Ch22 Cutting Tool Materials and Cutting Fluids
Ch22 Cutting Tool Materials and Cutting Fluids
Ch22 Cutting Tool Materials and Cutting Fluids
(EPP 201)
1
Chapter 22
Cutting-Tool Materials and Cutting
Fluids
Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.
ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.
Introduction
Figure 22.6 Relative time required to machine with various cutting-tool materials, indicating the
year the tool materials were first introduced. Note that machining time has been reduced by two
orders of magnitude with a hundred years. Source: Courtesy of Sandvik.
COATED TOOLS - Coating Materials
• Coatings thickness of 2-15 μm, are applied on cutting tools and
inserts by the following techniques:
1. Chemical-vapor deposition (CVD), including plasma-assisted
2. Physical-vapor deposition (PVD)
• Coatings for cutting tools, as well as dies, should have the
following general characteristics:
1. High hardness at elevated temperatures
2. Chemical stability and inertness to the workpiece material
3. Compatibility and good bonding to the substrate to prevent flaking
or spalling
4. Little or no porosity
• Honing of the cutting edges is an important procedure for the
maintenance of coating strength; otherwise, the coating may peel or
chip off at sharp edges
COATED TOOLS - Coating Materials
Ceramics Coatings:
• Chemical inertness
• Low thermal conductivity
• Resistance to high temperature
• Resistance to flank and crater wear
• Most commonly used ceramic coating aluminum oxide
(Al2O3). However oxide coating generally bond weakly to
the substrate.
COATED TOOLS - Coating Materials
Multiphase Coatings:
• Carbide tools with 2 or 3 layers of such coatings.
• Particularly effective in machining cast irons and steels.
• Typical applications of multiple-coated tools:
➢ High-speed, continuous cutting: TiC/Al2O3.
➢ Heavy-duty, continuous cutting: TiC/Al2O3/TiN.
➢ Light, interrupted cutting: TiC/TiC + TiN/TiN.
Multiphase Coatings on a Tungsten-Carbide
Substrate
Multiphase Coatings:
•Functions of coatings:
1.TiN: low friction
2.Al2O3: high thermal stability
3.TiCN: fiber reinforced with a good balance of resistance to
flank and crater wear for interrupted cutting
4.A thin carbide substrate: high fracture toughness
5.A thick carbide substrate: hard and resistant to plastic
deformation at high temperatures.
COATED TOOLS - Coating Materials
Diamond-Coated Tools:
• Thin films are deposited on substrates with PVD and CVD
techniques.
• Thick films are obtained by growing a large sheet of pure
diamond, which is then laser cut to shape and brazed to a
carbide shank.
• Diamond-coated tools are particularly effective in
machining nonferrous and abrasive materials, such as Al
alloys containing Si, fiber-reinforced and metal-matrix
composite materials, and graphite.
COATED TOOLS - Coating Materials
• Miscellaneous Coating Materials
• Titanium carbonitride (TiCN) and titanium-aluminum nitride (TiAlN)
are effective in cutting stainless steels.
• TiCN (which is deposited through physical-vapor deposition) is harder
and tougher than TiN and can be used on carbides and high-speed steel
tools.
• TiAlN is effective in machining aerospace alloys.
• Chromium based coatings, such as chromium carbide (CrC), have been
found to be effective in machining softer metals that tend to adhere to
the cutting tool, such as aluminum, copper, and titanium.
• Other new materials include zirconium nitride (ZrN) and hafnium
nitride (HfN)
• More recent developments are:
• nanolayer coatings, including carbide, boride, nitride, oxide &
combination
• Composite coatings, using a variety of materials.
ALUMINA-BASED CERAMICS
• Low friction
• High wear resistance
• Ability to maintain sharp edge
• Used when good surface finish and dimensional accuracy are
req. (soft non-ferrous & abrasive non-metallic materials)
• Low rack angles are generally used > strong cutting edge
• Used at high speed
• Most reasonable for light uninterrupted finishing cut
• Diamond is not recommended for machining plain carbon
steels or titanium, because of its strong chemical affinity.
CUTTING FLUIDS
• Reduce friction and wear – improve tool life and surface finish
• Cool the cutting zone
• Reduces forces and energy consumption
• Flush away chips
• Protect machined surface from corrosion
Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.
ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.
CUTTING FLUIDS
Manufacturing, Engineering & Technology, Fifth Edition, by Serope Kalpakjian and Steven R. Schmid.
ISBN 0-13-148965-8. © 2006 Pearson Education, Inc., Upper Saddle River, NJ. All rights reserved.
Proper Methods of Applying Cutting Fluids