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3 d printing.pptx
1. BITS Pilani, Hyderabad Campus
What is 3 D printing/Additive Manufacturing ?
โข The construction of a three-dimensional object from a CAD
model or a digital 3D model.
โข It is method converting virtual 3D model into physical
model. Where 3D object is created by laydown successive
layers of materials
[2]
Types of 3D Printing method
๏ฑ Fused deposition method
๏ฑ Stereolithographic
๏ฑ Laminated Object Manufacturing.
๏ฑ Selective Laser Sintering (SLS).
๏ฑ Selective Laser Melting (SLM).
2. BITS Pilani, Hyderabad Campus
What is
FDM?
Fused Deposition Modeling (FDM), a layer-wise 3D
printing technology, has been developed by
Stratasysยฉ for fabricating complex geometrical parts .
The materials used are thermoplastic polymers and
come in a filament form.
Examples of thermoplastic used for FDM are PVA ,PLA
ABS ,NYLON/POLYAMIDE ,PP ,PE ,PEEKโฆ
FDM Process
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1 Filament spools
2 Main filament
3 Support filament
4 Extrusion head
5 Printed part
6 Support structure
7 Build platform
A Typical FDM Machine
4. BITS Pilani, Hyderabad Campus
Summary of a basic FDM process.
Step 1: Import of CAD data in .stl
(STereoLithography) format into
Slicing Software
Step 2: Slicing of the CAD model into
horizontal layers
Step 3: Generation of .gcode file.
Step 4: FDM fabrication process using
a filament modeling material to build
actual physical part in an additive
manner layer-by-layer
Step 1 Import of
CAD data in .stl
format
Import Slicing Software and set
printing parameter
Generation of
.gcode file.
Layer by layer
printing of
finial part
Outline of a FDM production
6. BITS Pilani, Hyderabad Campus
Outline of a FDM production
Polymer Filament
Polymer extrudate
7. BITS Pilani, Hyderabad Campus
Part Orientation Raster width Raster Angle
The orientation of the
part is defined as how the
part should be positioned
when produced
Raster width or road width which refers
to the width of the deposition path related
to tip size. It also refers to the tool path
width of the raster pattern used to fill
interior regions of the part curves .
Raster angle or orientation
which is measured from the X-
axis on the bottom part layer.
Also, it refers to the direction of
the beads of material (roads)
relative to the loading of the part.
The deposited roads can be built
at different angles to fill the
interior part.
Processing Parameters
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The layer thickness which is recognized
as the height of the deposited slice from
the FDM nozzle
The air gap parameter which is defined as the space
between the beads of deposited FDM material
Processing Parameters
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Processing Parameters
Rectangular - Standard infill pattern for FDM prints. Has
strength in all directions and is reasonably fast to print.
Requires the printer to do the least amount of bridging
across the infill pattern.
Triangular or diagonal - Used when strength is needed in
the direction of the walls. Triangles take a little longer to
print.
Wiggle - Allows the model to be soft, to twist, or to
compress. Can be a good choice particularly with a soft
rubbery material or softer nylon.
Honeycomb - Popular infill. It is quick to print and is very
strong, providing strength in all directions.
Infill geometry
For a standard print, infill is simply printed as an angled hatch or a
honeycomb shape. The four most common infill shapes are:
Infill percentage
FDM prints are typically printed with a
low-density infill. Most FDM slicer
programs will by default print parts with a
18%-20% infill which is perfectly adequate
for the majority of 3D printing applications.
This also allows for faster and more
affordable prints.
Infill percentage ranging from 20% (left), 50% (center) and 75% (right)
10. BITS Pilani, Hyderabad Campus
Factors effecting the final properties
of the printed parts
Processing Parameters
โข Layer thickness
โข Raster angle and width
โข Infill Percentage and pattern
โข Number of contours
Machine Properties
โข Nozzle Diameter and temperature
โข Print bed and chamber temperature
โข Printing speed
Material properties
โข Type of polymer
โข Melting point
โข Viscosity at printing temperature
Final properties of the
printed parts printed parts
โข Mechanical
โข Thermal
โข Electrical properties
11. BITS Pilani, Hyderabad Campus
A B
Type Of Extrusion system used
A. Direct extrusion system
Direct extruders, as the name implies, are
directly attached to the hot end and are a
part of the print head.
B. Indirect Extruder or Bowden extrusion system
The difference between Direct and Bowden extruders is the
location of the extruder in relation to the hot end.
The opposite of Direct extruders, Bowden
extruders are not attached to the hot end or print
head. Instead, the extruder is removed from the
print head and is most often attached to the printer
body. The filament is then fed to the hot end using
a Bowden tube
12. BITS Pilani, Hyderabad Campus
Benefits, Limitations & Application of 3D printing
Benefits Limitations
Geometric complexity at no extra cost Lower strength & anisotropic material properties
Very low start-up costs Less cost-competitive at higher volumes
Customization of each and every part Limited accuracy & tolerances
Low-cost prototyping with very quick turnaround Post-processing & support removal
Large range of (specialty) materials
Application
Biomedical
Aerospace, Automobile
Tooling
Electrical and Electronic
Energy Storage
13. BITS Pilani, Hyderabad Campus
3D printing(FDM) offers great geometric flexibility and can produce custom parts
and prototypes quickly and at a low cost, but when large volumes, tight tolerances
or demanding material properties are required traditional manufacturing
technologies are often a better option.
To Summarize
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Printers in our workshop
Flashforge Inventor 2 Raise 3D N2Plus
15. BITS Pilani, Hyderabad Campus
Printers in our workshop
Manufacturer RAISE3D
Layer Thickness (microns) 10 โ 300
Printing Technology Fused Filament Fabrication
Volume Build Volume W x D x H (mm) 305 x 305 x 610
Resurrection System Resume Printing Function after power interruption
Advertised Manufacturer Speed (mm/s) 10-150 mm/s
Advertised Manufacturer Material
PLA / PLA+ / ABS / PC / PETG / R-flex / TPU / HIPS / Bronze-filled /
Wood-filled
Nozzle Temperature up to 300ยฐC / 572ยฐF
Heated Bed up to 110ยฐC / 230ยฐF
Connectivity WIFI, SD Card, USB, Ethernet
Enclose Machine Yes
Dual Extrusion Yes
Nozzle Diameter (mm) 0.4
Propriatery filament No
Filament Diameter (mm) 1.75
Printer Software IdeaMaker
Workstation Compatibility Windows, Mac OS
File Input Format STL / OBJ
Printer Volume W x D x H (mm) 616 x 590 x 960
Weight Volume (kg) 50
Material parameters: Polymer type its chemical ,thermal and mechanical priorities
Build Orientation: It refers to the inclination of the part in a build platform with respect to X, Y, Z axis. X and Y-axis are considered parallel to build platform and Z-axis is along the direction of part build.
Raster angle: Direction of the raster relative to the X-axis of build table.
Layer thickness: It refers to the thickness of the deposited layer.
Nozzle diameter: It depends upon the type of nozzle used. Commercial printers mostly use 0.4 mm nozzle diameter.
Raster width: Width of raster pattern used to fill interior regions of the part.
Number of contours: The number of contours of the part outside
Raster to raster gap (air gap): It is the gap between two adjacent rasters in a same layer. Negative air gap refers to the overlap of rasters. Positive air gap allows space between rasters. Printing with zero air gap is highly recommended.
Infill density: The amount of material that is used to build the part inside. For example; the inner layers of the part can be printed in hexagonal or rectangular pattern.
Since Direct extruders are located above the hot end with little space between them, a Direct extruder keeps the distance that filament must travel from the extruder to the hot end to a minimum. This leads to the main advantages of this style of extrusion.
1.Better Extrusion and Retraction
Since there is less distance for the filament to travel, extruding and retracting the filament becomes much easier. Essentially, the filament is more responsive to the extruder. This means that there is less stringing and oozing that occurs because of worse retraction and leads to a higher quality print.
2. Smaller Motors
In addition, the closeness of the extruder to the hot end means that less torque is required from the stepper motor than in a Bowden extruder. Because of this, the stepping motor does not need to be as large or as powerful as in a Bowden setup. However, a large motor can provide more power with a Direct extruder, which can be beneficial.
3.Wider Range of Filaments
Direct extruders are also able to effectively print a wider range of filaments, most notably, Composite filiment. While flexible filaments can work with Bowden extruders, Direct extruders can print them more effectively. This is because a Direct extrusion system is more constrained.
Disadvantages
However, the location of the Direct extruder also leads to its main disadvantages. The weight of the extruder on the print head can lead to several problems. Since the print head is constantly moving, additional weight to move around could lead to backlash, banding, overshoot, or frame wobble. Additionally, the size of the extruder can be disadvantageous for some 3D printers, as it makes up a majority of the print head.
Advantages of Bowden extruders
Lighter, Faster, and More Accurate
Like the Direct extruder, many of the advantages and disadvantages come from the location of the extruder in relation to the print head. The largest advantage is the reduced weight of the print head. Since the extruder is removed from the print head, there is less weight on the print carriage. Also, because the print head is lighter, a printer using a Bowden extruder can print faster, more accurately, and more precisely. This can result in either higher quality prints or quicker prints, as the print head can move at higher speeds. Additionally, Bowden extruders are more compact and take up less space than Direct extruders.
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Disadvantages
While Bowden extruders can increase print speed and reduce the print head weight, there are several disadvantages that make them less appealing than Direct extruders. For one, they cannot use as many filaments as effectively as Direct extruders. While they can print flexible filaments, these filaments tend to bind in the Bowden tubing. Additionally, Bowden extruders cannot use abrasive filaments because these filaments will wear away the inside of the Bowden tubing.
BENEFITS
Geometric complexity at no extra cost
3D printing allows easy fabrication of complex shapes, many of which cannot be produced by any other manufacturing method. The additive nature of the technology means that geometric complexity does not come at a higher price. Parts with complex or organic geometry optimized for performance cost just as much to 3D print as simpler parts designed for traditional manufacturing (sometimes even cheaper since less material is used)
Very low start-up costs
In formative manufacturing (Injection Molding and Metal Casting) each part requires a unique mold. These custom tools come at a high price. To recoup these costs identical parts in the thousands are manufactured. Since 3D printing does not need any specialized tooling, there are essentially no start-up costs. The cost of a 3D printed part depends only on the amount of material used, the time it took the machine to print it and the post-processing - if any - required to achieve the desired finish
Customization of each and every part
With traditional manufacturing, it is simply cheaper to make and sell identical products to the consumer. 3D printing though allows for easy customization. Since start-up costs are so low, one only needs to change the digital 3D model to create a custom part. The result? Each and every item can be customized to meet a userโs specific needs without impacting the manufacturing costs.
LIMITATIONS
Low-cost prototyping with very quick turnarounds
One of the main uses of 3D printing today is prototyping - both for form and function. This is done at a fraction of the cost of other processes and at speeds, that no other manufacturing technology can compete with: Parts printed on a desktop 3D printer are usually ready overnight and orders placed to a professional service with large industrial machines are ready for delivery in 2-5 days. The speed of prototyping greatly accelerates the design cycle (design, test, improve, re-design)
Large range of (specialty) materials
The most common 3D printing materials used today are plastics. Metal 3D printing finds also an increasing number of industrial applications. The 3D printing pallet also includes specialty materials with properties tailored for specific applications. 3D printed parts today can have high heat resistance, high strength or stiffness and even be biocompatible. Composites are also common in 3D printing. The materials can be filled with metal, ceramic, wood or carbon particles, or reinforced with carbon fibers. This results in parts with unique properties suitable for specific applications.
Lower strength & anisotropic material properties
3D printed parts have physical properties that are not as good as the bulk material: since they are built layer-by-layer, they are weaker and more brittle in one direction by approximately 10% to 50%. Because of this, plastic 3D printed parts are most often used for non-critical functional applications.
Less cost-competitive at higher volumes
3D printing cannot compete with traditional manufacturing processes when it comes to large production runs. The lack of a custom tool or mold means that start-up costs are low, so prototypes and a small number of identical parts (up to ten) can be manufactured economically. It also means though that the unit price decreases only slightly at higher quantities, so economies of scale cannot kick in. In most cases, this turning point is at around 100 units, depending on the material, 3D printing process and part design. After that, other technologies, like CNC machining and Injection Molding, are more cost effective.
Limited accuracy & tolerances
The accuracy of 3D printed parts depends on the process and the calibration of the machine. Typically, parts printed on a desktop FDM 3D printer have the lowest accuracy and will print with tolerances of ยฑ 0.5 mm. This means that if you design a hole with diameter of 10 mm, its true diameter after printing will something between 9.5 mm to 10.5 mm.
Post-processing & support removal
Printed parts are rarely ready to use off the printer. These usually require one or more post-processing steps. For example, support removal is needed in most 3D printing processes. 3D printers cannot add material on thin air, so supports are structures that are printed with the part to add material under an overhang or to anchor the printed part on the build platform. When removed and they often leave marks or blemishes on the surface of the part they came in contact with. These areas need additional operations (sanding, smoothing, painting) to achieve a high quallity surface finish.