In machining, cutting tools are hardened metal tools used to shape a workpiece via machining tools or abrasive tools through shear deformation, mostly on metals. Single-edge tools, crafted from hardened alloys, are used in turning on a lathe and held by a tool post. Multipoint tools include milling cutters and drilling bits, which create holes with two cutting edges. Grinding stones feature many cutting edges, functioning as abrasive tools harder than the metal they grind. Effective cutting tool materials must be harder than the workpiece, withstand heat and force, and have optimized geometry and speeds and feeds for a long working life.
Types
Linear cutting tools include tool bits (single-point cutting tools) and broaches. Rotary cutting tools include drill bits, countersinks and counterbores, taps and dies, reamers, and cold saw blades. Other cutting tools, such as bandsaw blades, hacksaw blades, and fly cutters, combine aspects of linear and rotary motion. The majority of these types of cutting tools are often made from HSS (High-Speed-Steel).
Cutting tools with inserts (indexable tools)
Cutting tools are often designed with inserts or replaceable tips (tipped tools). In these, the cutting edge consists of a separate piece of material, either brazed, welded or clamped on to the tool body. Common materials for tips include cemented carbide, polycrystalline diamond, and cubic boron nitride.2 Tools using inserts include milling cutters (endmills, fly cutters), tool bits, and saw blades.
Holder
Tool setup
The detailed instructions of how to combine the tool assembly out of basic holder, tool and insert can be stored in a tool management solution.
Cutting edge
The cutting edge of a cutting tool is a very important for the performance of the cutting process. The main features of the cutting edge are:
- form of the cutting edge: radius or waterfall or trumpet (reverse waterfall)
- cutting edge angles
- form and size of the chamfers
The measurement of the cutting edge is performed using a tactile instrument or an instrument using focus variation. To quantify a cutting edge the following parameters are used:
- cutting edge radius for symmetric edges
- cutting edge ellipse axis for asymmetric edges
- factor K, this is the relation between Sγ and Sα. This can also be calculated by the ratio of the two axis of the ellipse. This factor describes the form of the cutting edge.
- 3 angles: clearance angle, wedge angle, rake (chipping) angle
- Δr
- length and orientation of the bevel
One of the most important cutting edge parameters is the K factor. It specifies the form of the cutting edge. 1 means a symmetric cutting edge. If the value is smaller than 1 the form is called a waterfall. If the value is larger than 1 it is called a trumpet. Depending on the material being cut, feed rate and other factors, a cutting tool with the optimum K factor should be used.
References
Explain Cutting Tools[usurped], https://mechanicalsite.com, retrieved 2019-05-12. https://web.archive.org/web/20190512035101/https://mechanicalsite.com/cutting-tools ↩
Stephenson, David A.; Agapiou, John S. (1997), Metal cutting theory and practice, Marcel Dekker, p. 164, ISBN 978-0-8247-9579-5. 978-0-8247-9579-5 ↩