Robot cell package for mould unloading applications

Citation

(2006), "Robot cell package for mould unloading applications", Industrial Robot, Vol. 33 No. 5. https://doi.org/10.1108/ir.2006.04933eaf.002

Robot cell package for mould unloading applications

Robot cell package for mould unloading applications

Keywords: Robotics

With six-axis industrial robots increasingly regarded as a cost- competitive and flexible alternative to conventional Cartesian gantry systems for plastic injection demoulding applications, process automation specialist Barr & Paatz of Totnes had developed a complete robot cell package from as little as £35k. Aimed at OEMs and contract moulders, who are looking for automated solutions to more complex demoulding and handling tasks, the package includes one of the latest purpose-designed articulated arm robots from Stäubli or Mitsubishi, interface packages for coordinating with moulding machines, customised gripper assembly, protective guard system and specific application programming. Employing its Cosimir 3D robot simulation and programming software, Barr & Paatz will also verify that the robot cell actually works, in a “dry run” representation, then install and commission the system and provide technical after-care (Plate 3).

Plate 3 The package includes one of the latest robotic aims from Stäubli or Mitsubishi

Barr & Paatz has more than sixteen years at the leading edge of automated production systems, specialising in industrial robotics, work cells and machine vision technology, and is an official integration partner of such global automation brands as Mitsubishi, Stäubli, Bosch Rexroth and Festo.

The company positions itself as an early adopter of automation technology, channelling the latest breakthroughs and cost efficiencies to clients, and has invested in state-of- the-art MRP2 manufacturing planning software, enabling it to apply volume production cost-efficiencies to systems, such as these robot cell packages. It has extensive applications experience in plastic injection moulding, currently installing a whole series of automated demoulding cells for a major OEM.

For years, gantry-style Cartesian, or linear, three-axis systems have been used as robotic unloaders in the injection moulding industry, but continued pressure to reduce operating costs and moves toward shorter product cycles have prompted interest in `flexible automation’ in the shape of six-axis robots. Whilst offering all the features of simple Cartesian systems, notably high speed, slim forearms and straightforward programming, the latest articulated arm robots have the right acceleration, reach and physical capabilities for demoulding duties and can be readily reprogrammed for other tasks, including post-mould downstream applications. Thus, they give moulders an opportunity to break away from `hard automation’ where the equipment is bought solely for a specific task, and offer a major advantage in a market where products and process cycles change so rapidly.

Six degrees of freedom provide an extremely large work envelope within a small footprint, points out Barr & Paatz, while a modern six-axis robot will generally require less installation space than a Cartesian system, without occupying any headroom above the moulding machine. They can also be floor, wall or shelf-mounted to suit different space constraints and, thanks to their compact nature and light weight, robots can be readily repositioned into another work cell.

Thanks to price reductions on articulated arm robots over recent years, the cost of a straightforward mould unloading system is also competitive with an equivalent Cartesian setup, especially using one of the newest six- axis products developed specifically for the plastics sector, like the Stäubli TX Series or the Mitsubishi RV-6SL.

Stäubli has the fastest industrial robot on the market, with a die interrupt time of just 0.59 s, whilst its TX90 model has a 20 kg payload and 1,000 mm reach, making it suitable for mainstream mould unloading duties. Designed for handling tasks with payloads up to 6 kg, the Mitsubishi RV-6SL features an industry-standard metre (987 mm) reach, class-leading 0.02 mm repeatability and slimline construction, again ideal for lateral unloading. High positional accuracy on both series also means that robot arms can be moved precisely to the demoulding position, irrespective of the installation point.

Using these and other models, Barr & Paatz will design and program a robot cell for mould unload operation, adding other downstream handling and assembly functionality as necessary; then provide Euromap- standard hardware and software for interlocking with specific injection moulding machines and supply suitable end-of-arm tooling. To protect both processes and personnel, it will also fabricate a guarding system, employing Rexroth’s modular EcoSafe aluminium barriers, keeping the work cell safe, compact and aesthetically pleasing.

Moreover, controller reprogramming and modular components mean that Barr & Paatz can readily redeploy the robotic package elsewhere, for future tasks such as trimming, decorating, assembly, packaging and palletising. Thus, other than reprogramming charges, the investment in hardware is effectively zero, underlining the cost benefits of flexible automation.

Further enquiries to Barr & Paatz, 7-11 Paragon Units, Ford Road, Totnes Industrial Estate, Totnes TQ9 5LQ, Tel: 01803 869 833, E-mail: s.paatz@barr-paatz.co.uk