Tech Front: Trunnion HMC for Machining Hard Metals
The new 2500-mm HU100A-5XLL HMC from Mitsui Seiki (Franklin Lakes, NJ) is designed for machining large, complex, and heavy hard metal parts. Mitsui Seiki has built several custom-engineered machines with similar configurations and attributes. The custom machines were primarily supplied to aerospace, power generation, refrigeration, and mold-and-die parts manufacturers, because these industries have fundamental common requirements for machine rigidity and stiffness, low-frequency machining, and high accuracy.
The HU100A-5XLL offers an X-Y-Z working envelope of 2500 × 1750 × 1400 mm. Its A and B tilting and rotating trunnion-table axes represent the fourth and fifth axes of motion. Although the standard spindle is a 50 taper, many manufacturers taking extra-heavy roughing cuts in titanium and tough steels could opt for the HSK 100 or HSK 125 spindles, which provide extra high torque—3332 N•m. This HMC has a pallet size of 1700 × 1000 mm and accommodates weight to 3000 kg. Its ATC accommodates 360 tools with lengths as great as 500 mm, diam to 305 mm, and weights of 30 kg.
According to the manufacturer, the machine’s accuracy and rigidity are consequences of close monitoring and analysis of its 3-D FEA-designed structure, hand scraping all castings for geometry and frequency tuning, and the use of hardened and ground steel box ways.
For more information, contact Mitsui Seiki USA Inc.,
Ph: 201-337-1300; or go to: www.mitsuiseiki.com.
Robotic Abrasive Grinding Spindles
Combining spindle expertise with knowledge of harsh grinding environments, Dynomax Inc. (Wheeling, IL) has produced the new Dynogrind spindle series designed specifically for robotic grinding of abrasive materials such as glass, ceramic, composite, and forged materials.
With a maximum speed of 18,000 rpm, the Dynogrind spindle series is a modular design that’s said to be suitable for a variety of applications. The manufacturer says the HSE070-812289 model was designed from the beginning to be a lightweight solution for robotic abrasive grinding applications. It weighs 15 kg and is rated at 8.5 hp (6.4 kW) at S1 Duty. At approximately 12,000 rpm, the spindle will generate 3.8 lb-ft (5.2 N•m) of torque, which the builder says is the best level for glass and ceramic grinding applications.
Supplied as a turnkey system, spindles are equipped with a complete abrasive grinding package.
The system’s standard HSK tool change system allows quick tool change for increased productivity and accuracy, especially when operating at higher speeds. An optional automatic system is well-suited for closed-cell machining, and further reduces the time required for tool changes. A custom tool adapter, which is more accurate when high-precision tolerance is required, is reportedly quicker to change grinding disks, and can spin in both directions. The spindles are also available with other tooling systems.
The spindle’s power management/interconnect system provides protection from the slurry, dust, water, and other invasive materials present during abrasive grinding applications. Its interconnect system is specifically designed to handle the flexibility demands of robotic applications.
In addition, the spindle’s closed-loop cooling system is described as engineered for easy installation and low maintenance. All Dynomax abrasive grinding spindles employ the company’s proprietary Dynoguard sealing technology, which is designed to protect against abrasive environments. Field trials have resulted in MTBF of up to two years. The system also reduces the frequency of replacement for machine housings typically destroyed by abrasive spray.
For more information contact: Dynomax Inc., Ph: 847-680-8833, E-mail: firstname.lastname@example.org,
or go to: www.dynospindles.com.
Vertical Honing to
The SV-1005 series vertical CNC honing system from Sunnen (St. Louis) with integrated air gaging provides closed-loop control of tool size, along with downloadable SPC data. Matched with the company’s superabrasive MMT tool, the air-gage-equipped machine can automatically control hole size to accuracies of 0.25 µm without operator intervention, working in a bore size range of 3–65-mm diam. It’s said to be well-suited for automated, high-Cpk production of small engines, hydraulic valves/bodies, fuel injectors, gears, compressor parts, turbocharger housings, and gun barrels, in medium and high volumes.
According to the manufacturer, combining the new air gaging system with the machine’s patent-pending tool-feed control eliminates the need for an experienced honing operator to adjust the process. Instead, the new air-gaging system controls bore diameter and geometry by taking postprocess measurements of parts while they are still fixtured on the machine’s rotary table. Feedback from the air gage provides the highest possible accuracy for tool-feed control.
The honing system matches an ultraprecise tool-feed system with CNC control to allow any CNC-experienced machinist to master honing without great difficulty. Setup involves using a three-axis hand wheel for fine-tuning the tool feed, the servocontrolled stroke system, and the rotary table. The control includes features such as a switchable autocorrect feature for bore shape. Using measurements from the air-gage system, it allows the operator to select from a library of "problem" bore images (taper, barrel, etc.) to match to the part on the machine. The servocontrolled stroke system ensures a consistent crosshatch pattern, and can dwell in any part of the bore, end-to-end, selectively removing stock for ultraprecise straightness and roundness. The machine’s vertical design requires just 2400 × 2300 × 2700 mm (W×D×H).
A cast-polymer base and cast-iron column enhance vibration damping, while removable stainless side doors facilitate integration with automatic part loading systems. The high-torque, belt-driven spindle is rated at 7.5 kW.
For more information contact: Sunnen Products Co.,
Ph: 800-325-3670, or E-mail email@example.com.
Wire EDM Machines
Now available from Methods Machine Tools Inc. (Sudbury, MA) the new Fanuc RoboCut iE Wire EDM Series features a new power supply for accurate, efficient cutting performance in difficult materials. These new machines also offer seven-axis simultaneous machining as an option.
According to Methods, the iE Wire EDMs are capable of better finishes, improved geometric accuracy (to less than 0.0001" or 2.5 µm), and produce virtually no recast. Recast is said by Methods to be virtually undetectable at 1000:1 magnification in high-nickel alloys like Inconel and Waspaloy. The iE Wire EDMs are said to be well-suited for applications that require machining a wide range of materials including cobalt-chrome, high-nickel alloys, and titanium.
The machine’s upgraded Ai Pulse Control II provides high speed and highly accurate cutting for stepped workpieces by enabling optimum control based on the accurately detected number of discharge pulses. It also reportedly ensures a minimized witness line at both the wire approach and step point, in addition to improved oval shape and small round-hole accuracy.
A redesigned lower arm includes a system that isolates the lower arm power feed contact during final cuts. This design is said to improve finishes during skim cutting with fewer passes, straighter parts, and improved cutting speeds.
Along with showing cumulative electric power, a new energy-saving function displays power consumption in real time. The energy-saving setting reduces surplus electric power usage during idle time, reducing overall electrical consumption by up to 20%. To significantly reduce operating costs and heat output, the iE Series uses high-efficiency inverter-style chillers.
In addition, the Auto Wire Feed System (AWF) has been enhanced to thread while submerged through the start-hole of a workpiece with a maximum thickness of to 8.0" (200 mm). In the event of a wire break, the iE Series Ai auto wire repair system can now thread through the kerf, while submerged, to a depth as great as 6.0" (150 mm) without returning to the start point.
The iE series also offers software enhancements. High-speed graphic-drawing capability provides a drawing time that is three times faster than in previous units. Software checks the real-time machining status, sends and receives NC programs, and changes cutting conditions. Options include a feature that allows easy generation of NC programs, including tapers with upper and lower irregular figures or tapers with angle commands. An optional new microfinish generator ensures high accuracy and efficient cutting. In addition, it’s able to handle thick-work cutting, providing skim cutting to 4" (100-mm) work thickness without requiring an isolation jig. The iE Series is equipped with the Fanuc 31is-WA Control with a 15.1" LCD touchscreen. Models include: 0iE 10" standard and iMed with X-Y-Z travels of 14.6 × 10.6 × 10" (370 × 270 × 250 mm), and U-V-travels of ±2.362" (±60 mm); 1iE 12" (305-mm) standard and iMed with X-Y-Z travels of 23.6 × 15.7 × 12" (600 × 400 × 305 mm) and U-V travels of 3.937" (100 mm); and 1iE 16" (406 mm) standard with X-Y-Z travels of 23.6 × 15.7 × 16" and U-V travels of 3.937".
For more information, contact Methods Machine at Ph: 978-443-5388, E-mail: firstname.lastname@example.org, or go to: www.methodsmachine.com.
A project underway at Missouri University of Science & Technology (Rolla, MO) is designated Advanced NDE Development for Bonded Repair of Aging Aircraft. Researchers are taking advantage of previous work in this area, including the recent Structural Repair of Aging Aircraft (SRAA) program, to deal with issues involved in addressing bonded-repair inspections. These include detection of weak bonds, and detection of cracks under thick repairs. Weak-bond conditions will be addressed using a new correlation image process for ultrasonic calibration. A microwave method developed at Missouri S&T will be used to develop a process for detection of cracks under thick boron repair patches. Because boron is nonconductive at microwave frequencies, this infrequently used method becomes worthy of investigation. The third aspect of this project will be to investigate structural health monitoring (SHM) concepts, such as piezoelectric and acoustic-emission sensors, as a means to rapidly detect damage conditions. This is a concept envisioned for the future of aircraft maintenance and inspection. More-traditional NDE approaches will still be required to support SHM concepts, according to researchers, especially in the area of accurate flaw sizing. They feel this point helps make the research project attractive, as it recognizes the marriage between NDE and SHM, and places equal emphasis on both.
For more information go to: campus.mst.edu/camt/
This article was first published in the April 2011 edition of Manufacturing Engineering magazine. Click here for PDF.