Introduction to Advanced Manufacturing Technology

Lihong Qiao (乔立红)

School of Mechanical Engineering and Automation

Department of Industrial and Manufacturing Systems Engineering

Beihang University

Introduction to Advanced Manufacturing Technology

先进制造技术概论

Topic 4 Rapid Prototyping and

Manufacturing

Introduction to Advanced Manufacturing Technology L. Qiao IMSE

Outline

Introduction of Rapid Prototyping and Manufacturing

Principles of different kinds of RP&M

Applications of RP&M

Challenges of Additive Manufacturing

Specific Rapid Prototyping

Technologies



Rapid prototyping and manufacturing technologies are

new techniques to quickly produce one or more pieces of

solid part from CAD data using additive manufacturing

technology, irrespective of the complexity of the shape

It uses advanced computer and laser technologies et al. to

produce complex three-dimensional prototypes in a

fraction of the time required by traditional technologies

Terms in RP&M (Link)

RP&M terms.pdf


It has been researched and developed for almost 30 years, also

known as additive fabrication, additive processes, direct digital

manufacturing, rapid prototyping, rapid manufacturing, layer

manufacturing and solid freeform fabrication.

There are a large number of AM processes like Stereolithography

(SLA), Fused Deposition Modeling (FDM), Selective Laser Sintering

(SLS), Laminated Objective Manufacturing (LOM), Laser Metal

Deposition (LMD)…

Process of joining materials to make objects from three-dimensional

(3D) model data, usually layer upon layer, as opposed to subtractive

manufacturing methodologies

Additive manufacturing (AM)



Joining materials by layer upon layer

method

Build from 3D model data

One single step

Several parts in one build

Do not need designation and fabrication of

moulds

Differences between AM and traditional manufacturing

-differences and characteristics Introduction of Rapid Prototyping and Manufacturing


CAD

Modeling

File Format

Convert

Process

Parameters

Set

File

Transfer

Build Remove Post-

Processing Application

-Additive Manufacturing Processes General Structure of RP&M Process


General Structure of RP&M Process

The primary advantage to additive manufacturing is its

ability to create almost any shape or geometric feature. Slice+additive fabrication


STL file

solid CATIA STL

facet normal 0.000000e+000 0.000000e+000 1.000000e+000

outer loop

vertex -1.447732e+001 -1.447732e+001 2.000000e+001

vertex -3.869037e+000 -9.340682e+000 2.000000e+001

vertex -7.149049e+000 -7.149049e+000 2.000000e+001

endloop

endfacet

endsolid CATIA STL

STL: Surface Triangle List

●Standard format

● Use Triangle meshes to represent models

● Supported by CAD systems

● Applied mostly in rapid prototyping systems


The process of new product development

Concept design

Meet the need?

Technical design CAE

Creation of

physical modelTest

Mass Production

Yes

No

Rapid prototyping and

manufacturing


Common types of RP&M processes

Prototyping technologies Base materials

Stereo Lithography Apparatus (SLA)

立体光刻 Photopolymer 光聚合物

Selective laser sintering (SLS)

选择性激光烧结

Thermoplastics, metal powders

热塑性塑料，金属粉末

Fused deposition modeling (FDM)

熔融沉积成型

Thermoplastics, eutectic metals

热塑性塑料，共熔合金

Laminated object manufacturing (LOM)

分层实体制造 Paper

Electron beam melting (EBM)

电子光束溶解法

Titanium alloys

钛合金

3D printing (3DP)

3D打印 Various materials

Principles and Applications of Rapid

Prototyping


Stereo Lithography Apparatus (SLA) 立体光刻

Stereo lithography is an additive manufacturing process

using a vat of liquid UV-curable photopolymer “resin” and

an ultraviolet laser to build parts a layer at a time.


The sequence of steps for producing a stereo lithography

layer is shown in the following figures:

(a) (b)


(c) (d)

(e)


During fabrication, if extremities of the part become too weak,

it may be necessary to use supports to prop up the model.

The supports can be generated by the program that creates

the slices, and the supports are only used for fabrication. The

following three figures show why supports are necessary:


Stereo Lithography

SLA system

SLA Demo

The first working stereo lithography system,

invented by Chuck Hull. Photo circa 1986

Wheel Hub

Plastic Shells

链接文件-SLA.exe


Advantages and disadvantages

Efficient. A functional part can even be created within one day.

Prototypes made by SLA can be very beneficial as they are

strong enough to be machined and can be used as master

patterns for injection molding, thermoforming, blow molding,

and also in various metal casting processes.

Expensive.


Selective Laser Sintering (SLS)选择性激光烧结

Selective laser sintering is an additive manufacturing technique that uses a high power laser to fuse small particles of plastic, metal , ceramic, or glass powders to form a whole model of the 3D object.

The laser selectively fuses powdered material by scanning cross-sections generated from a 3-D digital model of the part (for example from a CAD file or scan data) on the surface of a powder bed. After each cross-section is scanned, the powder bed is lowered by one layer thickness, a new layer of material is applied on top, and the process is repeated until the part is completed.


Selective Laser Sintering

HRPS SLS System (China)

SLS Demo

Different materials

链接文件-SLS工艺.avi


Advantages

SLS can produce parts from a relatively wide range of

commercially available powder materials, including

polymers, metals and green sand.

In many cases large numbers of parts can be packed within

the powder bed simultaneously, allowing for very high

productivity.

SLS does not require support structures because the part

being constructed is surrounded by unsintered powder at all

times.


Fused Deposition Modeling (FDM) 熔融沉积成型

A plastic filament or metal wire is unwound from a coil and supplies material to

an extrusion nozzle which can turn on and off the flow. The nozzle is heated to

melt the material and can be moved in both horizontal and vertical directions

by a numerically controlled (NC) mechanism. And the mechanism is directly

controlled by a computer-aided manufacturing (CAM) software package. The

model or part is produced by extruding small beads of thermoplastic material

to form layers. The material becomes solid at once after its extrusion from the

nozzle.

1 - nozzle ejecting molten plastic, 2 - deposited

material (modeled part), 3 - controlled movable table


FDM

Cardiff University (UK)

QUANTUM FDM System

FDM center at Materialise HQ in Leuven FDM Demo

链接文件-FDM工艺.avi


Laminated Object Manufacturing (LOM) 层合实体制造

The paper is unwound from a feed roller (A) onto the stack and bonded to the

previous layer using a heated roller (B). The roller melts a plastic coating on

the bottom side of the paper to create the bond. The profile of the layer is

traced by an optical system that is mounted to an X-Y platform(C). The

process generates considerable smoke, so either a chimney or a charcoal

filtration system is required (E) and the build chamber must be sealed.


After cutting, the geometric features of a layer is completed, the remaining paper is cut away to separate the layer from the web. The extra paper of the web is winded on a take-up roller (D). The method is self-supporting for overhangs and undercuts. Areas of cross sections which are to be removed in the final object are heavily crossed. So the laser can be used to help removal. It can be time consuming to remove extra material for some geometries.


LOM

LOM System of Helisys Corp. (US)

LOM process

LOM Demo

链接文件-LOM工艺.avi


Advantages and disadvantages

The surface finish and accuracy of LOM are not so

good as with some other methods. However the

products have the look and feel of wood and can be

worked and finished in the same manner.


3D Printing

The method is quite similar to selective laser sintering, except that the

laser is replaced by an inkjet head. The multi-channel jetting head (A)

deposits a liquid adhesive compound onto the top layer of a powder

bed made of object material (B). The particles of the powder become

bonded in the areas where the adhesive is deposited.


Once a layer is completed the piston (C) moves down by the thickness of a layer. In the powder supply system(E), the piston moves upward incrementally to supply powder for the process and the roller (D) spreads and compresses the powder on the top of the build cylinder. The process is repeated until the entire object is completed within the powder bed.

After completion the object is elevated and the extra powder is brushed away leaving a "green" object. Parts must usually be infiltrated with a hardener before they can be handled to avoid the risk of damage.

3-D Printing Demo

链接文件-3DPrint工艺.avi

链接文件-3DPrint工艺(新).mp4




Comparison of 3D

Printing and Selective

Laser Sintering (SLS)

3D Printing

Selective Laser Sintering (SLS)

Progress in Additive Manufacturing


Material

Build

Method

Liquid

Filament/

Paste

Powder

Solid

sheet

-Additive Manufacturing Processes

(Williams, Mistree, and Rosen 2011) (Guo and Leu 2013) (Wong and Hernandez 2012)

Summary of Additive Manufacturing Process


Material

Build

Method

Material extrusion

Powder bed fusion

Vat photopolymerization

Material jetting

Binder jetting

Sheet lamination

Directed energy

deposition

Fused Deposition Modeling (FDM)

Paper Lamination Technology (PLT)

Selective Laser Sintering (SLS)

Electron Beam Melting (EBM)

Stereolithography (SLA)

Material Jetting (MJ)

Binder Jetting (BJ)

Ultrasonic Additive Manufacturing

(UAM)

Direct Metal Deposition (DMD)

-Additive Manufacturing Processes

American Society for Testing and Materials (ASTM)

Summary of Additive Manufacturing Process


An example of a real object replicated by means of 3D scanning and 3D printing: the model on the left was digitally acquired by using a 3D scanner and the produced 3D data was processed using MeshLab. The resulting digital 3D model is shown on the screen and can be used by a rapid prototyping machine to create a real resin replica of the original object.

Original object

Digital 3D model

Resin

replication

Example


Commodity Architecture

Transportation Medical Science

世界第一辆“3D打印”的汽车（新锋网）_标清.mp4


Advantages of 3D Printing

Enables the creation of prototypes that closely emulate the

mechanical properties of the target design.

Complete 3D models can be manufactured including those

with hollow parts that could not be made by hand in one

piece, even by the most skilled engineer or craftman. Parts

such as bearings, engineering parts and complex working

models can be manufactured.

Save time and cost by removing the need to design, It

prints and ‘glues together’ separate model parts made

from different materials in order to create a complete

model.


Applications of RP&M

Engineering Design Visualization

Verification and optimization

Marketing Product demonstration

Gain customers’ feedback for design modification

Manufacturing Fabricate products for actual use


Prototypes in the Product Design and Development Process

Cosmetic prototypes (Mock-ups)

To evaluate the appearance and feeling of the design, and get

early comments from potential clients

Apart from the fact that they are non-solid and non-functional,

cosmetic prototypes are the same as finished product in

aspects like shape, color, texture and hardness


Industry

Taking Advantage of Porosity

Processes such as selective laser sintering (SLS) and Three

Dimensional Printing (3DP) use intrinsic materials in a powdered state,

so they can produce parts which are naturally porous.

Fabricate products for actual use



Transportation


Architecture and Construction


Medical


Daily necessities


Lack of fundamental design guidelines or standardization of best

practices

The same digital input (3D model) rarely results in identical printed

objects across different processes and printing machines

Difficult to control product quality like surface roughness and

dimensional deviations

Challenges

Limited materials compared with traditional processes

Extra waste of time and cost due to the multiple trial-and-error

iterations.

Problem of AM

-challenges and problem

(Anderson 2012) (Pessard et al. 2008) (Doubrovski, Verlinden, and Geraedts 2011) (Benjamin Vayre,

Vignat, and Villeneuve 2012) (Gibson, Rosen, and Stucker 2010) (Gao et al. 2015)

Challenges Additive Manufacturing


New Development of Additive Manufacturing

μ-SLA(micro-stereo lithography ): Working principle is the

same as that of a normal SLA. The difference between

them is the resolution of the system. μ-SLA systems are

typically able to build very accurate (a few microns)

objects of several cubic centimeters.


Top-down SLA: Top-down setups have a non-adhering, transparent plate

acting as the bottom of the liquid reservoir. The photosensitive material get

polymerized when it receives irradiation from underneath, and the fabrication

platform moves in the opposite direction as in the bottom-up approach. Every

newly formed layer is located under the previous one.

The vat content can be minimized, the irradiated surface will not be exposed

to the atmosphere, so recoating the structure with a new resin layer is not

required, and the illuminated area is always smooth.

Scheme of bottom-up and top-down stereolithography setups


Two photon-polymerization(2PP): 2PP initiates the polymerization through

irradiation with near-infrared femtosecond laser pulses of 800 nm. In the focus

point, a suitable photoinitiator absorbs two photons, with a wavelength of 800

nm, simultaneously, causing them to act as one photon of 400 nm, and thus

starting the polymerization reaction. The nonlinear excitation nature triggers

polymerization only in the focus point, while other regions remain unaffected.

Moving the laser focus enables the fabrication of a direct ‘true’ 3D object into the

volume of the photosensitive material. It can create reproducible micron-sized

objects with feature sizes of less than 100 nm, thus enjoying the highest

accuracy and resolution among other techniques.

Working principle of two-

photon photopolymerization


3D-Bioplotter: In the 3D-Bioplotter system, the nozzle works pneumatically or

via volume-driven injection. This also illustrates the principle of nozzle-based

systems in general, where a nozzle is used for the deposition of material. Key

difference with other nozzle-based systems is the ability to plot into a liquid

medium with matching density, thus introducing buoyancy compensation.


Web-based RP&M: Web-based RP&M systems have been developed and

employed to implement remote service and manufacturing for rapid prototyping,

enhance the availability of RP&M facilities and improve the capability of rapid

product development for a large number of small and medium sized enterprises.

Architecture of the Web-

based RP&M system


Documents

Introduction to Advanced Manufacturing Technology