If the big show in Chicago was any indicator, linear servo drives and jointed-arm designs may be the next trends in robots for injection molding.
Injection molders visiting NPE 2000 last June may have glimpsed the future of injection molding automation. Exhibits there suggested two fledgling trends that promise to bring take-out robots with greater speed, precision, and dexterity. First, a handful of exhibitors appeared to be betting that more molders will adopt six-axis, jointed-arm robots in place of, and as adjuncts to, conventional three-axis traversing parts removers. Meanwhile, conventional beam-style robots have a powerful new trick up their sleeves in the form of zippy linear-servo drives. There were also new models at the show that seemed to be a happy hybrid of beam-style and jointed-arm designs.
In addition, the show displayed a large crop of new servo and pneumatic robots and sprue pickers that offer higher speeds, improved controls, and in some cases, lower cost.
Servos go linear
Three companies showed traversing robots with linear servo drives. Unlike conventional electric motors, which convert rotary to linear motion by means of gears, a rack-and-pinion, or other means, the linear motor has no mechanical parts. Instead, an electromagnetic field drives a moving coil along a linear magnet (or vice versa). Linear drives have been used for years in machine tools and pick-and-place machinery for semiconductor manufacturing, packaging, and assembly operations. Now they are coming to injection molding.
Although robot makers are still debating the pros and cons of linear servos, there seems to be general agreement that linears are capable of faster acceleration, higher overall speeds, and greater position accuracy and repeatability. Some sources say they use less power. Maintenance is also said to be minimal because there is no lubrication, no wear due to friction, and no need to maintain or replace motors, gearboxes, racks and pinions, belts, or ballscrews. The lack of lubrication may be an advantage in clean-room situations.
Linear servo-driven robots for injection molding apparently showed up first in Europe—from Hekuma of Germany and Sytrama of Italy. The first in the U.S. was Mark 2 Automation, which released the Model 320ELH last fall. This unit reportedly can hit speeds around 200 in./sec, about twice as fast as the company’s belt-driven models. The 320ELH provides dry-cycle extraction times of 0.5 sec and overall operating cycles of less than 4 sec on presses of 50 to 150 tons.
Mark 2 sources and others agree that the linear drives tend to be heavy, which may limit them to use only on the horizontal beam axis (as is the case on the 320ELH). There is also no argument that linear drives are expensive, though their cost is said to be coming down. For instance, the 320ELH costs around $80,000 as compared with $65,000 for a comparable standard servo model. That may be a bit much for many customers, admits Patrick Walsh, Mark 2 senior product-development engineer. “However, for some customers, a 1-2 sec improvement in cycle time is easily justified.” The increased repeatability of 0.005 in., a result of zero backlash, is another possible justification, he says.
NPE saw the U.S. debut of linear-servo robots from Sytrama, versions of which are marketed here by its sister companies, AEC/Automation Engineering and Sterltech. Unlike others on the market, the Sytrama robot has linear drive on all three axes. A special braking mechanism on the vertical axis overcomes the heaviness of the drive.
Most robot suppliers are studying linear servo technology. Two that are actively developing linear-drive models are Star Seiki of Japan (represented here by Star Automation) and Remak of Germany, which has a new U.S. office.
Jointed arms reach out
No plastics show before NPE 2000 saw so many six-axis, jointed-arm robots on display. Several suppliers of parts removers have allied with makers of six-axis machines to pursue downstream automation that could include degating, trimming, routing, decorating, sealant dispensing, assembly, and packaging.
For example, both AEC/Automation Engineering and Sterltech have a new technology and marketing partnership with ABB Flexible Automation, a maker of free-standing and overhead gantry-mounted six-axis robots. ABB robots and AEC or Sterling parts removers can “talk” to each other via SPI communications protocol. Base price of the ABB robot at the show was around $60,000.
Meanwhile, Conair has teamed up with Fanuc Robotics to develop work cells for vertical-clamp insert molding. A small jointed-arm robot will load inserts, demold parts, place them in a degating fixture, move them to an inspection fixture, and finally place good parts on a conveyor. Benefits can include both labor savings and improvements in productivity and quality through cycle consistency.
Also allied with Fanuc is Automated Assemblies, which will integrate its take-out robots with Fanuc’s six-axis models to automate downstream operations.
Using a six-axis robot for insert molding was highlighted by PlastiMatix, distributor of Gluco vertical presses. PlastiMatix offers mid-size robots from Kawasaki, whose F Series can carry 4.4 to 6.6 lb and cost around $44,000.
For horizontal-clamp insert-molding jobs, Motoman introduced the UP6R, a small six-axis robot that mounts atop the press’s stationary platen. Motoman also offers a floor-mounted UP6 for side entry from the back of the press. Both versions have a 13.2-lb payload.
Nissei of Japan thinks jointed arms can substitute for traversing robots in more than just insert molding. Last fall, Nissei came out with its own T1 and T3 jointed-arm models that mount on the fixed platen (see PT, Feb. ’99, p. 11).
Injection molders may find it easier to accept jointed-arm parts removers when they come in a more familiar guise. NPE saw the first U.S. display of hybrids in which the arm hangs gantry-style from a traversing rail. Two all-servo series were displayed by Fanuc Robotics. Its Toploader series, launched in 1999, has six axes of motion. Overhead rail mounting allows it to serve multiple machines or workstations. It can also perform top, front, or side entry and can reach behind itself. At NPE, Fanuc showed off its newest and largest member of the family, the M-710iT (pictured on this month’s cover). It has a 154-lb payload capacity and reach of 74 in. At the show, System integrator Robotic Production Technology showed how the M-710iT could be mounted on a 4-meter rail to serve two injection presses of 1000 tons or larger. Automated Assemblies is also distributing Toploader robots for use on large molding machines.
Also new at NPE was the smaller SR Mate series, which provides four- to six-axis parts removal for injection machines of 50 to 300 tons. Its extraction times are said to be as short as 0.75 sec.
Another believer in gantry-style jointed-arm robots is Battenfeld, whose new Unirob RG 80 can lift parts weighing up to 176 lb from either horizontal or vertical-clamp presses.
Fast new servo models
At least 20% higher speed is claimed for the newly enhanced AZ-100HP servo robot from Automated Assemblies. It has a new controller and motor configuration that are said to give take-out times of 0.22 sec. Price of the unit has been cut 15%, even though a color graphical display is now standard.
The company also boosted speeds of its economical Servo Express robots by 25 to 50% with the addition of a new drive package. Color graphic display is also now standard on this line, despite the low price of $33,900.
Conair’s fastest all-servo robot is the new Sepro Model 3020 HP, which boasts 0.4-sec take-out and 3.5-sec overall cycle. Payload capacity is 6.6 lb. The unit gets extra zip by mounting the traverse motor on the beam to minimize mass on the moving arm. Also, the controls feature two microprocessor boards, one of them just for the vertical stroke. It has software optimized for speeding the take-out stroke. Speed is coupled with accuracy by a mechanical wrist lock that stabilizes the end-of-arm tooling against acceleration forces.
Two new Falcon HAS II Series servo robots from Conair have increased vertical speeds and stroke lengths, yet total height on telescoping-arm models has been trimmed by about 4 in. The HAS II 200 has vertical speed of 14.7 ft/sec, giving a take-out time of 0.95 sec. Overall cycle is 4.1 sec. Main vertical stroke has been extended to 35 in. and the sub-arm vertical stroke to 37 in.—almost 4 in. longer than competing models. It is sized for machines up to 500 tons.
Also new is the HAS II 150, with 0.75-sec take-out for the telescopic version and 3.5-sec overall cycle. Both these Harmo-built robots have a new color graphical touchscreen controller and “absolute” servo positioning, so the controller always knows where the robot is, even when power is shut off and then restarted.
Ichikoh Engineering Co. of Japan, newly represented by InSol Inc., introduced the TA-Series absolute-servo robots that need 40% less headroom than other models, owing to a three-stage telescoping arm. They also feature an extra 19 to 29 in. drop distance outside the press, allowing parts conveyors to be placed down at floor level.
The new EPC3000 Windows/PC-based controller is now standard on all servo robots from Mark 2 Automation. It controls three servo drives (expandable to eight) and 64 I/O (expandable to 256) to control the robot and secondary equipment. It provides templates for preformatted routines, as well as free programmability. Over 1000 programs can be stored. Its large (10.4-in.) color touchscreen can display robot electrical and pneumatic diagrams, the operator manual, and parts list—all stored in the controller. Optional devices like modems, floppy-disk drives, and vision systems can readily be added.
The new Performance Series from Ranger Automation Systems is a revamped line of all-servo three- to five-axis models for presses of all sizes. Minimum take-out times are as short as 0.5 to 1 sec. Options include a T-beam for delivery to either side of the press. A new color touchscreen control is standard for the whole line (also on pickers). It offers both customizable standard templates and free teachability. Positions and speeds can be changed on the fly. Fifty programs can be stored.
Raycon Industries showed a new low-cost, all-servo robot from Super Tech Co. Ltd. of Taiwan. The model STW-850A, sized for machines of 150 to 300 tons, costs less than $30,000.
The redesigned RF 10 all-servo robot from Remak North America is designed for high rigidity (with double linear guides on all axes) and for high acceleration. Standard models provide acceleration of 1.5 G, and the high-speed version reportedly achieves 8 G on the vertical axis. It’s sized for presses of 220 to 1100 tons.
Sailor U.S.A. brought out its new standard line of servo robots, the RZ-N Series. They are said to be faster and smarter, thanks to new motors and controls. Standard RZ-N-L models have 0.8-sec take-out and 5-sec overall cycle times. Super-high-speed RZ-N-C versions boast take-out times as short as 0.35 to 0.4 sec and overall cycles less than 3 sec on models sized for 200- to 300-ton presses.
These robots have new absolute-servo controls that can store 200 mold set-ups and handle complex peripheral sequences like layer packing and palletizing. The enlarged color touchscreen offers menu-driven teach programming with increased flexibility to add functions. The controls also provide off-line sequence testing and three standard templates.
Sailor demonstrated at NPE the new SE-300 high-speed side-entry robot. It demolded, oriented, and assembled CD jewel boxes from an eight-cavity mold. Take-out was 0.3 sec and overall cycle less than 5 sec.
New L-Series servo robots from Star Automation have extra-long strokes on all three axes. They cover a press-size range from 150 to 1000 tons.
Also new from Star are the small T-400FMIII-3 servo model (400-mm vertical stroke) and the medium-size, high-speed TW-800HMII-U for presses of 150 to 220 tons. The latter is said to give 0.55-sec take-outs and 2.8-sec overall cycles.
Star’s new MHY-1800FMIII-3 is designed to pull long parts like bumpers from machines of 850 to 1600 tons. Its unusual feature is a moving carriage on the strip stroke instead of a moving arm along a fixed track.
Wittmann has a new larger model in its Six Series. The W670 has a 220-lb payload and 9-meter beam for use on machines of 2200 to 5000 tons. New standard features on Wittmann’s Six Series are digital vacuum switches for faster and more accurate part sensing, as well as a servo wrist that combines A and C axes. It gives Six Series robots six-axis motion in a standard beam-style robot.
Also new is Wittmann’s C66 controller with color graphical “TeachBox.” Users can select preformatted routines or teach their own more detailed sequences—all on line. Up to 12 programs for peripheral devices can run simultaneously, and they can be saved to a floppy disk. The system also has been expanded to include 128 I/O, 32 vacuum circuits, and faster processing, which is said to speed take-out times.
Yushin’s new VN-EA-35S is its smallest all-servo robot, which permits gentle and precise handling of tiny parts from presses of 15 to 50 tons. Providing cavity separation for quality control is one value of this baby robot.
Yushin also has new E-Touch version 4 control software for its VNXII servo robots. The color graphical touchscreen is said to permit easy on-line programming by shop-floor personnel with little training required. Special features include an optional visual teaching mode that lets the operator view the mold in an on-screen window by means of a camera on the robot tooling. This method reportedly can help achieve more precise settings.
Also unusual are two artificial-intelligence functions. One optimizes the take-out motion by integrating the programmed robot position points into a smooth arc that minimized mold-open time. Another AI function looks at the robot’s waiting time outside the press and then slows down movements outside the mold area so as to use up all the idle time. The benefit is less wear and tear and lower energy consumption, Yushin says.
New pneumatic models, too
Arburg demonstrated its new Multilift H side-entry robot, which is all pneumatic except for the stripping stroke, which can be servo-electric if required. Swiveling and rotary axes can be added to this modular unit as needed.
Ranger’s new Value Series is a low-cost line of all-pneumatic or combination servo/pneumatic robots. A robot with servo only on the vertical axis reportedly can achieve take-out times as short as 0.5 sec and still cost less than $25,000.
Model RX 21 from Remak is a brand-new all-pneumatic unit for presses from 20 to 440 tons. It has a carbon-fiber arm and a wheel on the end of the arm that makes it easy to set intermediate stops. Price is $11,000.
Star Automation introduced the NP-FIII series of low-cost, “entry-level” pneumatic robots that have an electric induction motor on the strip axis to permit multiple stripping movements. Two sizes cover presses from 30 to 220 tons. The larger unit (800-mm vertical stroke) costs $12,000.
Yushin came out with the economical AT-120, which has pneumatic vertical and kick axes, plus a servo-driven traverse. The latter permits multiple stops to release parts at multiple positions (e.g., for good/bad parts separation). Price with wrist, vacuum, and grippers is only $12,100.
New pickers galore
AEC/Automation Engineering introduced an upgraded controller for its Excel Series sprue pickers. The hand-held pendant has an LCD display that prompts users through programming sequences. The system stores 16 programs and has a four-line display of full-text troubleshooting messages.
A brand-new sprue picker from Automated Assemblies, called the AX Express, has linear bearings and vertical stroke of 18, 24, or 32 in. Price is $4750.
The latest from CBW Automation is the TP-197 top-entry servo robot with take-out times as short as 0.51 sec, including verification of part presence. Total cycle is 4 sec. It’s suited to presses of 50 to 700 tons and takes a payload up to 6 lb. The carbon-fiber arm has curved sidewalls that act as bearing guides to prevent vibration at high speed. To further minimize vibration, the robot has fixed tooling that hands off parts to a wrist device outside the mold. The vertical axis reportedly achieves acceleration of 26 G and speed of 56 ft/sec.
A lightweight carbon-fiber vertical arm on Conair’s newly enhanced FXF 450 sprue picker is said to improve vertical-axis speed by 15%. This new Harmo unit boasts 1.2-sec take-out time and overall cycle of 4.2 sec, a 10% gain. Vertical and kick strokes can be set from the hand-held pendant. Sized for machines of 150 to 500 tons, it has 2.2-lb payload capacity.
Conair’s brand-new low-cost picker is the UCR 150L, made by Fairway of Taiwan. This beam-mounted unit can traverse horizontally, rather than merely pivoting like standard pickers. With a payload capacity of 6.6 lb, it can perform most of the functions of a beam robot on machines up to 300 tons, though it costs about the same as many sprue pickers.
Prices start at less than $4500 for new EC2 sprue pickers from Mark 2 Automation. Two sizes, with vertical strokes of 15 and 20 in. and 1-lb payload, are aimed at presses up to 100 tons. They feature the EMC2001 operator’s pendant and a solid-state sprue-sensing system that needs no adjustment for varying sprue sizes.
New to the U.S. is Remak’s RX 5 picker, which provides take-out times of 0.25 to 0.3 sec. Price is $4500.
Star Automation added a smaller picker to its XQ series. Model XQ-300FII has 300 mm vertical stroke.
Both Wittmann and Yushin introduced pickers with electric kick stroke. This feature adds operator convenience and safety by permitting remote programming. They also accommodate unscrewing molds by waiting behind the parting line, away from the rack, and then kicking forward, dropping down, and kicking forward again after the mold opens. Yushin’s N-HOPIII 450 and 550 models of this type handle presses from 30 to more than 300 tons. Their controller can store 15 set-ups with servo positions and speeds.
Lots of New EOAT Components
A large selection of new end-of-arm tooling components was introduced at the show by >SAS< Automation:
The “Grip It!” line of chucking and gripper components comes from Argofile of Japan. These were designed especially for Star, Sailor, Harmo, and Yushin robots.
The line of “Nip It!” sprue nippers are from Nile Air Tools.
Smart Box logic-interface board and junction box for robot grippers and downstream automation minimizes wiring and accepts different kinds of sensor logic.
New gripper fingers flip behind part edges for difficult part-removal applications that require high force and/or flexing the part. They have pneumatic single action and spring return.
New line of spring-loaded vacuum-cup holders accept cups with various thread sizes.
Gripper spring-release system allows gripper compliance during rapid part ejection.