Driving up production

A company supplying cooling and air conditioning systems to Ford Motor Company is undergoing a manufacturing process overhaul, with a view to enhancing production efficiency and improving supply scheduling.

Ford, with it's new range of cars, aims to please not only aesthetically and on the road, but it also has ambitions to make them the best logistical choice for owners in the UK and, indeed, world-wide. By ensuring the best possible availability from its assembly lines and offering a comprehensive parts replacement service within tight time schedules, Ford hopes to make its latest vehicles the easiest to buy and run.

The process is beginning at grass roots level, with supply companies being asked to provide just-in-time delivery of components to both assembly plants and parts distributors in order to meet demand as it arises. Visteon, a key supplier to the Ford Motor Company, has taken this forward at its Basildon plant with the creation of the Vision 98 project, which aims to optimise supply scheduling by maximising automation as far as possible.

The first stage of the project has been the installation of a fully automated conveyor system by BA Ridgwell Limited, a specialist in the design and manufacture of integrated conveyor and automation systems.

The function of the conveyor system is to deliver radiators of varying sizes from two heat curing ovens at carefully controlled speeds to operatives at a single line who sort them, add the tanks, label and leak test them, ready for dispatch.

Reliability is key because the line is in operation 24 hours a day, 7 days a week, as is total speed control to allow the assembly operatives to complete their tasks with minimal duress, and hence error, while maintaining throughput on schedule. Flexibility to meet possible line changes in future as the Vision 98 project moves to further stages is also a consideration.

To achieve the desired effect, BA Ridgwell Limited constructed a series of 27 individual belt conveyors, combining dual lines exiting the curing ovens into one and then making three 90 degree turns over the course of the 162 metre line, finishing with a single line of conveyors at the assembly point.

A 550-Watt motor, turning over at relatively low speeds, powers each conveyor and a separate Hitachi three phase 0.4kW L100 AC frequency inverter, housed in a central panel with the PLC, controls the speed of each motor. With relatively few changes in speed, PC control is not required, so centralised potentiometers set the speed of groups of conveyors to suit throughput requirements.

Infrared detectors mounted at the end of each conveyor trip a stop signal when too many radiators are queuing up and an alarm system allows any of the assembly operatives to halt the line.

Dave Eldret, technical sales engineer for BA Ridgwell Limited, explained why they specified the Hitachi inverters: " We introduced Hitachi inverters into this plant because the Hitachi inverter is compact and easy for the operative to understand and use. Hitachi inverters have, in fact, become something of a standard with our conveyor systems."

The Hitachi L100 inverter drive is available in single phase from 0.2kW to 2.2kW in the 200V class and in three-phase from 0.4kW to 7.5kW in the 400V class. The Hitachi L100 inverter incorporates PID control and RS422 communications and has seven inputs, of which five are programmable, plus two programmable outputs and an alarm output.

Speed setting is by a simple potentiometer on the front panel of the Hitachi inverter or by external analogue or digital signals. A standard on-board keypad and LED is used for programming. The Hitachi L100 inverter is protected by alarms for over-current, over-voltage under-voltage, over-temperature, overload, ground fault, etc. Acceleration and deceleration ramps can be set between 0.1 and 990 seconds.

The Hitachi L100 inverter carries UL and CSA approvals, as well as CE certification for low voltage and EMC Directives.

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