rapid prototyping systems the term rapid prototyping (rp) refers to a class of technologies that can...

Rapid Prototyping Rapid Prototyping SystemsSystems

The term The term rapid prototypingrapid prototyping (RP) refers to a class of (RP) refers to a class of technologies that can automatically construct technologies that can automatically construct physical models from Computer-Aided Design physical models from Computer-Aided Design (CAD) data.(CAD) data.

These "three dimensional printers" allow designers These "three dimensional printers" allow designers to quickly create tangible prototypes of their to quickly create tangible prototypes of their designs, rather than just two-dimensional pictures.designs, rather than just two-dimensional pictures.

http://www.me.psu.edu/lamancusa/rapidpro/primer/chapter2.htm This material is based upon work supported by the National Science Foundation under Grant No. 0402616. Any opinions, findings and conclusions or recommendations expressed in this material are those of the author(s) and do not necessarily reflect the view of the National Science Foundation (NSF).

Rapid Prototyping SystemsRapid Prototyping Systems Of course, "rapid" is a relative term. Of course, "rapid" is a relative term.

Most prototypes require from three to seventy-two Most prototypes require from three to seventy-two hours to build, depending on the size and complexity of hours to build, depending on the size and complexity of the object.the object.

This may seem slow, but it is much faster than the This may seem slow, but it is much faster than the weeks or months required to make a prototype by weeks or months required to make a prototype by traditional means such as machining.traditional means such as machining.

These dramatic time savings allow manufacturers to These dramatic time savings allow manufacturers to

bring products to market faster and more cheaply.bring products to market faster and more cheaply.

http://www.me.psu.edu/lamancusa/rapidpro/primer/chapter2.htm

Rapid Prototyping SystemsRapid Prototyping Systems Such models have numerous uses:Such models have numerous uses:

Excellent visual aids for communicatingExcellent visual aids for communicating

Prototypes can be used for design testing.Prototypes can be used for design testing.

Used to make tooling Used to make tooling

Used to make production-quality parts Used to make production-quality parts


Rapid Prototyping SystemsRapid Prototyping SystemsAll RP techniques employ the same basic five-All RP techniques employ the same basic five-

step process.step process.

1.1. Create a CAD model of the design Create a CAD model of the design

2.2. Convert the CAD model to STL format (stereolithography)Convert the CAD model to STL format (stereolithography)

3.3. Slice the STL file into thin cross-sectional layers Slice the STL file into thin cross-sectional layers

4.4. Construct the model one layer atop anotherConstruct the model one layer atop another

5.5. Clean and finish the model Clean and finish the model http://www.me.psu.edu/lamancusa/rapidpro/primer/chapter2.htm

Rapid Prototyping SystemsRapid Prototyping Systems CAD Model Creation:CAD Model Creation:

First, the object to be built is modeled using a Computer-First, the object to be built is modeled using a Computer-Aided Design (CAD) software package. Aided Design (CAD) software package.

Solid modelers, such as Pro/ENGINEER, tend to Solid modelers, such as Pro/ENGINEER, tend to represent 3-D objects more accurately than wire-frame represent 3-D objects more accurately than wire-frame modelers such as AutoCAD, and will therefore yield modelers such as AutoCAD, and will therefore yield better results. better results.

This process is identical for all of the RP build This process is identical for all of the RP build

techniques.techniques.


Rapid Prototyping SystemsRapid Prototyping Systems Conversion to STL Format:Conversion to STL Format:

To establish consistency, the STL (stereolithography, the To establish consistency, the STL (stereolithography, the first RP technique) format has been adopted as the first RP technique) format has been adopted as the standard of the rapid prototyping industry. standard of the rapid prototyping industry.

The second step, therefore, is to convert the CAD file The second step, therefore, is to convert the CAD file into STL format. This format represents a three-into STL format. This format represents a three-dimensional surface as an assembly of planar trianglesdimensional surface as an assembly of planar triangles

STL files use planar elements, they cannot represent STL files use planar elements, they cannot represent curved surfaces exactly. Increasing the number of curved surfaces exactly. Increasing the number of triangles improves the approximation triangles improves the approximation


Rapid Prototyping SystemsRapid Prototyping Systems Slice the STL File:Slice the STL File:

In the third step, a pre-processing program prepares the In the third step, a pre-processing program prepares the STL file to be built. STL file to be built.

The pre-processing software slices the STL model into a The pre-processing software slices the STL model into a number of layers from 0.01 mm to 0.7 mm thick, number of layers from 0.01 mm to 0.7 mm thick, depending on the build technique. depending on the build technique.

The program may also generate an auxiliary structure to The program may also generate an auxiliary structure to support the model during the build. Supports are useful support the model during the build. Supports are useful for delicate features such as overhangs, internal cavities, for delicate features such as overhangs, internal cavities, and thin-walled sections. and thin-walled sections.


Rapid Prototyping SystemsRapid Prototyping Systems Layer by Layer Construction:Layer by Layer Construction:

The fourth step is the actual construction of the The fourth step is the actual construction of the part. part.

RP machines build one layer at a time from RP machines build one layer at a time from polymers, paper, or powdered metal. polymers, paper, or powdered metal.

Most machines are fairly autonomous, needing Most machines are fairly autonomous, needing little human intervention. little human intervention.


Rapid Prototyping Rapid Prototyping SystemsSystems Clean and Finish:Clean and Finish: The final step is post-processing. This involves removing The final step is post-processing. This involves removing

the prototype from the machine and detaching any the prototype from the machine and detaching any supports. supports.

Some photosensitive materials need to be fully cured Some photosensitive materials need to be fully cured before use before use

Prototypes may also require minor cleaning and surface Prototypes may also require minor cleaning and surface treatment. treatment.

Sanding, sealing, and/or painting the model will improve Sanding, sealing, and/or painting the model will improve its appearance and durability. its appearance and durability.


Rapid Prototyping SystemsRapid Prototyping Systems

Stereolithography Stereolithography

Patented in 1986, stereolithography started Patented in 1986, stereolithography started the rapid prototyping revolution. The the rapid prototyping revolution. The technique builds three-dimensional models technique builds three-dimensional models from liquid photosensitive polymers that from liquid photosensitive polymers that solidify when exposed to ultraviolet light. solidify when exposed to ultraviolet light.


PT CAM uses a stereolithography machine produced by 3-D Systems and shown here:

http://computer.howstuffworks.com/stereolith1.htm

The Stereolithography Machine

Picture of a statue using Picture of a statue using StereolithographyStereolithography

http://home.att.net/~castleisland/faq/faq250.htm

Laser CuttingLaser Cutting

Laser cutting is just one of a number of Laser cutting is just one of a number of processes used to cut metal into desired processes used to cut metal into desired shapes. Other typical cutting processes shapes. Other typical cutting processes include plasma cutting, flame or oxyfuel include plasma cutting, flame or oxyfuel cutting, water jet cutting, and even metal cutting, water jet cutting, and even metal stamping which competes on certain stamping which competes on certain levels levels

http://www.teskolaser.com/tips.html

Benefits of Laser CuttingBenefits of Laser Cutting There are many benefits to laser-cutting service There are many benefits to laser-cutting service

providers that directly translate to the process end-providers that directly translate to the process end-users. Some are:users. Some are: Improved parts production and reduced part distortion as Improved parts production and reduced part distortion as

a result of the small heat affected zones (HAZ)a result of the small heat affected zones (HAZ) Greatly reduced tool wear due to the non-contact cutting Greatly reduced tool wear due to the non-contact cutting

process. process. Increased saving due to more efficient utilization of Increased saving due to more efficient utilization of

materials materials Reduced inventory due to typical efficiency of production Reduced inventory due to typical efficiency of production

runs.runs. Improved part appearance since a laser's minimal Heat Improved part appearance since a laser's minimal Heat

Affected Zone eliminates distortion.Affected Zone eliminates distortion.

http://www.teskolaser.com/laser_cutting1.html

Examples of Laser Examples of Laser CuttingCutting

http://www.tysica.co.za/laserpics.html Pictures from:

Fused Deposition Fused Deposition ModelingModeling

(FDM) is a solid-based rapid prototyping method that (FDM) is a solid-based rapid prototyping method that extrudes material, layer-by-layer, to build a model. extrudes material, layer-by-layer, to build a model.

A thread of plastic is fed into an extrusion head, where it is A thread of plastic is fed into an extrusion head, where it is heated into a semi-liquid state and extruded through a very heated into a semi-liquid state and extruded through a very small hole onto the previous layer of material.small hole onto the previous layer of material.

Support material is also laid down in a similar manner.Support material is also laid down in a similar manner.

http://www.padtinc.com/rm/fdm/default.htm

Advantages of FDM Process Advantages of FDM Process

High strength High strength Cost-effective Cost-effective Waterproof Waterproof ABS material ABS material Multiple material colors Multiple material colors


Fused Deposition ModelingFused Deposition Modeling

FDM 2000 Specifications Prodigy Specifications

•Build Volume: 10" x 10" x 10" •Materials:ABS, Casting Wax •Build Step Size: 0.005" to 0.030"

Build Volume: 8" x 8" x 10" Build Volume: 8" x 8" x 10"

Materials: ABS, Casting Wax Materials: ABS, Casting Wax

Build Step Size: 0.007", 0.010", 0.013" Build Step Size: 0.007", 0.010", 0.013"

Up to 4x faster than the FDM 2000Up to 4x faster than the FDM 2000


Examples of Examples of Fused Deposition ModelingFused Deposition Modeling


Laminated Object Laminated Object ManufactureManufacture

As the name implies the process As the name implies the process laminates thin sheets of film (paper or laminates thin sheets of film (paper or plastic) plastic)

The laser has only to cut/scan the The laser has only to cut/scan the periphery of each layer periphery of each layer

http://www.foundryonline.com/laminate.htm


The process:The process: The build material (paper with a thermo-setting resin The build material (paper with a thermo-setting resin

glue on its under side) is stretched from a supply roller glue on its under side) is stretched from a supply roller across an anvil or platform to a take- up roller on the across an anvil or platform to a take- up roller on the other side. other side.

A heated roller passes over the paper bonding it to the A heated roller passes over the paper bonding it to the platform or previous layer. platform or previous layer.

A laser, focused to penetrate through one thickness of A laser, focused to penetrate through one thickness of paper cuts the profile of that layer. The excess paper paper cuts the profile of that layer. The excess paper around and inside the model is etched into small squares around and inside the model is etched into small squares to facilitate its removal. to facilitate its removal.



The process continued:The process continued: The process of gluing and cutting continuous layer The process of gluing and cutting continuous layer

by layer until the model is complete. by layer until the model is complete.

To reduce the build time, double or even triple To reduce the build time, double or even triple layers are cut at one time which increases the size layers are cut at one time which increases the size of the steps on curved surfaces and the post of the steps on curved surfaces and the post processing necessary to smooth those surfaces.processing necessary to smooth those surfaces.



Applications of LOM objects: Applications of LOM objects: LOM objects are durable, multilayered structures which LOM objects are durable, multilayered structures which

can be machined, sanded, polished, coated and painted. can be machined, sanded, polished, coated and painted.

Used as precise patterns for secondary tooling Used as precise patterns for secondary tooling processes such as rubber moulding, sand casting and processes such as rubber moulding, sand casting and direct investment casting. direct investment casting.

Used for limited testing. Used for limited testing.

Used as visual models.Used as visual models. http://www.foundryonline.com/laminate.htm


http://www.webarchive.org.uk/pan/10778/20050203/www.uclan.ac.uk/clt/calm/lom.htm

Examples of Laminated Examples of Laminated Object ManufactureObject Manufacture

Wind Turbine Wind Turbine In this case the LOM In this case the LOM

process was initially used process was initially used to check the CAD to check the CAD geometry: subsequently geometry: subsequently the model was used as a the model was used as a sand casting pattern. The sand casting pattern. The picture opposite shows 5 picture opposite shows 5 identical blades identical blades assembled around an SLA assembled around an SLA hub. hub.

http://www.imcuk.org/rapid/lom_example.html

Examples of Laminated Examples of Laminated Object ManufactureObject Manufacture

A LOM model was A LOM model was built for a customer built for a customer who required a who required a prototype to test the prototype to test the fit and operation of fit and operation of internal components internal components in an electrical in an electrical housing. housing.

http://www.imcuk.org/rapid/lom_example.html

Standards to be Covered:Standards to be Covered:

2.AA2.AA 10.I10.I

2.BB2.BB 10.J10.J

rapid prototyping systems the term rapid prototyping (rp) refers to a class of technologies that can...

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