The March issue of Gear Production (a quarterly supplement to Modern Machine Shop) contains two examples of shops that were able to not only embrace, but optimize equipment and software to streamline production. Click the cover image above to access the digital edition and read about:
How a shop serving the mining industry eliminated multiple machining steps on large gears with a 6-meter profile grinder.
A shop that optimized its separate production paths for “cut-teeth-only” and “make-complete” gear jobs via scheduling and resource allocation software.
This issue also includes an overview of waterjet machining for gear production and new product coverage.
For an established manufacturer, adopting additive manufacturing entails something even more than a fundamental shift in thinking about how to make the part. It also entails different thinking about material.
John Hunter has a perspective on this. He is the general manager of the newly opened U.S. office of LPW Technology, a company dedicated to supplying metal powder engineered for additive manufacturing. Founded in the U.K., LPW works with additive manufacturing machine makers to tailor powders to their machines, and also supplies powder to the end users of this equipment. I spoke with Mr. Hunter at the new U.S. facility in Pittsburgh.
Starting out, he says, shops that adopt additive manufacturing typically buy powder from the machine OEM. This source can provide a particular formulation of an alloy along with proven machine parameters for that formulation. But later, the shop might become comfortable enough at fine-tuning machine parameters that it is willing to try obtaining comparable stock (or even a novel formulation) from a third party.
Experienced with all of the major metal additive machines, LPW can counsel customers on which particle size distribution (PSD), for example, might work better for a particular machine type. Some anecdotes from Mr. Hunter illustrate other material considerations that can determine additive manufacturing’s success, including:
Purity. He says one customer came to LPW because aluminum alloy parts were cracking. Powder and parameters were supplied by the OEM—the build should have been successful. However, micrographs revealed the culprits. Just a half-dozen particles of Inconel 625 were the impurities from which the cracks propagated. The customer was not cleaning its machine thoroughly enough between jobs.
Flow. In additive manufacturing, the powder metal has to move. LPW once tested powder from four sources that was all identical in terms of measured specs, but still not identical in performance. At a given energy, only one sample delivered a fully dense part. Thus, some different spec was needed to predict performance. The answer proved to be powder flow rate. Like pharmaceutical firms, LPW now uses rheometers to gage this parameter.
Change over time. The metal powder changes with use, Hunter notes. Specifically, since smaller grains are consumed in the first few additive builds, the material’s PSD is prone to change.
In 2014, LPW introduced a service called PowderSolve to address the challenge of changing material properties. Users enter key measurements of their own powder samples into online software in order to track changes and predict performance. Thus, instead of guessing when a batch of material has reached its limits, the aim is for users to be able to determine this for certain. That is, the aim is to let the user perhaps employ 90 percent of a batch of powder instead of stopping at only 70 percent. In certain cases, Mr. Hunter says, powder that has gone past the acceptable limits for some applications might even still be useful for applications that have different requirements.
For multi-axis machining, a good workholding fixture gets the part away from the worktable surface, yet holds the part securely for aggressive machining. This video shows a dovetail pedestal doing this job.
Note the extra “elbow room” the spindle head needs to access five sides of this workpiece. The video is also a good example of 3+2 machining, which is one of the most valuable options for a machine with full five-axis capability. In this case, the machine is a DMG MORI DMU 50 five-axis machining center under power at Boldt Machinery Inc. in Erie, Pennsylvania, for a recent customer demo event highlighting 3+2 machining.
You don’t need to watch the entire video (it’s 10 minutes long). Sampling different segments, however, reveals a variety of operations, mostly with short, stout cutting tools that make 3+2 machining an advantageous option.
What the video does not show is the new triangular geometry incorporated into the dovetail clamping surfaces of this pedestal fixture. You can get that story here. The new fixturing system is from AMT Innovations of Orchard Park, New York.
In addition, examples of using multiple pedestal fixtures to hold large parts can be seen here. Of course, the applications shown are useful for thinking about the flexibility of pedestal workholding fixtures in general.
Each month Modern Machine Shop focuses on a specific type or category of manufacturing equipment in the Modern Equipment Review Spotlight section. The March 2015 issue highlights machining centers ranging from compact five-axis VMCs to large HMCs designed to accommodate aerospace parts. Click the photo above for a slideshow featuring these machines and more, and check the print or digital edition of the magazine for the equipment spotlight in each issue.
The digital edition of Modern Machine Shop's March 2015 issue is now available.
The digital March 2015 issue of Modern Machine Shop is now available. The cover story discusses the evolution of micromachining and some lessons one shop in particular has learned along the way. Other stories discuss how advances in wire EDM technology have made it acceptable for machining critical aerospace parts, how a job shop relying on homegrown talent was able to win aerospace and defense work while expanding its five-axis capabilities, and how additive manufacturing already plays a major role in aircraft production.
Our Rapid Traverse section takes an in-depth look at spindle housings and motors, an automotive cylinder coating for high-production applications, and a multi-axis workholding system that uses a three-side dovetail.
This month’s Better Production section explores how a shopfloor CMM reduces production bottlenecks, how in-house CNCs helped an automotive shop gain manufacturing control, and how one shop used CAM software as the key to its continuous improvement efforts.
The Modern Equipment Review section highlights machining centers.