Cutting Tools Commodity Spotlight

Commodity Group Description

Any tool that is used to remove material from the work piece by means of shear deformation. Cutting may be accomplished by single-point or multipoint tools. Single-point tools are used in turning, shaping, plaining and similar operations, and remove material by means of one cutting edge. Milling and drilling tools are often multipoint tools. Grinding tools are also multipoint tools. Each grain of abrasive functions as a microscopic single-point cutting edge and shears a tiny chip.

Cutting tools must be made of a material harder than the material which is to be cut, and the tool must be able to withstand the heat generated in the metal-cutting process. Also, the tool must have a specific geometry, with clearance angles designed so that the cutting edge can contact the work piece without the rest of the tool dragging on the work piece surface. The angle of the cutting face is also important, as is the flute width, number of flutes or teeth, and margin size. In order to have a long working life, all of the above must be optimized, plus the speeds and feeds at which the tool is run.

Single-point cutting tools can be classified by their motion as linear or rotary, depending on whether they rotate while cutting. Linear cutting tools include tool bits (single-point cutting tools) and broaches. Rotary cutting tools include drill bits, countersinks and counterbores, taps and dies, milling cutters, and reamers. Other cutting tools, such as band saw blades and fly cutters, combine aspects of linear and rotary motion.

Cutting tools are often designed with inserts or replaceable tips (tipped tools). In these, the cutting edge consists of a separate piece of material, brazed, welded or clamped on to the tool body. Common materials for tips include tungsten carbide, polycrystalline diamond, and cubic boron nitride. Tools using inserts include milling cutters (end mills, fly cutters), tool bits, and saw blades.i

Industry Analysis

Cutting Tools are a subset of the larger Machine Tool Manufacturing industry, which is made up of over 7500 companies with combined annual revenue of about $30 billion. Large companies include Kennametal, Thermadyne, and Hardinge. The industry is fragmented, with the largest 50 companies holding less than 30 percent of the market. Large companies may have annual revenue over $100 million, but a typical company has revenue under $10 million. Perishable cutting tools and accessories represent about 20% of the industry, or approximately $6 billion.

For the most part, cutting tools are used in the metal removal process for heavy industrial manufacturing. These environments are usually high volume production facilities that require specialized tooling. In many high production environments blueprint/special tooling can represent as much as 80% of the total perishable tooling requirement. While there are thousands of distributors of standard cutting tools, blueprint tooling usually requires dealing directly with the manufacturer.

Increased global competition in all aspects of manufacturing has created demand for better, longer lasting tools and accessories. Extensive development of tougher cutting tool materials and coatings has been the driving force of change in this industry, along with improved cutting tool design that leads to extended performance.

Longer lasting cutting tools with specialized coatings extend the wear life of the tool—sometimes as much as four times the normal wear. With improved cutting tool materials and geometry, the volume of machine tool sales will inevitably drop because the tools are designed to reduce the frequency of replacement. Likewise, improved engineering design of metal castings intentionally reduces the amount of removable machine stock, requiring less cutting tool activity. ii

Top Industry Users

  • Metal Cutting Environments
  • Automotive manufacturing
  • Heavy Truck & Off-Road Equipment
  • Aerospace (Engine and Airframe)
  • Energy
  • Pumps and Fluid Power manufacturing
  • Power Transmission manufacturers


Key Items in the Commodity

Adaptors, Arbors, Tool Holders, Boring Bars, Broaches, Burnishing Tools, Burrs, Drill Bushings, Chucks, Collets, Counterbores, Countersinks, Drills, End Mills, Inserts, Mill Cutters, Reamers, Taps & Dies

Cutting Tools Types
iii

Key Cost Drivers


Raw material costs, special design requirements, tooling performance requirements and special coatings

Common Coatings

  • Titanium Nitride (TiN)
    General purpose PVD coating that increases hardness and has a high oxidation temperature. This coating works great while cutting or forming with HSS tooling.
  • Titanium Carbo-Nitride (TiCN)
    The addition of carbon adds more hardness and better surface lubricity. This coating is ideal for HSS cutting tools.
  • Titanium Aluminum Nitride (TiAlN or AlTiN)
    A formed layer of aluminum oxide gives this tool better life in high heat applications. This coating is primarily selected for carbide tooling where little to no coolant is being used. AlTiN offers a higher surface hardness than that of TiAlN, along with different percentages of aluminum and titanium. It is another viable option in the world of HSM.
  • Chromium Nitride (CrN)
    The anti-seizure properties of this coating makes it preferred in situations where BUE is common. HSS or carbide cutting and forming tools will be seen with this almost invisible coating.
  • Diamond
    A CVD process that offers the highest performance available in non-ferrous materials. Ideal for cutting graphite, MMC (Metal Matrix Composites), high silicon aluminum and many other abrasive materials (Note: True diamond coatings should not be used while machining steels. More heat is generated while cutting steels and thus causes chemical reactions that break down the bonds that hold this coating to the tool).

Coatings for hard milling, tapping and drilling all vary and are application-specific. Also available are multi-layer coatings that chip to the next layer instead of the tooling substrate, providing a further increase in tool life. iv

Cutting Tools Materials

Tool material Properties
Carbon steel

Unstable. Very inexpensive. Extremely sensitive to heat. Considered obsolete today although it is still found in non-intensive applications such as hand operated tools (reamers, taps, etc). Hardness up to about HRC 65. Sharp cutting edges possible.

High speed steel (HSS)

Unstable. Inexpensive. Retains hardness at moderate temperatures. The most common cutting tool material used today. Used extensively on drill bits and taps. Hardness up to about HRC 67. Sharp cutting edges possible.

HSS cobalt

Unstable. Moderately expensive. The high cobalt versions of high speed steel are very resistant to heat and thus excellent for machining abrasive and/or work hardening materials such as titanium and stainless steel. Used extensively on milling cutters and drill bits. Hardness up to about HRC 70. Sharp cutting edges possible.

Cast cobalt alloys

Stable. Expensive. Somewhat fragile. Despite its stability it doesn't allow for high machining speed due to low hardness. Not used much. Hardness up to about HRC 65. Sharp cutting edges possible.

Cemented carbide

Stable. Moderately expensive. The most common material used in the industry today. It is offered in several "grades" containing different proportions of tungsten carbide and binder (usually cobalt). High resistance to abrasion. High solubility in iron requires the additions of tantalum and niobium carbides for steel usage. Its main use is in turning tool bits although it is very common in milling cutters and saw blades. Hardness up to about HRC 90. Sharp edges generally not recommended.

Ceramics

Stable. Moderately inexpensive. Chemically inert and extremely resistant to heat, ceramics are usually desirable in high speed applications, the only drawback being their high fragility. Ceramics are considered unpredictable under unfavorable conditions. The most common ceramic materials are based on alumina (aluminium oxide), silicon nitride and silicon carbide. Used almost exclusively on turning tool bits. Hardness up to about HRC 93. Sharp cutting edges and positive rake angles are to be avoided.

Cermets

Stable. Moderately expensive. Another cemented material based on titanium carbide (TiC). Binder is usually nickel. It provides higher abrasion resistance compared to tungsten carbide at the expense of some toughness. It is far more chemically inert than it too. Extremely high resistance to abrasion. Used primarily on turning tool bits although research is being carried on producing other cutting tools. Hardness up to about HRC 93. Sharp edges generally not recommended.

Cubic boron nitride (CBN)

Stable. Expensive. Being the second hardest substance known, it is also the second most fragile. It offers extremely high resistance to abrasion at the expense of much toughness. It is generally used in a machining process called "hard machining", which involves running the tool or the part fast enough to melt it before it touches the edge, softening it considerably. Used almost exclusively on turning tool bits. Hardness higher than HRC 95. Sharp edges generally not recommended.

Diamond

Stable. Very Expensive. The hardest substance known to date. Superior resistance to abrasion but also high chemical affinity to iron which results in being unsuitable for steel machining. It is used where abrasive materials would wear anything else. Extremely fragile. Used almost exclusively on turning tool bits although it can be used as a coating on many kinds of tools. Sharp edges generally not recommended.

Strategic Sourcing Considerations

  • Review and understand lowest total cost
    • Tool life
    • Cost per hole/cost per manufactured part
    • Regrind/re-sharpening
    • Quantity Price breaks
    • Standard packs
    • Minimum order quantities
    • Lead time
    • Geography
      Are you sourcing for a single plant location, or across multiple locations in diverse geographical areas?
    • Freight
      Where will material be shipping from?
    • Standardization
      Is there an opportunity for the same tool or same manufacturer brand in multiple operations within a single plant, or across multiple plant locations?

  • Understand Impact of sourcing changes on finished part quality and tolerances
    • PPAP requirements must be understood
    • Tool tests are critical when changes are made to the manufacturer

  • Blueprint or custom tool versus standard tool
    • Ensure that Blueprint change process is in place and understood
    • Incent suppliers to offer standard cutting tools wherever feasible
    • Sourcing strategies will vary depending upon the specific situation.
      • If you are able to use standard cutting tools, you usually have virtually unlimited choice of suppliers, from large on-line catalog houses like Grainger, MSC and McMaster Carr, as well as a myriad of local distributors that can meet your needs.
      • When your applications require specials and blueprint items, your choices are more limited. Usually you’ll be dealing directly with the manufacturer or a very limited number of distributors.


References

  1. "Cutting Tools (Machining)." Wikipedia. n.d. Web. June 2010.
  2. "Industry Overview: Machine Tool Manufacture." Hoover’s. Hoover’s, Inc. n.d. Web. June 2010.
  3. "Milling." CustomerPartNet. n.d. Web. June 2010.
  4. Daggett, Scott, A. "Cutting Tools: How to Choose the Right Tool Coating for Your Machining Application." MoldMaking Technology Online. Gardner Publications, Inc. n.d. Web. June 2010.
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