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ME Channels / Alternative Machining

Technologies Offer Process Variety

Waterjet, PKM and robots with red faces offer many choices

By Jim Lorincz
Senior Editor


Manufacturers today have a greater variety of highly specialized alternative technologies to choose from to maximize productivity, throughput, and profitability. Applications range from one off and short run manufacturing in job shops to mid-volume production for applications in virtually every industry. Innovative technologies include robotics with a human touch, waterjet cutting, and parallel kinematics machine (PKM) technology.

The next generation of robots has a human-friendly feel to it. Baxter, the robot from Rethink Robotics (Boston), has two arms, a face screen, and an array of sensors that allow it to work side-by-side with workers performing a variety of tasks. “Baxter isn’t going to replace a traditional heavy weight-lifting robot that does high-precision movements at super speed,” said Mitch Rosenberg, vice president-product management and marketing. Intelli-MAX 18 software controls the six axes of OMAX JetMachining Centers for processing 3-D components

“This robot is a major breakthrough that can democratize automation in manufacturing. Baxter has two arms with a typical payload limit of 5 lb [2.3 kg] per arm. Baxter is designed to automate processes that are among the most mundane and boring jobs in a facility. Typical ones include repetitive motion for loading and unloading conveyors, loading scales with parts, or inserting gaskets into metal housings. In the near term, we’ll be adding software to Baxter that makes it possible to do machine tending: putting parts into a machine, pushing the button, unloading parts, and putting it on a conveyor. In the future, Baxter could also be trained to do finishing operations like grinding and polishing a part,” Rosenberg said.

Training Simplified, Vision Sensors, Safety Built In

The way in which Baxter is “trained by demonstration” is one of the most innovative and important aspects of the Rethink Robotics’ development, according to Rosenberg. “It doesn’t cost much or take a lot of time to train the robot, and the personnel who do the training are manufacturing workers, not engineers. Baxter is trained the same way in which you train a human. You walk over to operation, point out what to do, and show it what object to move. With Baxter, you do the same thing. Grabbing Baxter’s wrist lets the robot know that it’s a training move. Use the robot arm to point to the space, use an on-screen menu to select the task and then select the place to put the part to complete the task.”

Baxter is equipped with a variety of sensors including vision sensors for performing its tasks. There are five integrated cameras with range-sensing capabilities fully integrated into the user interface. All necessary safety systems are built into Baxter. The approach of a human triggers a slowdown in Baxter’s movements, and turns his screen face red to indicate the approach. 

Waterjet Cutting Races to Forefront

When Michael Waltrip Racing’s (MWR) famous #55 car ran in the 2012 Sylvania 300 NASCAR Sprint Cup series race, it was paying tribute to the ability of co-sponsor Jet Edge Inc.’s waterjet to provide precision cutting technology to MWR’s fab shop. MWR uses a 90 ksi (6205-bar) Jet Edge waterjet system to cut more than 1000 parts for each of its race cars. MWR builds about 56 cars per year. Baxter can work side-by-side with humans automating light-duty repetitive tasks using two arms, vision sensors and cameras, and safety built in.

For MWR, Jet Edge technology is cutting 2" (50.8-mm) 4140 parts and saving 20 minutes per part cutting at higher pressure with the X-Stream xP90-100 waterjet intensifier pump. X-Stream pumps are capable of producing 90 ksi and supporting 75-ksi (5171-bar) continuous operating pressure. The X-Stream pumps produce 50% more pressure than a 60-ksi (4137-bar) intensifier pump, resulting in a 40–50% increase in productivity for cutting many materials. At MWR, applications range from cutting composites for the downdrafting components on the front of the race car to cutting drivetrain and suspension components.

Jet Edge offers a wide range of electric and diesel waterjet intensifier pumps rated from 30 to 280 hp (22–209 kW). On its 90-ksi models, it offers 50 and 100-hp (37, 75-kW) pumps. The net result is that less water flows at higher pressure, higher velocity, and accelerates the garnet abrasive much faster, resulting in higher cutting throughput. The impact on operating costs can be a reduction of as much as 40% when considering less use of water, power, and abrasive. 

Software Makes 3-D Cutting a Breeze

At IMTS, OMAX Corp. (Kent, WA) demonstrated cutting with the OMAX 80X-1 DualBridge with Touch Screen control and 2626 JetMachining Centers and the MAXIEM 1515 JetCutting Center for cutting a wide range of materials from advanced composites and exotic alloys to traditional metals, rubber, and glass. Both OMAX model machines were shown equipped with the latest version of Intelli-MAX 18 Software Suite with multiple-axis coordinated motion capability and the new innovative Intelli-VISOR System Monitoring Package. As showcased on the 80X-1, Intelli-MAX 18 controlled the machine’s six axes—XYZ linear axes, the two tilt axes of its OMAX A-Jet articulated cutting head accessory, and the one axis of an added rotary system—for processing 3-D components. With such enhanced functionality, manufacturers are able to quickly and easily program and cut 3-D patterns in applications ranging from peripheries of tubes and pipes and fitting operations to prep cuts and bevels.  

A special feature within the intuitive new software provides three modes for the A-Jet bevel cutting accessory to  automatically correct for the taper normally found in an abrasive waterjet cut. The A-Jet’s two axes of motion, enable the cutting nozzle to tilt over a range of 0–60° from the vertical position to generate beveled edges or cut countersunk holes, as well as machine 3-D parts with complex geometries. In addition, the accessory eliminates the need for many secondary machining and grinding operations. A-Jet is retrofitable to existing machine models, and software updates are free to OMAX customers throughout the life of their machines.

Shop-Floor Machining in Sharp Focus

MC Machinery Systems Inc. (Wood Dale, IL) has continued to fill out its portfolio of machining technology for the shop floor with new additions to its waterjet, EDM, and milling machine lineup. The entry-level MWX3 waterjet machine features a solid-base construction and cantilever head design and is designed for production environments and new users of waterjet technology. MWX3 is equipped with a high-pressure S-50 KMT pump, which provides 60 ksi (4137 bar) of water traveling at high speed with 1.09 gpm (4 L/min) of water consumption through a maximum orifice size of 0.013" (0.33 mm). A smooth even flow of water is delivered to the cutting nozzle with a reciprocating hydraulic piston to ceramic water piston ratio of 20:1 pushing water into the accumulator. 

Mitsubishi’s MV wire EDM features noncontact cylindrical drive technology, an improved power supply, autothreading, and deep submerged wire threading. The new cylindrical drive technology features a round magnetic shaft that creates a noncontact design using 360° of magnetic flux. The design delivers no wear, no cogging (jerkiness inherent in flat plate systems), and no backlash for improved energy efficiency, accuracy, and speed. 

The ICON Tripod Powerflex Productivity Center delivers the flexibility of a robot with the stiffness and accuracy of a machine tool.

Waterjet Cutting Parts to 14-m Long

The newest addition to Flow International’s (Kent, WA) lineup of advanced waterjet technology is the Mach 4 which features expandable modular design to cut workpieces up to 14 m in length. The Mach 4 is a high-end production machine well-suited for aerospace production. At IMTS, it demonstrated the complex machining capability of the combination of Flow’s HyperJet pump, rated at 94 ksi (6481 bar), and its Dynamic Waterjet XD wrist. The Dynamic XD high-precision technology provides Flow’s patented high-precision taper and stream lag compensation software to 3-D bevel cutting applications. It allows users to cut complex 3-D parts free of taper.

The newest addition to the Mach 2 line is a value-priced machine tool optimized for either pure or abrasive waterjet cutting. The Mach 2 provides fast and accurate cutting whether cutting 3" (76-mm) thick steel plate or multistacked gasket material. The system demonstrated Dynamic Waterjet with Active Tolerance Control that provides two to three times faster cutting than conventional waterjet machines.

PKM Delivers Flexibility to Machining

At IMTS, ICON Technologies, a Hydromat company, introduced the ICON Tripod 700S Powerflex Productivity Center, a modular six-axis parallel kinematics machine. PKM technology combines the flexibility and envelope of a robot with the accuracy and stiffness of traditional machine tools. Motions in the XYZ axes are performed by three parallel axes that provide stiffness and accuracy while maintaining flexibility in the cutting area. As a result, the Tripod Powerflex doesn’t notice any difference between a perpendicular hole or surface compared to a compound angle and is well-suited for all complex machining. 

PKM technology design replaces the massive structures and wide beds that traditional machine tools depend upon to ensure accuracy and stiffness. Today’s PKM technology is able to deliver the flexibility of a robot through a design that is a pyramid-like moving tripod that transfers the forces from the wrist to the upper platforms and is a solid structure that completely takes care of the bending and torsion forces applied to the machine in all directions. The Tripod Powerflex uses lower joints with no more than one degree of freedom (DOF) and the use of actuators with two degrees of stiffness (DOS), linear and bending in one direction. 

The Tripod Powerflex design can be readily automated, used as a stand-alone machining center, or be integrated into a transfer line for applications in the automotive, aerospace, and other precision machining applications. The Tripod Powerflex is available in a variety of sizes, which are determined by the length of the actuating arms. The Model 700S has an 800 × 800 × 400-mm work envelope. The rotary table is 800 mm and features a zero-point clamping system. ICON is a licensee of the PKM technology from Exechon (Stockholm, Sweden). ME

This article was first published in the November 2012 edition of Manufacturing Engineering magazine.  Click here for PDF.  

Published Date : 11/1/2012

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