Automation not just for injection molders

Automation increasingly means much more than pick-and-place robotics destined for injection molding, with many processors, including thermoformers and blowmolders, now automating their lines.

With possible applications in thermoforming, molding, and composites processing, KMT’s RoboTrim RT-1002, which debuted at the K 2007 tradeshow, is described by its manufacturer as the next generation robotic router-trimmer. The turnkey system features CamPro offline programming software, which makes robotic milling feasible and enables manufacturers to create complete robot programs with a common CAD/CAM software.

For stretch blowmolding lines, Krones has helped fill the automation gap between stretch blowmolding machine and the filler line for inline blowing and filling of containers. The AirCo range of air conveyors reportedly offers quiet, energy-efficient operation and minimized changeover times between different container programs. New to the system is a triangular chute that has been designed to prevent bottle jamming due to ’climbing’ in the chute. In addition, the use of smaller nozzles, and enclosing the nozzle chute, allows even pressure distribution within the chute so complex bottles can be transported. Filters can be incorporated to meet different hygienic standards for the filling/transportation environment.

The design also uses plastic neck-ring guides secured with a slip-on or clip system so that in the event of wear and tear, the guides can be replaced quickly. As an option, automatic, pneumatically powered width adjustment of the neck-ring guides is available, and multi-position cylinders enable the rails to be adjusted to 12 different positions. Thanks to the new drives designed specifically for air conveyors, energy consumption has been reduced by about 30%, and noise emissions have been lowered.

A similar front-to-back automation system was put in place by Irish packaging thermoformer Quinn Packaging, which uses a vacuum tray unloader as an extraction system for steel-rule cutting machines. The automation supplier, Mould & Matic, has fitted a thermoforming machine with automation equipment for separate forming and punching, with the vacuum tray unloader extracting lids and trays from the machines and placing them in stacks. These stacks are then placed in bulk packaging. The system also enables the automatic sleeving of the stacks, with a second part of the order including two large molds for lids and cups.

On the injection side, continued development in inmold labeling (IML) systems is cutting cycle times and adding functions. Boasting a total cycle time of 3.6 seconds, Wittmann highlighted its turnkey inmold labeling (IML) automation capabilities at the K tradeshow with an IML system designed for the production of 2+2 cups and lids, using a stack mold running on a Demag 200-tonne El-Exis molding machine. The application applied a Borealis polypropylene copolymer with a melt-flow index of 100, labels from printer Verstraete n.v., and a balanced valve-gated hot runner system from Männer.

In the first mold, two round containers are produced, measuring 95-by-40 mm, with a weight of 6g. The second half of the mold produces the two 95-mm diameter lids, which weigh 4g apiece. Cup wall thickness is .50 mm with the lids measuring .55-mm thick. The tool, which was produced by Wittmann’s moldmaking facility in France, features a cooling manifold designed to produce parts with consistent geometry between cavities. Ejection is handled by a combination mechanical stripper ring/blow-off system.

The robot enlisted by the system is a modified W727H side-entry unit, dubbed the W727SM, which features two independent side-entry arms, a center arm for finished-part handover, and two stacking arms to place molded parts on the integrated conveyor. The side-entry arms pick up the lids and wrap-around labels from pneumatically operated label-separation units, which are located on opposite sides of the work cell. A label buffer feeds the tooling for 4 hours of production. The labels are then presented in a vertical alignment to the insertion end-of-arm-tools on the side-entry arms, and during movement into the mold are are statically charged by integrated electrical pads. Labels and parts are placed and removed from the tooling simultaneously. At this point, one set of side-entry arms picks up new labels while the other hands over finished parts to the double-sided center arm.

Beyond such system developments, Denso’s new line of six-axis articulated-arm robots have been designed to feature a slim, 130-mm-wide arm, that along with a reach of 1000 to 1300 mm, allows them to reach into and around injection molding tooling without interfering with peripheral equipment. Denso says that in comparison to single-purpose sprue-picker style robots, this more flexible system can also carry out a variety of secondary operations.

The VM-Series robots have internally concealed electrical wiring and air lines and feature cycle times from .89 to .95 second, with a repeatability of ±.05 to ±.07 mm. Maximum payload is 10 kg, and the maximum allowable moment of inertia is said to enable flexible end-effector designs and support for a wider variety of applications. The ANSI- and-CE compliant systems are available in dust- and mist-proof designs, with floor or ceiling mounts without robot modification possible.

Designed for its Generation IV Model 4060 beam robot platform and Axess Twin dual-arm 3-axis servorobots introduced at K (see MPW October 2007 K Preview for initial report), Sepro offers its Visual Control digital touch-screen control technology. The system features pick-and-place programming that doesn’t require knowledge of programming languages, but can control up to 8 axes of motion, including advanced wrist rotations. Embedded Program Source programming applies freely programmable templates and on-screen prompts to direct users through the teaching of robot positions. In addition, vacuum-flow settings can be set from the operator pendant, so that operators don’t have to adjust them on the arm, which, oftentimes, is out of reach on top of a molding machine.

Contacts

Denso Robotics; www.densorobotics.com

KMT Robotic Solutions; www.kmtgroup.com

Krones AG; www.krones.com

Mould & Matic Solutions; www.mouldandmatic.com

Sepro Robotique; www.sepro-robotique.com

Wittmann; www.wittmann-robot.at