Tech Front: Productivity Centers with Pallet Transfer, ATC
The ICON-150 and ICON-250 flexible multiple-station machines from ICON Technologies, a Division of Hydromat Inc. (St. Louis), offer precision machining capability for a wide variety of workpieces from automotive to medical components. “The idea of the ICON flexible series of machines is to offer a cost-competitive precision machining solution with easier changeovers on the lower-volume-type products compared with traditional special purpose dial machines,” said Rodger Boswell, vice president of sales. “Changeover for the traditional dial machines involves difficulties refixturing and longer setups with manual mechanical settings, hard stops, and valve adjustments compared with the series of ICON machine technology.”
The machines are a different breed, which is highlighted in the careful attention to naming the machines and the division, ICON and ICON Technologies, to distinguish them from the iconic Hydromat name. The series is available in two versions, the ICON 6-150 mill-turn machine for parts 6" (150-mm) cube or smaller and the ICON 6-250 for workpieces 10" (250-mm) cube and smaller. The 150 series is also available in eight-station versions. Each machining station is equipped with four-axis machining modules with cartridge-style motor spindles available between 10,000 and 60,000 rpm depending on machine type and the application. Each machining module is equipped with its own 12-position automatic toolchanger for a possible total of 96 tools available on a fully equipped Icon 6-250/8.
Each 6-150 or 6-250 machine has four CNC rotary tables installed on stations 2, 3, 5, & 6 with position accuracy of ±4 seconds. Each table is equipped with an Erowa zero-point clamping system to securely and accurately clamp the base pallet to the table with pallet positional repeatability of less than 0.002 mm. Workpieces are secured to the pallets using standard or custom workholding that bolts on to the modular pallet systems. “Once the workpieces are secured to the pallets, either externally to the machine or internally on station #1, the loading station, they are transferred to five other stations for cutting or auxiliary operations. With processes spread over four cutting stations, cycle times are greatly reduced, yielding higher productivity in a smaller footprint over other multiple stand-alone machining cells,” said Boswell.
Pallet transfer with the Erowa integrated pallet transfer workholding system presents the workpiece in front of standard four-axis machining modules. The heavy-duty integrated electromechanical pallet-changing system lifts, rotates, and places all size pallets and workpieces to the next station in 3.5 seconds for the ICON 6-150 and 4.5 seconds for the ICON 6-250. Maximum pallet payload is 55 lb (25 kg) for the 150 and 200 lb (90 kg) for the 250.
“Target workpieces for the 6-150 mill-turn are parts that are typically produced on single-spindle Swiss machines,” said Boswell. “An ICON equipped with a 60,000-rpm spindle would easily produce products like the most delicate medical devices burr-free, eliminating the need for costly secondary operations in most cases. All spindles are a cartridge design and can be installed to any of the four possible machine locations. They are air purged, liquid cooled and are permanently grease lubricated and therefore are virtually maintenance free.”
The ICON 6-250 is basically a bigger brother to the 6-150 and designed for larger workpieces like those for automotive manifolds and ABS parts. One significant difference is that a total of four, three-axis modules can be mounted from the top of the ICON 250 machine so that there can be two spindles working simultaneously on the workpiece. ME
For more information from ICON Technologies, go to www.icon.hydromat.com, or phone 314-432-4644.
Innovative Design Locks Tools in Place
Difficult-to-machine materials like titanium and Inconel, aggressive metal removal rates and long awkward tool overhangs require toolholders that provide strong gripping force, high precision and vibration control. The secuRgrip system from Rego-Fix Tool Corp. (Indianapolis, IN) uses a special threaded insert or key that eliminates the need to alter cutter shanks through machining special grooved patterns like reverse helixes, or other modifications that must be ground into a cutter’s shank.
To lock a cutter in place, the small insert of the secuRgrip system is placed in the Weldon flat of a cutter. The bottom profile of the insert matches that of the Weldon flat. Its exposed side has a thread pattern that matches with those of internally threaded powRgrip system collets. Users hold the insert in place while sliding the tool into the collet. The collet is turned so that its threads engage with those of the insert, and the tool is then screwed all the way into the collet. This cutter-collet assembly is pressed into a powRgrip system holder, and a special external cap nut is tightened onto the holder for added pullout security.
Users with existing powRgrip holders can easily transform their systems into a secuRgrip holder by simply threading the outside of any powRgrip PG 25 or PG 32 holder for accepting the cap nut. Rego-Fix can supply either the necessary thread specifications or factory-threaded holders. The secuRgrip holders accommodate cutter diameters from 0.472 to 1.000" (12–25.4 mm). And with holder body tensile strengths higher than those of the cutting tools being held, the secuRgrip holders can withstand cutting forces that could break the cutters before ever damaging the toolholder itself.
The powRgrip and secuRgrip systems ensure concentricity (TIR) with deviations of less than 3 µm for tool lengths up to 3 × D and length pre-adjustment with a repeat accuracy of less than 10 μm. The powRgrip system achieves high vibration dampening due to the functional contact surfaces between its toolholders and collets, and the collets and tool shanks. ME
For more information from Rego-Fix Tool Corp., go to www.rego-fix.com, or phone 317-870-5959.
Trends in Precision Grinding
Manufacturers are always striving to improve their process, through-put, part quality and cost position. "Today's materials are becoming increasingly difficult to machine and grind, therefore it is very important that the abrasive product requires the least amount of energy during geometrical shape and size generation," said Tim Finn, manager of Corporate Application Engineering, Precision Markets, Norton Abrasives. "In all abrasive products including superabrasive, bonded abrasive and coated abrasive, the grain type and size as well as the bond amount and type are the critical components," said Finn. Norton Abrasives has developed a new grinding wheel platform, Norton Vitrium3, which delivers improvements to a variety of applications.
The Vitrium3 platform is the strongest bond in the Norton portfolio, coupled with Norton's superior abrasive grain offerings. Norton Quantum is the ceramic grain that has been in the industry for five years. Norton Quantum delivers improved wheel life over all other ceramic gains with an additional sharpness that lowers the grinding forces needed to remove material.
Precision grinding manufacturers in industries such as aerospace, automotive, industrial heavy equipment and medical device depend on the ability to grind complex geometric designs and maintain surface finishes to meet increasingly challenging workpiece requirements and quality capabilities. Products including crankshafts, medical pins, vanes, blades, turbine housings, and gears are benefiting from this latest development in grinding wheel technology.
"An important characteristic of the grain is to stay sharp and break down at the micro-crystalline level," stated Jim Gaffney, senior product manager for Norton Abrasives. "These features put the least amount of energy or force into the workpiece to hold the required geometric tolerances," said Finn.
New stronger materials are being developed to last longer, reduce heat damage, and run at higher forces. All of these characteristics bring benefits to the end user. The only drawback is they are tough materials to machine." Many of the new materials are so tough, grinding is the only economic and technical option," said Gaffney. "The Norton Virtium3 platform has a diverse selection to meet these new grinding needs. There are designs to run at high grinding wheel speeds. There are porous offerings that hold form, as well as traditional structure wheels that will grind the tough new materials without producing damaging heat. The results are shorter grind cycles, longer wheel life, and better quality for customer applications," said Gaffney.
The key to any grinding process is to take into account all the elements of the grinding system—work material, abrasive product and the grinding machine including the fixturing, coolant system, wheel horsepower, overall stiffness and operating parameters. Norton Abrasives has a team of engineers that visit customer plants and assess their grinding operations to review and quantify improvement opportunities.
"We're making significant advances in the grinding industry toward that of cutting tools and we're obtaining material removal rates that are rivaling those of milling tools and inserts," said Gaffney. "This is being accomplished by the sharper grains and lower grinding forces, all with the ability to hold form and generate the consistent surface finishes required," said Finn.
How does a user get the best grinding system available for his application? "In a perfect world, they come to our business development manager, work with our OEM department and the machine tool builders under a trilateral confidentiality agreement to develop a machining solution from scratch," said Finn. "If the machine and process are already set up, request your local Norton representative to come in and assess your grinding system to evaluate the improvement opportunities capable with the new Norton Quantum grain and the new Norton Vitrium3 bond." ME
For more information from Norton Abrasives, go to www.nortonindustrial.com, or phone 508-795-2183.
This article was first published in the June 2013 edition of Manufacturing Engineering magazine. Click here for PDF.