FIRST COMBAT AIRCRAFT

WITH 3-D PRINTED PARTS

SELF STUDY 1st PHASE OF

EVALUATION REPORT

Sanjay Vinayak H.K

2nd semester ’F’ section, USN: 1RV13CS139

Computer Science Engineering

R.V. College of Engineering, Bangalore

sanjayhk7@outlook.com

Abstract-This document gives the brief report of the various schemes and techniques used in the development and manufacturing of 3-

D printed parts of a combat aircraft. This topic has been split into four different components namely Mathematics, Mechanical

Engineering, Electronics and Communication Engineering and Computer Science Engineering.

TABLE OF CONTENTS

INTRODUCTION TO 3-D PRINTING

FIRST COMBAT AIRCRAFT WITH 3-D PRINTED PARTS

MATHEMATICS COMPONENT

MECHANICAL ENGINEERING COMPONENT

ELECTRONICS AND COMMUNICATION ENGINEERING COMPONENT

COMPUTER SCIENCE ENGINEERING COMPONENT

ACKNOWLEDGEMENT

REFERENCES

I. INTRODUCTION TO 3-D PRINTING

Additive manufacturing or 3D printing is a process of making three dimensional solid objects from a digital

model. 3D printing is achieved using additive processes, where an object is created by laying down

successive layers of material. 3D printing is considered distinct from traditional machining techniques

(subtractive processes) which mostly rely on the removal of material by drilling, cutting etc.

Fig1. Stereolithographic apparatus (Type of Additive manufacturing)

3D printing is usually performed by a materials printer using digital technology. It is a rapid prototyping and

rapid manufacturing technology.

The technology is used in the fields of jewellery, footwear, industrial design, architecture, engineering and

construction (AEC), automotive, aerospace, dental and medical industries, education, geographic

information systems, civil engineering, and many others.

II. FIRST COMBAT AIRCRAFT WITH 3-D

PRINTED PARTS

Fig2.Tornado aircraft fitted with 3-d printed parts

BAE Systems plc, a British multinational defence, security and aerospace company has developed an aircraft

with 3-D printed parts for the Royal air force. The Panavia Tornado is a multirole, twin-engined aircraft

designed to excel at low-level penetration of enemy defences. Variable wing geometry, allowing for minimal

drag during the critical low-level dash towards a well-prepared enemy, had been desired from the project's

start. Advanced navigation and flight computers, including the then-innovative fly-by-wire system, greatly

reduced the workload of the pilot during low-level flight and eased control of the aircraft. For long range

bombing missions, the Tornado has a retractable refuelling probe .

The Tornado GR4 aircraft of the Royal Air Force has been fitted with 3-D printed components which

include protective covers for cockpit radios, support struts on the air intake door and protective guards for

power take-off shafts. BAE Systems is no stranger to 3D printing. It's been using and developing

stereolithography (SLA) internally for more than 15 years, for both rapid prototyping and development

tooling. "The knowledge and experience gained in SLA is now being adapted to support the emerging

additive manufacturing technologies with the aim of producing quicker and cheaper flying parts

III. MATHEMATICS COMPONENT

For every 3-D printed object, mathematical models have to be developed which are then converted to the

computer models.Using the computer model, the printer prints the required 3-D object.

Mathematical concept computer model 3D printed object

INTRODUCTION TO 3 DIMENSIONS:

Three-dimensional space is a geometric 3-parameters model of the physical universe (without considering

time) in which all known matter exists. These three dimensions can be labelled by a combination of three

chosen from the terms length, width, height, depth, and breadth. In mathematics, analytic geometry (also

called Cartesian geometry) describes every point in three-dimensional space by means of three coordinates.

Three coordinate axes are given, usually each perpendicular to the other two at the origin, the point at which

they cross. They are usually labelled x, y, and z. Relative to these axes, the position of any point in three-

dimensional space is given by an ordered triple of real numbers, each number giving the distance of that

point from the origin measured along the given axis, which is equal to the distance of that point from the

plane determined by the other two axes.

Other popular methods of describing the location of a point in three-dimensional space include cylindrical

coordinates and spherical coordinates, though there is an infinite number of possible methods. Another

mathematical way of viewing three-dimensional space is found in linear algebra, where the idea of

independence is crucial. Space has three dimensions because the length of a box is independent of its width

or breadth. In the technical language of linear algebra, space is three-dimensional because every point in

space can be described by a linear combination of three independent vectors. In this view, space-time is

four-dimensional because the location of a point in time is independent of its location in space.

The visual ability to perceive the world in three dimensions is called perception. With the space , the

topologists locally model all other 3-manifolds.Complex shapes like hyperbolic paraboloid, penrose triangle

can easily be printed using 3-D printers

Hyperbolic paraboloid : The hyperbolic paraboloid is a doubly ruled surface shaped like a saddle.

In a suitable coordinate system, a hyperbolic paraboloid can be represented by the equation in cartesian co-

ordinates as:

Fig3. 3-d model of a hyperbolic paraboloid

(courtesy: www.shapeways.com)

Penrose triangle: The Penrose triangle, also known as the Penrose tribar, is an impossible object or

an optical illusion. The tribar appears to be a solid object, made of three straight beams of square

cross-section which meet pairwise at right angles at the vertices of the triangle they form. This

combination of properties cannot be realized by any 3-dimensional object in ordinary Euclidean

space. Such an object can exist in certain Euclidean 3-manifolds. There also exist 3-dimensional

solid shapes each of which, when viewed from a certain angle, appears the same as the 2-dimensional

depiction of the Penrose triangle on this page. The term "Penrose triangle" can refer to the 2-

dimensional depiction or the impossible object itself.

The penrose triangle has been successfully printed using a 3-d printer as shown:

Fig4. 3-d printed penrose triangle

(courtesy: numbersixreprap.blogspot.com)

IV. MECHANICAL ENGINEERING COMPONENT

The different additive manufacturing methods used today are:

STEREOLITHOGRAPHY (SLA):

A SLA 3D printer works by concentrating a beam of ultraviolet light focused onto the surface of a

vat filled with liquid photocurable resin. The UV laser beam draws out the 3D model one thin layer

at a time, hardening that “slice” of the eventual 3D model as the light hits the resin. Slice after slice

is created, with each one bonded to the other, and next thing you know you have a full, extremely

high-resolution three dimensional model lifted out of the vat. Unused resin is reusable for the next

job.

FUSED DEPOSITION MODELLING (FDM):

In FDM, the object is produced by extruding a stream of melted thermoplastic material to form

layers. Each layer stacks on top of and fuses with the previous layer as the material hardens almost

immediately after leaving the extrusion nozzle. It is one of the less expensive 3D printing methods.

Most FDM printers print with ABS plastic (think Lego), as well as PLA (Polylactic acid), a

biodegradable polymer, which is produced from organic material

SELECTIVE LASER SINTERING (SLS):

SLS works similarly to SLA, but instead of liquid photopolymer in a vat, you’ll find powdered

materials, such as polystyrene, ceramics, glass, nylon, and metals including steel, titanium,

aluminium, and silver. When the laser hits the powder, the powder is fused at that point (sintered).

All unsintered powder remains as is, and becomes a support structure for the object. The lack of

necessity for any support structure with SLS is an advantage over FDM/FFF and SLA — there’s

none to remove after the model is complete, and no extra waste was created. All unused powder can

be used for the next printing.

SELECTIVE LASER MELTING:

With SLM thin layers of atomized fine metal powder are evenly distributed using a coating

mechanism onto a substrate plate, usually metal, that is fastened to an indexing table that moves in

the vertical (Z) axis. This takes place inside a chamber containing a tightly controlled atmosphere of

inert gas, either argon or nitrogen at oxygen levels below 500 parts per million. Once each layer has

been distributed each 2D slice of the part geometry is fused by selectively applying the laser energy

to the powder surface, by directing the focused laser beam using two high frequency scanning mirrors

in the X and Y axes. The laser energy is intense enough to permit full melting (welding) of the

particles to form solid metal. The process is repeated layer after layer until the part is complete.

The 3-D printed parts used in the Tornado GR4 are:

POWER TAKEOFF SHAFT GUARD:

A power take-off or power take off (PTO) is any of several methods for taking power from a power source,

such as a running engine, and transmitting it to an application such as an attached implement or separate

machines. A guard covers the shaft to prevent injuries during maintenance called the PTO shaft guard.

Fig5. A PTO shaft covered by a guard

(Courtesy: www.adlib.everysite.co.uk)

METAL BRACKET FOR CAMERA MOUNTING:

The Tornado’s camera bracket was manufactured using Selective Laser Melting Technique.

Fig6. Support struts for landing gears are seen attached sideways

(Courtesy:BAE systems)

All the metal parts on the RAF’s Tornado have been printed using stainless steel and all the non metallic

parts using acrylonitrile butadiene styrene (ABS) which is a thermoplastic.

V. ELECTRONICS AND COMMUNICATION ENGINEERING

COMPONENT

Fig7. Block Diagram of a 3-D printer

(Courtesy:www.ti.com)

3-D Printer process successive layers of material to produce a 3-D physical objects. The object is specified

by a 3D Computer Aided Design (CAD) model. 3D printer software transforms the virtual 3D model into a

series of layers suitable for printing the object.

It is often used to quickly create detailed prototypes. With this technology, printing parts of a material can

be done in a single process flow. 3D printers are becoming more affordable for medium and small scale

businesses in which rapid prototyping is brought all the way into the office, no longer requiring

manufacturing floor space.

Two common methods for 3D printing are digital exposure and laser sintering. The high level principles for

incorporating DLP technology into a 3D printing solution can be applied to both methods, but digital

exposure is represented in the system block diagram.

For the digital exposure technique, the 3D object is constructed by laying down successive thin horizontal

cross-sections or layers of an ultraviolet (UV) curable liquid photopolymer resin. For each layer, the UV

light image from the DLP Digital Micro mirror Device (DMD) creates a pattern which hardens the polymer

resin where it is exposed to the light.

The cross-section pattern is produced by the individual mirrors that correspond to each pixel on the current

layer. This pattern projects through an imaging lens onto the surface of the UV curable liquid photopolymer

resin, curing or hardening it where the pixels are on. As depicted in the diagram, one resin is the build

material and the second is material to support overhanging features and thin vertical walls during

construction. The support material is later removed by heat or dissolved with a solvent or water.

These layers fuse automatically and the process repeats one layer at a time until the model is built. Cure

rates are possible under 0.2 seconds per layer. Layer thickness typically ranges from 1um to 250um based

upon the resin and wavelength of the UV light used. More detailed images require more discrete cross-

sections to assume the continuous smooth surface effect of the resulting object.

The diagram shows a DLP chipset, which includes the DMD, and a DMD Controller chip, plus a DMD

Analog Control chip (depending on the specific DLP chipset). DLP chipsets are available with different

DMD sizes, pixel pitches, resolutions, and other specifications. DLP also offers devices targeted for use

with UV light. The best choice for a DLP chipset may depend on the desired object feature size, patterning

speed and necessary wavelengths to cure the resin.

The CAD model is produced by software running on a PC. The system control and signal processing is

accomplished by the Embedded Processor . The details of the optical layout and components are not shown

in the diagram. The diagram is intended to convey as simply as possible the overall functionality of a DLP-

based 3D Printer application.

VI. COMPUTER SCIENCE ENGINEERING COMPONENT

Fig8 . Flowchart of 3-D printing processes

(Courtesy: www.emeraldinsight.com)

Some of the 3-D printing software in use today are:

1. Google SketchUp 6. BRL-CAD

2. 3DCrafter 7. Blender

3. FreeCAD 8. AutoCAD

4. LeoCAD 9. Rhino3D

5. OpenSCAD 10. Solidworks

In the 2D world, a sheet of printed paper output from a printer was “designed” on the computer in a program

such as Microsoft Word. The file — the Word document — contains the instructions that tell the printer

what to do.

In the 3D world, a 3D printer also needs to have instructions for what to print. It needs a file as well. The

file — a Computer Aided Design (CAD) file — is created with the use of a 3D modeling program, either

from scratch or beginning with a 3D model created by a 3D scanner. Either way, the program creates a file

that is sent to the 3D printer. Along the way, software slices the design into hundreds, or more likely

thousands, of horizontal layers. These layers will be printed one atop the other until the 3D object is done.

Fig8. CAD design for 3-D printing of the parts of the Tornado aircraft

(Courtesy: BAE systems)

ACKNOWLEDGEMENT

I thank my teachers for providing me the opportunity to

learn about 3-D printing and its applications. I could learn a

lot about the topic and it has helped me in the overall

understanding of the topic under different subjects.

References

[1] www.baessytems.com/article/BAES_164442/3d-

printed-metal-part-flown-for-first-time-on-uk-fighter-jet

[2] www.custompart.net

[3] www.emeraldinsight.com

[4] ‘3-D printing for mathematical visualisation’ by Henry

Segerman, http://link.springer.com/article/10.1007/s00283-012-

9319-7

[5] ‘Thinking like Archimedes with a 3-D printer’ by

Oliver Knill and Elizabeth Slavkovsky