IMTEX 2019

Additive Manufacturing:

An Overview

K.P. Karunakaran

IIT Bombay

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions

• Conclusions

Outline

2

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions

• Conclusions

Outline

3

PrinciplePrinciple 1: Divide and conquer

• “Divide and conquer” approach degenerates

complex 3D into several 2D which is easier.

• Vertical growth: Bother only today, not troubled

by the past and future!

4

This approach is responsible for

the stairstep error!

AM is an

automatic process

of manufacturing

objects (parts,

prototypes, tools

and even

assemblies)

directly from their

CAD models

without any

cutters, tools or

fixtures specific to

the object

geometry.

PrinciplePrinciple 2: Need for support mechanism

Scaffolding for a water tank

It is a necessary evil in 3DP like friction or …

Support removal is responsible for further

loss of finish as well as high cost (of raw

material and time)!

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions

• Conclusions

Outline

6

Nothing rotates in nature (except at the extremes of celestial and

atomic scales!)

3D Printing Takes Us Closer to the Nature!Characteristics of Nature: Rotation?

7

Is wheel really the greatest

invention of mankind? Could

have been something else? Our

imaginations are blocked by the

symmetry of wheel!

Mathematically simpler horizontal flat surface “z=0” is more

expensive to produce than a cylindrical surface which is

mathematically more complex “x2 + y2 – r2 = 0”

3D Printing Takes Us Closer to the Nature!Characteristics of Nature: Rotation? …

8

The

cheapest

machine is

lathe, then

shaper,

milling

machine

etc.

Nothing in nature is flat (2D) or symmetric;

all are 3D, organic and asymmetric.

3D Printing Takes Us Closer to the Nature!Characteristics of Nature: Flat? Symmetric?

9

Is writing – expressing the

sense of sound through

symbols, the simplest form of

sense of vision, another worst

invention of mankind? It has

been a major source of

human conflict!

Engineering

graphics –

Effort to

capture 3D on

2D!

• Nothing in nature is homogeneous – different densities and

material compositions at different places

3D Printing Takes Us Closer to the Nature!Characteristics of Nature: Homogeneity?

10

• Nature does not make individual parts and assemble

3D Printing Takes Us Closer to the Nature!Characteristics of Nature: Assembly?

11

• Nature’s manufacturing has no wastage!

3D Printing Takes Us Closer to the Nature!Characteristics of Nature: Assembly?

12

3D Printing Takes Us Closer to the Nature!Characteristics of Nature: Assembly?

13

All these characteristics are because,

Nature never does subtractive manufacturing!

Subtraction means destruction!!

Nature does always Additive Manufacturing!!!

Since 3D printing also uses Additive Manufacturing, it

takes us closer to the Nature. So, it can realize direct

assemblies, complicated ducts, gradient matrix etc.

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions

• Conclusions

Outline

14

Total automation is the foremost advantage of 3D printing.

Objects of any kind of geometric (direct assemblies, non-linear ducts,

custom, difficult, optimal light/lattice structures) or material (any variety

– poly/ metal/ ceramic, non-equilibrium, gradient – mono/ composite/

gradient, porous/lattice, soft/hard) complexity can be produced.

DFM (compromise) vs DFAM (design freedom makes it disruptive).

3D Printing – A Disruptive TechnologyState-of-the-arts

Ge

om

etr

ic (

bo

un

da

ry)

Ma

teria

l (in

teri

or)

15

3D Printing – A Disruptive TechnologyGeometric complexity: Direct assemblies

Thin walled turbine combustion

chamber, produced on EOSINT M 270,

material EOS Nickel Alloy IN 718.

Courtesy: Materialise Solutions, U.K.

Courtesy: EoS, Germany

Courtesy: Stratasys, USA

16

3D Printing – A Disruptive TechnologyGeometric complexity: Non-linear ducts (CCC)

3D Printing – A Disruptive TechnologyGeometric complexity: Customized solutions

Mass customization – redefined!18

3D Printing – A Disruptive TechnologyGeometric complexity: Optimized light/lattice structure

Shape or topology

optimization: Popular

FEA packages now-a-

days have module for

iterating the shape to

remove non-load

bearing matter!

Eg.: Altair’s Optistruct

19

3D Printing – A Disruptive TechnologyMaterial complexity: Gradient and/or non-equilibrium Matrix

Courtesy: Optomec, USACourtesy: Bajaj Auto, Pune Courtesy: ZCorp, USA

20

Total automation is the foremost advantage of 3D printing.

Objects of any kind of geometric (direct assemblies, non-linear ducts,

custom, difficult, optimal light/lattice structures) or material (any variety

– poly/ metal/ ceramic, non-equilibrium, gradient – mono/ composite/

gradient, porous/lattice, soft/hard) complexity can be produced.

DFM (compromise) vs DFAM (design freedom makes it disruptive).

3D Printing – A Disruptive TechnologyState-of-the-arts

Ge

om

etr

ic (

bo

un

da

ry)

Ma

teria

l (in

teri

or)

Anything that can be modelled, can be printed!

21

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions

• Conclusions

Outline

22

CAD model

AM part

(i) Poor surface finish

due to stair-step error

(ii) Irregularities created during

support removal

When surface finish is very poor,

tolerance cannot be better than that!

Issues to be addressedPoor geometric quality: surface finish & accuracy

- Each RP process has a limited

material composition, that too,

in narrow band of properties

FDM – Polymers

(thermoplastics)

SLA – Photo-polymer

SLS/3DP – Good variety from

polymer to metal but one

machine for each.

LOM – Paper

- Inherently anisotropic

- All RP materials are

proprietary and exorbitantly

priced (60-70%). Exorbitantly

priced equipment too in order

to recover IP fast.

- Due to open loop (absence

of human)

- Commercial reasons

- Limited shelf life

Issues to be addressedPoor matrix quality: Less options, anisotropy, shelf life

Issues to be addressedPoor matrix quality: Residual stresses

The aspect ratio in 3D printing is too high. So, layers tend to warp so

much that they hit the blade causing chip off.

The part may have warpage or even breakage,

Matl: Ti64; Size: 83 x 68 x 131; layer thk. = 0.040 (1700); Time: 60 hrs.

MCP Realizer

at LERMPS-

UTBM, Belfort

Stand in front of a CNC machine for 5 min (when it is working!) and

then in from of a AM machine for 5 min. You will find out which is fast!

That is why we do not call it RP any more!!

Issues to be addressedLow build rate

RP

Indirect Processes

AM has linearity of cost

(& time) with quantity.

Issues to be addressedLinearity of cost & time with production volume

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions: Hybridization & Integration of

Multiple Technologies in One Machine

• Conclusions

Outline

28

Emerging Solutions: HybridizationApproach: Add/ Subtract/ Zero

Nomenclature:

Processes - One can replace the other within the group.

Technologies - None can replace the other.

Processes Technologies

Approach: Add/ Subtract/ Zero

Joining: Arc/ Laser/ EB/ Binder

Layering strategies: Hor/ Conf

Kinematics: 3-ax/ 5-ax; Sl/ Par

Preheating

Stress relieving

Face milling

Inspection

Raw stock: Wire/ Strip/ Powder/ … …

Emerging Solutions: HybridizationCombining material addition & subtraction

Additive Stage:

Focus: interior or matrix.

Result: near-net shape.

Subtractive Stage:

Focus: exterior or surface

Result: finished component.

We proposed scan milling using

angle cutters which will permit

higher layer thicknesses without

loss of precision. Alternately 5-

axis motions also are possible.

[JMPT Vol. 105 (2000) – pp. 371-381].

Synergic integration: Competing

processes complement.

Hybrid approach is not new to 3DP community. Eg.:

Early ones:

• Laminated Object

Manufacturing (LOM)

• Solid Ground Curing (SGC)

• Shape Deposition

Manufacturing (SDM)

• ModelMaker II

• HM (KIST, Korea; IITB etc.)

Recent ones:

• Solidscape

• Lumex from Matsuura, Japan

• Sodick, Japan

Emerging Solutions: HybridizationCombining material addition & subtraction

Emerging Solutions: HybridizationEarly hybrid 3D printers: Laminated Object Mfg (LOM)

Emerging Solutions: Hybridization Early hybrid 3D printers: Solid Ground Curing (SGC)

Emerging Solutions: HybridizationRecent hybrid 3D printers: Solidscape; Model Maker-II

Emerging Solutions: HybridizationRecent hybrid 3D printers: Lumex from Matsuura, Jp

Emerging Solutions: Hybridization Recent hybrid 3D printers: Hybrid Layered Mfg. (HLM)

3-axis HLM

5-axis HLM

Multiple torches

MIG→TIG→Laser

3-Axis HLM 5-Axis HLM (Positional) 5-Axis HLM (Continuous)

Monolithic dies

Composite Dies with conformal cooling

Components without undercuts

Components with undercuts

Components with several 3-

axis features in different

orientations

Impeller

Blisks

Emerging Solutions: HybridizationRecent hybrid 3D printers: Capabilities of MIG-HLM

Emerging Solutions: Hybridization Elimination of support using 5-ax deposition in HLM

Emerging Solutions: Hybridization Joining: Arc/ Laser/ EB/ Binder

Nomenclature:

Processes - One can replace the other within the group.

Technologies - None can replace the other.

Processes Technologies

Approach: Add/ Subtract/ Zero

Joining: Arc/ Laser/ EB/ Binder

Layering strategies: Hor/ Conf

Kinematics: 3-ax/ 5-ax; Sl/ Par

Preheating

Stress relieving

Face milling

Inspection

Raw stock: Wire/ Strip/ Powder/ … …

Feedstock: Powder form is more popular. But we use wire because:

Emerging Solutions: Hybridization Different energy sources: Laser with wire

- Bias (we started from MIG)

- Wire has high yield

- Wire gives high integrity

- Single inventory for hybrid energy

sources of laser and MIG

Emerging Solutions: Hybridization Combining diff energy sources: HLM (Laser & MIG)

Desired

layer

3 fine layers of 0.5mm thick in 5-axis using laser.

These may be adaptive too.

3-axis filling

using MIG.

Emerging Solutions: Hybridization Combining diff energy sources: HLM (Laser & MIG)

• Combining two energy sources

• Combining slicing strategies – 3-/5-axis

– discrete adaptive slicing

Emerging Solutions: Hybridization Different energy sources: EB – Its unique advantages

• Higher energy efficiency: EB is

95% whereas laser is 20-25%

• Need of vacuum: No longer a

limitation; high integrity of the

parts

• Higher scanning speeds: 10,000

times faster than laser.

• Versatility for metals:

Conductive, reflective, refractive

materials

• Less capital and running cost

• Right time to start

Emerging Solutions: HybridizationCombining layering strategies and kinematics

Nomenclature:

Processes - One can replace the other within the group.

Technologies - None can replace the other.

Processes Technologies

Approach: Add/ Subtract/ Zero

Joining: Arc/ Laser/ EB/ Binder

Layering strategies: Hor/ Conf

Kinematics: 3-ax/ 5-ax; Sl/ Par

Preheating

Stress relieving

Face milling

Inspection

Raw stock: Wire/ Strip/ Powder/ … …

Planar layers (adaptive & edge types) Conformal layers

Emerging Solutions: HybridizationCombining layering strategies and kinematics

Emerging Solutions: HybridizationCombining layering strategies and kinematics

Emerging Solutions: HybridizationDiff. layering strategies, kinematics: Conformal

Desired

layer

3 fine layers of 0.5mm thick in 5-axis using laser.

These may be adaptive too.

3-axis filling

using MIG.

Emerging Solutions: HybridizationCombining diff energy sources: HLM (Laser & MIG)

• Combining two energy sources

• Combining slicing strategies – 3-/5-axis

– discrete adaptive slicing

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions: Stress Management

• Conclusions

Outline

49

Emerging Solutions: Stress managementStress management: Prevention & cure

Nomenclature:

Processes - One can replace the other within the group.

Technologies - None can replace the other.

Processes Technologies

Approach: Add/ Subtract/ Zero

Joining: Arc/ Laser/ EB/ Binder

Layering strategies: Hor/ Conf

Kinematics: 3-ax/ 5-ax; Sl/ Par

Face milling

Preheating

Stress relieving

Inspection

Raw stock: Wire/ Strip/ Powder/ … …

Emerging Solutions: Stress managementNature of warpage and residual stresses in 3D printing

Tool steel die

broke into two

pieces due to

inadequate

preheating

(> 450°C) and

stress relieving.

Emerging Solutions: Stress managementResidual stress management: Preheating & hammering

Emerging Solutions: Stress managementResidual stress management: Comparison with organisms

Who Type Cause Relieving Methods

Engineering

components

Tensile/

Compressive

Manufacturing

process/ Loading

during use

• Pressure (incl.

vibration)

• Heat

Organisms

including

humans

-do- Day-to-day

working

environment

-do-

(Exercises,

entertainments, trips,

smoking, drinking …)

Emerging Solutions: Stress managementResidual stress management: Comparison with organisms …

A 3kW induction portable heating heating system was fabricated. It

costed hardly Rs. 55,000 but is very effective.

Emerging Solutions: Stress managementResidual stress management: Induction preheating

Emerging Solutions: Stress managementResidual stress management: Pneumatic hammering

a. Preheating

b. Deposition-MIG

c. Deposition-TIG

d. Deposition-laser

e. Face milling

f. Inspection

g. Stress relieving

SSMA → MSMA

Emerging SolutionsIntegrated Multi-Station Multi-Axis HLM

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions: Indigenization and Innovations

• Conclusions

Outline

58

• Equipment is priced

ruthlessly high. Raw

material contributes about

60-70% of cost.

• Our approach:

1. Indigenization

(price/3)

2. + Innovation (price/10)

• Govt supports proposals

generously if Industry

contributes in cash.59

Emerging SolutionsIndigenization and Innovations

• Powder manufacture (metal, plastics & ceramics)

• Software for 3D printing

• Expertise in Generative Design & Lattice Design

60

Emerging SolutionsIndigenization and Innovations

• Principle of AM/3DP

• Claim 1: 3D Printing takes us closer to Nature!

• Claim 2: 3D Printing is a disruptive technology!

• Issues to be addressed

• Emerging Solutions

• Conclusions

Outline

61

• Additive Manufacturing takes us closer to the Nature.

• Its ability to realize certain unique geometric and matrix features

makes it disruptive.

• No process is omni-potent. So, Hybrid processes integrated with

multi-technologies with synergy is the need of the hour.

• Arc (MIG/TIG), laser and EB are useful as deposition/cladding

technologies, each varying in precision, speed and cost and hence

they have their own windows of applications.

• Indigenization and Indigenizations can help us cut down the price of

imported goods by 10. Sand, foam and ice are the materials.

• We are developing hybrid 3D printers for Sand, foam and ice. We

have initiated EB machine development too. All are funded in PPP.

Conclusions

62

Thank You!

63

K.P. Karunakaran, Mech., IIT Bombay

Tel.: 022-25767530/ 9869541570

karuna@iitb.ac.in