Additively manufactured polymers and polymer composites for minerals processing technology

Espinoza, Ashlee

Thesis

Additively manufactured polymers and polymer composites for minerals processing technology

Download PDF

Creator

Espinoza, Ashlee

Rights statement

Strathclyde Thesis Copyright

Awarding institution

University of Strathclyde

Date of award

2023

Thesis identifier

T16721

Person Identifier (Local)

201767978

Qualification Level

Doctoral (Postgraduate)

Qualification Name

Doctor of Philosophy (PhD)

Department, School or Faculty

Department of Mechanical and Aerospace Engineering

Abstract

Hydrocyclones are particle separation equipment used in the minerals processing industry. They are exposed to aggressive environments and thus are normally comprised of structural steel casings with rubber liners for erosion resistance. The use of additively manufactured polymers and polymer composites for hydrocyclones was investigated. This was necessary as limited knowledge was available to determine the merit of the materials for the application. Two work packages were undertaken that highlight the novelty of the field. The first case study explored the use of fused deposition modelling (FDM) for a hydrocyclone casing. Analysis was performed for hydraulic loading relevant to the application and for 3 bar pressure certification using ANSYS. Locations of stress concentrations were identified; however, the majority of the structure exhibited low stress. From this initial analysis, acrylonitrile butadiene styrene (ABS) was chosen for an experimental study of a cylindrical pressure vessel manufactured by FDM. The vessel was tested to a pressure of 3 bar and strain was recorded. The vessel withstood the pressurisation, but did exhibit creep behaviour. After 6 days with only hydrostatic force applied, there were further creep events, however, the material did not fail or show significant signs of elongation or dilation. Subsequently, the vessel was pressurised to failure which occurred at 11 bar. Catastrophic failure can be anticipated to occur at locations where deposited material rasters meet. A novel fundamental study of erosion of polymers and polymer composites manufactured using FDM was completed. To date, published studies for the erosion of FDM materials were very limited. A recirculating slurry impingement rig was used to test Ultem 1010 and Nylon 12CF specimens and the epoxy sealed counterparts in a slurry of water and angular silica sand. The effects of the manufacturing method, presence of epoxy, and testing conditions were analysed. The Ultem 1010 specimens were compared to a traditionally manufactured counterpart, Ultem 1000. Overall, Ultem 1000 performed better than all additively manufactured materials. The sealed and unsealed Ultem 1010 specimens performed second best, with Nylon 12CF (sealed and unsealed) having the worst erosion performance. Ultem 1010 exhibits semi-ductile behaviour with the peak of erosion observed at the 45° impingement angle and highest material loss when the flow is 0° to the raster orientation. Ultem 1010 sealed with epoxy results in peak erosion at 90° to the raster orientation at 45° and 20° impingement angles. Overall, sealing the specimens provided protection at all angles except 20° impingement. Nylon 12CF experiences the most material loss at 90° impingement angle. The epoxy sealed Nylon 12CF exhibited different behaviour than the as deposited Nylon 12CF. The peak of material loss is at 45° impingement and 90° to the raster orientation. The epoxy provided protection at the 90° imingement angle with a significant reduction in material loss. 45° impingement with 90° to the raster orientation and 20° with 0° to the raster orientation had worse wear than the unsealed specimens for the same angle and orientation. The wear mechanisms observed for all materials were cracking, micro-cutting, micro-ploughing, and plastic deformation. Abrasive wear outside the direct impingement zone cannot be considered negligible in a number of cases.

Advisor / supervisor