2026 question paper

3D Printing and Design

28 questions

Q1(a). Which manufacturing process adds material layer by layer to produce a component? (i) Subtractive Manufacturing (ii) Additive Manufacturing (iii) Forming Manufacturing (iv) Conventional Manufacturing20262m
Module 1: Additive Manufacturing Introduction and CAD-CAM for 3D Printing
Which manufacturing process adds material layer by layer to produce a component?

(i) Subtractive Manufacturing
(ii) Additive Manufacturing
(iii) Forming Manufacturing
(iv) Conventional Manufacturing

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Worked Solution
Answer: (ii) Additive Manufacturing

Additive manufacturing builds a part by adding material layer by layer from a 3D CAD model. Subtractive processes (turning, milling) remove material instead.
Q1(b). Which 3D printing process uses a thermoplastic filament as the raw material? (i) SLA (ii) FDM (iii) SLS (iv) Binder Jetting20262m
Module 3: Solid Based 3D Printing Processes
Which 3D printing process uses a thermoplastic filament as the raw material?

(i) SLA
(ii) FDM
(iii) SLS
(iv) Binder Jetting

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Worked Solution
Answer: (ii) FDM

Fused Deposition Modeling melts a thermoplastic filament (PLA, ABS, PETG) in a heated nozzle and deposits it layer by layer. SLA uses liquid resin, SLS uses powder.
Q1(c). Which of the following is a common form of 3D printing raw material? (i) Powder (ii) Liquid (iii) Filament/Wire (iv) All of the above20262m
Module 2: 3D Printing Materials
Which of the following is a common form of 3D printing raw material?

(i) Powder
(ii) Liquid
(iii) Filament/Wire
(iv) All of the above

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Worked Solution
Answer: (iv) All of the above

3D printing raw materials come as powder (SLS, binder jetting), liquid resin (SLA) and filament or wire (FDM, wire-arc).
Q1(d). Which material property is important for selecting a 3D printing material? (i) Strength (ii) Thermal resistance (iii) Flexibility (iv) All of these20262m
Module 2: 3D Printing Materials
Which material property is important for selecting a 3D printing material?

(i) Strength
(ii) Thermal resistance
(iii) Flexibility
(iv) All of these

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Worked Solution
Answer: (iv) All of these

Material selection depends on strength, thermal resistance, flexibility, surface finish, cost and printability, all based on the end use of the part.
Q1(e). Which software can be used for slicing a 3D model? (i) Ultimaker Cura (ii) MS Word (iii) MS Excel (iv) PowerPoint20262m
Module 3: Solid Based 3D Printing Processes
Which software can be used for slicing a 3D model?

(i) Ultimaker Cura
(ii) MS Word
(iii) MS Excel
(iv) PowerPoint

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Worked Solution
Answer: (i) Ultimaker Cura

Cura is slicing software: it cuts the STL model into layers and generates G-code for the printer. Word, Excel and PowerPoint are office tools.
Q1(f). FDM stands for: (i) Fused Digital Manufacturing (ii) Fused Deposition Modeling (iii) Fast Deposition Method (iv) Fused Design Model20262m
Module 3: Solid Based 3D Printing Processes
FDM stands for:

(i) Fused Digital Manufacturing
(ii) Fused Deposition Modeling
(iii) Fast Deposition Method
(iv) Fused Design Model

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Worked Solution
Answer: (ii) Fused Deposition Modeling

FDM was developed by Stratasys; it extrudes molten thermoplastic through a nozzle to build parts layer by layer.
Q1(g). SLA stands for: (i) Selective Laser Application (ii) Stereo Lithography Apparatus (iii) Solid Layer Assembly (iv) Stereo Laser Application20262m
Module 4: Liquid Based 3D Printing Processes
SLA stands for:

(i) Selective Laser Application
(ii) Stereo Lithography Apparatus
(iii) Solid Layer Assembly
(iv) Stereo Laser Application

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Worked Solution
Answer: (ii) Stereo Lithography Apparatus

SLA cures liquid photopolymer resin layer by layer using a UV laser. It was the first commercial 3D printing process (3D Systems, 1986).
Q1(h). Which energy source is commonly used in SLS? (i) Laser (ii) Water jet (iii) Mechanical cutter (iv) Electric fan20262m
Module 5: Powder Based 3D Printing Processes
Which energy source is commonly used in SLS?

(i) Laser
(ii) Water jet
(iii) Mechanical cutter
(iv) Electric fan

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Worked Solution
Answer: (i) Laser

Selective Laser Sintering uses a high-power CO2 laser to fuse powder particles along each cross-section.
Q1(i). Binder Jetting uses a: (i) Liquid binder (ii) Filament (iii) Laser beam only (iv) Cutting tool20262m
Module 5: Powder Based 3D Printing Processes
Binder Jetting uses a:

(i) Liquid binder
(ii) Filament
(iii) Laser beam only
(iv) Cutting tool

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Worked Solution
Answer: (i) Liquid binder

Binder jetting sprays a liquid binding agent from an inkjet head onto a powder bed to glue particles together.
Q1(j). Which is a method of inspection? (i) Visual inspection (ii) Digital inspection (iii) Physical inspection (iv) All of the above20262m
Module 6: Post Processing and Quality
Which is a method of inspection?

(i) Visual inspection
(ii) Digital inspection
(iii) Physical inspection
(iv) All of the above

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Worked Solution
Answer: (iv) All of the above

Printed parts are checked by visual inspection, digital inspection (3D scanning, CMM, CT) and physical inspection (gauges, calipers, mechanical tests).
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Q2(a). Explain the concept of Additive Manufacturing. Differentiate between Additive Manufacturing and Conventional Manufacturing processes.20267m

Module 1: Additive Manufacturing Introduction and CAD-CAM for 3D Printing

Explain the concept of Additive Manufacturing. Differentiate between Additive Manufacturing and Conventional Manufacturing processes.

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Worked Solution

Additive Manufacturing (AM)

Additive manufacturing builds a physical part directly from a 3D CAD model by adding material layer by layer, instead of removing it. It is commonly called 3D printing.

MermaidDiagram

Rendering diagram…

AM vs conventional manufacturing

Point	Additive	Conventional (subtractive / formative)
Principle	Adds material layer by layer	Removes (machining) or shapes (casting, forging) material
Material waste	Very low	High in machining
Complex geometry	Easy, internal channels possible	Difficult or impossible
Tooling	No special tools, dies or moulds	Tools, dies, fixtures needed
Lead time	Short for prototypes and one-offs	Long set-up time
Customization	Easy, cost does not rise	Costly
Production volume	Best for low volume	Best for mass production
Surface finish	Often needs post-processing	Generally better
Material range	Limited	Very wide

Advantages of AM

Rapid prototyping, design freedom, customization (e.g. patient-specific implants), less waste, part consolidation.

Exam tip

Define AM, show the process flow and write at least 6 rows in the comparison table.

Q2(b). What is STL? Explain STL with advantages and limitations of the STL file format.20267m
Module 1: Additive Manufacturing Introduction and CAD-CAM for 3D Printing
What is STL? Explain STL with advantages and limitations of the STL file format.

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Worked Solution
STL File Format

STL (Stereolithography or Standard Tessellation Language) is the standard file format for 3D printing. It describes the surface of a 3D model as a mesh of triangles, with no colour, texture or units.

Each triangle is stored as three vertices (x, y, z) and a unit normal vector pointing outward. Formats: ASCII (readable, large) and binary (compact, common).

SVGVector Architecture Diagram (SVG)
ASCII STL structure

solid part facet normal 0 0 1 outer loop vertex 0 0 0 vertex 1 0 0 vertex 0 1 0 endloop endfacet endsolid part
Advantages

Universally supported by CAD and slicing software.

Simple structure, easy to generate.

Fine mesh gives good accuracy.

Limitations

Approximates curves, so accuracy depends on triangle count; a finer mesh gives large files.

No colour, material, texture or unit information.

Errors are common: gaps, flipped normals, overlapping or non-manifold edges, needing repair.

Only surface, not internal structure.

Exam tip

Draw a triangle mesh, show the ASCII facet and list 3 advantages and 3 limitations.

Q3(a). Write down the difference between direct slicing and adaptive slicing.20267m

Module 1: Additive Manufacturing Introduction and CAD-CAM for 3D Printing

Write down the difference between direct slicing and adaptive slicing.

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Worked Solution

Direct Slicing vs Adaptive Slicing

Slicing divides a 3D model into thin horizontal layers whose contours guide the deposition path.

Direct slicing: the layers are cut directly from the original CAD model (without making an STL), so there is no triangulation error.
Adaptive slicing: the layer thickness changes along the height of the part. Thin layers are used where curvature is high, and thick layers where walls are vertical.

MermaidDiagram

Rendering diagram…

Point	Direct slicing	Adaptive slicing
Input	CAD model directly	Usually STL (or CAD)
Layer thickness	Usually uniform	Variable by geometry
Main benefit	Removes STL approximation error, smaller files	Balances accuracy and build time
Staircase effect	Reduced by accurate contours	Reduced where it matters
Build time	Not directly reduced	Reduced (thick layers on flat sections)
Complexity	Needs CAD-specific software	More complex algorithm
Use	High-accuracy parts	Curved parts, time-critical builds

Exam tip

Mention staircase effect and that adaptive slicing trades accuracy against build time.

Q3(b). Explain part orientation and support generation in 3D printing.20267m

Module 1: Additive Manufacturing Introduction and CAD-CAM for 3D Printing

Explain part orientation and support generation in 3D printing.

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Worked Solution

Part Orientation and Support Generation

Part orientation

Orientation is how the part is placed on the build platform. It affects:

Factor	Effect
Surface finish	Staircase effect is worst on inclined and curved surfaces
Strength	Parts are weakest between layers (Z direction)
Build time	Taller orientation means more layers and more time
Support volume	Overhangs need supports
Accuracy	Critical features should face the plane with best resolution
Material use and cost	More supports waste material

Good practice: place the largest flat face on the bed, keep critical surfaces away from supports and align load direction with the layers.

Support generation

Supports are temporary structures that hold overhangs and islands, anchor the part and carry heat away. They are needed for overhang angles above about 45 degrees.

SVGVector Architecture Diagram (SVG)

Types of supports

Linear / tree / lattice (FDM), solid or perforated blocks (SLA), no supports needed in powder-bed processes (powder supports the part).
Support settings: density, overhang angle, contact gap, interface layers.
Drawbacks: extra material and time, surface marks and removal effort.

Exam tip

Draw the overhang with supports and explain how orientation reduces support use.

Q4(a). Explain polymers used in 3D printing and discuss their important properties.20267m

Module 2: 3D Printing Materials

Explain polymers used in 3D printing and discuss their important properties.

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Worked Solution

Polymers Used in 3D Printing

Polymers are the most widely used 3D printing materials, in two groups.

MermaidDiagram

Rendering diagram…

Polymer	Process	Key properties	Typical use
PLA	FDM	Biodegradable, easy to print, rigid, low heat resistance (about 60 C)	Prototypes, models
ABS	FDM	Tough, impact resistant, heat resistant, warps, fumes	Functional parts, enclosures
PETG	FDM	Strong, chemical resistant, little warping	Bottles, mechanical parts
Nylon (PA)	FDM, SLS	Strong, wear resistant, flexible, absorbs moisture	Gears, hinges
TPU	FDM	Elastic, rubber-like	Seals, grips, wearables
PEEK / PEI	FDM	Very high strength, heat and chemical resistance, biocompatible	Aerospace, medical implants
Photopolymer resin	SLA, DLP	High detail, smooth finish, brittle	Dental, jewellery, models

Important properties

Mechanical: tensile strength, stiffness, toughness, flexibility.
Thermal: glass transition and melting temperature, heat deflection.
Chemical resistance and moisture absorption.
Printability: shrinkage, warping, layer adhesion, viscosity (resins).
Biocompatibility for medical use.
Surface finish, cost and availability.

Exam tip

Give a table of 4 polymers (PLA, ABS, nylon, resin) with properties and uses.

Q4(b). Explain the different forms of raw materials used in 3D printing with suitable examples.20267m

Module 2: 3D Printing Materials

Explain the different forms of raw materials used in 3D printing with suitable examples.

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Worked Solution

Forms of Raw Materials in 3D Printing

MermaidDiagram

Rendering diagram…

Form	Process	Examples	Features
Filament / wire	FDM, wire-arc AM	PLA, ABS, PETG, nylon, TPU; metal wire (steel, titanium)	Cheap, clean, easy to handle, anisotropic strength
Liquid resin	SLA, DLP, PolyJet	Acrylate and epoxy photopolymers	High resolution, smooth surface, needs washing and curing
Powder	SLS, SLM, EBM, binder jetting	Nylon (PA12), stainless steel, titanium alloys, aluminium, ceramics, sand	No supports needed, strong parts, powder handling and safety needed
Sheet / laminate	LOM	Paper, plastic or metal foils	Low cost, large parts, limited accuracy
Paste / slurry	Extrusion bioprinting, ceramic printing	Ceramic paste, concrete, bio-ink	Special applications

Selection tips

Pick the material form according to process, required strength, accuracy, cost and post-processing.

Exam tip

Cover the three forms (solid, liquid, powder) with a table and 2 examples each.

Q5(a). Describe the construction and working of an FDM based 3D printer.20267m

Module 3: Solid Based 3D Printing Processes

Describe the construction and working of an FDM based 3D printer.

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Worked Solution

FDM 3D Printer: Construction and Working

Fused Deposition Modeling (FDM) melts a thermoplastic filament and extrudes it through a nozzle, building the part layer by layer.

SVGVector Architecture Diagram (SVG)

Main parts

Part	Function
Filament spool	Supplies thermoplastic filament (1.75 mm or 2.85 mm)
Extruder (cold end)	Stepper-driven gear pushes the filament forward
Hot end and nozzle	Heater block melts filament (about 190 to 250 C); nozzle 0.4 mm typical
Build platform / heated bed	Holds the part; heating prevents warping
Motion system	Stepper motors, belts and lead screws for X, Y and Z
Cooling fan	Solidifies the deposited material quickly
Controller board	Reads G-code and drives the motors and heaters
Frame and sensors	Structure, end-stops, temperature thermistors

Working

MermaidDiagram

Rendering diagram…

Advantages and limits

Low cost, wide material choice, easy to use. Visible layer lines, weaker in Z, supports needed for overhangs.

Exam tip

Draw the labelled schematic and write the 5-step working.

Q5(b). Explain the role of 3D printing software with any examples.20267m

Module 3: Solid Based 3D Printing Processes

Explain the role of 3D printing software with any examples.

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Worked Solution

Role of 3D Printing Software

Software turns an idea into a printable file and controls the machine. The workflow uses several tools.

MermaidDiagram

Rendering diagram…

Stage	Role	Examples
CAD modelling	Create the 3D geometry	SolidWorks, Fusion 360, AutoCAD, FreeCAD, Tinkercad
File conversion	Export surface mesh	STL, 3MF, OBJ
Mesh repair / checking	Fix holes, flipped normals, non-manifold edges	Meshmixer, Netfabb, Blender
Slicing	Orient, add supports, set layer height, infill, speed and temperature, then generate G-code	Ultimaker Cura, PrusaSlicer, Simplify3D, Chitubox (resin)
Machine control	Sends G-code, monitors temperature and progress	Pronterface, OctoPrint, printer firmware (Marlin)
Simulation / analysis	Estimate time, material, check overhangs and stress	Cura preview, Ansys, Autodesk tools

Why it matters

The software decides print quality, strength, time and material use, and lets the user preview errors before wasting material.

Exam tip

Name at least one tool for CAD, repair and slicing, and state that slicers output G-code.

Q6(a). Explain the photo polymerization process used in liquid-based 3D printing.20267m
Module 4: Liquid Based 3D Printing Processes
Explain the photo polymerization process used in liquid-based 3D printing.

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Worked Solution
Photopolymerization in Liquid-based 3D Printing

Photopolymerization is a chemical reaction in which a liquid photosensitive resin (monomers and oligomers with a photoinitiator) solidifies into a cross-linked polymer when exposed to light of a suitable wavelength (usually UV, about 355 to 405 nm).

MermaidDiagram
Rendering diagram…
Process steps

The platform is placed one layer height below the resin surface.

A UV laser (SLA) or projector (DLP, LCD) cures the cross-section of the layer.

The platform moves by one layer thickness and fresh resin flows over the part.

The steps repeat until the part is complete.

The part is washed (isopropyl alcohol) and post-cured under UV.

Processes using it

Process Light source

SLA UV laser scanning point by point

DLP Projector, whole layer at once

LCD / MSLA LED with LCD mask

PolyJet Jetted droplets cured by UV lamp

Key factors

Exposure energy, cure depth ( $C_d = D_p \ln(E/E_c)$ ), layer thickness, resin viscosity and wavelength.

Features

High accuracy and smooth finish; brittle parts, resin toxicity, supports and post-curing needed.

Exam tip

Explain the chemistry in 2 lines, give the layer cycle and list SLA, DLP, PolyJet.

Process	Light source
SLA	UV laser scanning point by point
DLP	Projector, whole layer at once
LCD / MSLA	LED with LCD mask
PolyJet	Jetted droplets cured by UV lamp

Q6(b). What are the common faults in Additive Manufacturing equipment?20267m

Module 6: Post Processing and Quality

What are the common faults in Additive Manufacturing equipment?

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Worked Solution

Common Faults in Additive Manufacturing Equipment

Fault	Cause	Remedy
Nozzle clogging	Debris, wrong temperature, moisture in filament	Clean or replace nozzle, dry filament, correct temperature
Warping / poor bed adhesion	Uneven cooling, dirty or unlevelled bed	Heated bed, brim or raft, level the bed
Layer shifting	Loose belts, overheated drivers, mechanical obstruction	Tighten belts, reduce speed, check motors
Under-extrusion	Partial clog, wrong flow, worn extruder gear	Clean path, calibrate flow, replace gear
Over-extrusion / blobs	Flow too high, wrong filament diameter	Calibrate extrusion multiplier
Stringing	Oozing during travel	Enable retraction, lower temperature
Layer separation (delamination)	Low temperature, excess cooling	Raise temperature, reduce fan
Thermal runaway or temperature error	Faulty heater or thermistor	Replace sensor, enable thermal protection
Dimensional inaccuracy	Shrinkage, loose axes, uncalibrated steps/mm	Calibrate, compensate scale
Laser or optics faults (SLA, SLS)	Dirty lens or mirror, misalignment	Clean and recalibrate
Powder or resin recoating issues	Uneven recoater, contaminated material	Level recoater, filter resin
Software / G-code errors	Corrupt file, wrong settings	Reslice, update firmware

MermaidDiagram

Rendering diagram…

Exam tip

Group the faults as mechanical, thermal, material and software, and give cause and remedy for at least 6.

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Q7(a). Why is post-processing required in Additive Manufacturing? Explain different post-processing techniques.20267m

Module 6: Post Processing and Quality

Why is post-processing required in Additive Manufacturing? Explain different post-processing techniques.

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Worked Solution

Post-Processing in Additive Manufacturing

Why it is required

Remove supports, loose powder or excess resin.
Improve surface finish (staircase effect, layer lines).
Improve dimensional accuracy and fit.
Enhance mechanical properties (strength, density, stress relief).
Add appearance: colour, coating, polish.
Make the part functional, safe or biocompatible (sterilization).

MermaidDiagram

Rendering diagram…

Technique	Used for
Support removal	All processes; soluble supports (PVA, HIPS) for FDM
Sanding and polishing	FDM, SLA surface smoothing
Vapour smoothing	ABS with acetone vapour
Bead / sand blasting	Metal and nylon powder parts
UV post-curing	SLA, DLP resin parts
Heat treatment, HIP	Metal parts: remove residual stress, close pores
Infiltration	Binder jetting parts: strengthen with resin or metal
Painting, dyeing, plating	Appearance and protection
Machining	Critical dimensions and threads

Exam tip

Give 4 reasons and classify techniques with examples for FDM, SLA and metal parts.

Q7(b). Explain the scanning and curing techniques used in SLA.20267m
Module 4: Liquid Based 3D Printing Processes
Explain the scanning and curing techniques used in SLA.

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Worked Solution
Scanning and Curing in SLA

In SLA, a UV laser scans each layer's cross-section on the liquid resin surface; the exposed resin cures (solidifies) and bonds to the layer below.

SVGVector Architecture Diagram (SVG)
Scanning techniques

Vector (point) scanning: the laser spot is steered by two galvanometer mirrors along the outline (contour) and then fills the interior, in lines (hatch).

Raster scanning: the beam sweeps line by line over the whole layer area, switching on only where needed.

Scan patterns: contour, hatch, cross-hatch, spiral. Spacing between lines and scan speed control the exposure.

Newer systems project a whole layer (DLP/LCD) rather than scanning.

Curing

Green curing: during scanning, the resin is only partly polymerized (green strength) so that the layer bonds to the previous one. The cure depth depends on exposure: $C_d = D_p \ln(E/E_c)$ .

Layer recoating: platform dips, a blade levels the resin.

Post-curing: after cleaning, the part is exposed to UV (and sometimes heat) in a chamber to complete polymerization, raising strength and stability.

Key parameters

Laser power, scan speed, spot size, hatch spacing, layer thickness and resin sensitivity.

Exam tip

Draw the laser, galvo mirrors, vat and platform, then explain scanning (contour and hatch) and post-curing.

Q8(a). Explain the Binder Jetting process with its working principle and applications.20267m

Module 5: Powder Based 3D Printing Processes

Explain the Binder Jetting process with its working principle and applications.

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Worked Solution

Binder Jetting

Binder jetting joins powder particles using a liquid binding agent sprayed by an inkjet print head, with no heat during printing.

MermaidDiagram

Rendering diagram…

Working principle

A recoater spreads a thin layer of powder on the build platform.
The print head moves in X and Y and deposits binder droplets where the part exists.
The platform lowers by one layer thickness and fresh powder is spread.
After the last layer, the part is left to cure, then removed and the loose powder cleaned off (the powder acts as support).
Depending on the material, the green part is sintered, infiltrated with resin or metal, or finished.

Materials

Metals (stainless steel, Inconel), ceramics, sand, gypsum, polymers.

Advantages and limits

Advantages	Limitations
No supports needed	Green parts are fragile
Fast and low cost, large build volume	Shrinkage on sintering
Full colour possible (gypsum)	Lower density and strength than laser melting
No thermal stress during print	Rough surface finish

Applications

Sand casting moulds and cores, metal tooling, architectural models, full-colour prototypes, ceramic parts and medical models.

Exam tip

Draw the powder bed with print head and roller; mention sintering or infiltration.

Q8(b). Describe the principle and working of Electron Beam Melting.20267m

Module 5: Powder Based 3D Printing Processes

Describe the principle and working of Electron Beam Melting.

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Worked Solution

Electron Beam Melting (EBM)

EBM is a powder bed fusion process that melts metal powder with a high-power electron beam in a vacuum, building fully dense metal parts layer by layer.

Principle

A heated tungsten filament emits electrons, which are accelerated by high voltage (about 60 kV) and focused and deflected by electromagnetic coils. The kinetic energy of the electrons turns into heat when they strike the powder and melts it.

MermaidDiagram

Rendering diagram…

Working

The chamber is evacuated (about $10^{-4}$ to $10^{-5}$ mbar), then a little helium is added.
A rake spreads a 50 to 100 micron layer of metal powder.
The beam first preheats the powder (about 700 C for Ti-6Al-4V), lightly sintering it so it will not blow away and reducing residual stress.
The beam then melts the cross-section selectively.
The platform lowers, new powder is spread and the cycle repeats.
The part cools slowly in vacuum, then loose powder is removed.

Materials

Titanium alloys (Ti-6Al-4V), cobalt-chrome, Inconel, tantalum.

Advantages and limits

Advantages	Limitations
Dense parts, good properties	Only conductive metals
Low residual stress (high temperature)	Rough surface finish
Vacuum prevents oxidation	Costly machine
Fast, high beam power	Powder removal and size limits

Applications

Orthopaedic and dental implants, aerospace parts (turbine blades), lightweight lattice structures.

Exam tip

Mention vacuum, preheating and electron beam source; compare with SLM (laser, inert gas).

Q9(a). Write a short note on: Vapour smoothing using acetone treatment and its application in 3D printing20267m
Module 6: Post Processing and Quality
Write a short note on: Vapour smoothing using acetone treatment and its application in 3D printing

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Worked Solution
Short Note: Vapour Smoothing with Acetone

Vapour smoothing is a chemical post-processing method mainly for ABS (and ASA) FDM parts. Acetone vapour softens the outer surface, which flows slightly and smooths layer lines, then re-hardens.

MermaidDiagram
Rendering diagram…
Procedure

Place the part on a stand in a sealed container with a little acetone below.

Warm gently to produce vapour (or use a cold method with a soaked tissue).

Expose for a short, controlled time (minutes).

Remove and let it dry fully.

Advantages and cautions

Gives glossy, smooth, watertight surface and better layer bonding.

Over-exposure causes loss of fine detail and dimensional change.

Acetone is highly flammable and toxic: use in ventilated area, away from flame, with PPE.

Applications

Enclosures, display models, fluidic parts, cosmetic prototypes, casting patterns. PLA is not affected by acetone (use other solvents).

Exam tip

Write the principle, the four-step procedure and the safety note.

Q9(b). Write a short note on: Future trends and challenges in Additive Manufacturing20267m

Module 1: Additive Manufacturing Introduction and CAD-CAM for 3D Printing

Write a short note on: Future trends and challenges in Additive Manufacturing

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Worked Solution

Short Note: Future Trends and Challenges in AM

Future trends

MermaidDiagram

Rendering diagram…

Medical: patient-specific implants, prosthetics, bioprinting.
Aerospace and automotive: lightweight consolidated parts.
4D printing: parts that change shape with heat, water or light.
Digital supply chain: on-demand, local production of spares.

Challenges

Area	Challenge
Cost	High machine and material cost
Speed	Slow build rates for large volumes
Quality	Repeatability, porosity, anisotropy, surface finish
Materials	Limited certified materials
Standards	Lack of qualification and certification standards
Skills	Need for design-for-AM expertise
IP and safety	Digital file piracy, powder and fume hazards

Exam tip

Give 4 trends and 4 challenges in crisp points.

Q9(c). Write a short note on: CAD-CAM integration process for 3D printing20267m

Module 1: Additive Manufacturing Introduction and CAD-CAM for 3D Printing

Write a short note on: CAD-CAM integration process for 3D printing

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Worked Solution

Short Note: CAD-CAM Integration for 3D Printing

CAD (Computer-Aided Design) creates the digital model; CAM (Computer-Aided Manufacturing) prepares the instructions to make it. In 3D printing the two are linked through a standard digital chain.

MermaidDiagram

Rendering diagram…

Stage	Activity
CAD	Parametric or solid modelling of the part
Conversion	Tessellation into triangles (STL)
Repair	Fix holes and inverted normals
CAM / slicing	Set orientation, supports, layer height, infill; generate toolpaths
G-code	Machine commands for motion, temperature, extrusion
Build and feedback	Print, inspect, then modify the CAD model

Benefits

Faster product development, less manual intervention, easy design changes, direct digital-to-physical manufacturing.

Exam tip

Draw the CAD to G-code flow with the feedback loop.

Q9(d). Write a short note on: Importance of SLA-based 3D printing20267m

Module 4: Liquid Based 3D Printing Processes

Write a short note on: Importance of SLA-based 3D printing

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Short Note: Importance of SLA-based 3D Printing

Stereolithography (SLA) was the first 3D printing technology and is still important for parts that need high accuracy and smooth surfaces.

Importance

High resolution: layers of 25 to 100 microns and fine details.
Excellent surface finish: little post-processing needed for visual parts.
Accuracy: typical tolerance about 0.1 mm, good for fit checks.
Variety of resins: clear, tough, flexible, castable, biocompatible, high-temperature.
Isotropic, watertight parts suitable for fluidics.
Complex geometry in fine features.

Applications

Field	Use
Dental and medical	Surgical guides, aligner models, hearing aids
Jewellery	Castable patterns for lost-wax casting
Engineering	Master patterns, prototypes, micro-fluidic devices
Education and design	Detailed models

Limitations

Brittle parts, resin cost, post-curing and washing, supports, UV degradation.

Exam tip

Write 4 points of importance with 3 applications.

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