Some options offer instant coating thickness measurement of almost any non-magnetic coating on ferrous substrates such as steel panels and non-ferrous substrates such as aluminum and carbon fiber reinforced plastic (CFRP). This is possible using only one hand, even on curved and complex surfaces.
Simplifying the testing process allows automotive original equipment manufacturers (OEMs) to increase quality checks while optimizing costs.
Thickness reading benefits
Coating thickness directly affects vehicle and component quality for paint, electroplating, anodizing, and other coating applications. Checking paint coating consistency on a vehicle provides a product with a superior finish and offers essential data about the consistency of the paint when it’s wet.
“Incorrect paint consistency can affect drying times or eventual flaking of the paint film,” says John Bogart, managing director of coating thickness tester manufacturer Kett US. “Too little paint coating and you are left with cosmetic issues in opacity and protective issues such as corrosion, wear, and exposure.”
When specificity and adhesion matter in anodizing and electroplating, a coating thickness gage should be able to read the coating thickness to the most minute measurement. This can play a major role in preventing corrosion while optimizing the process to eliminate excess use of expensive plating products.
Testing anti-corrosion pipe/piping coatings can also find weak spots where the coating is too thin and a coating breach could make the substrate susceptible to corrosion, Bogart says.
“Knowing about these trouble spots can prevent a problem well before it occurs,” he says. “This could involve engine piping and tubing or exhaust tail pipes. A nondestructive gage is a perfect way to ensure that the protective coating has not been applied too thinly. Excessively thin coatings are more likely to be chipped or breached, which can lead to corrosion promoters such as water or oxygen getting under the coating and accelerating corrosion in the substrate.”
Traditional laboratory coating thickness measurement techniques are useful in the right settings but lack the simplicity and flexibility required for frequent spot checks. Sampling, sample preparation, and taking the sample to the lab for evaluation require time and participation of trained staff.
Other conventional coating tests, such as scratch testing, are destructive or invasive and damage the sample. Scratched products cannot be returned to the production line, requiring re-coating or repairs that add time and expense to processes. Also, since only a small portion of the component may be tested, results may not represent the entire situation.
In certain environments with multiple substrates, many older handheld devices either had difficulty determining the substrate or using the correct test for the application. So, multiple measurement devices had to be used, complicating testing.
Finally, typical coating measurement methods were usually unable to accurately measure curved or complex surfaces, preventing easy spot checking of pipe, piping, and convoluted component design coating compliance.
Kett’s LZ-990 portable coating thickness gage combines two of the most widely used measurement methods – magnetic inductance and eddy current – in a dual-mode device that measures thickness of almost any non-magnetic coating on ferrous and non-ferrous substrates.
The unit automatically determines the substrate and uses the appropriate measurement circuit, enabling instant, non-destructive testing on painting, plating, anodizing, and organic coatings with up to 0.1µm accuracy. Such testing takes less than a second to display the measurement.
Providing accurate, repeatable measurements requires consistent contact between the instrument and the test surface, so the unit uses a spring-loaded probe to generate consistent contact pressure with the measured surface. The probe includes edge guides to ease measurement of curved and edged surfaces. The probe’s foot design provides a firm platform when placed onto the test piece.
Bogart says numerous design considerations in handheld coating thickness gages can simplify measurement and improve versatility.
Eliminating moving parts in the tester (other than the probe) improves accuracy and durability. Similarly, the unit should be impervious to vibration, with measurement independent of its orientation.
To save time during testing, he recommends units with large screens to quickly read results that can be stored in the gage and transferred to a computer and/or printer for documentation and process monitoring. An instrument that stores many test measurements allows operators to perform numerous tests before downloading results.
“Easier, more accurate automotive coating and plating measurement with handheld units will improve quality checks wherever needed. Defects can be immediately detected and corrective action undertaken to minimize scrap and faulty components,” Bogart concludes.
When producing electric power steering (EPS) systems, cycle time means everything. However, one manufacturer’s system was already optimized and could only further improve operations by adding new machine technology.
“At this point, the company turned to us at Liebherr because our machines are already employed there. They machine the steering segment while other machines make worms,” says Johannes Weixler from the technical quotations department at Liebherr-Verzahntechnik GmbH.
EPS systems typically use worm-gear systems – a gear with very few teeth turns a worm, a cylindrical, screw-like shaft with grooves that rotate the entire piece as the gear turns. Worms must be made with very high precision for electronic steering.
“Electronic steering is becoming more popular because it offers some advantages over hydraulic power-assisted steering,” Weixler says. “It only operates when actual steering movements are carried out and thereby saves a considerable amount of energy. Furthermore, it’s very quiet and therefore particularly ideal for electric cars.”
A 2018 report from the National Highway Traffic Safety Administration (NHTSA) estimates that 70% of the U.S. vehicle fleet will use EPS by the end of 2021. Virtually all new gasoline-powered vehicles use the systems to shift loads from the engine to the electrical system. EPS is a key component for advanced driver assistance systems (ADAS) and autonomous driving as electrified systems are easy to digitize and give computers more steering control.
Swivelled cutter head, no steady rest
“A worm of this kind is a gear with two teeth and this is why it should generally be made on gear hobbing machines,” Weixler explains.
The swivelling range of the cutter head of the customer’s LC 80 WD milling machine was extended for this task. The setup removes the steady rest typically used in worm machining.
“We solved this problem with an intelligent clamping fixture that’s extremely rigid,” Weixler says.
To adapt the machine to worm milling, designers considered the requirements of the machine table as well as the applied cutting forces to facilitate a stable process. Tool life tests indicate it was possible to increase cutter life by more than 40% – a potentially significant source of savings given the prices of specialty tools.
Chamfering, brushing included
Because the gear cutter can produce razor-sharp burrs, the machine is equipped with a multi-station ring loader and an additional chamfering unit. Conventional side milling cutters perform chamfering, which are significantly cheaper than the worm cutters. A brush installed in the same position removes any micro-burrs after chamfering, readjusting automatically as it begins to wear.
“We were able to provide added value for our customers in several aspects,” Weixler concludes. “The customer can now cut, chamfer, and brush parts on one machine. Chamfering during the machining process means faster cycle times and lower tool costs. This allows for major savings, particularly with the customer’s high volume.”Liebherr Gear Technology Inc.