University JNTU Kakinada

Regulation R 16

Year IV Year

Semester I Semester

Teaching Classes 3+1

Credits 3

Name of the Faculty Singuru Rajesh

Unit II- Solid-Based Rapid Prototyping

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ADDITIVE MANUFACTURING

UNIT-2:Solid-Based Rapid Prototyping

SYLLABUS

Laminated Object Manufacturing (LOM): Models and Specification, process,working principle, application, advantages and dis advantages, case studies

Fused Deposition Modelling (FDM): Models and Specification, process,working principle, application, advantages and dis advantages, case studies

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Cubic Technologies’ Laminated Object Manufacturing

• LOM rapid prototyping systems, the LOM-1015Plus and LOM-2030H.

• The LOM-2030H is a larger machine and produces larger prototypes.

• The work volume of the LOM-2030H is 810 mm×550 mm×500 mm

• The LOM-1015Plus is 380 mm×250 mm×350 mm.

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Cubic Technologies was established in December 2000 by Michael Feygin, the inventor

who developed Laminated Object Manufacturing® (LOM).

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Models and Specifications

Laminated Object Manufacturing..Schematic

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Laminated Object Manufacturing

Materials for LOM

• It has been demonstrated that plastics, metals, and even ceramic tapescan be used.

• However, the most popular material has been Kraft paper with apolyethylene-based heat seal adhesive system because it is widelyavailable, cost-effective, and environmentally.

• In order to maintain uniform lamination across the entire working envelope it is critical that the temperature remain constant.

• A temperature control system, with closed-loop feedback, ensures the system’s temperature remains constant, regardless of its surrounding environment.

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Ceramic tapes

Kraft paper

Principles

The LOM process is based on the following principles:

(1) Parts are built, layer-by-layer, by laminating each layer of paper or other sheet-form materials and the contour of the part on that layer is cut by a CO2 laser.

(2) Each layer of the building process contains the cross-sections of one or many parts.The next layer is then laminated and built directly on top of the laser-cut layer.

(3) The Z-control is activated by an elevation platform, which lowers when each layeris completed, the next layer is then laminated and ready for cutting.

(4) No additional support structures are necessary as the “excess” material, which arecross-hatched for later removal, act as the support.

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Laminated Object ManufacturingAdvantages

(1) Wide variety of materials. In principle, any material in sheet form can be used inthe LOM systems. These include a wide variety of organic and inorganic materialssuch as paper, plastics, metals, composites and ceramics.

(2) Fast build time. The laser in the LOM process does not scan the entire surface areaof each cross-section, rather it only outlines its periphery. Therefore, parts with thicksections are produced just as quickly as those with thin sections.

(3) High precision. The feature to feature accuracy that can be achieved with LOMmachines is usually better than 0.127 mm (0.005").

(4) Support structure. There is no need for additional support structure as the part is supported by its own material that is outside the periphery of the part built.

(5) Post-curing. The LOM process does not need to convert expensive, and in some cases toxic, liquid polymers to solid plastics or plastic powders into sintered objects.

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Laminated Object ManufacturingDisadvantages

• Precise power adjustment. The power of the laser used for cutting the perimeter (andthe crosshatches) of the prototype needs to be precisely controlled so that the lasercuts only the current layer of lamination and not penetrate into the previously cutlayers.

• Fabrication of thin walls. The LOM process is not well suited for building partswith delicate thin walls, especially in the Z-direction.

• Integrity of prototypes. The part built by the LOM process is essentially heldtogether by the heat sealed adhesives.

• Removal of supports. The most labor-intensive part of the LOM process is its lastphase of post-processing when the part has to be separated from its support materialwithin the rectangular block of laminated material.

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Laminated Object ManufacturingApplications

• Visualization. Many companies utilize LOM’s ability to produce exact dimensions ofa potential product purely for visualization.

• Form, fit and function. LOM parts lend themselves well for design verification andperformance evaluation.

• Manufacturing. The LOM part’s composition is such that, based on the sealant orfinishing products used, it can be further tooled for use as a pattern or mold for mostsecondary tooling techniques including: investment casting, casting, sanding casting,injection molding, silicon rubber mold, vacuum forming and spray metal molding.

• Rapid tooling. Two part negative tooling is easily created with LOM systems. Since the material is solid and inexpensive, bulk complicated tools are cost effective to produce.

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Fused Deposition Modelling (FDM)

• Stratasys Inc. was founded in 1989 and has developed most of the company’s products based on the Fused Deposition Modelling (FDM) technology.

• The technology was first developed by Scott Cramp in 1988 and the patent was awarded in the U.S. in 1992.

• The company’s rapid prototyping systems can be broadly classified into two categories, the FDM series and the concept modeler..

• The FDM series include models like FDM 3000, FDM Maxum and FDM Titan.

• The concept modeler series includes models like Dimension and Prodigy Plus.

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Fused Deposition Modelling (FDM-Series)

FDM Series

• These are high-end systems not only able to produce 3D models for mechanical testing and also to produce functional prototypes that work as well as a production unit.

• MODELS: FDM 3000, FDM Maxum and FDM Titan

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FDM Titan

•An advantageous point for selecting Titan over Maxum is that

the former allows users to have a wider selection of materials (ABS,

Polycarbonate and Polyphenylsulfone), whereas the latter can only

build models using ABS.

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Components

of FDM

Fused Deposition Method-- Working

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FDM Series

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Fused Deposition Modelling (FDM Concept Modeler Series)

Concept Modeler Series

• Two concept modelers, the Dimension and the Prodigy Plus.

• Dimension uses a 3D printing technology that is based onFDM, which uses a heated head and pump assembly to depositmodel plastics onto the build layers.

• Dimension as a low cost concept modeler helps designers toevaluate products by a quick 3D print of models and eliminatesall products’ imperfections in the early design stages.

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Stratasys’ Dimension concept modeler

Fused Deposition Modelling (FDM Concept Modeler Series)

Concept Modeler Series

• Prodigy Plus replaces the Prodigy which was developed by

Stratasys to “fill the void” between the old Genisys Xs and an

older version of the FDM series, the FDM 2000.

• Systems were designed to be used in a networked office

environment and to build the 3D conceptual model from any

CAD workstation.

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Stratasys’ Prodigy concept modeler

FDM Concept Modeler Series

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Principle of FDM

• Principle of the FDM is based on surface chemistry, thermal energy, and layer

manufacturing technology.

• The material in filament (spool) form is melted in a specially designed head, which

extrudes on the model.

• As it is extruded, it is cooled and thus solidifies to form the model.

• The model is built layer by layer, like the other RP systems.

• Parameters which affect performance and functionalities of the system are material

column strength, material flexural modulus, material viscosity, positioning

accuracy, road widths, deposition speed, volumetric flow rate, tip diameter,

envelope temperature, and part geometry.

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Advantages of FDM

• Ease of support removal. With the use of Break Away Support System (BASS) and

Water Works Soluble Support System, support structures generated during the FDM

building process can be easily broken off or simply washed away. This makes it very

convenient for users to get to their prototypes very quickly and there is very little or

no post-processing necessary.

• Ease of material change. Build materials, supplied in spool form (or cartridge form

in the case of the Dimension or Prodigy Plus), are easy to handle and can be changed

readily when the materials in the system are running low. This keeps the operation of

the machine simple and the maintenance relatively easy.

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Advantages of FDM

• Fabrication of functional parts. FDM process is able to fabricate prototypes with

materials that are similar to that of the actual molded product. With ABS

(Acrylonitrile Butadiene Styrene), it is able to fabricate fully functional parts thathave 85% of the strength of the actual molded part. This is especially useful in

developing products that require quick prototypes for functional testing.

• Minimal wastage. The FDM process build parts directly by extruding semi-liquid

melt onto the model. Thus only those material needed to build the part and its support

are needed, and material wastages are kept to a minimum. There is also little need for

cleaning up the model after it has been built.

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Disadvantages of FDM

• Restricted accuracy. Parts built with the FDM process usually have restricted

accuracy due to the shape of the material used, i.e., the filament form. Typically, the

filament used has a diameter of 1.27 mm and this tends to set a limit on how

accurately the part can be built.

• Slow process. The building process is slow, as the whole cross-sectional area needs to

be filled with building materials. As the build material used are plastics and their

viscosities are relatively high, the build process cannot be easily speeded up.

• Unpredictable shrinkage. As the FDM process extrudes the build material from its

extrusion head and cools them rapidly on deposition, stresses induced by such rapid

cooling invariably are introduced into the model.

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Applications of FDM

FDM models can be used in the following general applications areas:

(1) Models for conceptualization and presentation. Models can be marked, sanded,

painted and drilled and thus can be finished to be almost like the actual product.

(2) Prototypes for design, analysis and functional testing. The system can produce a

fully functional prototype in ABS. The resulting ABS parts have 85% of the strength

of the actual molded part. Thus actual testing can be carried out, especially with

consumer products.

(3) Patterns and masters for tooling. Models can be used as patterns for investment

casting, sand casting and molding.

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Thank You

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SINGURU RAJESHM.Tech (MD), PGDEEM, B.Tech (ME)

Assistant ProfessorRaghu Engineering College(Autonomous)

Dakamarri, Bhimunipatnam Mandal, Visakapatnam Dist, Andhra Pradesh