Cloud computing will be necessary to handle the large volume of data for connected manufacturing equipment and the digital twin. (Image courtesy of Amazon Web Services.)

Large industrial software vendors like GE, IBM and Siemens, amongst others, have pushed the concept of the digital twin— a full integration of the physical with the virtual world. In essence, this means that all product design data is available at the time of production. As an example, the full design data of a car body is compared in real-time with the as-is built data in a car body shop. In addition,production-relevant data is fed back into the design process, also reflected as closed-loop engineering. This frontloading of information will allow better decisions at a very early point of the product lifecycle and generate additional value. With asset data available in real-time from production through data aggregation and IoT, predictive and prescriptive applications will generate insight to increase overall equipment efficiency (OEE) and lift value from manufacturing assets in operation.

But, what happens as soon as insight is generated and the status of the physical process needs to be changed to a better state? In manufacturing for discrete and process industries, the process is defined by fixed code routines and programmable parameters. It has its own world of control code languages and standards to define the behavior of controllers, robot arms, sensors and actuators of all kinds. This world has remained remarkably stable over the past 40-plus years. Control code resides on a controller and special tools, as well as highly skilled automation engineers, who define the behavior of a specific production system. Changing the state of an existing and running production system changes the programs and parameters required to physically access the automation equipment—OT equipment needs to be re-programmed, often on every single component locally. To give a concrete example, let’s assume we can determine from field data, using applied machine learning (also referenced as Industrial IoT), that a behavior of a robotic handling process needs to be adapted. In the existing world, production needs to stop. A skilled engineer needs to physically re-teach or flash the robot controller. The new movement needs to be tested individually and in context of the adjacent production components. Finally, production can start again. This process can take minutes to hours depending on the complexity of the production system.

Current production systems are trimmed to high stability and low variability. For example, automotive production has a plethora of product variants, but still has an inflexible production system. With a car model lifetime lasting several years, production managers have learned to live with this inflexibility and value stable processes. However, customer- and technology-invoked trends will increase the need of fully flexible industrial control systems. First, the speed of innovation increases due to improved design systems and customer demand. For example, the product lifecycle of Volkswagen’s Golf I was 10 years and has now been shortened to three years for the Golf VI [3]. Second, requirements for customization increase steadily. Third, intelligent algorithms will produce a steady stream of proposals for process improvement. If we assume that Industrial IoT will fulfill its promises, the majority of manufacturers will be able to gain constant insight. Companies that are able to execute these insights faster will have a competitive advantage. Additionally, every new state of a production and supply chain system will be seen as a new experiment and fed back into ML systems, ultimately generating a virtuous cycle of a self-improving system.

The billion-dollar question will be: How can we design a system that immediately implements new insights? Similar to how cloud computing allows access to IT resources, as if they were software in a fully virtualized manner, a concept I named Software Defined Automation can unchain industrial automation from physical limitations. To realize this, all control code has a digital twin in the virtual world. The local instance is constantly updated from the virtual master code. A virtual model of the whole production system provides context for control code—these manufacturing planning systems are already heavily used by e.g. line builders for automotive and provided by major PLM software providers.

Having a full digital twin of a production system, including control code, insights can immediately be pushed down to change the state of a production system. For the case of Amazon Web Services’ edge technology, Greengrass, we are talking about milliseconds for locations in mainland Europe. Comparing this with hours of lost optimal production time, the potential of Software Defined Automation becomes evident.

Still, human interaction will be required. Production systems will optimize themselves based on simulated and real experiment. Improvements will rapidly be propagated around the globe. Labor will optimize the learning, not the system. This could also differ over time or by external influence. In times where renewable energy was cheap, output could have been one of the core drivers for optimization, while the minimization of input factors could have been paramount in other circumstances.

With the release of edge platforms, the technology is here today to minimize the time from insight to reaction. The power of the cloud is and will be the core enabler to realize software-defined automation fast and at an affordable cost.

[1]https://bdi.eu/media/user_upload/Digitale_Transformation.pdf

[2] https://www.forbes.com/sites/danielnewman/2017/08/08/top-5-digital-transformation-trends-in-manufacturing/#6ff9b733249f

[3] https://www.sjf.tuke.sk/transferinovacii/pages/archiv/transfer/29-2014/pdf/251-253.pdf

About the Author

Dr. Josef Waltl leads the global partner ecosystem for Industrial Software at Amazon Web Services (AWS). Prior to AWS he worked in Siemens building on software strategy & M&A for PLM, Smart Grid and Mobility. He holds a PhD and MBA from the Technical University Munich as well as an MSc in Computer Science from the University of Salzburg.

Not that I’d trust my piloting skills, but there is one company that might make it possible to make the flight from my tiny town to somewhere globally more relevant.

The CH750 Cruzer from Zenith Aircraft Company. (Image courtesy of Zenith Aircraft Company.)

Zenith Aircraft Company sells airplane kits. These aren’t the sorts of kits you pick up from a hobby shop for a meticulously fun Sunday afternoon. These are full-scale aircraft. We spoke to Zenith founder Sebastien Heintz to learn what it takes to create an airplane kit, including the CAD tools used to make one.

The Birth of the Kit Aircraft Industry

Heintz’s father, Chris Heintz, inspired the creation of Zenith. The elder Heintz earned an engineering degree in the 1960s, which he applied to design work on the Concorde. At the time, he wanted to own his own aircraft, but such a dream seemed out of reach— unless he built his own.

Chris Heintz went about designing his own two-seat, all-metal aircraft, which led to fellow flying aficionados commissioning designs and parts from him before he ultimately helped spawn an entire aircraft kit industry.

Sebastien Heintz grew up in the family business, developing a love for airplanes and all things flying. After attending business school, he founded Zenith Aircraft Company in Missouri in 1992. Through Zenith, the younger Heintz not only extended the work of his father, but modernized it, moving the business over from pen-and-paper drafting and manual manufacturing, to a completely digital workflow, including the use of SOLIDWORKS.

What It Takes to Make Kit Airplanes

So, what’s an aircraft kit? Imagine those balsawood planes you might find at a hobby store, blow it up 200 times, replace the wood with aluminum and you can start to imagine what Zenith makes. Though highly specialized, the industry is bigger than one might expect.

“There are more kit airplanes registered with the Federal Aviation Association (FAA) every year than there are factory built ones,” Sebastien Heintz said.

Zenith designs and manufactures aircraft kits, creating the individual parts to assemble the airframe—tail, rudder, cabin, etc.—leaving customers to purchase the engine and avionics. The company tries to put out one kit per working day, totaling about 250 per year. The kits can range around $20,000, and the engine and avionics typically cost an additional $20,000 each.

Altogether, the cost of a two-seater airplane compares to a luxury automobile or boat, but the experience of building it yourself is priceless. Plus, you get to pick out the engine, paint colors, upholstery and everything yourself, resulting in a customized plane.

“We design certain features like you would with any other product, like a car or boat: the actual wing, the position and location of the wing, the tail, etc. That part of the process isn’t really customized,” Sebastien Heintz said. “That said, every individual airplane becomes a one-off airplane. That’s one of the advantages and why the industry exists. People can build their own airplane and customize their needs. They get to choose the design because there are quite a few different designs out there. Then they can truly fully customize it as they’re choosing the engine on the airplane by choosing the avionics, radios and GPS equipment, for instance.”

If the idea of building your own airplane sounds fun, but a little daunting, Zenith hosts two-day workshops at its Missouri factory, where attendees pay to take part in the hands-on construction of the rudder tail section of an aircraft. At 3-feet tall and 2-feet deep, this component can be built easily in two days.

Sebastien Heintz explained that many customers have never really built anything before, but have a keen interest in learning.

“The real takeaway for folks is not only can they build it, but that they have invested in that interest,” he said. “It becomes more of a question of enjoying the learning process and not whether or not you have the skills and experience to build an airplane.”

If you do decide, one day, to take on such a project, it will take about 500 hours of work. Fitting this into your off-hours, vacation days and weekends, Sebastien Heintz estimates that this works out to about one to two years.

Manufacturing Kit Planes in the 21^st Century

Until Sebastien Heintz took over the family’s kit plane business in 1992, the operation was entirely dependent on manual labor: hand drafting and hand manufacturing.

“Back in ’92, most of our design work was basically done with pen and paper, and we were using basic sheet metal bending brakes and press brakes, cutting the parts out manually,” he said. “Little by little we started using CAD software, both for drafting purposes and, more and more, for design purposes. Now, we’ve pretty much switched all our design and parts drafting and so forth over to SOLIDWORKS.”

All of the kit parts required to build the CH750 Cruzer from Zenith Aircraft Company. (Image courtesy of Zenith Aircraft Company.)

Zenith manufactures the individual parts for its kits in-house, beginning with aluminum alloy sheet metal. The planes are first designed in SOLIDWORKS by the company’s engineers before the parts are translated into CAM for production. Zenith has several large CNC tables for cutting out the parts and CNC press brakes to shape the parts.

“That’s really where SOLIDWORKS kicks in, both on the design side and manufacturing side. It allows us to take manufacturing to the next level,” Sebastien Heintz said. “Because the design is a solid model, we can really finalize everything completely to the last definition. We can then send the SOLIDWORKS data to the CNC machine to make the part.”

Prior to adopting SOLIDWORKS about four years ago, Zenith would drill the necessary holes in individual pieces, including the rivets necessary to attach parts together, after they were manufactured. This could add up to more than 16,000 holes. Now, the team is able to drill holes while they’re in the flat stage. This also ensures that once the parts are cut and bent, they line up perfectly for assembly. Not only has this made the design and manufacturing process easier, but it’s even made life easier for customers assembling the airplanes.

“Before, we were using Mechanical Desktop and could lay out one section, but we didn’t have a full 3D model of what it was we were working on,” Sebastien Heintz said. “Now, building everything as a solid model with SOLIDWORKS, we can accurately reflect the final design, actually locate every single hole and then send that to the CNC. Even though we’re starting from flat parts, we can drill the holes and then swing them together after and the holes will translate exactly where they need to be.”

Assembly is made even easier because Zenith is able to post its SOLIDWORKS designs online. A couple of years ago, Dassault Systèmes started offering its free SOLIDWORKS Maker Edition to members of the Experimental Aircraft Association (EAA). Because most Zenith customers are members of the EAA, they can access Zenith’s designs. This also makes it easier for customers to customize their planes, finding avionics that will suit the design, for instance.

The SOLIDWORKS model for the CH750 Cruzer from Zenith Aircraft Company. (Image courtesy of Zenith Aircraft Company.)

According to Sebastien Heintz, the company continues to look at how it can use SOLIDWORKS tools in its design and manufacturing process. For instance, SOLIDWORKS has integrated CAM directly into SOLIDWORKS 2018, something that he is exploring. The company has begun using simulation tools, as well.

In the process of partnering with the EAA, Dassault Systèmes became enamored with the kit aircraft industry. Its employees present at the event had never been exposed to kit airplanes. They were so intrigued that they flew SOLIDWORKS CEO Gian Paolo Bassi to the Zenith factory, which ultimately inspired the company to purchase a Zenith kit for assembly at its headquarters in Waltham, Mass.

“[SOLIDWORKS] has managers, coders and engineers working on it. Their goal obviously isn’t to fly an airplane. It’s more of a hands-on building project that showcases what you can do with SOLIDWORKS in the everyday world,” Sebastien Heintz said. “It’s also become a fun team-building effort. Everyone I’ve talked to that’s worked on it has really enjoyed it. If you’re working in front of a computer screen all day, it’s refreshing to get in the shop, work with your hands and see how the parts come together, especially if you can connect that back to what you’re working on with the computer.”

If you’re thinking about building your own Zenith kit, visit the company’s website.

This brother-run auto shop not only provides aftermarket components for your average motorhead, but Jim and Mike Ring’s small team of professionals also completely restores and revolutionizes history’s favorite classic cars.

Unveiled at the SEMA Show 2017, the 1972 AMC Javelin has been completely redesigned for more power and a more aesthetically appealing design. (Image courtesy of Ringbrothers.)

To learn more, we spoke to Ringbrothers engineer Matt Moseman, who gave us a look under the hood of the Wisconsin operation and, in particular, let us in on how Ringbrothers uses modern machine tools and advanced CAD software to pull off some of the most exciting car mods on the road today.

Redesigning Classics from the Ground Up

For CAD enthusiasts who may not be familiar with the latest trends in custom cars, Ringbrothers has made a name for itself in recent years by overhauling such vehicles as 1965 Mustangs and 1970s Camaros.

The 15-person team both restores old cars and redesigns them, installing new, top-of-the-line components bought off-the-shelf or produced by Ringbrothers itself. By the end of a build, Ringbrothers will give its customers something that maintains the original spirit of the car while also adding a new dimension of performance and customization, with a touch of modern flair.

Ringbrothers takes on such a build every six to 18 months, giving the small team a few big projects per year. Creating dream cars for their customers obviously provides the satisfaction and income associated with such exciting projects, but it’s the parts that Ringbrothers makes along the way that really help fuel the business.

Moseman explained that making custom auto parts is “an extremely SKU [stock keeping unit] heavy and low volume” industry, so the amount of research and development required to make aftermarket parts is difficult to justify. However, when Ringbrothers completely redesigns a custom car, it is able to develop new components that it can then sell aftermarket.

Bring Engineering and Manufacturing In-House

While Ringbrothers has been in business since 1989, Moseman joined the team just a few years ago. Previously, he had worked for the crew as a third-party engineer, providing engineering services for the company.

He was then brought on fulltime about two years ago, along with machinists and CNC mills, to establish Ringbrothers engineering and manufacturing in-house.

“Prior to that, a lot of the engineering was contract and would end up being manufactured elsewhere,” Moseman recalled. “What we found was a massive issue with maintaining quality control timelines, and what we needed to do was vertically integrate. Having all of these outsourced components really created a bottleneck and an energy drain for Ringbrothers. We were spending all of this time trying to control the product line that we had already created, while failing to innovate new products as quickly.”

Ringbrothers now has three vertical CNC machines on the floor, and will be bringing another vertical and a five-axis mill online as well. This vertical integration means less time spent on communication and quality control and more time innovating and manufacturing.

However, to make the design-to-manufacture process as effective and streamlined as possible, Ringbrothers uses software tools that work seamlessly together.

From CAD to CAM

Moseman’s CAD package of choice is SOLIDWORKS. In part, this is because it is the software that he was trained on at the Milwaukee School of Engineering, but, more importantly, it connects seamlessly with accompanying CAM packages, such as CAMWorks—now SOLIDWORKS CAM for SOLIDWORKS 2018.

Using the two tools together, Moseman explained, provides a much more efficient workflow between the engineer and the machining crew. As Moseman works on a design, there’s no need to import and export files into separate CAD and CAM packages. Due to the tight link between SOLIDWORKS and CAMWorks/SOLIDWORKS 2018, it’s possible to make a design change and simply update the file for CAM.

Once the model has been made, it’s possible for Moseman to assign dimensions using SOLIDWORKS MBD to the part along the way so that drawings can be made from that information. Ringbrothers still uses third-party services for some parts. “I can just send them a drawing, and there’s little to no communication necessary anymore. They can just create it and ship it,” Moseman said.

“This mitigates the human error that might come up in translating a document to a separate CAM package or dictating changes to the machinist. That’s where most of the scrap metal comes from,” Moseman said.

SOLIDWORKS, in particular, helps Moseman in the design initiation process, as well. It’s no longer necessary for the engineer to sketch ideas on paper, though he still does so digitally with the Microsoft Surface Studio. However, once he creates a model in 3D, he can create the necessary 2D technical drawings from that model in SOLIDWORKS MBD.

“I hate 2D technical drawing,” Moseman emphasized. “I refuse to create a drawing for a product or part that is already modeled in 3D. I’m going to take it back, dumb it down, and make it 2D so it can be printed out as a PDF? That makes no sense to me.”

The 1972 AMC Javelin

Ringbrothers’ latest masterpiece, the 1972 AMC Javelin, is a great case study in Ringbrothers’ overall business model. Debuted at Specialty Equipment Market Association (SEMA) Show 2017, the Javelin began as a 100 percent clean vehicle, in storage with all of its original parts since 1977. In fact, Mike Ring was the last person to give the car an oil change before it was protected and hidden from the harsh outside world.

The original Javelin, brought in by longtime Ringbrothers customer Prestone. (Image courtesy of Ringbrothers.)

Due to its pristine condition, the Ringbrothers team was able to first 3D scan the entire vehicle and bring it into CAD, where all of the surfaces were reversed so that Ringbrothers designer Gary Ragle could begin working on designing other parts of the car. This included overlaying surfaces to fit the wheels they’d chosen into the wells of the Javelin and modifying the hood to fit the Hellcat engine with the 4.5-liter Whipple supercharger that was used to replace the Javelin's original 390-cubic-inch V8. Moseman then worked with Ragle on manufacturability, translating those designs into reality and ensuring that they would work with the other mechanical parts. Once the design was complete, they worked alongside a talented team of fabricators, manufacturing experts, and painters to bring everything together.

The Javelin prepped for 3D scanning. (Image courtesy of Ringbrothers.)

It’s updates like these that make acar like the AMC Javelin a prize for the car collector who already has everything. Along with the new drivetrain and engine, Ringbrothers brought in new materials made with the latest technologies.

“Those 3D scans then aided in designing the machining molds to create all of the fenders, bumpers, diffusers, spoilers and other parts, which we then turned into carbon fiber and fiberglass pieces,” Moseman said. “The scans also helped to make the bumpers and taillights that were machined from aluminum.”

3D scanning made it possible to redesign the body of the Javelin and create new carbon fiber parts. (Image courtesy of Ringbrothers.)

Throughout the restoration process, Ringbrothers is also able to leverage SOLIDWORKS to design prototype parts that are 3D printed on the company’s Form 2 3D printer. This enables first-time-right machining, but also helps Ringbrothers test out new products. For instance, on the Javelin, a key part to the mirror assembly was 3Dprinted and installed on the vehicle. At SEMA, the company can ask attendees if they would be interested in such a product as an aftermarket purchase.

Such parts as the exterior door handle above, originally a more generic design, are first prototyped in plastic on the Form 2 3D printer. (Image courtesy of Ringbrothers.)

As the car was redesigned and rebuilt from the ground up, Ringbrothers also created aftermarket parts, such as the hood pin and interior door handles. The hood pin doesn’t just fit the Javelin, but can fit all early model Chrysler, Ford and GM products. The interior door handles for the Javelin (different from what's pictured above) have been, as a new launch, one of Ringbrothers’ highest movers so far. Launched about two months ago, the firm sold out of preorders for the handles in the first few weeks.

SOLIDWORKS 2018

This entire process has been made more efficient with the release of SOLIDWORKS 2018, according to Moseman. Compatibility with the MicrosoftSurface Studio has helped to make Moseman a quicker designer, for instance.

“Currently, I have the 27-inch Surface Studio and then a Surface Book. The Surface Studio just changes the whole ergonomics of designing—the whole workflow, really,” Moseman said. “Being able to use both hands is what I’ve found really useful. You can actually be in the process of drawing or writing or clicking with your right hand, while you’re prepared to go onto the next step with your left hand using the Surface Dial, already clicking on the next icon.”

“When you have an idea, you might want to sketch it out on paper as quickly as possible before it escapes,” he continued. “Combining the Microsoft Surface Studio with SOLIDWORKS, I don’t need a sketchbook sitting next to my bed anymore. I have the Surface Book and Surface Studio, and I can open up SOLIDWORKS or the Sketch app and draw something really quickly.”

Ringbrothers has yet to implement the 2018 version of SOLIDWORKS CAM across the firm, but intends to do so. Meanwhile, Moseman has been working with the software on his own. With the new software, he sees a closer integration of SOLIDWORKS and SOLIDWORKS CAM.

“In the past, normally there’s still been a disconnect between engineering and machining because engineering would be working with parametric-based modeling within SOLIDWORKS, but then they’d have to output an STL to be imported into a lot of CAM packages,” Moseman said.“All of the toolpaths would be written around that, but as we all know, you never nail a prototype on the first pass. So, there was always this back and forth between these programs, which not only frustrates machining and engineering, but it creates a slower process and time to market.”

For a company like Ringbrothers, the use of CAD and CAM has made the design of custom cars and aftermarket parts as flexible as the team’s imagination. With the release of SOLIDWORKS 2018, that flexibility has only become greater so that, by next year’s SEMA event, the firm will have even more exciting projects to show off.

I’d love to hear your thoughts in the comment area below. If you are a designer, where would you specify asymmetrical tolerances? If you are a machinist, how would you handle asymmetrical tolerances?

Prashant Kulkarni shared his experiences with GE Power and Water. Figure 1 shows a drawing that he encountered, in which a hole diameter was defined as 1.5 in with a tolerance range of +0.0035 to -0.005 in, along with other asymmetrical tolerance requirements.

Figure 1. A drawing with asymmetrical tolerance ranges. (Image courtesy of GE.)

The designers wanted to make sure that a 1.5-in drill is used, so the hole can't be smaller than 1.5 in, except for the tolerance of the drill itself, which is 0.005 in.

On the other hand, for machinists, machining to the nominal dimension with an asymmetrical tolerance range would feel similar to driving a vehicle closely to one side of the lane but far away from the other side, rather than staying in the middle of the lane. The wiggle room on the nearside would be much smaller than the far side. One deviation on the near side could exceed the limit and scrap the part, while the same deviation could be tolerated on the far side.

You can manage to make it work if the upper and lower limits are spread apart on both sides of the nominal. It just increases the risks. However, for unilateral tolerances in which the limits are only on one side, machining to the nominal wouldn't work at all because the nominal dimension itself is out of the tolerance range.

Therefore, a typical handling of an asymmetrical tolerance window is to calculate its mean dimension to reach a symmetrical tolerance range. In other words, machining to the mean, rather than the nominal, allows machinists to drive safely in the middle of the lane. The benefit is to even the penalization risks between the upper and lower limits, increase the finished part pass rate and save the overall manufacturing cost.

That was what the GE manufacturing engineers ended up doing to the drawing in Figure 1. They manually modified the model features to reach symmetrical tolerance ranges. For the example above, the hole size was tweaked to 1.515 ± 0.020 in.

But throughout a design, there can be a large number of asymmetrical tolerance ranges. This kind of manual modification can take lots of a manufacturing engineer's time and introduce unnecessary human errors. To answer this challenge, CAMWorks came up with a solution shown in the green circle in Figure 2, “Machine to Mean.”

Figure 2. A “Machine to Mean” option in CAMWorks.

This option automatically assigns the cutter allowances to arrive at the mean sizes with symmetrical tolerance ranges, so that you don't have to tweak the model manually or recalculate the tolerances any more.

Let's take a look at one example as shown in Figure 3, in which the highlighted nominal pocket width size of 110 mm is defined with a tolerance range of +0.15 to -0.25 mm.

Figure 3. A nominal pocket width size is defined with an asymmetrical tolerance range, highlighted in green at the lower-left corner.

Don's scratch your head yet. Instead of running the numbers in your head or on a piece of paper, you can now run the CAMWorks tolerance-based machine. Figure 4 shows that the milling contour operation is automatically created. Furthermore, please pay attention to the tree node where the mean tolerance value is calculated automatically as 0.025 mm in the green circle.

Figure 4. A contour milling operation is automatically created with a mean tolerance value of 0.025 mm.

If you double-click on this milling operation, you will see the highlighted side allowance 0.025 mm at the upper-left corner on the dialog box as shown in Figure 5.

Figure 5. The side allowance is automatically calculated as 0.025 mm.

By the way, the allowance stands for the amount of material to leave on the sides of the part for a later contour milling cycle. This value is the actual distance the cutter stays away from the finished part. The amount is defined per side. The allowance can be positive or negative. Negative values up to the radius of the tool can be specified and will cause the tool path to overcut the part.

Just in case you are wondering how the allowance is calculated, let me walk you through the steps. First, let's calculate the mean width size, which is the average of the upper and lower limits, or (110.15 + 109.75)/2 = 109.95 mm. Then figure out the offset from the nominal size to the mean size—that is, 110 – 109.95 = 0.05 mm. Last, just evenly distribute the offset to both sides of the width feature, which is 0.025 mm as shown in Figures 4 and 5.

Here is another example as shown in Figure 6. The slot size is 30 mm wide and 70 mm long, with a unilateral tolerance zone on both the width and length from +0.1 to 0.0 mm.

Figure 6. A contour milling operation on multiple slots of a unilateral tolerance range from +0.1 to 0.0 mm.

Now you may wonder which nominal size to use here: the width of 30 mm or the length of 70 mm. The answer is that it doesn't matter. What matters is the tolerance distribution. Let's use the 30 mm as an example. The mean width is (30.1 + 30)/2, or 30.05 mm. Then the offset from the nominal size to the mean is 30 – 30.05, or -0.05 mm, so the cutter allowance on one side is half of that, or -0.025 mm, as shown in the tree node in Figure 6. You can verify it with the 70-mm length size yourself.

Please note the material allowance is negative here. It means that the cutter will overcut the part so that the openings are bigger than the nominal sizes, as required by the tolerance zones.

Now let’s capture the calculation in a formula as shown below, just in case you want to verify the allowances.

The material allowance = - (upper tolerance + lower tolerance)/4

However, the good news is that you don’t have to remember this formula, manually run these calculations or modify the tolerances any more. No matter how many asymmetrical tolerance ranges there are, CAMWorks takes the allowances into consideration automatically for the numerical control code programming. To learn more about machining to the mean size, please visit the CAMWorks product page.

About the Author

Oboe Wu is a SOLIDWORKS product manager with 20 years of experience in engineering and software. He is an advocate of model-based enterprise and smart manufacturing.

To get to know the company, the first thing you should be aware of is that OPEN MIND produces CAD/CAM software as well as postprocessors for the design and manufacture of complex molds and parts. The company offers 2D solutions packed with features for milling standard parts and software for five-axis simultaneous machining, among other products.

hyperMILL for SOLIDWORKS

OPEN MIND has an integrated CAM solution that you may find useful for high-performance engineering as well as tool and mold manufacturing and design. The central idea behind making a product like hyperMILL for SOLIDWORKS is to empower users to transform their CAD designs into numerical control (NC) code for machining without leaving SOLIDWORKS and worrying about interoperability issues or any other hiccups a user can experience transferring design data to third-party CAM software.

Not having to leave your design environment has several advantages. As an integrated process with universal data models, the production process is more transparent and secure. The obvious general productivity benefit of using a familiar design interface is that more people want to use it. Additionally, an entirely new software doesn’t need to be learned or taught, which also can simplify operations and increase efficiency in a given production process.

OPEN MIND Technologies accomplished something pretty remarkable by creating one user interface in SOLIDWORKS with 2D, 3D, high-speed cutting (HSC) and 5-axis machining strategies, as well as a mill turn module. With these options available  in the popular CAD software from Dassault Systèmes, users have simple yet sophisticated choices to create the best machining strategy. The better the strategy is, the less users find themselves spending time on programming and machining, which increases efficiency and productivity. This counts big time for everyone concerned with keeping costs down and getting new products, parts, molds and tools to market on time or even a bit early.

Standardizing and Automating CAM Tasks

One of the goals OPEN MIND has strived to accomplish with hyperMILL is to make the programming of 5-axis tasks as easy and familiar as 3D programming. Avoidance features and collision checking help make this possible with 5-axis tasks and hyperMILL automatically calculates tool positions with one preference angle inputted by the user. Machining strategies and tools can be combined, stored and retrieved from a graphical database, which is useful when users are creating CAM programs.

Checking the programs built by users is easy with OPEN MIND Utilities, because it amplifies the ability to make changes to tool paths right up to and including the last phase.

With hyperMILL, users can:

• perform multi-axis machining
• machine surfaces
• use hole feature recognition
• machine on surfaces
• perform milling and turning in one operation
• program and execute 5-axis drilling and mill and turn in one integrated operation.

For manufacturing operations, this means reduced cycle times.

Tangent Plane Machining in hyperMILL with Conical Barrel Cutter

OPEN MIND hit the whiteboards pretty hard and came up with a totally new kind of milling tool geometry to machine faces with minimal curvature using a conical barrel cutter. If you aren’t familiar with barrel-shaped tools, they use a portion of their circumference to allow for a 500-mm cutting radius.

The conical barrel cutter was integrated by OPEN MIND for hyperMILL to enhance what the company calls its tangent plane machining strategy. In order to spend less time machining vertiginous and bottom surfaces, the conical barrel cutters employed in this strategy cut machining time by 90 percent during tangent plane machining.

A conical barrel cutter using hyperMILL’s tangent plane machining strategy cuts into a structural part. The 500-mm radius is much larger than that of a ball end mill. (Image courtesy of OPEN MIND Technologies.)

Depending on what type of machining you’re doing, you may use a general barrel cutter or a tangential barrel cutter, but if you’re machining steep or flat planes in undercut situations, the conical barrel cutter will work best. hyperMILL also automatically aligns and nestles the conical barrel cutter to avoid collisions and mistakes that will cost you time and money.

Replacing the Traditional Ball Mill with the Conical Barrel Cutter

hyperMILL’s automatic alignment and nestling of barrel cutters is part of what OPEN MIND calls the “MAXX Machining” strategy. This coined term signifies the ability of users to automatically support the geometry and perform collision checking of conical barrel cutters as well as tangential barrel cutters and lens tools.

The CAM industry’s reaction to the MAXX Machining strategy has so far been cautious but optimistic. With any new change in machining strategies, the main issue is convincing cutting tool vendors to get on board and produce a tool that only displays a circle segment of the cutter. Quickgrind was one of the first to get on board. For other tool producers, a really important thing to remember for customers who want to keep their machine shop as up to date as possible is the following: Manufacturing a cutting tool with a shank diameter of only 15 mm can create a large radius of 500 mm.

The reason this is important is because it greatly increases the overall machining area, helping reduce cycle times and higher step-over rates without altering scallop heights. It not only allows users to create great surface finishes, but also diminishes tool degradation because it uses a larger surface area of the tool.

Besides increasing the machining area and reducing tool wear, the new strategy can protect users from suffering annoying deviations from spindle growth or heat warping.

Comparison of MAXX Machining with a Conical Barrel Against a Standard Ball Nose

At a recent technical seminar in the United Kingdom, a comparison demonstration took place to test the surface finish performance of the MAXX Machining strategy. The setting was the Mazak Technical Centre. The machine was the Mazak i-400 multi-tasking machine tool. The cutting tools were supplied by Quickgrind.

The contest was between a ball nose tool with a 10-mm diameter and a conical barrel tool with a radius of 500 mm on a 10-mm shank. Using a small step-over strategy of 0.2 mm, the ball nose tool compared poorly with the conical barrel tool, which had a 3-mm step over. This resulted in a tool path distance of 100 m for the ball nose tool. The barrel tool, by comparison, came in at slightly less than 7 m!

The difference in machining time was even more disparate and exaggerated: 39 minutes for the ball nose tool. It only took the barrel tool three minutes!

Conical barrel cutter in hyperMILL empowers a new wave of capabilities for machine shops. (Image courtesy of OPEN MIND Technologies.)

The ability of the MAXX Machining strategy to produce a 500-mm radius can certainly be scaled up as OPEN MIND hits the drawing board with cutting tool specialists. With MAXX Machining, the key takeaway is that a larger tool radius equals a larger step down.

Imagine what machine shops could accomplish with a 1,500-mm radius tool on a shank size from 5 to 20 mm in diameter. This allows customers and users to sync up the tool radius by matching it with the accuracy of the machine tool. Simply put, this is possible because a smaller radius amplifies the inherent precision of the machine tool by stabilizing and maintaining positional tolerance without rolling over the edge. This depends of course on the level of precision in a given machine tool.

However, it also yields a simple maxim for scalable improvement using barrel tools and hyperMILL’s MAXX Machining: the larger the radius, the greater the advantage.

About the Author

Andrew Wheeler is an optimistic skeptic whose lifelong passion for computer hardware has led him to 3D printing and his latest technological passion, Reality Computing.