Design for AM fundamentals Marc Saunders Director of AM - PowerPoint PPT Presentation

Design for AM fundamentals Marc Saunders Director of AM Applications 21/12/2018 Slide 1

Agenda • Why do we need design for AM? • Innovative AM product design • Lightweight AM parts are cheaper • Ideal AM product positioning • Buildability considerations • Residual stress • Orientation • Supports 21/12/2018 Slide 2

Additive manufacturing 3D printing • From research lab onto the factory floor • From prototypes & tooling to series production • From time compression to higher performance & low costs • From shapes to consistent, qualified parts • From plastics to high performance alloys • From 3D printing to an integrated production process 21/12/2018 Slide 3

Why do we need to design for AM? • The purpose of design for AM is to produce parts that: • Provide higher performance than conventional components • Can be built cost-effectively in series production • Require minimal post- processing • Get this right, and we have a profitable AM application 21/12/2018 Slide 4

Levels of AM deployment Best AM business cases at upper levels New product designs that deliver lifetime benefits in use or customisation Value creation Commitment Complex parts that simplify assembly Knowledge and enhance reliability Re-production parts that avoid complex manufacturing Low volume parts made directly from CAD 21/12/2018 Slide 5

Business impact of industrial AM Financial benefit Product benefits £ Less weight £ Faster product launch £ Product reliability Production benefits £ Higher performance £ Less materials £ Better adaptation £ Lower tooling costs £ Product attraction £ Shorter process time £ Reduced stocking £ Shorter lead time £ Higher £ Simpler assembly responsiveness £ Automation 21/12/2018 Slide 6

Agenda • Why do we need design for AM? • Innovative AM product design • Lightweight AM parts are cheaper • Ideal AM product positioning • Buildability considerations • Residual stress • Orientation • Supports 21/12/2018 Slide 7

Innovative product design Topology optimised car • Reduced weight door hinge Lattice test structures built on Renishaw AM250 metal AM system at The University of Nottingham, as part of the Aluminium Lightweight Structures via Additive Manufacturing (ALSAM) project.

Innovative product design • Reduced weight • Reduced space claim Compact heat Integrated exchanger micro-wave (HiETA) guide

Innovative product design • Reduced weight • Reduced space claim • Increased heat transfer Micro-turbine recuperator (HiETA)

Innovative product design • Reduced weight • Reduced space claim • Increased heat transfer • Efficient fluid flow Hydraulic manifold 3 into 1 exhaust manifold

Innovative product design Acetabular cups • Reduced weight with lattice exterior • Reduced space claim • Increased heat transfer • Efficient fluid flow • Efficient joining Double-lap adhesive joints

Agenda • Why do we need design for AM? • Innovative AM product design • Lightweight AM parts are cheaper • Ideal AM product positioning • Buildability considerations • Residual stress • Orientation • Supports 21/12/2018 Slide 13

Part cost-v-mass – subtractive manufacturing Unit cost • Low-weight products are Processing costs dominate expensive • Material is too expensive to remove Material costs • Exotic alloys used to dominate minimize weight Subtractive • If we minimize processing Minimum manufacturing cost costs, material costs rise • Minimum cost achieved by balancing material and Mass processing costs Minimum mass 21/12/2018 Slide 14

In AM, a lighter part is a cheaper part Unit cost • In AM, we have a virtuous Additive circle: manufacturing Lower part mass = lower part cost • The position and gradient of the AM part cost-v-mass Subtractive Minimum curve depends on several manufacturing cost factors: • Material cost • Mass AM productivity Minimum • Post-processing mass 21/12/2018 Slide 15

AM part cost-v-mass – material costs Unit cost • High cost material results in a steep Lower cost-v-mass curve alloy cost • Lower material costs make AM more competitive vs subtractive manufacturing Mass 21/12/2018 Slide 16

Part cost-v-mass – process productivity • Higher machine productivity (build Unit cost Higher AM rate) reduces build time process efficiency • Machine purchase and running costs determine hourly costs • Part costs per kg are reduced as machines become more cost effective Multi-laser AM machines increase Mass productivity and reduce build costs 21/12/2018 Slide 17

Productive laser powder bed fusion 21/12/2018 Slide 18

Part cost-v-mass – post-processing Unit cost • Post-processing costs affect the height Reduced of the cost-v-mass curve post- • Elimination / simplification of processing downstream processing through careful design for manufacture and processing efficiencies lowers AM part costs Efficient finishing, machining and Mass inspection reduces AM part costs 21/12/2018 Slide 19

Agenda • Why do we need design for AM? • Innovative AM product design • Lightweight AM parts are cheaper • Ideal AM product positioning • Buildability considerations • Residual stress • Orientation • Supports 21/12/2018 Slide 20

Typical market segmentation Unit cost • Products often used in Motorsport multiple market sectors • Same basic function, Space performance, reliability Aerospace • Different value assigned to Automotive weight and space claim Subtractive Minimum manufacturing • Motorsport, space, cost aerospace will pay more for Industrial lighter products (static) Industrial (mobile) • Automotive and industrial Mass sectors are more driven by Minimum cost mass 21/12/2018 Slide 21

Viable product cost & mass combinations Unit cost • Each sector will be attracted to products their either reduce weight, reduce cost, or Aerospace both Subtractive • e.g. Aerospace will be Minimum manufacturing cost attracted to products Viable AM product that fall into the blue combinations for aerospace region Mass Minimum mass 21/12/2018 Slide 22

Early AM solutions had limited appeal Unit cost Additive manufacturing • Appeal of an AM • Expensive materials product depends on: • Long builds • Extensive finishing • Relative position of the two cost-v-mass curves Aerospace – early AM product • How much we can reduce AM part mass Aerospace – through good design baseline product Subtractive Minimum manufacturing • Early AM products cost were lighter, but also expensive Mass • Appeal limited to Minimum weight-sensitive sectors mass 21/12/2018 Slide 23

Ideal AM product positioning Unit cost An innovative product Additive manufacturing design made from the right • Cheaper materials • Faster builds material, with an efficient • Capable process AM build and streamlined • Simpler finishing post-processing, could serve the whole market • One product instead of many Subtractive Minimum manufacturing • Simplified product cost configuration & sales process Single product suitable for all market sectors • Reduced inventories Mass • Streamlined servicing Minimum mass 21/12/2018 Slide 24

Case study – industrial hydraulics Domin Fluid Power • Direct drive servo values • Maraging steel valve bodies and spools • Lighter than best conventional product and cheaper than minimum cost offering 50 l/min Production build of servo valve bodies produced on 0.35 kg RenAM 500Q industrial AM machine 21/12/2018 Slide 25

Agenda • Why do we need design for AM? • Innovative AM product design • Lightweight AM parts are cheaper • Ideal AM product positioning • Buildability considerations • Residual stress • Orientation • Supports 21/12/2018 Slide 26

Origins of residual stress • Each new layer generated by moving focussed laser across powder bed • Layers fuse to each other • Heat flows mostly down into the substrate as weld track cools and solidifies – very quickly • Cooling layer contracts, setting up shear forces with the layers below 21/12/2018 Slide 27

Reducing residual stress • High temperature build Cantilever displacement as an indicator of residual stress • Cantilevers built at a range of pre- 4.5 heat temperatures Baseline 4 • Residual stress reduces with higher 3.5 pre-heating Z-displacement (mm) -24% 3 • Over 70% reduction at 500 °C 2.5 -52% 2 • Scan strategy 1.5 -74% • Stripes or 1 chessboard 0.5 recommended 0 for bulky parts 170C 300C 400C 500C Build plate temperature 21/12/2018 Slide 28

Why orientation is important • Each layer needs physical support from below, and a path to conduct heat away • Solid metal is much more thermally conductive than un-fused powder • Down-skin surfaces can be rough and misshapen 21/12/2018 Slide 29

Orientation and supports • Supports required on overhanging surfaces • Parts can be built in multiple orientations • Select orientations that minimise the need for supports • Nominate bulk areas as datums that will be machined for precision • Build these directly onto the build plate with additional machining stock 21/12/2018 Slide 30