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New parts-removal robots feature speed, reliability and programmability.

New Parts-Removal Robots Feature Speed, Reliability and Programmability

Programmable versatility, speed, and durability are claimed for a new line of parts removers for injection machines ranging from 50 to 2500 tons. Sterltech Div. of Sterling, Inc., Milwaukee, says one key to its new Sterltech/ Star TW-B Series of robots, manufactured by Star Seiki of Japan, is the patented dual vertical motion. The TW-B Series employs a pneumatic vertical cylinder combined with a belt-drive mechanism. The belt drive is said to multiply the speed of the pneumatic cylinder, as well as provide a cushion to absorb shock at the ascent end. This combination is reported to dramatically improve take-out times without sacrificing reliability. For example, the Model TW-800B, designed for 100-250 ton machines, achieves a dry-cycle take-out time of only 1.8 sec (mold-open time).

Another speed-enhancing feature of the TW-B Series is a new electric traverse motor. The three-phase induction motor, with pulse-modulated drive, is said to deliver fast, smooth, accurate performance. Sterltech says that its newest series offers improved variable acceleration and deceleration, as well as multiple-stop capabilities said to be accurate [plus or minus] 0.039 in. When combined with the speed of the dual vertical motion, the overall cycle time of the TW-B Series is shorter than for previous Sterltech/Star models. For the previously referenced TW-800B, the overall dry-cycle time is said to be 8.0 sec.

Besides speed, these robots are designed for accuracy. Slow-speed descent at the product-drop end is said to give smooth and precise product placement. And linear-motion guide rails ensure smooth, accurate motion on both vertical and traverse stroke.


New microprocessor controls also come with the TW-B Series. The STEC-311 programmable microprocessor controller includes a removable programming pendant with a new ergonomically designed handle. Connected to the main control panel by a fiber-optic cable, the hand-held pendant is said to allow convenient setup and operation of the robot while the control box is kept in an out-of-the-way location.

Up to 10 multiple-stop positions can be programmed along the traverse stroke. Sprue placement can be during either outbound or return traverse motion. A 40-character, two-line LCD message panel on the STEC-311 pendant is standard. The display provides I/O status, mode-selection information, timer and counter display, and alarm messages. In the event of a malfunction, the message display will inform the operator of the cause of the problem, as well as the corrective action required.

Fiber-optic links between the STEC-311 controller and both the pendant and the robot are said to ensure interference-free communications.

Other standard features are said to include: low-profile design, ability to clear higher-than-normal safety gates, venturi vacuum system for more reliable air supply to end-of-arm tools, and synchronized ejection of the press ejector stroke with the crosswise stroke of the robot arm.

Sterltech also offers several optional features, including a second vertical arm for sprue and runner removal from three-plate and stack molds; insert-loading into either mold half; selectable product removal from either mold half; gate cutter; mold-release spray system; product rotation after removal; defective-part rejection circuit; and delayed traverse, moving the "home" position away from the mold area to provide clearance for core-pull cylinders or other vertical obstructions.

The TW-B Series will become available in March at prices starting at under $30,000. A two-year parts warranty is standard. (CIRCLE 22)

PHOTO : New Sterltech/Star TW-B Series robots employ a patented dual vertical motion. A standard pneumatic cylinder combined with a belt mechanism is said to multiply speed of the cylinder while absorbing shock at the ascent end and improving take-out time.

PHOTO : TW-B Series robots come with a removable control pendant connected to the main control panel by fiber-optic cable, which improves communication reliability as it isn't susceptible to EMI interference.
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Copyright 1990, Gale Group. All rights reserved. Gale Group is a Thomson Corporation Company.

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Publication:Plastics Technology
Date:Feb 1, 1990
Previous Article:Straw-handling technology moves into the nineties.
Next Article:PVC-based TPE's seek niche in automotive, wire & cable markets.

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