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Overview of 1st year D4AM project progress

Overview

The current project “Design for Additive Manufacturing” (hereafter referred to as D4AM) funded under the ‘Design the ‎Future’ phase 1 call in 2014 has established a strong basis for continuation including increasing scope and depth. The ‎constraints of the phase 1 call necessitated a focus on only the two most frequently used Additive Manufacturing (AM) ‎polymer processes, fused deposition modelling (FDM) and laser sintering (LS) whilst we found that other established processes are being used. D4AM-1 established the theoretical ‎framework for design guidance for AM and provided the structure for the data gathering, synthesis and presentation of ‎design guidance that provides the foundations for expanding the work to include other well established AM processes, ‎such as stereolithography and ink-jetting and begin developing design guidance for emerging AM process ‎including multiple-materials (e.g. Object Connex), faster processes (e.g. HP Multi Jet Fusion) and metals.

Findings

  • There has been an explosion of academic interest in design for AM and there is a great deal of excitement about the industrial potential of AM amongst government and industry bodies.
  • There is still a lack of design experience or expertise and that design guidance for AM or readily available case studies remains extremely limited.
  • Design for AM expertise is ad hoc, limited, geographically constrained and based mostly on self-taught, experiential or trial-and-error learning.
  • To date much so called design guidance for AM is limited to ensuring “printability”; that is avoiding or adding features to ensure the build process does not fail. Designs following such guidance may be “printable” but have no design optimisation at all.
  • More useful design guidance for AM is typically limited to detail design rules that are ‎typically only ‎applied at an individual feature level (e.g. minimum wall thickness) or is focused only on the perceived ‎advantages ‎of AM without due regard for their implications on the design of the whole product.
  • Many studies have focused ‎on ‎ultimate capabilities for specific geometric features rather than on reliable, predictable or repeatable tolerances. ‎For ‎example part complexity is frequently espoused as a key advantage despite the fact that the increased complexity ‎may be ‎unnecessary, lead to much slower build times or create difficulties with downstream processes (such as finishing ‎or ‎assembly) resulting in poor manufacturing efficiency and increased cost.
  • A large number of the design principles that can ‎be ‎achieved with AM are being applied on a component level rather than a product or assembly level. For example, ‎part ‎consolidation is a key advantage of AM but only where issues such as cost, accuracy, strength, service life, ‎maintenance, repair or ‎replacement have been properly considered.
  • There are ‎contradictions in design guidance ‎from different sources. Lack of experimental validation of design ‎guidance to eliminate these contradictions.
  • Whilst there is much activity in industrial research and an increasing amount in academia, it is still dominated by ‎aerospace applications and safety critical / weight critical design optimisation for load-bearing metal components. Topology optimisation for example is being widely explored in AM for safety critical applications.
  • Industrial research into design for AM is understandably being withheld as intellectual property and ‎commercial advantage, which means that the design guidance being developed is not available for wider education and is not subject to ‎wider scrutiny, validation or adoption. This is being reinforced by consolidation in the industry (e.g. GE taking over both ‎Arcam and Concept Laser). These developments will restrict the adoption and growth of AM across industry, especially ‎amongst manufacturing SMEs.
  • Despite these limitations above, there are commercially successful applications of AM for series production of end-use parts, typically very low volume high value components but also some low-value and simple components made in high numbers.
  • We surveyed more than 100 designers to determine the desirability of different modes of guidance. The results show ‎that designers prefer online and video formats for the presentation of design guidance.
  • The need for a wider consideration of design for AM guidance for other industry ‎sectors and particularly for ‎industrial / product design remains and is now recognised as a potentially limiting factor in the ‎growth and ‎exploitation on AM in UK and European industry.

We created a framework to organise the current DfAM knowledge (a simplified version is shown below), highlight gaps and inform future research.

DfAM Simplified Framework