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Peter Zelinski

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.

Posted by: Peter Zelinski 13. November 2014

Additive Manufacturing Award Website Now Live

AMT—the Association for Manufacturing Technology—and VDW, the German Machine Tool Builders’ Association, recently announced the launch of the International Additive Manufacturing Award (IAMA) competition. Rules, submission guidelines and additional details about the competition can now be found at the new IAMA website.

The award recognizes innovations in additive manufacturing for industrial applications. Equipment providers, users, component suppliers, data modelers and members of academia all qualify to enter. The winner will receive a $20,000 cash prize and a marketing and promotional package worth $80,000. Modern Machine Shop publisher Gardner Business Media is one of the media partners for this award, which will be presented at the MFG Meeting in March in Orlando, Florida.

Applications are being accepted through December 31. Visit additive-award.com for more information.

Posted by: Peter Zelinski 4. November 2014

Two Heads Better Than One in New Hybrid Additive/Subtractive Machine

The two laser cladding heads reside with the machine’s cutting tools in the tool magazine.

In “subtractive” manufacturing (that is, machining), we take it for granted that an efficient process might consist of both a high-speed roughing step and a high-precision finishing step. Why shouldn’t additive manufacturing have these same two options?

At the JIMTOF show concluding this week in Japan, Mazak introduced a new hybrid additive/subtractive multitasking machine, the Integrex i-400AM, which features heads for both high speed and high precision laser cladding for direct metal deposition.

The new machine extends the definition of multitasking, including turning, milling, drilling, additive manufacturing and laser marking in the same machine.

Collaboratively developed with Hybrid Manufacturing Technologies (a company we reported on here), the dual laser cladding heads (or additive manufacturing nozzles) provide options for either rapid  and coarse metal deposition or slower deposition with fine precision. The two heads complement one another—and provide for efficient processing—in much the same way that roughing and finishing tools work together in machining.

The cladding heads reside in the machine’s tool magazine and can be called up as needed. Mazak says it views metal deposition as a natural extension of multitasking—that is, an opportunity to perform more steps and add still more value within a single CNC cycle.

The laser cladding can be used to build near-net-shape 3D forms. Thus, the machine is a potentially attractive choice for small-lot production of parts made from difficult-to-machine metals, because it provides the option for some part features to be grown instead of being generated entirely through machining.

The laser cladding can also be used to coat chosen sections of the part with metal, allowing the machine to repair worn or damaged components such as turbine blades. This cladding could even be used to join different metals in the same cycle.

The full five-axis milling and turning machine tool features machining capabilities comparable to other models in its family. The milling spindle feeds through a B-axis range of –30/+210 degrees, while the spindle that holds the part for turning also permits full C-axis contouring. The tailstock too is fully programmable. Learn more about the Integrex i-400AM here.

Combining laser cladding and machining in the same cycle means that surfaces can be added to parts or features can be grown onto parts within the same cycle that also performs turning or five-axis milling.

Posted by: Peter Zelinski 29. October 2014

Ensuring Accuracy by Containing Coolant

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.

Posted by: Peter Zelinski 27. October 2014

Where Do 3D-Printed Molds Make Sense?

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.

Posted by: Peter Zelinski 23. October 2014

Weldon-Flat Tools in a Precision Toolholder

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.

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