FDM based Additive manufacturing

1. The Additive Manufacturing(AM)

2. Definition:
It is defined as the process of joining materials to make
objects from 3D model data, usually layer upon layer, as
opposed to subtractive manufacturing methodologies.

3. General principles:
1.Modeling
2.Printing
3.Finishing
1. Modeling:
models may be created with a Computer Aided Design
(CAD) package, via a 3D scanner, or by a plain digital
camera and photogrammetry software

4. 2.Printing
 Elimination of errors from STL file using “repair”
command
 The model is converted into series of thin layers
using “Slicer”

5. 3.Finishing
The model is printed slightly oversized than required
then metal is removed in order to obtain higher
precision

6. Some of the materials used in additive
manufacturing are
Plastics
 ABS - acrylonitile butadiene
styrene
 PLA - polylactic acid
 PVA - polyvinyl alcohol
 PC – polycarbonate
 SOFT PLA - polylactic acid
Metals
 Steel
 Stainless steel
 Titanium
 Gold
 Silver

7. Advantages of AM
 Faster, cheaper, more flexible, and easier
manufacturing and design processes
 Lower defect rate and higher quality consistency
 Less material waste in production steps
 Weight reduction
 No assembly required
 Waste reduction
 Eliminating of tooling

8. Disadvantages of AM
 Slow build rates
 High production costs
 Considerable effort in application design and setting
process parameters
 Requires post-processing
 Discontinuous production process
 Limited component size/small build volume
 Poor mechanical properties

9. Applications of AM
• Cloud-based additive manufacturing
• Mass customization
• Rapid manufacturing
• Rapid prototyping
• Research
• Food
• Medical applications
• Agile tooling

10. Types of AM
1)Material Extrusion (FDM)
2)Material Jetting (Objet, Solidscape, 3D systems)
3)Binder jetting (Z-corp, Voxeljet)
4)Sheet lamination (LOM, PLT)
5)Vat photo polymerization (SLA, DLP)
6)Powder bed fusion (SLS, SLM, EBM)
7)Direct Energy Deposition

11. Material Extrusion (FDM)
FDM was developed by Stratasys, Inc. of Eden
Prairie, MN, in the early 1990s
Process fabricates the parts by extruding molten
thermoplastic material through a small nozzle to form
a thin bead or road that is deposited in a
predetermined manner
The FDMs can be equipped to build with investment
casting wax, acrylonitrile butadiene styrene (ABS)
plastic, medical grade ABS thermoplastic, and/or
Elastomer
Currently ABS is used in most of the cases

12. Figure Shows a FBM 3000
(a photo of FBM 3000 by Stratasys)

13. Path generation
CAD file preparation:
 QS software is used to convert the STL file so that the
machine(FDM) can read it.
 The STL file is read into QS, and is displayed graphically on screen
in the Cartesian coordinate system (x, y, and z)
Slicing:
 thickness is decided based on the geometry of CAD model
 Slicing is a software operation that creates thin, horizontal
cross sections of the STL file

14.  plastic filament is heated to a malleable state and
extruded through a nozzle then deposited on the
surface.
 In order to create a part, a CAD model is sliced into
layers.

15.  The nozzle uses g-code to draw each layer, one at a
time, with the heated plastic, which then cools and
transitions back into a solid state.
 The nozzle follows a tool-path controlled by
a computer-aided manufacturing (CAM) software (G-
codes)

16. Advantages:
 Excellent surface finish
 High strength material properties
 Availability of transparent materials
 High build speed
 Low, predictable shrinkage factors for resins

17. Disadvantages:
Degradation from prolonged UV exposure
Post-Curing UV process required
Limited biocompatibility for prolonged contact