modern machining process_Dr.Deepak.pdf

Advanced Machining Process

PRESENT DAY DEMAND TRENDS IN INDUSTRIES(AEROSPACE , MISSILES ,

AUTOMOBILES, NUCLEAR REACTORS, ETC.)

Advanced Materials

Need for Advanced machining process

Non-traditional machining

The term non-traditional machining refers to

this group that removes excess material by

various techniques involving mechanical,

thermal, electrical, or chemical energy (or

combinations of these energies).

They do not use a sharp cutting tool in the

conventional sense.

Technological importance of the nontraditional

The need to machine newly developed metals and nonmetals. These new materials often have special properties (e.g., high strength, high hardness, high toughness)that make them difficult or impossible to machine by conventional methods.

The need for unusual and/or complex part geometries that cannot easily be accomplished and in some cases are impossible to achieve by conventional machining.

The need to avoid surface damage that often accompanies the stresses created by conventional machining

Many of these requirements are associated with the aerospace, nuclear and electronics industries, which have become increasingly important in recent decades.

Advanced Machining Process

MACHINING OF COMPLEX SHAPED WORKPIECES?

ELECTROCHEMICAL MACHINING

PRECISION WIRE EDM

Chemical Milling

(a) Missile skin-panel section contoured by chemical milling to improve the stiffness-to-weight ratio of the part. (b) Weight reduction of space launch vehicles by chemical milling of aluminum-alloy plates

Super alloy turbine blades of jet engines

Turbine blade with cooling holes for film

cooling

Laser-drilled holes permit film

cooling in this first-stage nozzle

guide vane

Parts made using EBM

Typical parts made by electrochemical machining.

(a) Turbine blade made of a nickel alloy, 360 HB

(b) Thin slots on a 4340-steel roller-bearing

cage.

(c) Integral airfoils on a compressor disk.

EDM process

Stepped cavities produced with a square

electrode by EDM

(a) Examples of cavities produced by the electrical-discharge-machining process, using

shaped electrodes. The two round parts (rear) are the set of dies for extruding the aluminum

piece shown in front. (b) A spiral cavity produced by a rotating electrode (c) Holes in a fuel-

injection nozzle made by electrical-discharge machining.

LBM

(a) Schematic illustration of the laser-beam-machining process. (b) and (c) Examples of holes produced in nonmetallic parts by LBM.

Classification of nontraditional processes 1. Mechanical. Mechanical ene rgy in some form other than the action of a conventional cutting tool is used in these nontraditional processes. Erosion of the work material by a high velocity stream of abrasives or fluid (or both) is a typical form of mechanical action in these processes.

2. Electrical. These nontraditional processes use electrochemical energy to remove material; the mechanism is the reverse of electroplating.

3. Thermal. These processes use thermal energy to cut or shape the workpart. The thermal energy is generally applied to a very small portion of the work surface, causing that portion to be removed by fusion and/or vaporization. The thermal energy is generated by the conversion of electrical energy.

4. Chemical. Most materials (metals particularly) are susceptible to chemical attack by certain acids or other etchants. In chemical machining, chemicals selectively remove material from portions of the workpart, whereas other portions of the surface are protected by a mask.

CLASSIFICATION BASED ON THE KIND OF ENERGY USED : MACHANICAL,

THERMOELECTRIC, ELECTROCHEMICAL & CHEMICAL,

Over view of non-traditional machining process

Ultrasonic machining

abrasives contained in a slurry are driven at high velocity against the work by

a tool vibrating at low amplitude (0.075 mm) and high frequency (20,000 Hz.)

The tool (steel and stainless steel) oscillates in a direction perpendicular to

thework surface, and is fed slowly into the work, so that the shape of the tool

is formed in the part.

the action of the abrasives (boron nitride, boron carbide, aluminium oxide,

silicon carbide and diamond) impinging against the work surface, that

performs the cutting

Grit size ranges between 100 and 2000m.

The slurry in USM consists of a mixture of water and abrasive particles.

Concentration of abrasives in water ranges from 20% to 60%


The cutting action in USM operates on the tool as well as the work. As the abrasive particles erode the work surface, they also erode the tool, thus affecting its shape.

to machine hard, brittle work materials, such as ceramics, glass, and carbides.

It is also successfully used on certain metals, such as stainless steel and titanium

Shapes obtained by USM include non-round holes, holes along a curved axis, and coining operations, in which an image pattern on the tool is imparted to a flat work surface.

WATER JET MACHINING (WJM), ABRASIVE WATER JET MACHINING (AWJM) ,

ABRASIVE JET MACHINING (AJM)

ELETRIC DISCHARGE MACHINING

LASER BEAM MACHINING (LBM)

ULTRASONIC MACHINING

PLASMA ARC MACHINING (PAM)

ELECTRO CHEMICAL MACHINING (ECM)

ELECTROCHEMICAL ENERGY DETACHES METAL

FROM ANODE ATOM BY ATOM

ELECTRIC DISCHARGE MACHINING (EDM) :

MACHINE ELEMENTS

ELECTRON BEAM MACHINING (EBM)

Process capability-Non traditional machining

process

Detailed study

MECHANICAL ENERGY PROCESSES

MECHANICAL ENERGY PROCESSES

(1) Ultrasonic machining and Rotary Ultrasonic machinig

(2) Water jet machining

(3) Abrasive jet machining

(4)Abrasive water jet machining

(5)Abrasive flow machining process

(6) Magnetorheological abrasive finishing process

Abrasive Jet Machining

Abrasive Jet Machining

A jet of inert gas consisting of very fine abrasive particles strikes the work piece at high velocity (usually between 200-400 m/s) resulting in material removal through chipping / erosive action

In abrasive jet machining (AJM) a focused stream of abrasive grains of Al2O3 or SiC carried by high-pressure gas or air at a high velocity is made to impinge on the work surface through a nozzle of 0.3- to 0.5-mm diameter

This erosive action has been employed for cutting, cleaning, etching, polishing and deburring

This method of material removal is quite effective on hard and / or brittle materials (viz glass, silicon, tungsten, ceramics, e tc ) but not so effective on soft materials like aluminum, rubber, etc.

AJM system

In the machining system a gas (nitrogen, CO2,He or air) is supplied under a pressure of

2 to 8 kg/cm2. (Oxygen should not be used ???)

After filtration and regulation, the gas is passed through a mixing chamber that

contains abrasive particles

From the mixing chamber, the gas, along with the entrained abrasive particles (1040

m), passes through a 0.45 -mm-diameter Sapphire or tungsten carbide nozzle at a

speed of 200 to 400 m/s.

Aluminum oxide (Al2O3) and silicon carbide powders are used for heavy cleaning,

cutting, and deburring

AJM

Tolerances are typically 0.13 mm though 0.05 is possible with process optimization

Surface roughnesses of 0.2 to 1.5 m using 10 and 50 m particles, respectively, can be attained

Mixing ratio(M)=Volumetric flow rate of

abrasive/ volumetric flow rate of carrier gas

Material removal in AJM

Material removal in AJM takes place due to

brittle fracture of the work material due to

impact of high velocity abrasive particles

The MRR (mm3/s) due to chipping of the work surface by

impacting abrasive particle is given by

ma=abrasive flow rate, v= velocity of abrasives, H as the

hardness or the flow strength of the work material ,g=density

of the abrasive grains

3/2

1/4 3/4

a

g

m vMRR

H

AJM-Process control

Effect of process parameters in MRR

Mixing ratio(M)=Volumetric flow rate of abrasive/ volumetric flow rate of carrier gas

Process Characteristics of AJM

AJM-Applications

1. Drilling holes, cutting slots, cleaning hard surfaces, deburring, polishing, and radiusing

2. Deburring of cross holes, slots, and threads in small precision parts that require a burr-free

finish, such as hydraulic valves, aircraft fuel systems, and medical appliances

3. Machining intricate shapes or holes in sensitive, brittle, thin, or difficult-to-machine materials

4. Insulation stripping and wire cleaning without affecting the conductor

5. Micro-deburring of hypodermic needles

6. Frosting glass and trimming of circuit boards, hybrid circuit resistors, capacitors, silicon, and

gallium

7. Removal of films and delicate cleaning of irregular surfaces because the abrasive stream is

able to follow contours

AJM-Limitations

The removal rate is slow.

Stray cutting cant be avoided (low accuracy of (low accuracy of 0.1mm)

The tapering effect may occur especially when drilling in metals.

The abrasive may get impeded in the work surface.

Suitable dust-collecting systems should be provided.

Soft materials cant be machined by the process.

Silica dust may be a health hazard.

Ordinary shop air should be filtered to remove moisture and oil

Water jet and Abrasive Water jet cutting

What is Waterjet Cutting?

Erosion process of material

Types of Waterjets?

Abrasive Waterjet (AWJ): involves the entrainment

of abrasive particles into the high pressure water

jet

Waterjet (WJ): using only high pressure water jet

energy with no additives

What is an Orifice?

The primary component of the nozzle

where the energy formation occurs

Waterjet (WJ)?

Orifice

Waterjet

Nozzle

Plastic

Foam

Paper

Rubber

Food

Gaskets

Waterjet Applications

Waterjet Applications

Abrasive Waterjet (AWJ)?

Abrasive

Jet

High Pressure Water

AWJM-History

Dr. Franz in 1950s first studied UHP water cutting for forestry and wood cutting (pure WJ)

1979 Dr. Mohamed Hashish added abrasive particles to increase cutting force and ability to cut hard materials including steel, glass and concrete (abrasive WJ)

First commercial use was in automotive industry to cut glass in 1983

Soon after, adopted by aerospace industry for cutting high-strength materials like Inconel, stainless steel and titanium as well as composites like carbon fiber

Introduction to Waterjet

Fastest growing machining process

One of the most versatile machining processes

Compliments other technologies such as milling, laser,

EDM and plasma

True cold cutting process no HAZ, mechanical

stresses or operator and environmental hazards

Not limited to machining food industry applications

WJM - suitable for cutting plastics, foods, rubber insulation, automotive

carpeting and headliners, and most textiles.

Harder materials such as glass, ceramics, concrete, and tough composites

can be cut by adding abrasives to the water jet.

Abrasive water jet machining (AWJM) Developed in 1974 to clean metal prior

to surface treatment of the metal.

The addition of abrasives to the water jet enhanced MRR and produced

cutting speeds between 50 and 450 mm/min.

Generally, AWJM cuts 10 times faster than the conventional machining

methods of composite materials.

Abrasive water jet is hundreds of times more powerful than the pure water jet.

Introduction-AWJM

Water is pumped at a sufficiently high pressure, 200-400 MPa (2000 4000

bar).

Intensifier works on the principle of pressure amplification using hydraulic

cylinders of two different cross-sections.

When water at such a pressure is passed through a suitable orifice (nozzle

having = 0.2 0.4 mm), the potential energy of water is converted into kinetic

energy.

This yields high velocity (~ 1000 m/s) jet of water.

Such a high velocity water jet can machine thin sheets/foils of aluminium,

leather, textile, frozen foods, etc.

WJM commercially pure water (tap water) is used for machining.

Basic Methodology-WJM

Schematic of Abrasive water jet cutting machine

Water Jet Cutting

Water jet cutting (WJC) uses a fine, high-pressure, high-velocity stream of water directed at the work surface to cause cutting of the work

To obtain the fine stream of water a small nozzle opening of diameter 0.1 to 0.4 mm is used

Water Jet Cutting

To provide the stream with sufficient energy for cutting, pressures up to 400MPa are used, and the jet reaches velocities up to 900 m/s

Water jet cutting can be used effectively to cut narrow slits in flat stock such as plastic, textiles, composites, floor tile, carpet, leather, and cardboard.

Robotic cells have been installed with WJC nozzles mounted as the robots tool to follow cutting patterns that are irregular in three dimensions, such as cutting and trimming of automobile dashboards before assembly.

Abrasive Water Jet Cutting

When WJC is used on metallic work parts,

abrasive particles must usually be added to the

jet stream to facilitate cutting.

This process is therefore called abrasive water

jet cutting (AWJC).

Introduction of abrasive particles into the

stream complicates the process by adding to

the number of parameters that must be

controlled. Among the additional parameters

are abrasive type, grit size, and flow rate.

Abrasive Water jet Machine

Water jet machine

Types of Abrasive

Garnet: Most widely used, cost effective and best balanced performance.

Fine particles of sand (silicate) Aluminum Oxide: Very aggressive, increases wear of focusing tube and abrasive

mixing chamber. Specialty applications. Silicon Carbide: Very aggressive, increases wear of focusing tube and abrasive

mixing chamber. Specialty applications.

62

Cutting Heads

Schematic View Photographic View

Intensifier Pump

Intensifier

Intensifier

Intensifier driven by a hydraulic power pack.

Heart of hydraulic power pack is a positive displacement hydraulic pump.

The power packs in modern commercial systems are often controlled by

microcomputers to achieve programmed rise of pressure, etc.

Hydraulic power pack delivers hydraulic oil at a pressure ph to Intensifier.

Intensifier Contd.

Ratio of cross-section of the two cylinders, A ratio = A large / A small

Thus, pressure amplification at the small cylinder takes place as follows:

Thus, if the hydraulic pressure is set as 100 bar and area ratio is 40, pw = 100

x 40 = 4000 bar.

By using direction control valve, the intensifier is driven by the hydraulic unit.

The water may be directly supplied to the small cylinder of the intensifier.

Intensifier Contd.

Or it may be supplied through a booster pump, which typically raises the water

pressure to 11 bar before the intensifier.

Sometimes water is softened or long chain polymers are added in additive unit.

Thus, as the intensifier works, it delivers high pressure water.

As the larger piston changes direction within the intensifier, there would be a

drop in the delivery pressure.

To counter such drops, a thick cylinder is added to the delivery unit to

accommodate water at high pressure.

This is called an accumulator which acts like a fly wheel of an engine and

minimises fluctuation of water pressure.

INTENSIFIER PUMP

The "intensification principle" varies the area component of the pressure equation to intensify, or increase, the pressure.

Pressure = Force /Area

If Force = 20, Area = 20, then Pressure = 1. If we hold the Force constant and greatly

reduce the Area, the Pressure will go UP. For example, reduce the Area from 20 down to

1, the Pressure now goes up from 1 to 20. In the sketch above, the small arrows denote

the 2 MPa psi of oil pressure pushing against a biscuit face that has 20 times more area

than the face of the plunger. The intensification ratio, therefore, is 20:1.

Abrasive Waterjet

ABRASIVE

FEEDER

NOZZLE

ON/OFF VALVE

Electric Motor & Hydraulic Power

Pack

HP WATER

HYD. OIL

LP WATER

Catcher

Orifice material

Sapphire is the most common orifice material used today. It is a man-made, single crystal

jewel. It has a fairly good quality stream, and has a life, with good water quality, of

approximately 50 to 100 cutting hours. In abrasive Waterjet applications the Sapphires

life is that of pure Waterjet applications. Sapphires typically cost between Rs 1000 and

Rs 2000 each.

Ruby can also be used in abrasive Waterjet applications. The stream characteristics

are well suited for abrasivejets, but are not well suited for pure Waterjet cutting. The

cost is approximately the same as the sapphire.

Diamond has considerably longer run life (800 to 2,000 hours) but is 10 to 20 times more

costly. Diamond is especially useful where 24 hour per day operation is required.

Diamonds, unlike the other orifice types, can sometimes be ultrasonically cleaned and

reused.

Typical Parameters in Entrained AWJM

Orifice Sapphires 0.1 to 0.3 mm

Focussing Tube WC 0.8 to 2.4 mm

Pressure 2500 to 4000 bar

Abrasive garnet - #125 to #60

Abrasive flow rate - 0.1 to 1.0 kg/min

Stand off distance 1 to 2 mm

Machine Impact Angle 60o to 900

Traverse Speed 100 mm/min to 5 m/min

Depth of Cut 1 mm to 250 mm

Key Parameters

Operating pressure

Abrasive: flow rate, type & mesh size

Standoff distance

Cut rate; AWJ a single parameter process

Typical Parameters

Abrasive Waterjet Attributes

Extremely versatile process No Heat Affected Zones

No mechanical stresses

Easy to program

Thin stream (0.5 mm to 1mm in diameter)

Extremely detailed geometry

Thin material cutting

Up to 250 mm thick cutting

Little material loss due to cutting

Simple to fixture

Low cutting forces (under 5 N while cutting)

One jet setup for nearly all abrasive jet jobs

Easily switched from single to multi-head use

Quickly switch from pure waterjet to abrasive waterjet

Reduced secondary operations

Little or no burr

Mixing

Mixing means gradual entrainment of abrasive particles within the water jet and finally the abrasive water jet comes out of the focussing tube or the nozzle.

During mixing process, the abrasive particles are gradually accelerated due to transfer of momentum from the water phase to abrasive phase and when the jet finally leaves the focussing tube, both phases, water and abrasive, are assumed to be at same velocity

Mixing process Mixing process may be mathematically modelled as follows. Taking into account the energy loss during water jet formation at the orifice, the water jet velocity may be given as,

Mixing process

MRR estimation

Process accuracy

When cutting materials under 1 inch (2.54 cm)

thick, a conventional water jet machine

typically cuts parts from .07 to .4 mm in

accuracy.

For materials over 1 inch thick the machines

will produce parts from .12 to 2.5 mm

Process variables

Pressure

Nozzle diameter

Standoff distance

Abrasive type and grit number

Workpiece feed rate

An abrasive water jet cuts through 356.6 mm thick slabs of concrete or 76.6-mm-

thick tool steel plates at 38 mm/min in a single pass.

Surface roughness ranges between 3.8 and 6.4 m.

Tolerance - 0.15 mm.

Straightness 0.05 mm per axis length.

Process Capabilities

Jet lag

When the Waterjet,

, the stream will deflect backwards (opposite direction of travel) when cutting power begins to drop. This problem causes:

increased taper,

inside corner problems, and

sweeping out of arcs.

Reduce this lag error by increasing cutting power or slowing down the cut speed.

Material Removal in AWJM

Mechanism of material removal in WJM or AWJM is rather complex.

In AWJ machining of ductile materials, material is mainly removed by low

angle impact of abrasive particles.

Further at higher angle of impact, the material removal involves plastic

failure of the material at the sight of impact.

In AWJ machining of brittle materials, material would be removed due to

crack initiation and propagation because of brittle failure of the material.

In water jet machining, the material removal rate may be assumed to be

proportional to the power of the water jet.

Product quality in AWJM

The cut generated by an AWJM is called a kerf.

Top of the kerf (bt) is wider than the bottom of the

kerf (bb).

bt is equal to the diameter of AWJ or AWJM.

Diameter of AWJ is equal to the diameter of the

focussing tube or the insert if the stand-off distance

(SOD) is around 1 to 5 mm.

Taper angle of the kerf can be reduced by

increasing the cutting ability of the AWJ.

90


Waterjet cutting Vs. Laser cutting

After laser cutting

After waterjet cutting

Edge Quality

Coarse Medium Fine Extra Fine

Edge quality is a function of speed, pressure, nozzle size

and abrasive flow rate

Striation marks are the bend in the stream


Thus, in WJM and AWJM the following are the

important product quality parameters.

Striation formation.

Surface finish of the kerf.

Tapering of the kerf.

Burr formation on the exit side of the kerf.

KMT US Inc. - KMT Waterjet

Edge Quality

Edge Quality

Waterjet vs. Others

AWJ EDM Laser Plasma Gas

Thickness + + + - + + + +

Cut Rate - - - + + + + +

Surface Finish + + + + + - - -

Heat Affected Zone + + + + - - - -

Environment Safety + + - - - - - - - -

Material Flexibility + + - + - - - -

Secondary Operation + + + + - - -

Operation Cost - + - + + +

Capital Investment 100% 60% 200% 80% 40%

WATERJET vs. Plasma vs. Laser vs. EDM

Why Waterjet?

No special tooling, minimal or no setup

Minimal kerf width & maximum material utilization

Rapid prototyping, programming

Minimal or no burr & quality surface finish

Why Waterjet?

Versatile and Flexible Process

Metals & exotic materials such as Titanium

Highly reflective, thermal conductive materials

& polished materials. Aluminum, Brass, Copper

& Galvanized Steel

Why Waterjet?

Versatile and Flexible Process

Marble, granite, ceramic tiles & glass

Fiberglass, composites & laminates

Etc.

Titanium Alloy..


Brass.. SS.. Aluminum..


Stone.. Glass..

FAQ in water jet cutting

What can be cut with waterjet or abrasivejet?

Virtually anything! Materials commonly cut with waterjet include rubber, foam, plastics, composites, stone, tile, metals, food, paper and much more. The only materials that cannot be cut with waterjet are tempered glass, diamonds and certain ceramics.

How thick can a waterjet cut?

Can cut metals as thick as 20 inches, including 15 inch titanium, with abrasive waterjet. Usual range is up to 12 inches


How much water do waterjets use?

use a 1.5 to 3 litres of water per minute for

cutting, depending on the cutting head orifice

size. In addition 10 to 15 liters per minute are

used to cool the waterjet pump. The water can

be recycled using a closed-looped system.

Waste water usually is clean enough to filter

and dispose of down a drain.


How much garnet abrasive does an abrasive

waterjet use?

Abrasive waterjets use approximately 0.25 to

1.36 Kg of abrasive per minute. Garnet abrasive

is the most common abrasive used for

abrasivejet cutting. It is a natural material that

can usually be disposed of in a landfill.


How much does it cost to operate a waterjet

system?

A typical abrasivejet costs about $19-35 per

hour (Rs 1200 to Rs2000 ) to run per nozzle

depending on horsepower, plus labor. This

includes consumable parts, garnet, water and

electricity. Utility costs vary depending on your

location.


How much do waterjet systems cost?

Precision industrial waterjet systems can cost

$150,000-$500,000+ (1 crore to 3 crore),

depending on the table and pump size,

accessory items and custom engineering

needs. Smaller budget systems cost around

$80,000-$100,000. Mobile waterjet systems

generally cost more than $100,000, depending

on the system.

Water jet technology

Some examples of aerospace Original Equipment Manufacturers (OEMs) using waterjet technology include: custom control panels, structural components for special purpose aircraft, turbine blades, jet engines, aluminum skins, struts and brake components

Custom control panels and structural components for special purpose aircraft such as crop-dusters and float planes

Rough trimming of turbine blades on jet engines

Aluminum skin, struts, seats, shim stock, brake components, titanium & exotic metals used in manufacturing landing gear

Water jet technology

In these applications, advantages of WJC

include:

(1) no crushing or burning of the work surface

typical in other mechanical or thermal

processes,

(2) minimum material loss because of the

narrow cut slit,

(3) no environmental pollution, and

(4) ease of automating the process.

What Materials Can a Waterjet Cut?

rubber

Glass(cracking issue is there) metal

granite

abrasive water jet- Application

Waterjets are ideal for food cutting

applications. They are non-contact and never

need sharpening.

Turbine part cut with abrasive waterjet


Alliance Automation LLC incorporates Jet Edge waterjets into its robotic waterjet cutting systems, which are commonly used in the automotive industry.


The Boston-area water jet contractor cut a 55-inch diameter hole in the top of the underground tank to allow for the installation of a robotic system that will remove 247,000 gallons of radioactive and chemical waste stored in the tank during the Manhattan Project and Cold War so it can be vitrified for safer storage.


ULTRASONIC MACHINING (USM) isa process that utilizes the ultrasonic (20 kHz) vibration of a tool in the machining of hard, brittle, nonmetallic materials.

The USM process consists of two methods:

Ultrasonic impact grinding (known as Ultrasonic machining): Involves an abrasive slurry and the ultrasonic vibration of a non-rotating tool

Rotary ultrasonic machining: Involves the ultrasonic vibration of a rotating diamon core drill or milling tool


The tool, which is a negative of the workpiece, is vibrated at around 20KHz with and amplitude of between 0.01 mm and 0.1 mm in abrasive slurry at the workpiece surface.

Material removal is by 3 mechanisms:

Hammering of grit against the surface by the tool.

Impact of free abrasive grit particles (erosion).

Micro-cavitation.

Material removal mechanism of USM

1. Mechanical abrasion by localized direct hammering of the abrasive grains stuck between the vibrating tool and adjacent work surface.

2. The micro-chipping by free impacts of particles that fly across the machining gap and strike the work-piece at random locations.

3. The work surface erosion by cavitation in the slurry stream.


abrasives contained in a slurry are driven at high velocity against the work by

a tool vibrating at low amplitude (0.075 mm) and high frequency (20,000 Hz.)

The tool (steel and stainless steel) oscillates in a direction perpendicular to

thework surface, and is fed slowly into the work, so that the shape of the tool

is formed in the part.

the action of the abrasives (boron nitride, boron carbide, aluminium oxide,

silicon carbide and diamond) impinging against the work surface, that

performs the cutting

Grit size ranges between 100 and 2000m.

The slurry in USM consists of a mixture of water and abrasive particles.

Concentration of abrasives in water ranges from 20% to 60%

Relative Machinability Ratings for Some

Materials by USM

glass has a higher machinability than that of a metal of similar hardness.

because of the low brittleness criterion of steel, which is softer, it is used as a tool material.

Abrasive slurry - Ultrasonic machining

A constant stream of abrasive slurry is circulated between the tool and the workpiece.

Abrasive slurry is usually composed of 50 percent (by volume) fine abrasive grains (100800 grit number) of boron carbide (B4C), aluminum oxide (Al2O3), or silicon carbide (SiC) in 50 percent water.

The slurry is pumped through a nozzle close to the tool-workpiece interface at a rate of 25 liters per minute (L/min).

In addition to providing abrasive grain to the cutting zone, the slurry is used to flush away debris. The vibrating tool, combined with the abrasive slurry, abrades the material uniformly, leaving a precise reverse image of the tool shape.


High-frequency, low-amplitude energy is transmitted to the tool assembly.

A constant stream of abrasive slurry passes between the tool and workpiece.

The vibrating tool, combined with the abrasive slurry, uniformly abrades the material, leaving a precise reverse image of the tool shape.

The tool does not come in contact with the material; only the abrasive grains contact the workpiece


The cutting action in USM operates on the tool as well as the work. As the abrasive particles erode the work surface, they also erode the tool, thus affecting its shape.

to machine hard, brittle work materials, such as ceramics, glass, and carbides.

It is also successfully used on certain metals, such as stainless steel and titanium

Shapes obtained by USM include non-round holes, holes along a curved axis, and coining operations, in which an image pattern on the tool is imparted to a flat work surface.

Characteristics of the USM process

USM- The machining system

The machining system is composed mainly the convertor (magnetostrictor, or piezoelectric) concentrator, tool, and slurry feeding arrangement.

The magnetostrictor is energized at the ultrasonic frequency and produces small-amplitude vibrations. Such a small vibration is amplified using the constrictor (mechanical amplifier) that holds the tool.

The abrasive slurry is pumped between the oscillating tool and the brittle workpiece.

A static pressure is applied in the tool-workpiece interface that maintains the abrasive slurry.

Converter or transducer

A converter to change the electrical energy into

mechanical vibrations.

Two types of converters are available for USM

systems.

magnetostrictive device,

quartz or a lead zirconate titanate piezoelectric

transducer

Magnetostictive transducer

The magnetostrictor used in USM, shown in has a high-frequency winding wound on a magnetostrictor core and a special polarizing winding around an armature

Magnetostictive transducers work on the principle that if a piece of Ferro-magnetic material (like nickel alloys) is magnetized, then a change in dimension occurs.

The transducer has solenoid type winding of wire over a stack of nickel laminations (which has rapid dimensional change when placed in magnetic fields) and is fed with an A.C supply with frequencies up to 25,000 c/s.

Magnetostriction due to a variable magnetic field Magnetostictive transducer

magnetostrictive elongation The coefficient of magnetostriction elongation m is

where l is the incremental length of the magnetostrictor core and l is the original length of the magnetostrictor core, both in millimeters.

Materials having high magnetostrictive elongation are recommended to be used for a magnetostrictor

In order to obtain the maximum amplification and a good efficiency, the magnetostrictor must, therefore, be designed to operate at resonance where its natural frequency must be equal to the frequency of the magnetic field.

m

l

l

Schematic of complete vertical USM equipment

Mechanical amplifier or booster horns

The elongation obtained at the resonance frequency using a magnetostrictor is usually 0.001 to 0.1 m, which is too small for practical machining applications.

The vibration amplitude is increased by fitting an amplifier (acoustic horn) into the output end of the magnetostrictor.

Larger amplitudes, typically 40 to 50 m, are found to be suitable for practical applications.

Depending on the final amplitude required, the amplitude amplification can be achieved by one or more acoustic horns

Acoustic horns

The choice of the shape of the acoustic horn controls the final amplitude.

Five acoustic horns (cylindrical, stepped, exponential, hyperbolic cosine, and

conical horns) have been reported

Piezoelectric Transducer-USM

The main drawbacks of the magnetostrictive transducer are the high losses encountered, the low efficiency (55 percent), the consequent heat up, and the need for cooling. Higher efficiencies (9095npercent) are possible by using piezoelectric transformers to modern USM machines.

Piezoelectric transducers utilize crystals like quartz whose dimensions alter when being subjected to electrostatic fields.

The charge is directionally proportional to the applied voltage.

Lead zirconate titanate piezoelectric disks are used which convert the electrical energy from the power supply into a mechanical vibration.

To obtain high amplitude vibrations the length of the crystal must be matched to the frequency of the generator which produces resonant conditions.

USM-Tool

Tool material should be tough and ductile.

The cutting tool, custom shaped to the hole or cavity required, is most commonly made of type 304 stainless steel for durability.

For low-volume production, brass can be used.

Brass is easier to shape than stainless steel, but is less wear resistant.

Tools are attached to the horn by threading up and screwed (small tools) or silver soldered (large tools) directly to the face of the horn.

Because the horn and tool assembly must be resonant at 20 kHz to operate effectively, the size of the tools that can be used is limited.

The maximum diameter is about 38 to 50 mm depending on wall thickness and length.

Grinding and thread-cutting wheels up to 32 mm in diameter have also been successfully used.

Mass of tool should be minimum possible so that it does not absorb the ultrasonic energy.

abrasive material-USM

the removal rate rises at greater grain sizes until the size

reaches the vibration amplitude, at which stage, the material

removal rate decreases.

The abrasive material used should be harder than the workpiece

Because of its higher hardness, B4C achieves higher removal

rates than silicon carbide (SiC) when machining hard workpiece.

abrasive material-USM Aluminum oxide, for example, would be suitable for glass and the more brittle materials, while harder materials, such as sapphire, will require boron carbide, the hardest of the abrasive materials.

The rate of material removal obtained with silicon carbide is about 15 percent lower when machining glass, 33 percent lower for tool steel, and about 35 percent lower for sintered carbide.

the larger the grit size, the faster the cutting but the coarser the surface finish. Small grit sizes cut slower but produce a better surface finish.

A surface finish of 0.5 to 0.2 m can be expected from a 240-grit and an 800-grit abrasive, respectively,

Abrasive slurry-USM

The slurry consists of 50 vol% abrasive particles and 50 vol% water.

The slurry is pumped through a nozzle close to the tool /work piece interface at a rate of about 25 L/min

In addition to its cutting action, the slurry provides cooling for the tool and the workpiece.

The slurry will eventually become less effective as the particles wear and break down.

Expected life is between 150 and 200 h of ultrasonic exposure.

Factors affecting USM performance

Process parameters effect on ultrasonic machining process

Amplitude of vibration (ao) 15 50 m

Frequency of vibration (f) 19 25 kHz

Feed force (F) related to tool dimensions

Abrasive size (dg) 15 m 150 m

Abrasive material Al2O3 -

SiC B4C - Boronsilicarbide Diamond

Flow strength of work material

Flow strength of the tool material

Volume concentration of abrasive in water slurry C

Ultrasonic machining-advantages Parts are burr-free with no residual stresses, distortion or thermal effects.

There are no changes to the metallurgical, chemical or physical properties of the workpiece.

Good for machining very brittle materials.

USM) is a non-thermal, non-chemical and non-electrical machining process that leaves the chemical composition, material microstructure and physical properties of the workpiece unchanged

UM is a mechanical material removal process that can be used for machining both conductive and non-metallic materials with hardnesses of greater than 40 HRC (Rockwell Hardness measured in the C scale).

The UM process can be used to machine precision micro-features, round and odd-shaped holes, blind cavities, and OD/ID features.

Multiple features can be drilled simultaneously, often reducing the total machining time significantly

The process offers good surface finish and structural integrity

The process is free from burrs and distortions.

Ultrasonic machining-disadvantages USM has low material removal rate.

Tool wears fast in USM.

Machining area and depth is restraint in USM.

The USM process consumes higher power and has lower material-removal rates compared to traditional fabrication processes

Soft materials like lead and plastics are not suitable for machining by the USM process, since they tend to absorb the abrasive particles rather than to chip under their impact

While producing deeper holes through USM method, there is ineffective slurry circulation leading to presence of a fewer active grains under the tool face. Due to this, the bottom surfaces of blind holes tend to become slightly concave.

The economics-Limitations

Suitable for low production rates only.

Special tooling required for each job. High

tooling costs.

Multiple cuts required for progressively better

finish.

Tool wear is a problem requiring frequent

changes.

Ultrasonic machining-applications

UM effectively machines precise features in hard, brittle materials such as glass, engineered ceramics, SiC, quartz, single crystal materials, PCD, ferrite, graphite, glassy carbon, composites and piezoceramics.

A nearly limitless number of feature shapes-including round, square and odd-shaped thru-holes and cavities of varying depths, as well as OD-ID features-can be machined with high quality and consistency

Machining ceramic substrates for drilling holes in borosilicate glass for the sensors used in electronic industries

In machining, wire drawing, punching or blanking of small dies

Process capabilities of USM

Tolerances that can be achieved by this process range between 7m and 25 m

Holes as small as 76 m have been drilled.

Hole depths up to 51 mm have been easily achieved while 152 mm deep holes have also been drilled by using special flushing technique

The aspect ratio of 40:1 has been achieved.

Linear material removal rate, MRR, (also known as penetration rate) achieved during USM ranges from 0.025 to 25.0 mm/min, and it depends upon various parameters.

Surface finish achieved during the process varies from 0.25 m to 0.75 m.

Honeycomb structure machined on the back

of a silicon mirror for NASA

Rotary Ultrasonic Machining

Rotary ultrasonic machining is similar to the conventional drilling of glass and ceramic with diamond core drills, except that th rotating core drill is vibrated at an ultrasonic frequency of 20 kHz.

Rotary ultrasonic machining does not involve the flow of an abrasive slurry through a gap between the workpiece and the tool.

Instead, the tool contacts and cuts the workpiece, and a liquid coolant, usually water, is forced through the bore of the tube to cool and flush away the removed material.

Rotary ultrasonic machining (RUM)

Rotary ultrasonic machining (RUM) is a hybrid machining process that combines the material removal mechanisms of diamond grinding with ultrasonic machining (USM), resulting in higher material removal rates (MRR) than those obtained by either diamond grinding or USM alone

In rotary ultrasonic machining, a rotating core drill with metal-bonded diamond abrasives is ultrasonically vibrated in the axial direction while the spindle is fed toward the work piece at a constant pressure.

By using abrasives bonded directly on the tools and combining simultaneous rotation and vibration, RUM provides a fast, high-quality machining method for a variety of glass and ceramic applications.

RUSM

The amplitude of vibration in rotary ultrasonic

machining is usually about 0.025 to 0.05 mm and

the longitudinal extension and contraction of the

drill tip improves drilling performance by:

Reducing the friction between the tool and the

material at the point of cutting

Eliminating seizure of the core piece by allowing

greater coolant flow in the bore of the tool

Preventing the diamond tool from loading with

removed material

Increasing drilling speed with less pressure on

the tool and reduced tool wear

ROTORY ULTRASONIC MACHINING

The machining efficiency on brittle materials by

ultrasonic machines is 4 times higher

compared to traditional ways.

Vibration frequency of ultrasonic: 18KHz-30KHz,

which is 36-60 times higher than the

performance of high speed spindle.

Surface roughness done by ultrasonic

machine:0.2m

RUM vs. USM

One of the major differences between USM and RUM equipment is that USM uses a soft tool, such as stainless steel, brass or mild steel, and a slurry loaded with hard abrasive particles, while in RUM the hard abrasive particles are diamond and are bonded on the tools.

Another major difference is that the RUM tool rotates and vibrates simultaneously, while the USM tool only vibrates.

These differences enable RUM to provide both speed and accuracy advantages in ceramic and glass machining operations.

Abrasive flow machining- Introduction

Abrasive flow machining (AFM), also known as abrasive flow deburring or extrude honing, is an interior surface finishing process characterized by flowing an abrasive-laden fluid through a workpiece.

Abrasive flow machining finishes surfaces and edges by extruding viscous abrasive media through or across the workpiece. Abrasion occurs only where the flow of the media is restricted; other areas remain unaffected.

Schematic of the AFM process. (a)

Abrasive media in the lower cylinder. (b)

Abrasive media being extruded through

the workpiece and tooling


This fluid is typically very viscous, having the consistency of putty, or dough. AFM smooths and finishes rough surfaces, and is specifically used to remove burrs, polish surfaces, form radii, and even remove material.

Abrasive flow machining can process many inaccessible passages on a workpiece simultaneously, and it can accommodate several dozen parts in one fixture.

The nature of AFM makes it ideal for interior surfaces, slots, holes, cavities, and other areas that may be difficult to reach with other polishing or grinding processes.

Vertical column of

AFM abrasive media

after extrusion

Principle of material removal mechanism in two

way AFM process

Process principle during abrasive flow machining (AFM).


Abrasive flow machining is used to deburr, polish, or radius surfaces and edges.

A variety of finishing results can be achieved by altering the process parameters.

The process embraces a wide range of applications from critical aerospace and medical components to high-production volumes of parts.

Teeth on the

extrusion die shown

in left figure(a) Before

AFM. (b) After AFM

Extrusion die

abrasive flow machining (AFM).

The AFM process uses two opposed cylinders to extrude semisolid abrasive media back and forth through the passages formed by the workpiece and the tooling

By repeatedly extruding the media from one cylinder to the other, an abrasive action is produced as the media enter a restrictive passage and travel through or across the workpiece.

The machining action is similar to a grinding or lapping operation as the abrasive media gently polish the surfaces or edges.

Tooling for restricting the flow of

the media. To process external

edges, the part is contained

within a fixture that directs and

restricts media flow in the

appropriate areas

Process Characteristics

The process is abrasive only in the extrusion area, where the flow is restricted.

When forced into a restrictive passage, the polymer carder in the media temporarily increases in viscosity; this holds the abrasive grains rigidly in place.

They abrade the passages only when the matrix is in this thicker viscous state.

The viscosity returns to normal when the thickened portion of media exits the restrictive passage

Schematic showing uniform flow through

the passage. This removes an even

amount of stock from the passage walls

Schematic showing the flow pattern of media

entering a passage, which generates the

machining action used for deburring and

radiusing

Progressive stages in AFM polishing

Progressive stages in AFM polishing from a 1.9 m finish (left) to a 0.2 m finish

Schematic diagram of abrasive flow

machining of a hole to explain

its working principle

ABRASIVE FLOW MACHINING (AFM) SYSTEM

It consists of three elements, viz., machine, tooling, and media.

(i) Machine

Machine having two cylinders and abrasive media controls the extrusion pressure and flow volume.

The media is extruded (or forced) back and forth from one cylinder to another with the help of a hydraulic ram. These cylinders/chambers are clamped together with the workpiece sandwiched between them.

The enclosed workpiece area through which the media is forced, is called the extrusion passage.

The media extruding pressure ranges from 0.70 to 22 MPa. To maintain a constant media viscosity, in some applications, coolers for lowering the temperature of the media are also used.

The controllable variables are volume of media, no. Of stroke, number of cycles and pressure.

ABRASIVE FLOW MACHINING (AFM) SYSTEM

(ii) Tooling

Tooling is that element of an AFM system which

is used to confine and direct the flow of media

to the appropriate areas

Tooling for AFM machine is designed with two

aims:

(i) to hold the parts in position, and

(ii) to contain the media and direct its flow.

AFM-Different tooling and configrations

Deburring/finishing of

inaccessible holes

using AFM process.

Finishing of multiple

parts having the

same configuration

Finishing of

two parts but

with different

configurations

Finishing and radiusing

of an internal hole

Tooling for deburring and finishing of a

gear using AFM process

Tooling for external surfacc to

be finished

AFM systems- (iii) Media

Characteristics of media determine aggressiveness of action of abrasives during AFM process.

AFM media is pliable (easily moulded) material which is resilient enough to act as a self deforming grinding stone when forced through a passageway

It consists of base material and abrasive grits. The base material (viscoplastic/viscoelastic material) is made up of an organic polymer, and hydrocarbon gel.

The stiffest media is used for largest hole, while soft media is used for small holes.

Media acting as a self-deformable stone

AFM systems- (iii) Media

When the abrasive grains laden media comes in contact with the workpiece surface to be machined, the abrasive grains are held tightly in place and the media acts as a deformable grinding stone

Types of abrasives used are A120 3, SiC, cubic boron nitride (CBN) and diamond (written in the order of their increasing hardness and cost).

The abrasives have limited life. As a thumb rule, when the media has machined an amount equal to 10% of its weight, it must be discarded.

To assure a proper mixing of a new it should be cycled 20-50 times through a scrap part.

Machined parts should be properly cleaned before use, by air or vacuum

Variables and responses of AFM process

PROCESS PERFORMANCE

AFM has produced surface finish as good as 0.05 m (= 50 nm).

Surface irregularities like deep scratches, large bumps, out-of-roundness, and taper cant be corrected by this process because it machines all surfaces almost equally.

A minimum limit on the hole size that can be machined / deburred properly is 0.22 mm and the largest size (or diameter) that has been machined is around 1000 mm.

It can produce dimensional tolerance as good as 0.005 mm ( 5 m ).

AFM Applications and Benefits

Radiussing: Generates continuous, true-edge radii or round-edge radii, such as jet engine disks.

Surface Stress Relief: The ability to smooth out critical fatigue points and remove stress risers that may lead to crack propagation.

Polishing: Improves surface finish, including complex shapes, and uniformly smoothes and polishes workpiece, while preserving geometry. AFM reaches inaccessible areas of workpieces, such as internal passageways of automotive intake manifolds and hydraulic/pneumatic manifold blocks.

Geometry Optimization: Abrasive flow machining can improve air, gas, or liquid flow behavior (flow coefficient) and reduce or eliminate cavitation tendency. Generating laminar flow helps improve volumetric efficiency.

Deburring: Abrasive flow machining deburrs internal/external or otherwise inaccessible holes, slots, and edges. Cross-drilled and intersecting holes that present a major problem for conventional deburring methods are easily handled by the AFM media.

AFM applications

AFM is suitable to automate finishing operations

that ask for high cost and which are labour

intensive, and can be performed manually.

It is very useful for finishing of extrusion dies,

nozzle of flame cutting torch, and airfoil surfaces of

impellers; deburring of aircraft valve bodies and

spools; removing recast layer after EDM, etc.

It is also employed for finishing operations,

specially in the industries related to the

manufacture of aerospace, automotive,

semiconductor, and medical components

AFM applications Conditions of the airfoil surface (compressors and turbines) are improved. Such surfaces are made by ECM, EDM, casting (say, investment castings), or milling. For finishing of such surfaces, this process easily works even in inaccessible areas.

Removal of thermal recast layers left by EDM, or laser beam machining.

Accessory parts like fuel spray nozzles, fuel control bodies, and bearing components are finished.

Resistance offered to the flow of air by blades, nozzles, diffusers, etc can be

adjusted or tuned accurately by modifying surface using AFM process.

AFM improves the mechanical fatigue strength of blades, disks, hubs, shafts,

etc.

AFM is also employed for removing coke and carbon deposits, and to

improve surface integrity.

It can also be employed to remove left out light machining marks. The surface finish can be improved from say 1.75 to 0.4 m

Both radiusing and deburring of cooling turbine blades are done in one pass by AFM.

Dies and Moulds:

1. Multiple passages can be processed at one time.

2. Surface finish can be improved to a large extent with least change in dimension.

3. It saves considerable time when compared with finishing by skilled hands.

Jobs demanding hours for polishing can be completed in minutes automatically.

4. Finishing of two-stroke cylinders and four-stroke engine heads is done using

AFM for improved air flow and better performance. Stainless steel impeller made by investment casting is polished to 0.37 m using this process.

AFM applications-Componets

Comparison of four abrasive finishing processes

Benefits-AFM

AFM can be applied to any metal materials,

including titanium, super alloys, hardened, and

difficult-to-machine materials.

Material can be removed from targeted and

hard-to-reach locations. Roughing and finishing

in one pass.

Media can be engineered to match the

application requirements.

Process control delivers consistent quality and

highest repeatability.

Magnetorheological Abrasive Flow Finishing (MRAFF)

The MRF process relies on a unique "smart fluid", known as Magnetorheological (MR) fluid

MR-Fluids are suspensions of micron sized magnetizable particles such as carbonyl iron, dispersed in a non-magnetic carrier medium like silicone oil(polymeric organic oil), mineral oil, synthetic oil, water or glycol

In the absence of a magnetic field, an ideal MR-fluid exhibits Newtonian behaviour.

On the application of an external magnetic field to a MR-suspension, a phenomenon known a Magnetorheological effect, is observed.

Magneto Rheological Effect

Fig. a shows the random distribution of the particles in the absence of external magnetic field.

In Fig. b, particles magnetize and form columns when external magnetic field is applied.

Fig. c shows an increasing resistance to an applied shear strain, due to this yield stress.

When the field is removed, the particles return to their random state and the fluid again exhibits its original Newtonian behavior.

Magneto Rheological Effect The particles acquire dipole moments proportional to magnetic field

strength and when the dipolar interaction between particles exceeds their

thermal energy, the particles aggregate into chains of dipoles aligned in the

field direction.

Because energy is required to deform and rupture the chains, this micro-structural transition is responsible for the onset of a large "controllable"

finite yield stress.

A typical MR fluid consists of 20-40 percent by volume of relatively pure, 3-10 micron diameter iron particles, suspended in a carrier liquid such as

mineral oil, synthetic oil, water or glycol

A variety of proprietary additives, similar to those found in commercial lubricants to discourage gravitational setting and promote particle

suspension, are commonly added to LORD Corporations MR fluids to

enhance lubricity, modify viscosity and inhibit wear

MR-fluids exhibit dynamic field strength of 50-100 kPa for applied magnetic

fields of 150-250 kA/m

Magneto Rheological Effect

Rheologically, the behaviour of MR-fluid in presence of magnetic field is described by Bingham Plastic mode

The rheological properties of controllable fluids depend on concentration and density of particles, particle size and shape distribution, properties of the carrier fluid, additional additives, applied field, temperature, and other factors.

The interdependency of all these factors is very complex, yet is important in establishing methodologies to optimize the performance of these fluids for particular applications.

Magneto Rheological fluid

Because the magnetic polarization mechanism

is unaffected by temperature, the performance

of MR-based devices is relatively insensitive to

temperature over a broad temperature range

(including the range for automotive use).

Used for hydraulic controls, servo valves,

dampers, and shock absorbers, clutches and

brakes, finishing and polishing

chucking/locking devices, dampers, breakaway

devices and structural composites,

Mechanism of MRAFF process

Magnetorheological polishing fluid comprises of MR-fluid with fine abrasive particles dispersed in it

On the application of magnetic field the carbonyl iron particles (CIP) form a chain like columnar structure with abrasives embedded in between.

The magnetic force between iron particles encompassing abrasive grain provides bonding strength to it and its magnitude is a function of iron

concentration, applied magnetic field intensity, magnetic permeability of particles and particle size.

MRAFF process

In MRAFF process, a magnetically stiffened slug of magnetorheological polishing fluid is extruded back and forth through or across the passage formed by workpieceand fixture.

Abrasion occurs selectively only where the magnetic field is applied across the workpiece surface, keeping the other areas unaffected.

MRAFF process-Material removal mechanism

The abrasive (cutting edges) held by carbonyl iron chains rub the workpiece surface and shear the peaks from it.

The amount of material sheared from the peaks of the workpiece surface by abrasive grains depends on the bonding strength provided by field-induced structure of MR-polishing fluid and the extrusion pressure applied through piston.

In this way magnetic field strength controls the extent of abrasion of peaks by abrasives.

(a) Abrasive grain along with CIP chains approaching roughness peak, (b) Abrasive

grain takes a small cut on roughness peak in presence of bonding forces, (c) Abrasive

grain crossing the roughness peak after removing a microchip during cutting action

Magnetorheological Abrasive Flow Finishing

(MRAFF)

A special configuration of MRAF finishing

process for optical industry

MRAF of Lenses and optical devices

Aspheric lenses

Aspheric optics provide

performance advantages.

Precision Optics Fabrication

MRAF of Lenses and optical devices

MRAF of lenses-Principle

A workpiece is installed at a fixed distance from a moving spherical wheel.

An electromagnet located below the wheel surface generates a magnetic field in the gap between the wheel and workpiece.

When the MR fluid is delivered to the wheel, it is pulled against the wheel surface by the magnetic field gradient and becomes a subaperture polishing tool.

A sophisticated computer program determines a schedule for varying the position of the workpiece as it sweeps through the polishing zone, in either a rotating or raster pattern.

MRAF of lenses-Principle

Dark-field microscopy of etched MRF

surfaces shows a near-absence of

the sub-surface damage normally

associated with conventional finishing

Material Compatibility - Glasses/Glass Ceramics

MRF polishing fluids: Standard MR polishing fl

uid for glasses (cerium oxide abrasive)

Diamond MR polishing fluid for various

materials (diamond abrasive)

Material Compatibility

Geometry Compatibility - Size

Geometry Compatibility - Shape

Thank You.

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