The Challenge
A supercar manufacturer required a new curing and marriage fixture for a vehicle programme where build volumes are low, unit values are very high, and every assembly operation has to be repeatable to a standard that leaves no room for rework.
Two things make a fixture of this type demanding. The curing process has to be controlled and evidenced, because a bonded joint that has not cured correctly is not something that can be inspected away afterwards. And the marriage operation brings together major assemblies that are expensive, awkward to handle and unforgiving of misalignment, which puts the emphasis firmly on positional control, interlocking and getting the sequence right every time.
The client needed a single supplier to take the controls scope end to end rather than coordinating separate design, panel build, installation and software contractors for what is, in system terms, a small package. Splitting a job of this size across four suppliers costs more in coordination than it does in engineering.
The brief: Deliver the complete controls scope for the curing and marriage fixture — electrical design, panel manufacture, installation, PLC software and commissioning — proven and signed off at factory acceptance test before the fixture moved to the client's facility.
What Duke Did
Duke Control Systems delivered the full controls scope in-house. Keeping design, panel build and software under one roof removes the interfaces where this kind of project usually loses time, because the engineer writing the software is working from drawings produced by the person sitting next to them, against a panel built in the same building.
Electrical Design
A complete electrical design package was produced covering the panel layout, schematics, cable schedules and field installation drawings, with the safety circuit defined at design stage rather than added later.
Panel Manufacture
A single control panel was manufactured, wired and tested in Duke's workshop, housing the PLC, the safety circuit and the operator controls. The system is deliberately simple — push button operation, pressure switches and timed cycle control — because that is what the application needs. A fixture like this does not benefit from complexity, it benefits from being reliable and obvious to the operator using it.
Electrical Installation
Duke carried out the installation on the fixture, covering panel mounting, cable containment and installation, field device wiring, termination and continuity testing. Taking installation as part of the same scope meant the engineers commissioning the system were working on wiring they had installed themselves, which shortens fault-finding considerably when something does not behave as expected.
PLC Software
The control software was written by Duke's software engineers on Siemens. The curing cycle is timer controlled with pressure monitored through the clamping sequence, and the marriage operation is interlocked so the sequence cannot be driven out of order or released early.
The engineering effort in a system like this sits in the interlocking rather than the size of the program. Getting the sequence right means thinking carefully about what happens when a cycle is interrupted partway through, with an expensive assembly clamped in the fixture and an operator waiting to know what to do next.
Commissioning and FAT
The system was commissioned and proven at the build facility in the Midlands, culminating in a factory acceptance test with the client present. The fixture then shipped to Italy for installation into the production facility.
That destination is precisely why FAT mattered. Once a fixture is on a lorry to another country, any outstanding control system issue becomes expensive and slow to resolve. Everything the fixture would be asked to do — the sequence, the interlocks, the behaviour of an interrupted cycle — was demonstrated before it left the building.
Small systems still have to be right. On a low-volume, high-value programme the fixture is not where anyone wants to find a problem, so it gets proven before it ships, not after.
Electrical Design
Panel layouts, schematics, cable schedules and installation drawings produced in-house, with the safety architecture defined at design stage.
Panel Manufacture
Control panels built, wired and functionally tested in Duke's workshop before delivery to the fixture.
Installation
Panel mounting, cable installation, field device wiring, termination and continuity testing carried out on the fixture.
Software and Commissioning
Control software developed, bench tested and commissioned on the fixture, including the curing cycle control and the marriage sequence interlocking.
Factory Acceptance Test
Full functional demonstration to the client, with the fixture proven against its specification before shipping.
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The fixture passed its factory acceptance test first time, with no functional issues raised against the control system. For a scope that ran from blank drawing through to signed-off FAT, that is the result worth having — it means the design, the panel, the installation and the software all agreed with each other before the client ever saw it.