Relatively few shops perform frequency response measurements (like the one shown in the photo) to determine the optimal, chatter-free spindle speeds and depths of cut for their machines.
However, a much larger share of shops do run at something like these optimal parameters, because they eventually arrive at these parameters through the trial-and-error process of adjusting a machine’s speed until the chatter stops, and then cutting as deep as they can at that speed. The difference is: Measuring to find these parameters can get the shop to the optimal process faster, without so many parts being cut inefficiently along the way.
Jerry Halley of Tech Manufacturing experienced this. He was looking for a machining center that would perform well in heavy cutting of aluminum using a ¾-inch or 1-inch tool. For each of the machine models he considered, he went to where that machine was in use so he could measure to find the machine’s chatter-free milling speeds with these tools. (That measurement is often called a “tap test.”) A machine from SNK gave him the best performance he measured with the tools he wanted to use.
He shared this information with the machine’s user, the shop he was visiting to measure the machine. That is, he told team members at this shop the exact spindle speed at which they could run the machine to get the best efficiency with a 1-inch tool.
They said, essentially, “That sounds right.” The staff here had already figured out that this particular speed was best.
Mr. Halley nevertheless says there is an important point here that illustrates the value of the frequency response evaluation. In questioning the staff members further, he learned that they had fine-tuned the machine’s cutting parameters over the course of several months before coming to the correct findings that they did. By contrast, he came to the same correct conclusion with a measurement that took 15 minutes. Measurement and experience arrived at the same place, but measurement made it there much more quickly.
Learn more about measuring machine tools to find chatter-free cutting conditions here and here.
Surgery on the anterior cruciate ligament (ACL) in the knee is a complex procedure that demands precision and control. In order to repair or replace an ACL, the surgeon removes any remnants of the natural ACL and then attaches a replacement ligament (a graft usually taken from elsewhere in the patient’s body) to the tibia and femur. The positioning of the grafted ligament is critical, as it should accurately mimic that of the natural ACL.
To help make this precise surgery easier, orthopedic surgeon Dr. Dana Piasecki designed a two-part system consisting of a flexible pin (drill) and a guide for positioning the pin inside the knee. This guide is the key to a less invasive surgery, as it allows the surgeon to move and hold the pin without opening the knee or contorting it to place the new ligament.
Though 95 percent of the guide is made up of a simple shaft, the end of the device is the critical part. The shape of the neck is intended to follow the ligament’s normal path to ensure that it is placed at the right location and angle, and the tip is precisely sized to hold the 2.2-mm pin.
To machine this guide tool from a block would have required many setups with multiple angles and undercuts. Instead, Dr. Piasecki and his business partner Jim Duncan of DanaMed worked with Stratasys Direct Manufacturing to have the device manufactured with direct metal laser sintering (DMLS). This powder-bed additive process allowed the device to be built at the correct angle and build orientation to accommodate the critical features, without any machining necessary. Producing the guide additively also saved on material and reduced its overall cost, while enabling ongoing design changes.
Learn more about this device—including its design, manufacture and postprocessing—in this article from Additive Manufacturing magazine.
Metrology holds a clue to how the story of manufacturing can be retold along bold new lines, says Ole Rollén, president and CEO of Hexagon. In his keynote address at the recent HxGN Live event, he made the point that, in manufacturing, dimensional measurement data have to be part of the total process narrative—from beginning to end.
In manufacturing, the single source of truth is metrology, he said. That’s because the only way to verify that a manufacturing process is producing parts that meet specifications is to measure the parts. Good parts get shipped. Bad parts get scrapped. And that, he said, is how most manufacturing stories end. He insisted that this has to change. This kind of story is incomplete.
The new, complete narrative for manufacturing processes must include a feedback loop in which measurement data, the “truth” about manufactured parts, flows back to the design model in CAD, to the simulation and optimization results from CAE (computer-aided engineering) and to the plan and control decisions made in CAM. The new storyline in manufacturing must be about self-improving, auto-correcting systems. “We have to leverage the lessons learned from metrology. It has to tell us what to do and what to avoid— at every step along the way,” he said, noting that the gaps that now exist can be bridged by metrology data.
This data is the missing link in the story of how most products, from gears and bone screws to automobiles and airplanes, are manufactured. For example, metrology data can and should be used to adjust or refine CNC programs in CAM software to update files being executed on the shop floor—seamlessly and automatically.
Mr. Rollén explained that manufacturers have been missing this link because the connections needed to close the loop have not existed before or were not fully utilized. All this has changed as the Industrial Internet of Things has emerged. In this context, metrology can bring new levels of automation, conductivity and intelligence to the manufacturing story. These three elements are the key enablers that make the new narrative possible.
He concluded this part of his keynote by focusing on the worldwide automotive industry and how it is being reshaped. You can find his keynote address here. (Suggestion: fast forward to 0:13:00 to jump to remarks most pertinent to manufacturers.)
Other events, presentations and product demos during Hxgn Live fleshed out how Hexagon is positioned to provide these solutions to manufacturers through Hexagon Manufacturing Intelligence, one of Hexagon’s primary businesses. Significantly, Hexagon Manufacturing Intelligence is a 2015 rebranding of Hexagon Metrology. This change reflects how this business has moved beyond its core competence in dimensional metrology to include statistical process control and CAD/CAM software.
Those attending Tube Innovation Week, presented by the BLM Group, watched live machine demos, discussed equipment specifications with company experts, and saw a wide variety of the parts it is capable of making.
Tube Innovation Week, presented by the BLM Group USA, revealed a variety of new tube-processing equipment to its customers, representatives and members of the trade press June 6-10 in Wixom, Michigan. More than 100 guests attended to learn about BLM’s latest technologies.
They included the LT8.10 fully automated 3D fiber laser tube cutting system for workpieces made of brass, copper and aluminum up to 9.5 inchs in diameter. The system can process round, square, rectangular, flat oval and D-shaped tubes, as well as open profiles such as C- and U-shaped channel bar. The 3D cutting head provides the necessary agility for producing these shapes, including tilt cutting of thick-walled steel. The LT8.10 is available in a number of load/unload configurations and includes features such as Active Marking for part marking and tracking and Active Scan, which detects material variations.
The LT8.10 fully automated 3D fiber laser tube cutting system can handle workpieces made of brass, copper and aluminum up to 9.5 inch in diameter. The system can process round, square, rectangular, flat oval and D-shaped tubes.
The 3D cutting head on the LT8.10 provides the ability to perform tilt cutting of thick-walled steel.
Also on display was the LT Free, a five-axis fiber laser machine for cutting 3D formed or shaped parts such as bent tubes and welded assemblies. The machine allows traditional cutting, drilling, punching and milling to be performed on one machine instead of sequentially. Other equipment on view included the LC5 laser machine, which is capable of switching from tube to flat sheet and features automatic loading and unloading, and the E-Turn all-electric tube bender. The E-Turn series can bend tubes that are round, square, rectangular, flat-sided, oval or elliptical, and it is available in four models: the E-Turn 32 (up to 1.18 inch in diameter); the E-Turn 35 (1.38 inch); the E-Turn 40 (1.63 inch); and the E-Turn 52, for tubes up to 2.0 inch in diameter.
During the event, BLM marked 15 years in the U.S. market and also announced that it will be moving into a new 75,000 square-foot facility—basically doubling its size—in 2017.
Machine tool distributor and systems integration expert Gosiger recently announced a new agreement to supply and service Stratasys 3D printers. The move is a natural advance for the company, whose customers are increasingly showing interest in additive manufacturing. However, the move is also strategic on the part of the 3D-printing equipment builder. Stratasys sees the future of its equipment not primarily among home or hobbyist users (though that might be a part of it) but instead in manufacturing facilities. The goal—for both Gosiger and Stratasys—is to help advance AM into applications out on the shop floor, and even into production.
As Josh Claman, chief business officer for Stratasys, put it: “The history of 3D printing is design and prototyping. The future is that, plus manufacturing.”
Claman addressed an audience at 3D4U, an event hosted at Gosiger’s Dayton, Ohio, headquarters shortly after the initial announcement was made. The June 14 open house and keynote presentation was a chance for Gosiger customers to learn about Stratasys technology as well as an opportunity for Stratasys to articulate its vision for additive manufacturing as a valuable tool for shopfloor applications as well as design and prototyping functions. Partnering with Gosiger provides necessary relationships and manufacturing expertise to help achieve that vision.
From Gosiger’s perspective, supplying 3D printing equipment is another way to serve its customers in addition to the machine tools, robotics, inspection equipment and complete turnkey systems it already provides. The company also sees great potential for using its own Stratasys machines to produce custom objects for its clients such as jigs and fixtures.
“As we expose our engineers to this technology, they are coming up with new ideas daily,” says John Haley, Gosiger CEO.
A number of sample components were on display during the 3D4U event, including some from Stratasys, but also many that were created by Gosiger employees following training on Stratasys 3D printers. These parts illustrate some of the services that Gosiger can provide with its new 3D printing capacity—and they may inspire customers to seek 3D printers of their own. A few examples of these applications are pictured below:
Gosiger frequently supplies machined custom fixtures for workholding and inspection. A metal CMM fixture such as the one on the left (holding the 3D-printed model stator) might cost upwards of $600 and take a week at a machine shop. The 3D-printed fixture (on the right) cost only $82 and was produced within a day on a Stratasys 450mc.
Robotic arms are another key component that Gosiger supplies, often as part of larger robot-tended cells. Custom grippers tailored to the customer’s application are commonly part of the package. Tools such as vacuum end effectors (like the one on the left) and jawed grippers (right) can be created and produced faster and more cost-effectively with a 3D printer than they can be machined. As an added benefit, they are also lighter than machined grippers.
1.3D-printed models can help speed the setup of CMMs and other systems. This model of an injection-molded vacuum cleaner component as well as the fixture it is resting on were 3D printed so that a CMM could be programmed before the actual parts arrived, reducing the quality control setup time from about a month to just one day.