1.

List out the advantages of 3d printing process

2.What is 3D printing? State the history of 3d printing
systems and its fundamental developmen
3.List out the classification of 3d
printing systems.
4.Classification of 3D printing
technologies:
5.Explain the Generic of 3d printing
Process
6.State about STL File Format in brief.
7. Discuss on slicing relevant to CAD for 3d printing.
8.Define and explain fused deposition modeling(FDM)
9.Explain the fundamental principle of stereo lithography process.
10.How does stereolithography work?
11.How does SLS 3D printing work?
12.Discuss the use of metallic materials in 3D printing
13.Discuss the use of Liquid Based Materials in 3D printing
14.Discuss the use of Powder-Based materials in 3D printing
15.How do you design for FDM printing?
16.State the design of Support structures and part orientation for Material Jetting
17.How do you integrate Multi-material in: Material Jetting process.
18.Discuss Support structures and part orientation of Material Jetting
19. Explain Support structures for FDM printing
20.State the options for SLA post processing
21.State the most common defects found in the FDM process and their causes.
22.State the most common defects found in the SLA process and their causes
23.Define 3d printing. Explain the roles of3d printing in prototype development
process.
24.State the application of 3d printing.
25. Explain the limitations of 3d printing
26. Define and Explain 3D printing.
27. State the Characteristics of Additive Manufacturing/ 3d printing,
28. Explain Additive Manufacturing and Product Development.
29. Differentiate between additive manufacturing (AM) and CNC machining.
30. Describe in detail the basic steps involved in 3D printing.
31. Explain the various demands on CAD system used in 3D printing
32. Describe the advantages and disadvantages of the STL file format.
33. Explain slicing for 3d printing.
34. Describe the advantages and disadvantages of the STL file format.
35. What is the process for creating STL files from a CAD system?
36. Describe the STL file problems.
37. Define Tessellation
38. Explain the data format in 3d printing.
39. Discuss the different interface tolerance in cad.
40. Explain slicing for 3d printing
41. State the most common defects found in the FDM process and their causes Most
common defects found in the FDM process:
42. State the most common defects found in the SLA process and their causes..
43.Additive Manufacturing and Product Development:
44.State the Characteristics of Additive Manufacturing/ 3d printing,
45. Define and Explain 3D printing?
46. Describe in detail the basic steps involved in 3D printing.
47. Explain the various demands on CAD system used in 3D printing.
48. Describe the advantages and disadvantages of the STL file format.
49. The STL formulation, however, possesses practical
advantages:
50. Describe the STL file problems.
51.What is the process for creating STL files from a CAD system?
52.Explain slicing for 3d printing
53.Define Tessellation
54.Explain the data format in 3d printing.
55. Discuss the different interface tolerance in cad.
56. Explain Post-Processing requirement for 3D printing. b)
How do you Create STL Files from a CAD System. c) Classify 3D
printing technologies.
57. State 3D printing applications in different domain (mention
at least five)
58.What materials are used for SLS printing? State their
characteristics.
59.What are the options for SLS post-processing? C) Discuss
Common applications of SLS.
60.Discuss Shrinkage & Warping, and Over-sintering for SLS
printers b) How do you remove powder of SLS process. c) What
are the characteristics of SLS 3D printing?
61. State the advantages and disadvantages of SLA 3D printing b) How does SLS 3D
printing work?: c) Can you use SLS 3D printing for rapid prototyping?
62. Explain Bridging in FDM b) Discuss different Types of support used in FDM
printer. c) FDM 3D printing best practices
63. Discuss the material properties of the most popular FDM 3D printing plastics –
PLA and ABS - to find the best option for your application b) Discuss
Thermosetting Polymers. c) Explain Powder-Based Materials used in AM process
64. a.Discuss the different types of materials currently being used in 3D printers.
b.Discuss in brief Liquid Based Materials that are currently being used in 3D
printers c) Discuss Common Binder Jetting Materials.
65.Why polymer materials are used for 3D printing system. b)
Discuss most popular type of Thermoplastic polymers
materials that are used for 3D printing. c) State the
advantages and disadvantages of different thermoplastic
polymers used in 3D printing.
66. a) Compare SLM & DMLS. b) How does metal 3D printing work? c) Discuss
Benefits & Limitations of Metal 3D Printing. d) State the main characteristics of
SLM and DMLS systems.
67.A.Compare Bottom-up (Desktop) and Top-down (Industrial) SLA printer b)
State the main characteristics of SLA 3D printing c)What are the options for
SLA post-processing? d) Mention some best practices of SLA 5+4+2+4
68.a) Discuss about the FDM printer parameters. B)characteristics of FDM c)
Explain Infill and shell thickness. c) What are the advantages and disadvantages of
FDM 3D printing
67. a. Compare Bottom-up (Desktop) and Top-down (Industrial) SLA printer
Desktop 3D Printing
Desktop 3D or consumer SLA printing targets hobbyists and small-time manufacturers with small 3D
printers. The build size is small and the printer is not very expensive. It lets the consumers or hobbyists
experiment with their CAD designs and print prototypes with good detailing.
Features
 Price: The printer’s price may start with already 300€. Compared to its counterparts like FDM and
MJF, which are also mainly used for prototyping, SLA is expensive but offers good detailing.
 Build volume: Consumer 3D printers are designed to produce small parts and small batches.
Hence, they are called mini versions of their industrial counterparts. The size of print on average is
medium and at 145 X 145 x 175 mm.
 Materials: Even though the printer is small, its material space extends to resins that are used in
making clear, tough, dental, flexible parts also. The most common materials for desktop 3D
printing are PC like, ABS like, EPU resins. Many cheap materials are available in the market even
for a price of about 15€ per 500 ml.
 Resolution: The usual resolution of a desktop 3D printer is excellent for the price and the layer
thickness is about 25-200 microns. It falters a lot with repeatability.
 Weight: The weight of a desktop SLA printer weighs less than 10 kg making it very portable.
Applications
Generally, desktop SLA 3D printers are neither powerful nor efficient enough to be used for rapid
prototyping in industrial applications. Yet, they are able to produce parts that can be used as dental
implants, flexible parts, castable and also tough parts. The resolution of desktop SLA is low compared to
industrial and hence requires post-processing and for a complex design, the complete time taken to finish
the part can be several hours.
Limitations in terms of build size and time mean that consumer 3D printers are best used in homes.

Limitations
 Less build volume: The build volume of desktop 3D printers rarely exceeds 150 x 150 x 150
mm. This limits the printer’s applications to small-scale objects.
 Low repeatability: Desktop 3D printers usually print at high definition and are almost similar to
industrial printers but they cannot achieve the same definition on repeated use.
 Less selection of materials: Consumer 3D printers can use only a handful of resin materials for
printing.
 Slow printing speed: Slow printing speed and frequent printing errors are major challenges to
the widespread adoption of 3D printing.
 Low accuracy: Although accuracy is gradually improving with each generation of desktop SLA
3D printers, it remains low when compared with professional 3D printers. This limits the
complexity of objects that can be printed.
Industrial 3D Printing
Industrial 3D printing (also called “professional 3D printing”) is the industrial-grade counterpart to
consumer 3D printing. Industrial SLA machines stand out in terms of build size and the accuracy with
which they print parts.
Features
 Price: Professional SLA 3D printers are used for many industrial grade and medical grade parts.
They must also be capable of printing large assemblies efficiently and with the best precision and
hence are expensive. The build material is expensive too which makes any project with industrial
3D printing at least 10 times costlier than consumer printing.
 Build Volume: Build volume is a significant consideration in professional 3D printers as it
determines the largest part that can be built at once. Large assemblies can be built easily with
 industrial printers. The build size is very large and varies from 2100 x 800 x 700 mm depending
on the printer.
 Materials: Industrial SLA printers can print with more materials than desktop SLA. Most
manufacturers have their own specially engineered portfolio of proprietary materials. The wide
range of available materials means end-users can select the material that fits their printing
requirements.
 Resolution: Resolution usually refers to the minimum thickness of the build layer. It is a key
requirement for professional applications. Professional printers can print at resolutions as low as
50-100 microns. High-end production-grade printers can even print layers just 25 microns thick.
Applications
Industrial SLA is the prime choice for applications where precision and smoothest surface finish are the
top priority. The big build size also allows for big machine components to be manufactured. Some of the
common industrial SLA applications include:
General Applications
 CAD verification models for aesthetics and proof-of-concept models
 Models for wind tunnel analysis
 Functional prototypes for form and fit testing
 Transparent parts
 Complex assemblies
 A large batch of parts
 Mass customization

Tooling and Patterns

 Injection moulding tools, moulds and dies
 Investment casting patterns
 Assembly jigs and fixtures (customised)
 Vacuum casting master patterns
Medicine and Biocompatible Materials
 Surgical tools/guides
 Dental appliances
 Hearing aids
 Food grade products
Limitations
Expensive Printing
Expensiveness in printing arises due to the high machine cost, plus the expensive build material. There
are other processes like SLS which are almost on the same price level and also offer different materials.

Major Differences Between Desktop and Industrial SLA

The main advantage of industrial printers is their precision and tolerances. A good industrial printer can
print the same part repeatedly and achieve the same result every time. This is the main reason why the
companies pay huge amounts for professional SLA printers, as they want the equipment to be consistent
and dependable.
Desktop printers may offer high resolutions but are inconsistent. One cannot expect it to print with
similar characteristics as it printed the first few parts.

b. State the main characteristics of SLA 3D printing

Main characteristics/advantages
High level of detail and accuracy: SLA printers are capable of producing intricate and highly detailed
prints, capturing even the finest features and textures.
 Smooth and finely finished surfaces: SLA prints exhibit a smooth surface finish with minimal
visible layer lines, making them ideal for applications requiring a high-quality, professional
appearance.
 Wide range of material options: SLA printing offers a variety of resin materials to choose
from, ranging from standard and flexible resins to specialized options like clear, tough, and
castable resins. This allows for versatility in terms of object properties and applications.
 Ability to create complex geometries and intricate designs: SLA printers can produce
complex and intricate designs that may be challenging or impossible with other 3D printing
methods. The layer-by-layer curing process allows for precise control and the creation of
intricate internal structures.
 Supports for small and intricate parts: SLA printing is particularly well-suited for small and
delicate parts, where precision and fine details are crucial. The ability to print thin walls and
intricate features makes it an excellent choice for jewelry, miniatures, and other precision
applications.
 Efficient use of materials: SLA printing typically results in less wasted material compared to
other 3D printing technologies. As the resin is used selectively to solidify each layer, there is
minimal material wastage.
 Prototyping and iteration: SLA printing is widely used in rapid prototyping due to its ability to
quickly produce accurate and highly detailed prototypes. This allows for faster design iterations
and iterations, facilitating the development and refinement of products.
 Smooth integration with post-processing techniques: SLA printed objects can be easily post-
processed with techniques like polishing, sanding, or painting to achieve the desired final
appearance. The smooth surface finish allows for consistent and effective post-processing.
 Great for visualizing concepts: SLA prints are visually appealing and can effectively
communicate design concepts and ideas. They are often used for presentations, demonstrations,
and marketing purposes.
 Wide range of applications: SLA printing finds applications in various industries, including
product development, jewellery, dental and medical fields, engineering, architecture, and artistic
creations.
c. What are the options for SLA post-processing?
Support removal Strip and Ship
The support structure is removed from the supported side of the part, leaving a dotty surface. If a high-
quality surface finish is required, we suggest adding extra material (at least 0.1 mm). Added material
allows for sanding and avoids affecting the part geometry.
Process Notes
 Supports are made from the same material so must be removed manually.
 This is the basic finish at no extra cost
Sanding
Sanding generally achieves the smoothest surface finish by using multiple sand grits. Whether we are
trying to remove the support bumps or build lines, dry or wet sanding will result in a smooth surface.
Process Notes
 Removes signs of supports
 Surface finish close to injection molded products
 Level of sanding and lead time is different depending on the required finish
 This process is at a cost
Spray paint clear UV protective acrylic
Spray painting printed SLA parts conceal built layer lines and reduces the need for sanding. The clear
coat also protects the parts from yellowing and post-curing by limiting UV exposure.
Process Notes
 Protects the surface against UV using a clear coating
 Can be used to finish the model in a specified color
 Color matching is possible at a cost
 Process steps and lead time will depend on the required finish
 This process is at a cost

Sanding and polishing translucent parts

When printing parts from Somos Watershed, the result is a translucent finish from the printer. The
surface can then be sanded with different sandpaper grits to achieve the required clarity. The last step
will be, apply a clear coat to hide the scuffing from sanding surfaces. This process is manual and will
only be possible on easily accessible surfaces.
Process Notes
 Printed part are translucent when using a clear resin
 Sanding / polishing steps lead time depends on the required finish
 Not suitable when using the parts to reflect light, as the sanding will cause the beams of light to
scatter
 After sanding a clear coat is applied to cover the scuffed surface and restore the shine
 This process is at a cost

Sanding

Polishing
Staining
Parts can be stained in many colors using special alcohol-based dyes.
Process Notes
 Clear parts can be stained in different colors after sanding
 This service is combined with sanding, and it is at an extra cost

d. Mention some best practices of SLA

Increase STL File Resolution
Before starting the 3D printing process, you have to store key information about the digital 3D model in
an STL file. The STL file acts as an interface between the 3D model and the 3D printer. The 3D printer
refers to the STL file to understand the surface geometry of the part to be 3D printed.
Choose the Best 3D Printing Material
3D printing materials come in multiple formats – filament, resin, and powder. But each 3D printing
material is compatible with a specific 3D printing technology. Hence, you must compare and choose
materials according to your 3D printer.
Don’t Ignore Support Structures
While planning 3D printing projects, beginners do not use support structures to avoid post-processing
activities. But you must remember that certain 3D printers cannot produce complex and detailed parts
when you do not use a support structure. Hence, you should focus on using the right support material
while planning a 3D printing project..
Set the Right Print Speed
While configuring a 3D printer, you can improve print quality by setting the right print speed. When you
increase the print speed, the 3D printer will deposit filaments before sets and cool down properly. On the
other hand, you can allow more time for the cooling down of a layer by setting a lower print speed..
Test Both Nozzle and Bed Temperature
You will impact print quality without setting the nozzle and bed temperature accurately. High nozzle
temperature will result in the malformation of the part due to strings of filament left between layers.
Also, you need to use additional cooling to cool down layers properly.
Prepare the Build Surface
The printer’s build surface impacts the 3D-printed part’s texture directly at the bottom. 3D printers these
days come with a variety of build plates. But you can control the part’s surface using the appropriate bed
materials.
Monitor the 3D Printing Process
It becomes difficult for you to fix the defects and flaws in a part when you discover them after the 3D
printing process. But you can improve print quality effortlessly when you detect inconsistencies and
flaws during the 3D printing process.
Invest in Post-Processing Equipment
You have to perform a variety of post-processing activities to improve its output once the part is
separated from the 3D printer. Some of these post-processing activities boost the part’s usability, while
others enhance its look, feel, and aesthetics.
Maintain and Clean the 3D Printer Regularly
You cannot improve print quality without making the 3D printer work optimally. Hence, you must clean
the 3D printer thoroughly after each project. Likewise, you need to maintain its parts properly according
to the instructions shared by the manufacturer.

68.PROCESS PARAMETERS OF FDM

Most FDM systems enable you to change a number of process parameters. These include the
temperature of the build platform and nozzle, the build speed, the layer height, and the speed of the
cooling fan.
Build size and layer height are other crucial considerations. A desktop 3D printer typically has a build
area of 200 x 200 x 200 mm. You can divide a large model into smaller pieces and then reassemble it if
you’d rather print your part on a desktop printer.
The normal layer height for FDM is in the region of 50 to 400 microns. Although printing taller layers
allows you to make parts more rapidly and at a lesser cost, printing shorter layers provide smoother parts
and better captures curved geometries.
b. Characteristics of FDM 3D printing
1.Warping
Warping constitutes one of the most common FDM problems. The extruded substance contracts in size
as it cools and solidifies. Because different sections of the print cool at varied rates, their dimensions
also change similarly. Internal stresses are increased by differential cooling, which pulls the bottom
layer upward and results in distortion.
2.Adjustable parameters
In most FDM systems, you may change the temperature of the build platform and the nozzle. The build
speed, the layer height, and the cooling fan speed can also be adjusted. However, these vary depending
on the material and are often established by the printing service provider.
3.Build volume
The largest component that a machine can create is the build volume. The build volume of a DIY 3D
printer is typically 200 x 200 x 200 mm. While designing, consider the build volume of the printer you
will use. You can create larger models with an FDM printer by producing and reassembling smaller
pieces. It is also a preferred method for better cooling.
4.Layer height
FDM uses layers with a height varying from 0.02 mm to 0.4 mm. A higher layer height produces parts
that print more quickly and more cheaply, whereas a lower layer height produces components that are
smoother and better represent curved geometries.
5.Layer adhesion
Good adhesion between the deposited layers is essential for an FDM component. As the nozzle extrudes
the current, the molten thermoplastic is pressed up against the layer before it. The previous layer’s
surface re-melts due to high temperature and pressure, enabling the new layer to adhere to the previously
printed area. The bonding strength between the several layers is always less than the base strength of the
material.
6.Support structure
In FDM printing, geometries to be created with overhangs call for a support structure. The surfaces
printed on supports will have reduced surface quality than the rest of the item. As a result, it is suggested
that to design such parts, the need for support structures should be minimized.
7.Infill and shell thickness
To shorten the print time and save materials, FDM printers do not create solid components. Instead, the
machine makes several rounds to print the shell or exterior perimeter and then fills the interior, or infill,
with an internal, low-density structure.

C. Shells
As discussed earlier, shells are outside the border or the perimeter of every layer. Shells determine the
number of layers printed for a part and are the first to be printed on a layer. Shell dimensions are heavily
dependant on the model boundary constraints and dimensions, which indeed determine the quality of the
print.
Shell thickness arguably varies in proportion to the layer height. Greater the layer heigh, the greater the
shell thickness. Having a thick shell protects the infill well and provides good support to the structures,
however printing a thick shell has its drawbacks.
Shells are required to be high in thickness when it comes to SLA and SLS printing due to the post-
processing technique, where the surface thickness is reduced. Shells are needed to be at least in the
standard thickness levels so that the strength of the component isn’t compensated.
If the shell thickness is increased over its specified range for a part, there are high chances that shells
might get printed as a solid block, which is completely out of the specified interior dimensions. But
when you’re creating a part that focused on interior finesse, how will you obtain the finish without
compensating for its strength? For these purposes, 3D printers use something called infills. Let us
discuss infills in detail.
Infills
Infills are the print material that is used to print support structure in the interior of the object to increase
its mechanical strength. Infills directly correspond to the density of the objects as it fills the voids in
shells of the object. Infills are generally spoken in terms of volume density percentage. The greater the
infills percentile, the greater the mechanical stability and strength of the part, the greater the time it takes
to print.
It is quite essential to maintain a considerable level of infill percentile for a fully functioning mechanical
part since the part requires strength to withstand a considerable amount of stress and strains. The best
case is to opt for an infill percentage between 25%-80% for fully functioning parts, as it requires greater
durability than light and test parts.
The infill percentage plays a crucial part in determining the drilling and screwing of printed parts. A
printed part with less infill percentile will have a lesser number of inter filling spaces, thus having large
gaps in between, which is not suitable enough to get hold of the bolt tightly. So, it is necessary to
understand the usage of proper infill percentage in the case of screwing and bolting operations.

d. FDM ADVANTAGE AND DIS ADVANTAGES

S.No. Advantages Disadvantages

1. Budget-Friendly Rough Surface Finishing

2. Filament Reusable Warping is common

3. Cloud Server Printing Nozzle Clogging

4. Less Complex Longer Printing Time

5. Easy Ergonomics Layer Adhesion Problem (Layer Shift)

6. Variety of Material Choice Weak in Strength

7. Easily Portable Bed Calibration is Needed Frequently

8. Compact Design