June 2012 / Volume 64 / Issue 6|
Workholding product review
By CTE Staff
Euro-style collets for U.S. market
HARDINGE GROUP, Elmira, N.Y., (www.hardinge.com) manufactures solid collets, master collets and pads, solid feed fingers and master feed fingers and pads for Euroturn, Gildemeister, INDEX and Schütte multispindle machines, with 24-hour shipping of standard fractional and whole metric sizes. Decimal metric sizes and products for other machine builders are available for 5- to 7-day delivery. Hardinge has a semifinished blank program for pickoff burring collets and special-shape collets.
According to Hardinge, shops should match the collet size (order hole) exactly to the workpiece or bar stock diameter. “If you use inch bar stock, you should use fractional collets—not metric,” said Rick Schonher, Hardinge workholding product manager. Few metric sizes have a direct fractional equivalent. Metric collets for metric bar stock, fractional collets for inch bar stock and decimal collets for decimal bar stock will provide the best results, according to Schonher.
If the shop is using a ¼” bar stock with a 6mm collet, it could experience push-back, chatter or poor concentricity because the collet is smaller than the bar stock.
“Most operators don’t realize the ramifications of such a small variance in diameter,” Schonher said. “If the collet order hole is larger than the workpiece or bar stock, the part may pivot at the line of contact at the face of the collet. If the collet order hole is smaller than the workpiece or bar stock, the edges of the slots will bite into the workpiece and may damage the bar. When the collet is the proper size for the workpiece or bar stock, there is a full bearing along the angle and the circumference of each segment of the collet where they mate with the spindle angle (seat).”
Tilting rotary table works with multiple workholders
KOMA PRECISION INC., East Windsor, Conn., (www.komaprecision.com) distributes Tsudakoma’s RTT-111, CA, a high-speed, drop-trunnion, tilting rotary table that can use multiple workholding systems. The table is now equipped to utilize more systems, including system 3R and Erowa chuck and pallet systems, Northfield’s 5C collet closer and 2-jaw and 3-jaw chucks, and Hirschmann’s chuck and pallet system. The RTT-111, CA can also be used with a standard faceplate. The rotary table, with its pallet system, allows for five-sided access to the part when 5-axis machining. Vises, chucks and clamps limit access to the part, thus decreasing process efficiency, according to the company. Because the table rotates on center, shorter tools and less spindle travel are required. The pallet system creates a lower profile than parts held with conventional workholding, thus increasing rigidity.
Miniature swing clamps provide high clamping forces
FIXTUREWORKS, Fraser, Mich., (www.fixtureworks.com) offers an expanded lineup of Imao One-Touch clamps that offer high clamping force and come in miniature sizes. They are available with clockwise and counterclockwise clamping actuation. New designs include swing clamps with rotational or cam handles, swing clamps with torque control and retractable clamps with cam or adjustable handles. Clamping forces for the miniature swing clamps with a rotating handle range from 247 to 787 lbs., forces for swing clamps with a cam handle are from 180 to 629 lbs., retractable clamps with a cam handle offer clamping forces from 150 to 247 lbs., and swing clamps with an adjustable handle offer 449 to 1,348 lbs. of clamping force. These workholders clamp straight down on the workpiece. The arm swings away to allow part loading/unloading. The adjustable handle allows for greater clamping stroke, force and tightening in limited space and can be moved to avoid interference. The clamps’ adjustable contact-screw position may be reversed, offering pinpoint pressure loads for heavy-duty roughing.
Vise can be manually or hydraulically actuated, uses different jaw packs
HAINBUCH AMERICA CORP., Mequon, Wis., (www.hainbuchamerica.com) offers the QUADROK vise, which can be manually or hydraulically actuated. The vise’s jaws rest on the clamping unit, which is available in two different styles. With four screws and a 90º turn of the clamping unit, the upper unit can be separated from the lower unit. Depending on the application, the operator can choose different jaw packs or set up the vise for ID or OD clamping. The lowest clamping base is 195mm when using the QUADROK 120 and 200 clamping units. The mandrel adaptation for ID clamping brings the base to 115mm, leaving five sides of a workpiece accessible, even on a large machining table, according to the company. Depending on the version, the clamping ranges from 0mm to 150mm for type 120 and 80mm to 250mm for type 200. Jaw pairs provide 31 kN of force while providing an actuation force of 97 Nm at the manual jaw and 50 bars for the hydraulic clamping unit, according to Hainbuch.
New steady rest for Haas turning centers
KITAGAWA-NORTHTECH INC., Schaumburg, Ill., (www.kitagawa.com) has a new custom steady rest for Haas ST-40 turning centers. The steady rest supports the extreme rigidity and heavy cutting capabilities of the large-capacity machines and allows clearance for clamping and turret operations, according to Kitagawa-Northtech. It can grip workpieces up to 12.20" long. The company packages the ST-40 steady rest as a complete kit, according to Stuart Fishman, business development manager, OEM machine tool divsion. CTE
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