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Plasma Additive Layer Manufacture Smoothing Technology

Periodic Reporting for period 2 - PALMS (Plasma Additive Layer Manufacture Smoothing Technology)

Reporting period: 2018-07-01 to 2019-11-30

Additive manufacturing (AM) offers unprecedented design freedom and the possibility to produce lightweight optimised components that are impossible to make with traditional techniques. Despite the significant progress made in AM, the surface roughness of parts produced by this method continues to be an issue. As a result, the application of AM parts in industry is being constricted, particularly in the aerospace and medical industries, where the surface finish of components is highly critical. We have developed PALMS, an innovative cost-effective macro-polishing solution based on novel electrochemical plasma technology. AM parts are rapidly treated in a highly controlled manner in less than 20 minutes, leaving a uniform, smooth micro-finish (<0.1μm), resulting in considerably improved aesthetics and mechanical performance.

PALMS macro-finishing technology relies upon intensification of conventional electrolytic alkaline cleaning by a plasma discharge that is initiated at the surface of a cathodically polarised work-piece due to abundant gas liberation and electrolyte evaporation at high voltages. The PALMS concept applies cutting edge innovation to existing electrochemical plasma technology, revolutionising its use from basic micro-polishing of parts with surface roughness <2μm, and enabling it to be used on macroscopic surfaces (2-100μm), such as those encountered on AM produced parts. The PALMS technology involves applying a potential across a work-piece (e.g. the AM part) submerged in a bath of specially configured electrolytes. The procedure produces gas which is wetted to the work-piece (anode), evolving into the process-induced development of a plasma skin across all surfaces. This delivers rapid, uniform material removal.

The use of electrochemical plasma, typically characterised with fast and uniform removal rates, makes for a particularly effective method of finishing components, regardless of complexity or geometry. The use of an electrolytic bath/cell for submerging the work-piece provides both the environment for electrical transfer and the ability to apply the process uniformly to all surfaces. Furthermore, unlike other finishing processes, our specially developed electrolytes are environmentally friendly, non-toxic, easily disposable and re-usable, with the main constituent being water. PALMS can be applied to individual or multiple metal components, of all sizes, shapes and a range of metal elements and alloys, with no pre-cleaning required prior to processing the AM components.

Specific objectives for the action: To refine, scale-up and bring to market readiness our novel AM part finishing system, that will for the first time fully satisfy the market need and enable accelerated adoption of AM produced parts across a range of industries and applications. In turn, savings will be delivered in the following areas: complex component manufacturing costs, scrap, weight, reduced time-to-market, fuel consumption and CO2 emissionxiv, and ultimately, 'buy to fly' ratio.
The initial research regarding standards and regulations indicated the Additive Manufacturing sector still represented a grey area as most of the work currently done was focusing on the development of the various available technologies. However standard such as ASTME1558 -9(2014) dedicated to conventional electrolytic polishing gave us a indication of possible standard development and confirmed once again the PALMS technology would completement very well the development of AM.

The guidance documents for the creation of the Beta prototype were centered around the need of finding an appropriate power supply (that could be used for production purposes) and the discovery of Cr VI posttreatment when dealing with higher current and bigger load. The initial trials demonstrated that the technology was capable of reducing the roughness of stainless steel test discs within 10 min (Ra<1micron). More complex geometries were also studied such as rods, tubes and manifolds revealing that internal surfaces could also be treated and give satisfactory results, although the process was slighlty slower than for external surfaces. The focus on the beta prototype development was first to be reliable, automated and safe with the addition of a filtration system, a bund and drainage system to contain any potential Cr VI. To improve efficiency, a bigger heater and better insulation was also added as well as an improved extraction of the fumes.

At the end of period 1, the hardware and Human Machine Interface were completed and the debugging was taking place. Milestone 1 was completed and the machine fully validated on 15/07/2018.
As far as we understand the current situation, there do not seem to be a technology that could rival the PALMS one.

Our participation in the FTI programme, will allow us to accelerate the commercialisation process for the PALMS TRL6 technology and achieve market uptake by month 32 after project start. In doing so, we will capture up to 3.0% of the global market by year 5 post project, generating >€68million in revenue, with associated ROI of 1063%, and the creation of over 160 new jobs.
PALMS advanced prototype
PALMS pilot machine design for industry
PALMS Human Machine Interface - prototype