 Utilisation
of an Inductive Power Transfer (IPT) system by Excel Automation
to deliver drive to individually powered trolleys that support
cockpit assembly throughout a multi-station assembly line for
the new Mini is believed to be a first in the UK and has resulted
in a more versatile production process.
The new line installed at Intier Automotive Interiors for assembly
of the Mini cockpit is a radical departure from the initial thinking
of Intier project engineers which was to have a more conventional
flow line with an overhead return for empty carriers, the latter
to eliminate too much intrusion onto the floor area. Unfortunately
plant height restrictions would not allow this style design.
During discussions with Excel Automation, its design team put
forward the idea of using individually powered trolleys, channel
guided throughout the process. Concern over excessive use of floor
space was soon quashed since each trolley would be only 60cm wide.
Now fully operational, the system enables Intier Automotive Interiors
to release one cockpit every 80 seconds for shipment to the main
car production line.
Trolley Design
Each trolley supports a cockpit carcass between end clamps, and
to facilitate the most convenient working position for component
assembly at each of the 27 stations a large handwheel and associated
simple pull brake-release has been incorporated allowing rotation
of the whole cockpit.
 At
completion of each specific assembly process the operator presses
a button and upon release of an 80 second tact time the trolley
moves to the next station. To bring flexibility to the whole assembly
process Excel Automation chose to design each cockpit support
in the form of a narrow, four-wheel trolley with free running
castors at each corner to facilitate movements around bends. Guidance
of each trolley is achieved by front and rear guide rollers, these
run in a floor channel, guiding
it through each of the 27 assembly stations prior to moving it
to one of three electrical inspections stations. Any rejects move
into a special remedial work area before re-entering the inspection
stations. Diverter plates set within the floor channel control
the flow of the trolley to a vacant test station.
After inspections approved cockpits route to a release station,
here they are removed by a manipulator and loaded onto a shipping
platen, which in-turn feed into a transfer and accumulation area
where the platens are stored in sequence order prior to loading
directly onto roll-on / roll-off Lorries, all of this equipment
was also designed and built by Excel Automation.
Empty trolleys return automatically to a buffer area at the start
of the assembly process to start the next build programme.
Success of the operation is attributed to the use of the IPT
® contactless inductive power transfer system that allows
electrical energy to be supplied to cockpit trolleys without any
electrical or mechanical contact.
Inductive Power
The IPT inductive power transfer system combines two parts, primary
and secondary
which are magnetically coupled, similar to a conventional transformer.
The primary consists of a track power supply and track cable embedded
in the floor and running either side of the guide channel. The
pickups and pickup regulators (the secondary element), are mounted
on the trolley frame. Unlike a conventional transformer, where
primary and secondary are tightly coupled, the IPT is a loosely
coupled
system, and allows power to be transferred across 5mm air gaps
due to the high operating frequency of 10 kHz to 25 kHz.
 The
adoption by Excel Automation of the IPT power drive system for
this production line brought individual control and progress through
the assembly process. Should a unit need to be removed from the
line this is easily carried out by simply raising the drive assembly
which is complete with guide rollers, without affecting progress
of other trolleys.
The automated assembly line, designed and built by Excel Automation
at its’ Worcester plant, is essential to the smooth, efficient
JiT transfer of Mini cockpits from the assembly line to the main
car production plant.
Commenting on the new line, Prawin Singh, Lead Project Engineer
at Intier Automotive Interiors says, “Although the trolley
concept for the new Mini cockpit production line was a radical
departure from our initial thinking we are delighted with the
solution Excel put forward, it has kept the whole process at ground
level and
brings added flexibility.”
The Docking Station
Cockpits released for delivery from the production line are placed
on an Excelvayor power roller accumulation conveyor and move to
a transfer station comprising turntable, powered roller section
and scissor lift. It accepts individual cockpits, rotating them
through 90 degrees ready for entry into a two-tiered powered roller
accumulation rack. Strategically positioned sensors enable the
monitoring of the number of cockpits passing into the lower deck.
 When
the prescribe number, 15 in the case of the Mini cockpit, have
accumulated in the lower level, each new cockpit arriving on the
turntable is raised by scissor lift and simultaneously turned
through 90 degrees, before being released to the upper deck. When
full, the cockpits await final transfer to a vehicle’s trailer
ready for JiT despatch to the main plant.
Each vehicle trailer has been fitted out by Excel with a two-tier
roller conveyor arrangement mirroring that of the holding bay.
As a trailer moves into the docking station a series of traffic
lights provide indication to the driver and a levelling system
ensure that the trailer is aligned with the of board conveyors.
The driver then
triggers via a push button the loading sequence and release of
cockpits. The transfer sequence means that the last unit to enter
the holding bay is first into the trailer. At the main car production
plant the first cockpit to be automatically released is the first
that entered the holding bay at the cockpit build plant.
The Intier Automotive Interiors installation highlights how,
given a design brief Excel
Automation looks for the most advantageous solution for its client,
not necessarily following conventional guidelines. |
