Mark Golab | University of Cambridge (original) (raw)

Papers by Mark Golab

Heliyon, 2022

Goal: Material extrusion additive manufacturing, is a relatively inexpensive and popular manufact... more Goal: Material extrusion additive manufacturing, is a relatively inexpensive and popular manufacturing technique that can be used to fabricate complex 3D geometries at low cost. However, parts produced by this process are often characterised by poor quality, particularly with regards to dimensional and geometrical accuracy. This review provides a comprehensive analysis of experimental studies conducted over the past 25 years that have aimed to improve these quality variables via printing parameter optimisation.
Methods: An initial non systematic scoping study coupled with a subsequent scientific systematic literature review protocol to identify experimental studies on dimensional quality in material extrusion additive manufacturing was conducted. 127 individual studies are identified and analysed.
Results: The authors critically analysed the relevant and salient studies (127) by evaluating which machines; materials; sample sizes; artefact designs; and most importantly what printing parameters have been used in the experimental investigations. A total of (79) machine variations were used; ABS and PLA made up (43%) and (36%) of materials investigated respectively; (84%) of studies had sample sizes of less than (40); and artefact dimensions ranged from (10–270 mm) (1–240 mm), and (3.5–220 mm) in the X, Y, and Z axes respectively. In many cases, the relationships between printing parameters (independent variables) and dimensional qualities (dependent variables) were found to be uncertain or even contradictory between studies.
Conclusions: A wide range of studies have sought to optimise parameters (e.g., Nozzle gap height, print head velocity, filament volumetric velocity) to address dimensional quality issues in ME AM. However, the authors have demonstrated that a lack of agreement among studies limits the generalisability of these parameter opti- misation findings. More recent studies have considered the local dimensional variance of deposited single strands. This offers greater potential to understand the underlying causes of component defects and inaccuracy.

Industrializing Additive Manufacturing

Fused Deposition Modelling (FDM) is a relatively low-cost additive manufacturing process that is ... more Fused Deposition Modelling (FDM) is a relatively low-cost additive manufacturing process that is commonly characterised by poor dimensional accuracy and precision. Prior work indicates that dimensional errors may be the result of fundamental issues relating to how the filament behaves during deposition and not due to limitations in FDM machine design. Some studies have examined the cross-sectional area of single strands, highlighting the dimensional variation, but there have been no studies examining these changes in other orthogonal planes and along the whole strand length. This study seeks to characterise the behavior of deposited material, to explore the impact of different process parameters on single and multiple strand geometries. Single layer strands of Poly-Lactic Acid (PLA) are deposited through a 0.4 mm diameter nozzle at varying nozzle gap heights, filament volumetric velocities, and print head velocities. Image analysis is used to quantify the width, height, cross sectional shape, and qualitatively analyse strand geometries. Basic print repeatability is shown to be in the order of AE75 lm at a strand length of 20 mm. By altering processing parameters, strand width variation of 2.6 mm has been demonstrated. Variations at the start and end of each strand are more significant than in the middle. Variations in shape becomes much more pronounced when printing multiple strands on top of each other. These results demonstrate the importance of careful process parameter selection on part quality, which to date has not been sufficiently well acknowledged.

Industrializing Additive Manufacturing , 2020

Fused Deposition Modelling (FDM) is a relatively low-cost additive manufacturing process that is ... more Fused Deposition Modelling (FDM) is a relatively low-cost additive manufacturing process that is commonly characterised by poor dimensional accuracy and precision. Prior work indicates that dimensional errors may be the result of fundamental issues relating to how the filament behaves during deposition and not due to limitations in FDM machine design. Some studies have examined the cross-sectional area of single strands, highlighting the dimensional variation, but there have been no studies examining these changes in other orthogonal planes and along the whole strand length. This study seeks to characterise the behavior of deposited material, to explore the impact of different process parameters on single and multiple strand geometries. Single layer strands of Poly-Lactic Acid (PLA) are deposited through a 0.4 mm diameter nozzle at varying nozzle gap heights, filament volumetric velocities, and print head velocities. Image analysis is used to quantify the width, height, cross sectional shape, and qualitatively analyse strand geometries. Basic print repeatability is shown to be in the order of ± 75 µm at a strand length of 20 mm. By altering processing parameters, strand width variation of 2.6 mm has been demonstrated. Variations at the start and end of each strand are more significant than in the middle. Variations in shape becomes much more pronounced when printing multiple strands on top of each other. These results demonstrate the importance of careful process parameter selection on part quality, which to date has not been sufficiently well acknowledged.

Purpose This research examines an approach for enhancing the efﬁciency of spinal surgery utilisin... more Purpose This research examines an approach for enhancing the efﬁciency of spinal surgery utilising the technological capabilities and design functionalities of wearable headsets, in this case Google Glass. The aim was to improve the efﬁciency of the selective dorsal rhizotomy neurosurgical procedure initially through the use of Glass via an innovative approach to information design for an intraoperative monitoring display. Methods Utilising primary and secondary research methods the development of a new electromyography response display for a wearable headset was undertaken. Results Testing proved that Glass was ﬁt for purpose and that the new intraoperative monitor design provided an example platform for the innovative intraoperative monitoring display; however, alternative wearable headsets such as the Microsoft HoloLens could also be equally viable. Conclusion The new display design combined with the appropriate wearable technology could greatly beneﬁt the selective dorsal rhizotomy procedure.

Heliyon, 2022

Industrializing Additive Manufacturing

Industrializing Additive Manufacturing , 2020

Fused Deposition Modelling (FDM) is a relatively low-cost additive manufacturing process that is ... more Fused Deposition Modelling (FDM) is a relatively low-cost additive manufacturing process that is commonly characterised by poor dimensional accuracy and precision. Prior work indicates that dimensional errors may be the result of fundamental issues relating to how the filament behaves during deposition and not due to limitations in FDM machine design. Some studies have examined the cross-sectional area of single strands, highlighting the dimensional variation, but there have been no studies examining these changes in other orthogonal planes and along the whole strand length. This study seeks to characterise the behavior of deposited material, to explore the impact of different process parameters on single and multiple strand geometries. Single layer strands of Poly-Lactic Acid (PLA) are deposited through a 0.4 mm diameter nozzle at varying nozzle gap heights, filament volumetric velocities, and print head velocities. Image analysis is used to quantify the width, height, cross sectional shape, and qualitatively analyse strand geometries. Basic print repeatability is shown to be in the order of ± 75 µm at a strand length of 20 mm. By altering processing parameters, strand width variation of 2.6 mm has been demonstrated. Variations at the start and end of each strand are more significant than in the middle. Variations in shape becomes much more pronounced when printing multiple strands on top of each other. These results demonstrate the importance of careful process parameter selection on part quality, which to date has not been sufficiently well acknowledged.