Light-weighting using Advance Simulation and Tooling free Investment Casting AM (Additive

Manufacturing) Process

Jiten Shah

Founder and President

Product Development & Analysis (PDA) LLC

Naperville, IL 60563

www.PDA-LLC.com

Oct 13-21,2020 ICI Virtual Conference

Outline

• Introduction

• Product Development Process

• Light-weighting Opportunities

• Casting Process Simulation Tool

• Additive Manufacturing for Metal Castings (AM4MC)

• Design Process with Tooling Free AM

• Case Studies

• Closing Remarks

Outline

Introduction

• In the Chicago area for over 27 years – Pioneered CAE applications in metal casting since early 90s.

• Provider of technological and engineering solutions to over 165 OEMs and metal casters in the Military, Transportation, Aerospace, Process Industries, Ag/Mining/Construction, Medical Devices & General Engineering.

• Design for additive manufacturing, New Product development, casting conversion, redesign, & reverse engineering in various processes and alloys with contract manufacturing and contract research.

• Silver Member of America Makes; institute focused on Additive Manufacturing (AM); participated in the project on

Accelerated Adoption of AM and currently a team member on Next Generation 3D Sand Printing Technology (AM4MC); providing support for Casting Process Design and Modeling Validation.

• Manufacturing Innovation Institutes - Member of American Lightweight Materials Manufacturing Innovation Institute (ALMMII) – LIFT – Lightweight Innovations for Tomorrow and involved with projects on thin wall casting development.

• Member of DMDII-Digital Manufacturing & Design Innovation Institute (MxD), a Mfg. Hub created by UI Labs-Chicago/DOD

and currently working on Rapid Certification for AM and finished a funded project on machining castings – IAMFix R.

• Partnership with various Metal Casters, 3D Printing, RP and Tooling Providers and Materials Test Laboratory.

Memberships:

Casting Product Development Process

• VE (CAPS and CADS)

• CAD

• DFMEA / PFMEA

• FEA

• Casting Simulation/ICME

• RP

• Additive Mfg. (Sand & Investment)

AM4MC (Additive Manufacturing for Metal Castings) is ready for serial production, beyond prototyping!!

Concurrent Engineering Process

INPUTS:� Customer

Requirements

� Goals

� Expectations

OUTPUTS:

Technical Data Package

� 3D Model

� Drawings

� Optimal Production Method

� Optimal Rigging Design

� Quality Req’s

� Analysis Report

PDAStructural Eng.

Casting Eng.

Foundry Eng.

Functional Design

Development

Optimization for

Performance &

Manufacturing Cost

Service Performance

Validation

Light-weighting Opportunities

• New Product Development for New Platforms• Design freedom with feature placement

• Optimization with Knowledge & Experience coupled with auto solvers, generative design & topology optimization

• Redesign/Conversion/Reverse Engineering for optimization• Refining existing cast or fabricated design to thin-walled casting

• Use of ICME approach

• Newer lightweight high strength alloys potentially replacing legacy parts

Casting Conversion

Castings

Fabrications Forgings

Drivers: Technology, Speed, Cost Economics (Tooling Cost Zero with Toolingless),

Quality, Versatility, Value Added, Optimization (min weight, better performance), Safety, Fuel Economy

Grab lost opportunities of the past

90% of the manufactured goods have metal casting and you will find within 10 feet !!

AEGIS Tower for GDDS – converted over 700 pcs of steel fabrications

into one piece Aluminum Casting weighing 525 lb from 750 lbs

Economic Drivers for Light-weighting

• Cost – life cycle including NRE (tooling, engineering, FAI, P-PAP), production and sustainment

• Lead time – concept to production

• Increase payload

• Improved performance and reliability

• Tooling logistics – storage, handling, upgrade

• Open up floor space – in-house fab to out sourced casting

• Reshoring Initiatives

• Regulatory – DOD, DOE (Nuke), EPA

• Aesthetics - Radar signature

Light-weighting Technologies

• Design Approach – Strain Life Fatigue, Optimization

• ICME (Integrated Computational Materials Engineering) & Process Modeling / Simulation

• Modified or New Alloys with enhanced properties

• AM4MC Toolingless 3D Printed Wax/Sand vs Traditional Casting or Hybrid of both!

• Rapid Certification / AI using process data

In some alloys, thinner walls have better mechanical properties than thicker relatively!

Only with directionally solidified alloys, drafting is useful!

• Design Approach

• Alloys

• Ni Based Super alloys, Al-Cu-Ce, Hi-Si, ADI, SSF, ….

• ICME (Integrated Computational Materials Engineering) & Process Modeling

• Additive Manufacturing

• 3D Sand & Wax Printing

• Fluidity

• Microstructure Control

• Control of Discontinuities

• Mold Metal Interaction

• Control of Distortion

• Precision / Dimensional

• Tighter Process Parameters

• Handling and Automation

Key Factors Solutions

Thin Wall Casting Production

Casting Process Modeling Tool

• Since no tooling exists, it is imperative to get casting right at the 1st time! Eliminate Pour and Pray Practice!!

• To validate for variations in process parameters.

• To evaluate various rigging (gating and risering) alternatives to ensure the predicted soundness, micro-structure and properties meet the requirements.

• To optimize the rigging, mold yield and through put per build box.

• To visualize the potential for core flotation and venting adequacy.

• To predict micro-structure and properties, hot tear & shrinkage tendency, distortion and residual stress, especially with thin wall high complexity designs.

• Effective tool for optimization and improvements – scrap reduction, problem solving for defects such as shrinkage, dross, inclusion, porosity

3DP/AM4MC is no different than conventional investment and sand casting processes, where

molten metal enters into the cavity and subsequently solidifies and provides desired properties and

soundness! Uses the same alloy grades, same thermal properties, inspection and specifications;

unlike metal additive!!!!

Wax Injection Filling Simulation

Additive Manufacturing for Metal Castings (AM4MC) –Tooling free Casting Technology

SLA - QuickCast FDM - PLA

Additive Manufacturing for Metal Castings (AM4MC) –Tooling free Casting Technology

3DPS M/C

3D Printed Wax like materials - PMMACourtesy: Voxeljet

Opportunities with 3DPS

• Hybrid Process using Core Consolidation (with and without redesign)

• Innovative Part Consolidation (expand envelop considering sub-assembly, multi-functionality)

• Light weighting with Thin Wall Casting Technology and Topology Optimization (Redesign or New Product)

• Tooling Free Legacy Parts Replacements

• Zero or negative draft and core consolidation

3DP Vs Conventional Investment/Sand Casting

• Casting orientation wrt build up direction (z axis)

• Mold Parting / Dry Joint for accessibility to remove un-bonded loose sand

• Single core assembly

• No draft requirements, leads to lower weight

• Filets and radii always possible

• Part and feature consolidation

• Machining relief area incorporated easily

• Tighter dimensional tolerances

• Topology Optimization

• Eliminates cores where used due to back draft.

• Casting Orientation wrt parting plane

• Wax die / Pattern and core box parting plane for tooling removal

• Intra core prints for multiple core assembling

• Needs certain draft angle for all features in the draw direction

• Fillets and radii limited

• Cast fab option

• Machining relief area causes undercut and requires cores

• Variability due to parting planes, tool wear & tear, core assembling

3DP Conventional Casting

Casting Design & Manufacturing Process

Conceptual Design

Detail Design – DFM, Process Modeling

Design Refinements and Validations using FEA

Detail Design for Manufacturing – Tooling, Rigging, Process Validations

Functional Prototyping – Tooling Fabrication, Casting

Production – Low Volume and Full Rate – Tooling Fabrication, Casting

3DP/AM4MC is agile (Agility – Ability to adopt design changes during development and production)

3DP provides ample freedom to design engineers with feature placements & rigging design

•Geometric

•Metallurgical•Economical

•Tooling

Constraints

Customization pc to pc, No Physical size limitation, Time Compression, No certification required unlike additive metal, Break even qty for cost

Strain Life Vs Stress Life Fatigue Approach

• Most of the cast structural components, the response of the material in critical locations (notches or discontinuities) is strain or deformation locally.

• At high loads, in low cycle fatigue (LCF) regime, the cyclic stress-strain response and material behavior are best modeled under strain-controlled conditions.

• Strain-life approach, plastic deformation is measured and quantified; lands optimized designs and lighter components.

• Linear Elastic Fracture Mechanics / Stress-life approach doesn't account for plastic strain and is applicable for HCF – High Cycle Fatigue.

Design Process for 3DP

Free Form Design for DFM (feature placement, drafting freedom)

Highly Complex and Cored Cast Part 3D Model

Rigging Design & Validation using Simulation

Scale up for solidification contraction allowance

Build Box Mold Design consisting of multiple parts or fractional molds (negative of

casting), nested cores, bottom base, mold dry joints/parting planes with spacer, prints for riser sleeves, chills and core vents, cradle for large cores for handling, etc

Slicing based on machine resolution

Transfer file to machine, typically in STL file format

Simulate to ensure accessibility for removing un-bonded sand, mold and core wash

Core Consolidation & Optimization – Lattice Structure

Manufacturability vs Pure Design Topology Optimization

Generative Designs for Lander Body for Space ExplorationAuto topology optimization occasionally

yields un-manufacturable design!

Casting Manufacturability based on experience

and rules should drive the design & optimization

and must be validated using virtual simulations

for any thin-wall casting development

Courtesy: AFS Casting Source /TEI

Core Consolidation

• Eliminate stack-up tolerances in-between cores

• Eliminate assembling time and cost

• Improved overall quality

• Redesign for lighter weights with thinner walls

Courtesy: Humtown/AFS

Core Consolidation Case study – Ductile Iron Manifold

• Casting weight: 22 lbs, Convectional design uses 4 cores assembly

• Core print Clearance of 0.040” (1 mm) per side

• FEA based design wall thickness 4mm and 9 mm

6 mm

+/- 2 mm11.5 mm +/- 2 mm

50.8 mm +/- 2 mm

Critical Dimensions with tolerances

3D Printed Single Core Design Yielded Better Dimensional Tolerances, Sounder Design and 10% Lighter Weight with Redesign

• Casting weight: 19 lbs, single core, zero core print clearance, no fins

6 mm

(5 mm)11.5 mm (10.5 mm)

50.8 mm (+/- 0.5 mm)

3DP will provide tighter wall thickness tolerance of +/- 0.5 mm

by eliminating stack up tolerances inherent with multi-piece core assembly

Fillet / Radii

Example of a Cast Iron Turbine Housing designed for 3DPS

• Representative of turbine (gas, steam, wind) housings, valves and pumps, volutes, impeller, chemical reaction chamber, split cases, compressors, etc representing Power Generation, Processing, Paper & Pulp, etc verticals.

• Conventional casting process typically requires multiple core assemblies, parting line gating, hard to reach hot spots, etc.

Grade: Ductile 65-45-12

Casting Weight: 2825 #

Overall Size: 70” x46” x24”

Example of a Cast Iron Turbine Housing designed for 3DPS

Rigging Flexibility with 3DPS

• Isolated hot spots can be fed with spot risers

• Bottom gating always possible for uniform filling with least turbulence

• Flexibility with feeding aids placement – chills, risers, filters, gates, in-gates, zircon facing cores

• No core split lines, flash, veins

• Isolated hot spots would need feed pad or would require to be a separate casting (cast fab)

• Bottom gating not always possible depending upon the parting plane location and tooling

• Rigging element placements constrained by the tooling design, parting, core print sizes etc

3DPS Conventional Sand Casting

Rigging Flexibility with 3DPS M/C

Conventional Parting Line Gating

Rigging Flexibility with 3DP / AM4MC

AM4MC Bottom GatingConventional parting line Gating

Scenario at 35% filled temperature profile

Cast Component: duplex fuel nozzle for aircraft jet engines and land based turbines

Material: 17-4 PH stainless steel

Overall size: 2.5” x 1.5” x 1.5”

Casting wt: 115 gram

Process: Printed shell investment casting.

• By combining multiple features and parts into a single, printed shell investment cast near net shaped

component with interconnected fuel passages was developed as a new product; and prototyped for the form, fit and functionality validation, before releasing the final design. There was 50% cost reduction and better

surface finish with the investment casting compared to metal additive method of DMLS.

Together with tooling free additive

manufacturing process of direct investment

shell further allows design engineers the

freedom of consolidating complex sub-

assemblies and features into one piece casting

configuration with no drafting and parting

plane restrictions.

3D printed direct shell investment casting offers agility and

allows the proof of concept design iterations and low volume

production in days as opposed to the traditional approach

with expensive and complex wax tooling and very cost

effectively compared to the metal additive manufacturing

processes such as DMLS – Direct Metal Laser Sintering.

• Courtesy: Aristocast/AFS

AM4MC vs Metal AM

Conventional Casting

• Split pattern with 2 degree radial draft on flanges, parting line gating, core box, core prints, core print clearances, parting line tolerances

3D Printed Toolingless Casting

• No pattern or 2 degree radial draft on flanges, bottom gating; no core box, core prints, core print clearances; no parting line tolerances

2 degree radial draft on flanges No draft on flanges

Wall Thickness of 15 mmWall Thickness of 12.4 mm

No Core or one piece core

Two piece paste core

Casting Dimensional Tolerances per ISO 8062

Conventional Sand Casting3DP Casting

Conventional sand Casting – CT11-14

Investment Casting – CT 4-6

Ductile Iron Sand Cast Valve Body

• Material: 60-45-12 Ductile Iron

• 1000 psi test pressure, working pressure of 500 psi

• Design minimum wall thickness of 12 mm

• FEA done for 1000 psi

• FOS min 1.75

Max von Mises stress of 17 ksi

Minimum Factor of Safety of 21000 psi pressure internal

3DP Configuration

Conventional Sand Casting Configuration

Thinner walls lead to higher

cooling rates, lead to better strength!

Design for Additive – One Piece Aluminum Casting for Racing – Twin Cylinder with Manifold and Water Jacket Cores

Part consolidation, higher value added features,

eliminated welded and bolted interfaces

Design Optimization and Lightweighting with 3D Printed Tooling Free AM4MC– Thin-wall Ductile Iron

Automotive Casting with 40% weight reduction

Casting Manufacturability experience, knowledge and CAE tools yielded in optimization !

Previous Design Redesigned Lighter Design

Novel Rigging & Process Design and Simulation Validation of Stainless Steel Impeller Casting for Process Industry

Tooling Less

In 7 Days

Solidification Simulation

Investment Cast E357 Aluminum Housing Development

Investment Cast Ni Base Super Alloy Valve Body

3D Printed Sand Casting for Obsolescence – Legacy part for an OEM

2D Drawing or Sample Part 3D Model of Casting Rigging Design, Simulation & Mold Box Design

3D Printed Sand Mold / Core Pouring into 3D Printed MoldFinished Sand Casting

Closing Remarks

• 3DP / AM4MC is a revolutionary new tooling free casting process – allows design engineers tremendous flexibility with feature placements, removes the tooling imposed constraints typical with most of the conventional processes, eliminates the need for assembling and handling multiple cores in highly cored components, allows optimum rigging such as bottom gating, remote riser and chill placements for better quality and soundness.

• 3DP allows higher complexity – thin to thick transitions, part consolidations, appendages and feature placements per design intent – form, fit and functionality; not constrained by tooling!

• 3DP should offer consistency and tighter dimensional tolerances (further research is being done in this area) as it eliminates the need for complex core assembling, higher resolution repeatable direct digital printed molds and cores vs. duplication off the tooling (cope and drag pattern, core boxes, which wear & tear over time).

• Casting Process Modeling and FEA are effective tools for Optimization.

Let us work together to get more tonnage converted from weldments, sheet metal and machined parts into metalcastings!

For additional information, please contact:

Jiten Shah

President

Product Development & Analysis (PDA) LLC

1776 Legacy Cir Suite #115

Naperville, IL 60563

630-505-8801

info@PDA-LLC.com

www.PDA-LLC.com

Visit us at virtual 3D expo Pavilion 2 Slot 3