Solid Ground Curing, FDM, LOM process & it applications

Solid Ground Curing, FDM, LOM process & it applications

1. Unit Unit --33
Solid Based Rapid Prototyping Solid Based Rapid Prototyping
Systems Systems Systems Systems
Laminated Object
Manufacturing (LOM)

2. Introduction
•Solid-based rapid prototyping systems are very
different from the liquid-based photo-curing
systems
•They are also different from one another, though
some of them do use the laser in the prototyping some of them do use the laser in the prototyping
process.
•The basic common feature among these systems
is that they all utilize solids (in one form or
another) as the primary medium to create the
prototype.

3. Classification-of-AM

4. LOM-Introduction
Solid physical model made by stacking layers of
sheet stock, each an outline of the cross-sectional
shape of a CAD model that is sliced into layers
•Starting sheet stock includes paper, plastic,
cellulose, metals, or fiber-reinforced materialscellulose, metals, or fiber-reinforced materials
•The sheet is usually supplied with adhesive
backing as rolls that are spooled between two
reels
•After cutting, excess material in the layer remains
in place to support the part during building

5. CUBIC TECHNOLOGIES’ LAMINATED
OBJECT MANUFACTURING (LOM)
Company
•Cubic Technologies was established in December 2000 by Michael
Feygin, the inventor who developed Laminated Object
Manufacturing.
•In 1985, Feyginset up the original company, HelisysInc., to market
the LOM rapid prototyping machines.the LOM rapid prototyping machines.
•However, sales figures did not meet up to expectations and the
company ran into financial difficulties.
•HelisysInc. subsequently ceased operation in November2000.
•Currently, Cubic Technologies, the successor to HelisysInc., is the
exclusive manufacturer of the LOM rapid prototyping machine.
•Cubic Technologies offers two models of LOMTM rapid
prototyping systems, the LOM-1015PlusTM and LOM-2030HTM
(see Figure).

7. LOM

9. Sheet based AM: Classification

10. Classification: Approach

11. Mechanism employed to achieve the
bonding between the layers.
•Gluing and adhesive bonding
•Thermal bonding processes
•Clamping
•Ultrasonic welding
Gluing or adhesive bonding
•The most popular lamination build material
has been paper with a thermoplastic coating
on one side. This type of adhesive -backed
paper is similar to the “butcher paper” used
to wrap meat.
•Paper thicknesses often range from 0.07 to
0.2mm.
•Paper thicknesses often range from 0.07 to
0.2mm.
•In one category, there are processes in which
the laminate is bonded firstto the substrate
and is then formed into the cross-sectional
shape (‘bond-then-form’ processes).
•In another category, there are processes in
which the laminate is formed firstand then
bonded to the substrate (‘form-then-bond’
processes).

12. Gluing or Adhesive Bonding
Bond : Bond-then-Form Processes
•In ‘bond-then-form’ processes, the building process typically consists of three
steps in the following sequence: placing the laminate, bonding it to the substrate,
and cutting it according to the slice contour.
•The original LOM machines used this process with adhesive-backed rolls of
material, where a heated roller melted the plastic coating, causing it to adhere to
the previous layer.
•A heated roller passes across the sheet after placing it for each layer, melting the
adhesive and producing a bond between layers.
A laser (or in some cases a mechanical cutting knife) designed to cut to a depth of •A laser (or in some cases a mechanical cutting knife) designed to cut to a depth of
one layer thickness cuts the cross-sectional outline based on the slice
information.
•The unused material is left in place as support material and is diced using a
crosshatch pattern into small rectangular pieces called “tiles” or “cubes.”
•This process of bonding and cutting is repeated until the complete part is built.
•After part construction, the part block is taken out and post-processed. The
crosshatched pieces of excess material are separated from the part using typical
wood carving tools (called decubing).
•It is relatively difficult to remove the part from the part block when it is cold,
therefore, it is often put into an oven for some time before decubingor the part
block is processed immediately after part buildup.

13. Cubic Technologies' LOM
Cubic : Paper --Bond then form –laser –Adhesive --Entire
Kira’sPaper Lamination Technology: Paper --Bond then form –Kinfe–Adhesive --Entire

14. Kira’sPaper Lamination Technology:
Paper --Bond then form –Kinfe–Adhesive --
Entire

15. Solidimensions’sPlastic Sheet Lamination
Solidimensions’sPlastic Sheet Lamination:
Plastic --Bond then form –Kinfe–Adhesive
–Selective

16. CAM-LEM (Computer-Aided Manufacturing of
Laminated Engineering Materials)
Dis-advantages
•Shrinkage
•Precise alignment
•Lack of support
CAM-LEM : Ceramic --form then bond –Laser–
sintering–entire
Advantages : Internal channels are possible
•No precise depth of cutting required as it is form and bond
approach
•No unwanted glue material
•Variable material and layer thickness is possible

17. Thermal Bonding
•This is primarily due to the fact that bond-then-
form processes require extensive post-processing
to remove support materials, and formthen-bond
processes are difficult to automate for arbitrary,
complex geometries.
•Thus, upward-facing features where each cross •Thus, upward-facing features where each cross
section’s geometry is contiguously interconnected
are the easiest to handle.
•Commercial interest in sheet lamination is primarily
in the area of inexpensive, full-color paper parts
and large tooling, where internal, conformal cooling
channels can provide significant benefits over
traditional cooling strategies.

18. Processes based on Sheet Metal
Clamping

19. Ultrasonic Consolidation (UC)
Ultrasonic Consolidation(UC) is a hybrid additive/subtractive manufacturing method based
on the ultrasonic metal welding of a sequence of metal foils with in-situ material removal
process through a three axis CNC contour milling.

20. Ultrasonic Consolidation
Fabrication procedure for a
honeycomb structure using UC
UC Process Parameters and Process Optimization
The important controllable process parameters
of UC are:
a)Oscillation amplitude,
b)Normal force,
c)Travel speed, and
d)temperature.

21. CUBIC TECHNOLOGIES Process
•The patented Laminated Object Manufacturing
(LOM) process is an automated fabrication
method in which a 3D object is constructed from
a solid CAD representation by sequentially
laminating the part cross-sections.laminating the part cross-sections.
The process consists of three phases:
•pre-processing;
•building;
•post-processing.

22. Pre-processing
•The pre-processing phase comprises several operations.
•The initial steps include generating an image from a CAD
derived STL file of the part to be manufactured, sorting
input data, and creating secondary data structures.
•These are fully automated by LOM Slice TM, the LOMTM
system software, which calculates and controls the slicing system software, which calculates and controls the slicing
functions.
•Orienting and merging the part on the LOMTM system are
done manually.
•These tasks are aided by LOM SliceTM, which provides a
menu-driven interface to perform transformations (e.g.,
translation, scaling, and mirroring) as well as merges.

23. Building
•In the building phase, thin layers of adhesive-coated material are
sequentially bonded to each other and individually cut by a CO2 laser
beam (see Figure ).
The build cycle has the following steps:
•LOMSliceTMcreates a cross-section of the 3D model measuring the
exact height of the model and slices the horizontal plane accordingly.
•The software then images crosshatches which define the outer
perimeter and convert these excess materials into a support structure.
•The computer generates precise calculations, which guide the
focused laser beam to cut the cross-sectional outline, the cross-
hatches, and the model’s perimeter.
•The laser beam power is designed to cut exactly the thickness of one
layer of material at a time.
•After the perimeter is burned, everything within the model’s boundary
is “freed” from the remaining sheet.

24. Post-processing
•The last phase, post-processing, includes
separating the part from its support material and
finishing it. The separation sequence is as follows
figure.

25. Materials
•Potentially, any sheet material with adhesive backing can
be utilized in Laminated Object Manufacturing.
•It has been demonstrated that plastics, metals, and even
ceramic tapes can be used.
•However, the most popular material has been Kraft paper
with a polyethylene-based heat seal adhesive system
because it is widely available, cost-effective, and because it is widely available, cost-effective, and
environmentally benign.
•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.

26. Principle
•The LOM process is based on the following principles:
•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.
•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.laminated and built directly on top of the laser-cut layer.
•The Z-control is activated by an elevation platform, which
lowers when each layer is completed, and the next layer is
then laminated and ready for cutting. The Z-height is then
measured for the exact height so that the corresponding
cross sectional data can be calculated for that layer.
•No additional support structures are necessary as the
“excess” material, which are cross-hatched for later
removal, act as the support.

27. Examples

28. Advantages
•Ability to produce larger-scaled models
•Uses very inexpensive paper
•Fast and accurate
•Good handling strength•Good handling strength
•Environmentally friendly
•Not health threatening

29. Disadvantages
•Need for decubing, which requires a lot of
labor
•Can be a fire hazard
•finish, accuracy and stability of paper objects •finish, accuracy and stability of paper objects
not as good as materials used with other RP
methods

30. Typical Uses
•Investment casting patterns
•Concept verification
•Masters for silicone-rubber injection tools
•Fit-check•Fit-check
•Functional model at low stress (Direct use)
applications

31. Important Questions
•Explain merits and demerits of Laminated
Object Manufacturing. Describe the principle
of FDM with its advantages, disadvantages
and applications
•Explain with the help of simple line diagram
explain the construction details of extrusion
head in FDM process.
•Describe Fused deposition modeling process
with a neat sketch.