Shimizu installs three six-axis Fanuc robots

Trevor Gaughan, Technical Director of Shimizu Industry UK Limited, explains his company's recent investment in three six-axis robot installations, saying: "Our intention is to automate any production process that returns a benefit to our customers and Shimizu." By the end of January 2007, a further two robot systems will be installed at the Telford Site.

Shimizu is a moulding and assembly company supplying automotive tier-one companies. Operating from two sites, in Welshpool and Telford, the business is clearly driven by the demand for high-quality products delivered on time. Trevor Gaughan says: "Automation of the moulding and assembly processes has given us a deviation of Ɔ' on cycle times with resultant improvements on quality and increased output. Without doubt this has allowed us to be competitive with Eastern European moulders and to pass the benefits on to our customers."

The core products moulded by Shimizu are radiator blower mouldings and assemblies, and aircon unit mouldings. Since the early 1990s, three-axis robots had been used by Shimizu for straightforward removal of mouldings from presses; but post-moulding operations, until recently, had remained manual. The decision to move to six-axis robots was based on being able to reduce manual intervention and reduce work-in-progress bottlenecks.

Specialist automation

Hi-Tech Automation Limited, the specialist plastics sector integrator, was contacted by Shimizu. Designing and manufacturing all the post-moulding equipment, including tooling and grippers, Hi-Tech's aim was to keep everything as simple forward as possible and customise standard or existing equipment wherever possible.

Fanuc Robotics was chosen as Hi-Tech's partner for the project and the ARCMate 120iBE robot arm was selected for each system - its reach, speed and, in particular, its ability to 'flip' over backwards made the arm the most cost-effective option for achieving the target cycle time.

Each system is dedicated to producing one product and its variants: cell one is producing the Yaris shroud, cell two shrouds for Honda and cell three Corolla fans.

Cell processes

In cell one the Fanuc ARCMate robot locates the shroud when the press tool opens after the moulding process. The tool ejects the moulding and the robot locates seven inserts into the tool. The robot then locates the shroud into a hot-plate welder into which it has previously loaded a lid; the welder cycle then begins and the robot drops the shroud sprue into the granulator. During the welding cycle the robot picks up another seven inserts ready for the next cycle.

After welding, the shroud assembly is removed from the welder and put into a pressure tester. A lid is then placed into the welder and the robot then takes the shroud from the pressure tester to the output conveyor, if passed, and then the cycle recommences. To date the only limitation of operating the cell at its maximum cycle rate has been the inability for an operator to assemble a heat shield and other parts quickly enough – but this limitation is planned to be addressed at some time in the future with further automation.

In cell two, moulding eight shroud variants for Honda, the robot removes the mould and inserts up to seven inserts and checks they are all moulded in place. On completion, each assembled shroud is placed securely into a dolly. The flexible design of the Fanuc Robotics ARCMate allows the cell to be compact, saving on floorspace. Recycling the sprue using the robot arm's 1.37m reach allowed the granulator chute to be positioned well above the cell.

Flexibility wins rewards

"The decision to purchase cell two was strongly based on the success of cell one and, in particular, the ability of the 'over arm' - or 'flip' - action to allow us to achieve cycle times," explains Trevor.

The third cell removes the Corolla Fan and places an insert into the tool, checks for an insert in the moulding and recycles the sprue. As with the other two cells, cycle time deviation is zero.

Trevor concludes: "Central to making these cells effective was providing the engineers on site with 'ownership of the project'. We involved the team right from the development stage and sent them on programming courses to Fanuc Robotics' Coventry-based training school. From the very start we made everyone clear at Shimizu that robots were essential to make the company increasingly efficient and competitive for the long term."