Metal surface finishing should always be considered at an early stage of any project.
. This is particularly important where coating thickness needs to satisfy critical tolerances.
High level of corrosion resistance needed for marine environment
Midland Alloy Ltd specialises in aluminium section bending, complex CNC machining & coded TIG welding. A recent project involved making aircraft seatback frames for the innovative airline seat designer and manufacturer Acro Aircraft Seating Ltd, the end customer being Saab.
The hoop shaped frames are destined for planes constantly operating in a marine environment with a high level of corrosion resistance required.
Optimising design to optimise surface protection
Midland Alloy and Acro Aircraft involved Powdertech Surface Science at an early stage, to discuss the design and manufacturing process for the hoop. Powdertech’s INTRICOAT service offers the operational and technical capability able to deliver a coating solution to meet the technical requirements and aesthetic requirement whilst maintaining the total coating thickness within the design parameters.
These early discussions would determine how the design could be optimised for maximum coating protection against corrosion and we helped Acro develop the specification by providing advice on how to achieve the technical requirements. Certain areas needed masking or bungs and tolerances would need to be determined to inform coating thickness levels.
“Midland Alloy is very pleased with Powdertech’s level of service and the team’s technical expertise and up-to-date knowledge for this special project.”
Testing procedures
Firstly, we worked with the manufacturer to conduct approval trials to show compliance with required fire tests.
Corrosion testing was then conducted on three coated hoops from an initial production run of seventy-two. This included 1000hrs salt spray testing. The aluminium had been treated with a TiZr passivation layer and primer coat before the topcoat in order to achieve maximum resistance to corrosion. Mounting holes for the frames needed to be bunged before coating could be carried out and removed at the most appropriate time within the powder curing cycle. Careful control of both the primer and topcoat thickness was conducted using a pre-cure ultra-sonic powder thickness tester. The thickness needs to be exact to meet tight tolerances.
Outcome
Involvement at an early stage in the design/manufacturing process ensured the best possible outcome for the final product and for efficiency in manufacturing. Full production runs of the seat hoops are now underway..