MEMS (Micro Electro Mechanical Systems) are devices that have static or movable components on the micron scale. They combine microelectronics and micromechanics. Some key MEMS components discussed include microgrippers, micromotors, and microvalves. Microgrippers are used to grip and manipulate microscopic objects and can operate using thermal, piezoelectric, electrostatic or other actuation methods. Micromotors can be linear or rotary and operate using principles like variable reluctance. Microvalves are used to control fluid flow at the microscopic level and have advantages like not leaking or requiring lubrication.

1. MICROGRIPPERS
MICROMOTORS
MICROVALVES
SUBMITTED TO: SUBMITTED BY:
PROF. TEJBIR KAUR DEEPANSHU
SID:18209025

2. What are MEMS and Micro Sytems?
 Micro Electro Mechanical Systems (MEMS ) are devices that have static or movable components
with some dimensions on the scale of microns. MEMS refers to a collection of micro sensors and
actuators that can sense its environment and have the ability to react to changes in that
environment with the use of micro circuit.
 MEMS combine microelectronics and micromechanics, and sometimes micro-optics.
They are referred by different names in different countries :-
MEMS : USA
MicroSystems Technology (MST): Europe
Micromachines: Japan
Smart materials and Smart Structures: India

3. Batch Processing and miniaturization
Batch Processing
Miniaturization
COST REDUCTION
Reliability &
Reproducibility
LOW POWER
OPERATION
BIOMEDICAL AND
AEROSPACE
APPLICATIONS

4.  Each component must be made piece by piece. Low price for large
production volumes are the result of mechanization.
 Ultrasonic machining, sandblasting, laser ablation and spark erosion have
aided in miniaturization.
 Finest details that can be machined are one to two orders larger than what
photolithography makes possible.
Conventional Micromachining Techniques
Silicon Micromachining
 Suitable for batch processing similar fabrication of Ics.
 Production costs of whole production isindependent from number of components
fabricated.
 Miniaturization with finest details in the range of 0.1 to 10µm possible based on
photo-lithography

5. Miniaturization approaches
Classification of MEMS
MEMS structures and devices can be classified into four major groups:
• Passive (nonmoving) structures (eg) microtips.
• Sensors, which respond to the world, (eg) pressure.
• Actuators (reciprocal of the sensors), which use information to influence
something in the world (eg) pump, valve etc.
• Micro-Systems that integrate both sensors and actuators to provide some useful
function.
• Conventional Micromachining
•Silicon Micromachining

6. MEMS Categories and Application
areas
Application Areas
Categories Transportation Communications
Analytical &
Medical
MEMS
Structures
Infrared Imagers
Optical & RF Signal
Guides, Field Emission
Arrays
Micro Filters, Micro
Channels & - Mixers
MEMS
Sensors13
13
Pressure,
Acceleration,&
Angular Rate
Acoustic sensors Gas sensors
MEMS
Actuators
Aerodynamic Flow
Control13
Displays, Optical
switches, &
RFSwitches & Filters
Micro-pumps
& -Valves

7. What are actuators ?
 Actuators use input energy and release output energy in a controlled manner.
 Mechanical actuators act upon something and move it with force or torque.
 There are many types of actuators.
– Based on the type of output energy released.
– Based on the way output energy is released.
– Based on the input energy used.

8. Actuators are transducers.
 Transducers coverts one form of energy to another form.
INPUT ENERGY OUTPUT ENERGY
Mechanical
Optical
Radiation
Acoustic
Fields
ACTUATOR

9. Actuators with different output
energies
 Mechanical actuators
Produce motion
Motors, engines, pumps
 Acoustic actuators
Produce sound
 Optical actuators
Produce light
LEDs, solid‐state lasers
 Others
Radiation
Fields

10. Microgripper
 Micromanipulation of micro parts in assembly, biological cells in micro
surgery and micro particles in material science is of great interest to
scientists and engineers.
 This resulted in innovation of micro tools such as MEMS based micro
gripper which is a typical MEMS device used to grip, hold and
transport micro-objects from one place to another.
 There are many types of micro grippers based on actuation systems
such as thermal, piezoelectric, electrostatic, electromagnetic, vacuum
type and mechanical.
 The general requirement of a microgripper is that it should be able to
pick up and release a component at a specified position. The
positional uncertainty during assembly should be well defined and
components should not be damaged during assembly.

11. PRINCIPLE/WORKING
 Microgripper works on the principle of microactuation
through electrostatic, thermal, piezo effect, shape
memory alloy etc. The gripping action at tip of gripper
initiated by applying voltage across the plates
attached to the drive arms and closure arms. The
electrostatic force generated by these pairs of
misaligned plates tend to align themselves, causing
drive arms to bend which in turn closes the
extension of arm for gripping. The length of gripper
produced by kim et al. was 400 µm and had tip
opening 10 µm.
Arrangement called as
COMB DRIVE

12. Microgrippers are widely used in
 Manufacturing Industry (assembly)
 Electronics (assembly)
 Medical and biological fields (diagnostics, drug delivery, biopsy tissue
 sampling etc.)
 Materials research (manipulation of micro particles)

13. TYPES OF MICROGRIPPER
 Mechanical microgrippers
 Thermal microgrippers
 Electrostatic microgrippers
 Piezoelectric microgrippers
 Vacuum type microgrippers
 Electromagnetic microgrippers

14. Shape memory alloy(SMA) used in
microgrippers
 Shape Memory Alloys (SMA) are alloys that exhibit the shape memory effect.
 The shape memory effect is the process of restoring a deformed material back to an
initial shape through a thermally induced crystalline transformation .The crystalline
transformation occurs between a low temperature ductile martensitic phase and a high
temperature high strength austenitic phase.

15. Advantages/Disadvantages of SMA
The main advantages of SMA’s for microactuation are: –
 SMA’s are capable of producing a large actuation force.
 SMA’s are capable of producing large displacements .
 SMA’s are activated through thermal heating.
The main disadvantages of SMA’s are: –
 Sensitivity of material properties in fabrication .
 Residual Stress’s developed in thin films.
 Nonlinearity of actuation force.
 Lower maximum frequency compared to othe microactuator devices.

16.  Gripping force is obtained by using integrated force sensor.
Three types of force sensors can be integrated in microgripper & They are
 Capacitive force sensor
 Piezoelectric sensor
 Piezoresistive sensor

17. PIEZOELECTRIC EFFECT
PRINCIPLE:
Piezoelectricity is the charge that accumulates in certain solid materials in
response to applied mechanical stress.
ADVANTAGES:
 Even though piezoelectric sensors are electromechanical systems that react to
compression,
the sensing elements show almost zero deflection.
 This is the reason why piezoelectric sensors are so rugged, have an extremely
high natural frequency and an excellent linearity over a wide amplitude range.
 Additionally, piezoelectric technology is insensitive to electromagnetic fields and
radiation, enabling measurements under harsh conditions.

18. Live examples
 https://www.youtube.com/watch?v=fHp95e-CwWQ&ut=
 https://www.youtube.com/watch?v=EqZIwujBSr8
 https://www.youtube.com/watch?v=MIgz7424L_E
 https://www.youtube.com/watch?v=cMSdLMcLIpU

19. Applications
This microgripper can be specifically used in micro-surgeries and
manipulation of micro bodies such as cells and micro-organisms due to its
low voltage and low temperature.
They can also be used to manipulating micro particles and microcomponents
in micro assembly as the force exerted by polymer microgrippers is very less.

20. MICROMOTORS
There are two types of micromotors used in microsystem:
linear and rotary motors.
Working principle of linear motor is linear motion between
two sets of parallel base plates which are separated by
non-compressible, frictionless dielectric material such as
quartz. Each of the two sets of base plates contains a no.
of electrodes made of electric conducting plates.

23. Principle of VR MOTORS

24. MICROMOTORS
(VR STEPPER MOTOR)
These types of micromotors have been operated continuously
for over three months at over 1010 rotational cycles and
reveal no change in operating characteristics, which for a
journal bearing is quite acceptable. The low wear rate that is
observed is suspected to be partially due to a vertical variable
reluctance rotor suspension, a consequence of a thinner rotor
than stator, that maintains rotor rotation off of the substrate. This
category of micromotors with integrated wire-bonded coils is
found to be rather inefficient, with output torques of the order of
10 nNm.

25. examples
 https://www.youtube.com/watch?v=-5jf_wwB_MI
 https://www.youtube.com/watch?v=i-Dm-5EfSAk&ut=
 https://www.youtube.com/watch?v=VbTUsluY2xU
 https://www.youtube.com/watch?v=uFZsH62ewYo

26. MICROVALVES
A microvalve was a part of the fluid control system found as form of enclosed space.
Responding to commands from the pilot or copilot, the valve would open or close to
allow pressurized fluid to follow a certain path along the flowtrack to prompt various
systems. Since its introduction in 1956, the MicroValve has provided successful service
through thousands of applications. Choose MicroValve, the best valve to solve liquid, air
and gas service design problems. It absolutely will not leak. With other miniature
valves, leakage occurs when flow is redirected from one port to another. But with the
MicroValve, flow is instantly redirected so there is no leakage. .With a unique, overcenter
snap-action, it will give a quick, sure response. There are no sliding seals, packing, or
tight-fitting moving parts to leak, wear out or stick. Therefore, no lubricants are
required.

27.  Micro valves will withstand abrasive-bearing fluids. With all ports having some connection,
external contaminants cannot enter the units. Dirt and grit will not prevent tight seating and
will not cause the valve to stick. These valve offers sure response, with no neutral position, and
no varying time lag between positions. Micro Valves maintain either position without holding
force, and cannot be vibrated or jarred out of position. Valve action is full-speed regardless of
operator speed or force applied. Trip-point position repeats accurately and is essentially
independent of the speed of the external actuating device. Light operating forces are required
and not affected by operating pressure or flow rate. Shut-off is bubble-tight up to rated pressures.
Types of microvalves
1) Active microvalves :- Active mechanical microvalves consist of mechanically movable membrane or
boss structure, coupled to an actuation method, that can close of an orifice, thus blocking the flow
path between the inlet and outlet ports. The actuator can either be an integrated magnetic,
electrostatic, piezoelectric or thermal microactuator, a "smart" phase change, e.g. Shape-memory
alloy, or rheological material, or an externally applied actuation mechanism, such as an external
magnetic field or pneumatic source.
2) Passive microvalves :- Passive microvalves are valves for which the operational state, i.e. open or
close, is determined by the fluid they control. Most common passive microvalves are flap valves,
membrane microvalves and ball microvalves.

28. PRINCIPLE/WORKING
 Microgripper works on the principle of microactuation. As
the give fig. shows the schematic diagram the heating of
two electrical resistor ring attached to the top diaphragm
can cause downward movement and flow resisted and vice
versa. Size of diaphragm is 2.5 µm in diameter and 10
µm thick. The heating rings are made up of aluminum 5
µm thick. The valve has a capacity of 300 cm3/min and
100 psi, and 1.5 kw power needed at 25 psig pressure.

29. PASSIVE MICROVALVE ACTIVE MICROVALVE

31. Features and benefits
 Flow is instantly redirected, so there is no leakage.
 Unique over-center snap action provides quick,
sure response.
 No sliding seals, packing or tight-fitting moving
parts to leak or wear out.
 Requires no lubrication; no need to introduce a
system lubricator.
 Suitable for vacuum service.

32. Applications
 Pressure switches.
 Level controls.
 Air switch to operate pneumatic tools and pumps.
 Pilot operation of main valves.
 Limit switches on cylinder actuated devices.
 Diverting valve used to introduce additive to two independent flow systems

33. Examples
 https://www.youtube.com/watch?v=0b8SQgMIkgc

34. THANK YOU