4d printing and applications, Summaries of Engineering

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A Seminar on

4 - D PRINTING

SATHWIK.S

4MW19ME

MECHANICAL (SANDWICH) ENGINEERING

INTRODUCTION

BACKGROUND

• This concept was first given by ‘Skylar Tibbits’ , an

MIT Researcher, architect, designer, computer scientist

and TED Senior Fellow.

• He had presented the concept of 4-d Printing & Self

Assembly at the TED Talks in 2013.

• It is based on the principle of self-assembly like

molecular self-assembly where molecules form

complex structures without any human intervention.

• The purpose of this project is to combine technology

and design to invent self-assembly and programmable

material technologies.

TYPES OF 4-D PRINTING:

1. Design Based Printing: Design based printing comprises the efforts applied in design, therefore on exposure to external stimuli the shape shows a controlled dynamic behaviour. 2. Material Based Printing: Material based printing depicts shape changing or shifting behaviour.

SHAPE CHANGE MECHANISM:

The idea of utilizing the change in the shape of a material is not novel to 4D

printing. Several shape programming techniques exist which utilize this feature. 2D

polymeric sheets are easily converted to 3D sheets by employing certain strategies.

Polymeric sheets are preferable for such processes because they are lightweight, cost-

effective, and extremely flexible.

1. Active origami & self-folding techniques.

2. Stimuli based actuation.

1. ACTIVE ORIGAMI & SELF-FOLDING TECHNIQUES:

Active origami basically relates to

the use of specific smart material to

create self-actuating structures,

which are capable of folding and

unfolding like the real-world origami

paper techniques.

This technique can potentially

provide a solution to large volume or

storage space engineering problems

by designing structures that can fold

and occupy smaller spaces.

Hinges based on polymeric sheets

combined with printed active composites

(PAC) were used to create active origami

structures. When exposed to external

stimuli, these conjoined sheets would

fold into the desired shape to form

complex structures like 3D boxes and

pyramids.

The polymeric sheets when coated

with black ink, folds to produce

origami structure or popup kirigami

structures when exposed to near-

infrared light.

2. STIMULI BASED ACTUATION:

The characteristic shape transformation exhibited by the 4Dprinted product is a response generated

because of stimuli. These 4D printed products contain a wide range of smart materials, each of which is

actuated by different kinds of stimuli.

Types:

1) Temperature

2) Moisture

3) Light

4) Magnetic Induction

TEMPERATURE-INDUCED ACTUATION: MAGNETICALLY INDUCED ACTUATION:

APPLICATIONS: ENGINEERING APPLICATIONS: BIOMEDICAL APPLICATION:

ENGINEERING APPLICATIONS **:

1. AEROSPACE & AERONAUTICAL INDUSTRY:**

• Spacecraft with SMP Deployment mechanism.
• SMP based deployment has advantage over traditional deployment.
• Low-cost Alternative.
• Benefit of Smaller storage volume.
• Less reliance on Mechanical Components.
• SMAs can also be utilized to achieve precise actuation in space antennas.
• Spoilers and rear upper panels designed from SMAs can significantly improve the aerodynamical performance of vehicles.

AEROSPACE APPLICATION OF

SMPS AS A SOLID SURFACE

REFLECTOR.

BIOMEDICAL APPLICATION:

1) Angiography:

• Procedure of introducing suitable materials

into the arteries to locate blocked areas.

• Guidewires composed of stainless-steel were

initially used for this process.

• Nitinol guidewires are now being extensively

used for this purpose.

• They have high flexibility and good kink

resistance.

MODEL OF A NITINOL-BASED STENT

EMPLOYED FOR ANGIOGRAPHY.

**BIOMEDICAL APPLICATION:

2. Stents:**

• Designed as a non-invasive way of dealing with physical anomalies.
• Highly expandable and provide means of forming a variety of SMP foams.
• Super elasticity of nitinol makes it ideal for this operation.
• Nitinol exhibits high compatibility with the body and unlike stainless-steel, it does not put a large amount of force on the blood vessels.

(A) PERFORATED SMP STENT (B) SMP

STENT-CATHETER SYSTEM.

**BIOMEDICAL APPLICATION:

4. Artificial cornea implants:**

• Scaffolds developed from interpenetrating polymer networks (IPN) were used to make artificial cornea devices.
• The use of IPNs allows the preparation of 3 D scaffolds possessing high strength and high-water retention capacity.
• These properties combined with their well-defined highly porous structure leads to the development of extremely biocompatible devices.

IPN BASED ARTIFICIAL CORNEA CROSS-

SECTION.

**BIOMEDICAL APPLICATION:

4. Regenerative medicines and tissue engineering:**

• Chitosan-based hydrogels have been used to manufacture wound dressing systems.
• These systems employ rutin which significantly enhances the cellular healing process.
• Polypeptide hydrogels have been employed for the fabrication of wound healing systems.
• These compounds possess antibacterial properties and exhibit a greater magnitude of cell proliferation which boosts the healing process.

FABRICATION OF NANOFIBROUS SCAFFOLDS

FOR TISSUE ENGINEERING.