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Solid based rapid prototyping systems

The solid is utilized as the primary medium

to create prototyping Cubic Technologies Laminated object

Manufacturing (LOM)

Cubic technologies is exclusive manufactureof LOM rapid prototyping machine

Product : LOM 1015 PlusTM and LOM 2030HTM

Co2 Laser are used

Process consist of 3 phases:Pre-Processing, Building andPost-processing

Software Used : LOMSliceTM - which a provides menu driven

interface to perform transformations

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Phase

Pre-processingphase comprise several operations generation

of from CAD-derived STL file of the part to be generated. Sorting inputdata and creating secondary data structure.

Building: LomSlice software create a cross section of 3d model measuring exact

height of the model and slices the horizontal plane accordingly

The computer generate precise calculations, which guide thefocused laser beam to cut the cross-sectional outline, the cross-

hatches and models perimeter. The laser beam power is designed

to cut exactly the thickness of one layer of material at a time. After

perimeter is burned , everything within the models boundary is

freed from the remaining sheet.

The platform with the stack of previously formed layers descendedand new section of material advances. The platform ascends and

the heated roller laminates the material to the stack with single

reciprocal motion, thereby bonding it to the previous layer.

The vertical encoder measures the height of the stack and relays

the new height to LOMSlice, which calculate the cross section of

the next layer.

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Post-processing: Separating the part from its support

materials and finishing. The separating sequence as shown Fork lift or hammer are used to remove the part

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RPT-LOM - Specifications

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Separation of Object

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Basic Steps

Step 1. Each sheet is attached to the block, using heat and pressureto form a new layer. Sheet material is supplied from a continuous roll

on one side of the machine and taken up on the opposite side. Theheated roller provides the pressure and heat needed for lamination.

Step 2.After a layer (sheet) is deposited, a laser is traced along thecontours corresponding to the current cross section. Usually a 25 or50 watt laser is used. As in the other processes, this step starts withthe bottom cross section. Note that only the contours are scanned inthis process more efficient than the RP&M processes that require afull raster scan.

Step 3. Areas of the layer outside the contours are cross-hatched bythe laser (i.e., cut into small pieces called tiles, for removal afterfabrication).

Step 4. Steps 1-3 are repeated until the top layer of the part islaminated and cut.

Step 5. After all the layers have been laminated and cut. The resultsis a imbedded within a block of supporting material. This material isthen broken into chunks along the cross-hatching lines.

Step 6. The resulting part may then be coated with a sealant to keepout moisture.

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Laminated-Object Manufacturing

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Advantages

Wide variety of materials can be used

Fast build time

High precision

Support structure- no need additional

support structure as the part is supported byits own material that is out side the periphery

of the part built.

Postcuring: no need

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Disadvantages

Precise power adjustment is required

Fabrication of thin walls

Integrity of prototypes

Removal of supports

Applications: Visualization

Form fit and function

Manufacturing

Rapid tooling

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Applications of Rapid Prototyping

Prototype for design evaluation

Prototype for function verification

Rapid tooling processes

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Laminated Object Manufacturing (LOM)

1) Sheet of material is laminated onto existing stack-up2) Laser perforates the outline of cross section into top sheet

(cross section is NOT completely cut out- full sheet remains)

3) Edges of top sheet are trimmed to match rest of stack-up

4) Next layer is bonded and process repeats

5) When finished- have solid block with perforations separatingthe actual workpiece from extra material. Extra material

must be removed & part is sanded.

LOM modelers use paper w/ polyester adhesive. They pose no

health hazards and can be set up in offices. Further theyare comparatively inexpensive, and require no supports for

any overhangs. Unfortunately, LOM modelers also require

more post-processing work (removing part from block).

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LOM Process

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LOM Example

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Fused-Deposition Modeling

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Rapid Tooling Process

Direct tooling method

Single-reverse methods

Double reverse method

Triple reverse method

As the number of reversals increases, the durability

of a product can be improved but the product cost

increases and the precision decreases.

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Direct Tooling Method

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Single Reverse Tooling Process

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Double Reverse Tooling

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Triple Reverse Tooling

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Details of Lithography Process

Geometry input

STL format is the standard format for Rapid Prototyping

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STL format

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Advantages of STL

Easy to conversion

Wide range of input

Simple-slicing algorithm

Splitting STL models

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7/12/2013

Disadvantage of STL

Verbosity and data redundancy

Error due to approximation

Truncation error

Lack of information

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Support Structure

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Selective Laser Sintering

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7/12/2013

Basic Steps

Step 1. A part cylinder is located at the height necessary for a layerof powdered material to be deposited on the cylinder to the desired

thickness. The powdered material being used for the prototype isapplied from the feed cylinder by the leveling roller.

Step 2. The layer of powder is selectively raster-scanned andheated with a laser, causing particles to adhere to each other. Thelaser scan forms the powder into the required cross section shape.Note that this step starts with the bottom cross section.

Step 3. The part cylinder is lowered by the layer thickness to permita n, layer of powder to be deposited.

Step 4. The new layer is scanned, conforming it to the shape of thenext upper cross section and adhering it to the previous layer.

Step 5. Steps 3 and 4 are repeated until the topmost layer of the

part is generated Step 6. Post-curing may be required for some materials.

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3D Printing