introduction to Am

• To reduce lead-time in Product Development

• To Produce Parts with Complex geometry

• Freedom for Designer

• Development of New Materials and Process

NEED FOR ADDITIVE MANUFACTURING

“A drawing is worth of 1000 Words

A Prototype is worth of 1000 Drawings ”

Manufacturing Sequence

TOO LONG TIME FOR PRODUCT DEVELOPMENT

Additive Manufacturing

INTRODUCTION

The ASTM has defined ‘Additive Manufacturing' AM) as a (ASTM

International, 2012): "process of joining materials to make objects

from 3D model data, usually layer upon layer, as opposed to

subtractive manufacturing methodologies, such as traditional

machining.”

Fig 1. Bee-hive-An Analogy for AM

Additive Manufacturing (AM) - Principle

3D CAD Data-

(STL File)

Slicing

Building of part on RP M/c

Physical part

Fig 3. Principle of Additive Manufacturing

Four major aspects of Additive Manufacturing

Fig .The Rapid prototyping wheel depicting the four major aspects of AM(Source: Rapid Prototyping,Chua C.K, Leong K.E and Lim C.S)

Source : Wohlers Associates ,Inc

Time compression engineering

Fig . Time-Compression Engineering(Source: Rapid Manufacturing, D. T. Pham and S.S. Dimov)

History of Additive Manufacturing

Fig . A method for making moulds for topographical relief maps [Blanther,1892](Source: Rapid Manufacturing, D. T. Pham and S.S. Dimov)

The roots of AM can be traced to two technical areas:

1. Topography

2. Photo sculpture.

• A layered method was

proposed by Blanther (1892)

for making moulds for

topographical relief maps.

• Both positive and negative 3D

surfaces were to be

assembled from a series of

wax plates cut along the

topographical contour lines.

TOPOGRAPHY:

(Source: Rapid Manufacturing, D. T. Pham and S.S. Dimov)


Fig 6. The layer manufacturing system proposed by Munz [1956]

Photo sculpture

• This is a technique [Bogart, 1979]

proposed in the 19th century for

creating replicas of 3D objects.

• The technique involves

photographing the object

simultaneously with 24 cameras

equally spaced around a circular

room and then using the silhouette of

each photograph to carve 1/24th of a

cylindrical portion of the object.

Development work in the area of AM continued in the 1960s and 1970s and a

number of patents have been filed on different methods and systems. These

include:

• A method for fabricating objects from powdered materials by heating particles

locally and fusing them together employing a laser, electron beam, or plasma

beam [Ciraud, 1972].

• A process for producing plastic patterns by selective 3D polymerisation of a

photosensitive polymer at the intersection of two laser beams [Swainson,

1977].

• A photopolymer RP system for building objects in layers [Kodama, 1981]. A

mask is used to control the exposure of the UV source when producing a

cross section of the model.

• A system that directs a UV laser beam to a polymer layer by means of a

mirror system on an x-y plotter [Herbert, 1982].


Advantages of Additive Manufacturing

The benefits of RP systems can be categorized into direct and indirect benefits.

Direct benefits:

The ability to experiment with physical objects of any

complexity in are relatively short period of time.

(Source: Rapid Prototyping,Chua C.K, Leong K.E and Lim C.S)

Project time and product complexity in 25 years’ time frame



Fig . Results of the integration of RP technologies


The benefits of RP systems can be categorized into direct and indirect benefits.

Direct benefits:

The ability to experiment with physical objects of any

complexity in are relatively short period of time.


Project time and product complexity in 25 years’ time frame

Benefits to Product Designers

• The product designers can increase part complexity with little significant effects on lead time and cost.

• They can reduce parts count by combining features in single-piece parts that are previously made from several because of poor tool accessibility or the need to minimize machining and waste.

• With fewer parts, time spent on tolerance analysis, selecting fasteners, detailing screw holes and assembly drawings is greatly reduced.

• There will also be fewer constraints in the form of parts design without regard to draft angles, parting lines or other such constraints.

• Parts which cannot easily be set up for machining, or have accurate, large thin walls, or do not use stock shapes to minimize machining and waste can now be designed.

• They can minimize material and optimize strength/weight ratios without regard to the cost of machining.

• They can minimize time-consuming discussions and evaluations of manufacturing possibilities.

FREEDOM FOR DESIGNER

Design For Manufacture

Not Possible by

conventional processes

They can minimize material and optimize strength/weight ratios without

regard to the cost of machining.


Fig: Load Bearing Hydraulic Manifold


They can reduce parts count by combining features in single-piece parts that

are previously made from several because of poor tool accessibility or the need

to minimize machining and waste.

Benefits to the Tooling and

Manufacturing Engineer

• The manufacturing engineer can minimize design, manufacturing and verification of tooling.

• He can also reduce parts count and, therefore, assembly, purchasing and inventory expenses.

• The manufacturer can reduce the labor content of manufacturing, since part-specific setting up and programming are eliminated, machining/casting labor is reduced, and inspection and assembly are also consequently reduced as well.

• Reducing material waste, waste disposal costs, material transportation costs, inventory cost for raw stock and finished parts (making only as many as required, therefore, reducing storage requirements) can contribute to low overheads.

• the manufacturer can simplify purchasing since unit price is almost independent of quantity, therefore, only as many as are needed for the short-term need be ordered.

• One can purchase one general purpose machine rather than many special purpose machines and therefore, reduce capital equipment and maintenance expenses,

need fewer specialized operators and less training.• Furthermore, one can reduce the inspection reject rate

since the number of tight tolerances required when parts must mate can be reduced.

• One can avoid design misinterpretations (instead, “what you design is what you get”), quickly change design dimensions to deal with tighter tolerances and achieve higher part repeatability, since tool wear is eliminated.

• one can reduce spare parts inventories (produce spare on demand, even for obsolete products).

Benefits to the Tooling and

Manufacturing Engineer

Benefits to the Tooling and Manufacturing Engineer

Plastic part

Core & Cavity

Build-time : 5 Hours

The manufacturing engineer can minimize design, manufacturing and verification of

tooling.

Indirect Benefits

Benefits to Marketing

It can greatly reduce time-to-market, resulting in

• Reduced risk as there is no need to project customer needs and

market dynamics several years into the future.

• Products which fit customer needs much more closely.

• Products offering the price/performance of the latest technology

• New products being test-marketed economically.

• Marketing can also change production capacity according to market

demand, possibly in real time and with little impact on

manufacturing.

• One can increase the diversity of product offerings and pursue

market niches currently too small to justify due to tooling cost

(including custom and semi-custom production).

• One can easily expand distribution and

quickly enter foreign markets.

Benefits to the Consumer

•The consumer can buy products which meet more closely individual

needs and wants.

•Much wider diversity of offerings to choose from.

•Consumer can buy products at lower prices, since the manufacturers’

savings

will ultimately be passed on.

Indirect Benefits

Part complexity & cost

-Conventional/CNC

Conventional milling M/c

CNC milling M/c

1. CNC milling M/c

2. EDM etc.,

Part Complexity


-AM Technology

Complexity of part

Aerospace

• Turbine blades made by DMLS from EOS (a Germanmanufacturer of laser sintering/melting systems) havefound their way onto test rigs.

• It is believed that a variety of metal parts made byadditive manufacturing will initially make their way ontoflying aircraft in 2-3 years and will become common in 10years.

• The opportunity is not only for flight hardware, but alsofor jet-powered boats, land-based power generators, andother applications of gas turbine engines.

Reference: David L. Bourell, Ming C. Leu, David W. Rosen, Roadmap for Additive Manufacturing Identifying the Future

of Freeform Processing, The University of Texas at Austin, Laboratory for Freeform Fabrication, 2009.

Biomedical

• Many universities and research institutes are exploring ways in which AM can be applied to medical implant design and manufacturing, tissue engineering, and regenerative medicine.

• Two companies in Italy have used AM to manufacturemore than 10,000 metal hip implants, thousands ofwhich have been implanted into human beings.(Theaverage life span is increasing-Japan)

• Meanwhile, Walter Reed Army Medical Center hasproduced 37 cranial (Skull) implants using electronbeam melting, an AM process from Arcam of Sweden.



Dentistry

• The market for the production of dental products using

AM is on the verge of explosive growth.

• Dental labs are using DMLS from EOS and other direct

metal AM processes for the production of copings for

crowns and bridges.

• EOS has reported that the dental business is currently its

fastest growing area of AM for production applications.



Automotive

• High-end cars of small production are

candidates for using AM.

• Bentley and Rover have shown that it is

feasible and have used AM for small,

complex parts.

• Motorsports industry –Helmet, car parts



Defence

• Many products for Defence are:– high value, complex, low volumes.

• Some are customised such as– Unmanned aerial vehicles (UAVs),

– Light-weight gear and armor for soldiers,

– Portable power units,

– Communication devices,

– Ground-based robots,

– Production of spare parts in remote locations,

– Mobile parts hospitals, and legacy parts for aircrafts.

• With AM improvements that are expected in 10-12 years, the militarywill likely become a major user of additive manufacturing.



Electronics

• AM can produce 3D printed circuit boards that wrap

around the contours of the product.

• Complex geometric features with multiple intake and

exhaust passages in a compact space for electrical

power generators can be fabricated using AM

• The potential to use various materials is also attractive

because some parts of these reactors/generators should

be made of low conductivity materials (e.g., plastics)

whereas other parts require high conductivity and/or

catalytic properties (e.g., metals).



Jewelry

• In the future, jewelers will use AM to manufacture custom andlimited edition products.

• Lionel Dean of Future Factories is currently manufacturingimpressive pendants in titanium alloys.

• Lena Thorsson, formerly of Particular AB, showed that it is possibleto laser sinter gold alloys to produce beautiful chains andnecklaces that normally require complex and expensive machinery.



Food

• Specialty food is said to be a $13 billion industry.

• With AM systems such as the open source Fab@Home machinefrom Cornell University, it is possible to make chocolates and cakeicing that include 3D figures, company logos, names, and otherobjects.

• It is also possible to consider the use of AM system to manufacturefood products in cheese, peanut butter etc that can be extrudedthrough a syringe.



Education

• In 10-12 years, it is anticipated that schools will offer courses andprograms that include instruction on how to design for themanufacture of parts using AM.

• Innovative organizations will develop methods of product design thattake advantage of AM processes and materials.



• Material

• Speed

• Complexity

• Accuracy

• Geometry

• Programming

Distinction Between AM and CNC Machining

Following are range of topics where comparisons between CNC machining and

AM can be made.

Distinction Between AM and CNC Machining

Material

AM CNC Machining

AM technology was

originally developed around

polymeric materials, waxes

and paper laminates.

Subsequently, there has

been introduction of

composites, metals,

and ceramics.

CNC machining to make

final products, it works

particularly well for hard,

relatively brittle materials

like steels and other metal

alloys to produce high

accuracy parts with well

defined properties.

AM parts may have voids or

anisotropy that are a

function of part orientation,

process parameters or how

the design was input to the

machine.

CNC parts will normally be

more homogeneous and

predictable in quality.

SPEED

AM CNC Machining

Shorter Lead time:

Irrespective of part complexity,

manufactured in single stage

Longer Lead time:

Multistage manufacturing process,

requiring repositioning or relocation of

parts within one machine or use of

more than one machine.

Setup and process planning time

remains same irrespective of part

complexity

Setup and process planning time,

increases particularly as parts become

more complex in their geometry.

Multiple parts are often batched

together inside a single AM build

which reduces setup lead time.

M/c and part set up is to be done

repetitively for each and every

component.

COMPLEXITY

AM CNC

Irrespective of part complexity, parts are

produced in single setup and in the AM

machine

M/c Setup and No of machines to produce

a component depends on part complexity.

AM processes are not constrained in

the same way and undercuts and

internal features can be easily built

without specific process planning.

Since a machining tool must be

carried in a spindle, there may be

certain accessibility constraints or

clashes preventing the tool from being

located on the machining surface of a

part.

Possible to build parts in single setup Certain parts cannot be fabricated by

CNC unless they are broken up into

components and reassembled at a

later stage.

Ex: a ship inside a bottle.

ACCURACY

AM CNC

Diameter of the laser beam would

determine the minimum wall thickness.

Wall thickness can be thinner

than the tool diameter since it is a

subtractive process.

The vertical build axis corresponds to

layer thickness and this

would be of a lower resolution

compared with the two axes in the

build plane

The accuracy of CNC machines is

mainly determined by positioning

resolution along all three orthogonal

axes and by the diameter of the rotary

cutting tools.

Geometry

AM CNC

The vertical build axis corresponds to

layer thickness would be of a lower

resolution compared with the two axes

in the build plane.

The accuracy of CNC machines is

mainly determined by positioning

resolution along all three orthogonal

axes and by the diameter of the rotary

cutting tools.

Diameter of the laser beam would

determine the minimum wall thickness.

Wall thickness can be thinner

than the tool diameter since it is a

subtractive process.

Programming

AM CNC

AM machines have options that must

be selected, but the range, complexity

and implications surrounding their

choice are minimal in comparison.

Program sequence for a CNC

machine is more which includes tool

selection, machine speed settings,

approach position, and angle, etc.

The worst that is likely to happen in

most AM machines is that the part will

not be built very well if the

programming is not done properly.

Incorrect programming of a

CNC machine could result in severe

damage to the machine and may even

be a safety risk.

Preliminary Summarized Comparison

Area of Comparison AM technology CNC

Materials Limited Nearly Unlimited

Maximum part size Varies Large enough to handle aerospace

parts

Part Complexity Unlimited Limited

Feature detail Varies Varies

Accuracy 0.125mm to 0.75mm 0.0125mm to 0.125mm

Repeatability Moderate High

Surface Finish 2.5 to 15 microns 0.5 to 5 microns

Reliability Moderate Moderate to high

Staffing Minimal Significant

Skilled Labor Minimal Moderate to high

Lead time Short to moderate Moderate

http://www.moldmakingtechnology.com/articles/is-cnc-machining-really-better-than-rp

41


-Conventional/CNC

Conventional milling M/c

CNC milling M/c

1. CNC milling M/c

2. EDM etc.,

Part Complexity


-AM Technology

Complexity of part

AM V/S Conventional machining -

Time

RPT V/S Conventional machining - Cost

Mass Customization• Hearing aids, dental crowns and implants, medical prostheses, and the

high-end interior design and fashion industries are the areas where

there is a huge demand for unique products, but these niche areas were

not pursued owing to

– the lower volumes

– high degree of customization requirements

• Increased automation in CAD software now is being extended to

encompass other industries, including consumer product industries.

Gilmar Ferreira Batalha et. al. & Laser-Sintering for Hearing Aids, Dental Restorations, EOS

Individually customized mass-produced hearing aid shells

46

AM – Max. size of part,

Accuracy

Sl.No. RP

Process

Maximum

size of part

(mm)

Dimensional

Accuracy (mm)

1 SLA 508 X 508 X 600 0.1

2 FDM 600 X 500 X 600 0.127

3 LOM 813 X 559 X 508 0.127

4 SLS 381 X 330 X 4570.1

5 DMLS 250 X 250 X 150 0.05

introduction to Am

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