Peter Zelinski has been a writer and editor for Modern Machine Shop for more than a decade. One of the aspects of this work that he enjoys the most is visiting machining facilities to learn about the manufacturing technology, systems and strategies they have adopted, and the successes they’ve realized as a result. Pete earned his degree in mechanical engineering from the University of Cincinnati, and he first learned about machining by running and programming machine tools in a metalworking laboratory within GE Aircraft Engines. Follow Pete on Twitter at Z_Axis_MMS.
The word “coolant” is deceptive. Coolant in machining is a heat-transfer device. While the fluid cools the cut by transporting heat away from the work zone, it carries that heat to wherever the coolant then lands.
Toyoda says it engineered its new GE4-i cylindrical grinder in part with attention to the thermal effects that might come from heat transfer via coolant. The machine is seen here at this year’s IMTS, where it debuted. The company says the machine’s redesigned casting contributes to thermal stability by capturing and channeling the coolant that falls from the workzone in order to isolate it from the structure of the machine.
Another feature of the GE4-i is an icon-driven and user-friendly control interface, which is valuable in part as manufacturers adapt to the difficulty of finding skilled labor in grinding. More on that here.
Is it possible to mold a plastic part using mold tooling that is also made of plastic? 3D printing technology provider Stratasys says this is not only possible, but preferable in some cases. These photos show examples of 3D-printed “digital ABS” tooling, which is used for both injection molding and blow molding.
The mold tooling material is produced on a Stratasys Connex 3D printer. This printer digitally creates combination materials by rapidly laying down tiny dots of different materials as it builds the part. To create mold tooling, it combines a heat-resistant plastic with a matrix engineered for high strength. The result is a material that can withstand both the high pressure and high temperature of a molding cycle. The mold tooling material is in fact one of the very strongest materials created on the Connex 3D printer, which is more frequently used to make multi-material prototype parts.
Stratasys sales manager Nadav Sella has been involved in the development of this machine’s application to mold tooling ever since an end user of the machine first hit on the idea of making molds this way nearly 5 years ago. He says the life of one of these digital ABS tools is heavily influenced by both the material being molded and the geometry of the part. On a six-cavity injection mold making ice cream spoons in polypropylene, he says the digital ABS mold delivered 600 spoons. By contrast, for more complex geometries using reinforced nylon, the tool might deliver 20 injected parts. In general, where tooling is needed for low quantities or for an initial run of parts, quickly 3D printing a mold can both save cost and speed the time to market, he says.
There are limitations. He and others within Stratasys have worked through a number of applications of digital ABS molds, and this has allowed them to develop a set of best practices that they share with users. That set of best practices keeps improving as digital ABS tooling is applied to more geometries and materials, he says, but the key is to respect the mechanical and physical properties of the tool. Heat conductivity is not like that of aluminum or tool steel, leading to tool design considerations aimed at avoiding heat concentration. One example concerns gate size and type; point gates, cashew gates and banana gates should be avoided.
Precision is also a consideration. The 3D printer is precise, but not as precise as a CNC machine tool. Thus, it can’t produce molds with the finest features, such as the tight-tolerance details of some electronics-industry molds. Also, to ensure the accuracy needed for precise seating of ejector pins, these holes should be 3D printed undersize, then reamed to achieve an accurate diameter.
“This is a different material,” he says. Established moldmaking professionals are accustomed to molds being made from metal. Compared to this, 3D printed tooling requires slight design and process changes. His advice to potential users is to expect to take some time getting used to what this option can do. However, “for the shop that does 100 molds per year—some in steel and some in aluminum—what if 10 or 20 of those molds could be 3D printed instead?” That portion is realistic, and could amount to considerable savings in cost and time.
Systems for locking end mills in place within a shrink-fit or hydraulic expansion toolholder, so that there is no danger of the tool pulling out during high-force cuts using a toolholder of this type, often require the shank of the tool to be modified for clamping.
However, there is one standard class of tools that already has a shank modified for clamping: tools with Weldon flats.
Schunk recently introduced a system that makes use of the Weldon flat for clamping during high-force milling with a precision holder. The system, seen here as it was displayed at this year’s IMTS, is based on the company’s Tendo line of hydraulic-expansion toolholders. As seen in this model, a metal sleeve holds the tool, clamping on the Weldon flat. That sleeve then provides the surface for the screw that locks the tool in the holder for the high-force milling typical of aerospace materials such as titanium and Inconel.
A video created by Acoustech Systems includes footage of holes being drilled with and without ultrasonic-assisted machining. This company’s newly developed system is essentially a toolholder that has ultrasonic actuation built in. Adding this toolholder to the process can actually increase a shop’s machining capacity, because standard machines and tools can cut faster thanks to the friction reduction that the ultrasonic effect achieves. Comparison cuts in the video seen here show a standard drill doubling its speed and cutting more smoothly in both 1-inch-thick steel and 1-inch-thick titanium. Learn more about ultrasonic-assisted machining in this article.
An event yesterday at Sandvik Coromant's U.S. headquarters in Fair Lawn, New Jersey, celebrated the opening of a new Productivity Center (photo above), part of a now-completed 2-year renovation of this site.
The layout, architecture and offerings of the site now match other, more modern Sandvik locations both in North America and around the world. The company's original Fair Lawn site was built in 1955 and significantly expanded in 1966. Since then, priorities have shifted.
One of the priorities today is collaboration. An open design encourages movement through the facility and interaction among both employees and guests at the site. Within the Productivity Center (Sandvik's term for its training and process-development facilities), spacious machining areas equipped with sophisticated CNC machines provide capacity for company personnel to be working with various customers on various different projects at any given time. A machining area that is not so open (the ITAR-certified shop can be closed off, and frosted glass blocks the view) provides machining capacity for customer projects that are sensitive or secret.
Another priority, as company president Klas Forsström stressed in his remarks at the event, is outreach. This latest investment in the company's U.S. presence is coupled with an awareness that it needs to support manufacturing here by attracting talented people into this field. As it also does at its Chicago-area Productivity Center, for example, the company will routinely seek opportunities to bring groups of young people and their parents and teachers into the new New Jersey site in order to provide an up-to-date view of manufacturing technology, as well as an appealing glimpse at what a modern manufacturing career could look like for those who might thrive in this field.