Cutting tools

objective is to define single point and multipoint cutting tool

1. Cutting tool RISHAV GARG SID- 16107032

2. Cutting Tools A   cutting tool  or  cutter  is any tool that is used to remove material from the work piece by means of shear deformation . One of most important components in machining process Success in metal cutting depends on selection of proper cutting tool for a given work material Performance will determine efficiency of operation Two basic types (excluding abrasives) Single point and multiple point 2

3. Single point cutting tool It is simpler form of cutting tool that have only one cutting edge.  Shear tools, lathe tools, planner tools, boring tools etc. are the examples of single point cutting tool . Boring Turning 3

4. Geometry of Single Point Cutting Tool Shank :  the shank is used as a tool holder. It is a main body of the tool. It is generally gripped in the tool frame. Flank :  It is a surface of the cutting edge or the surface adjacent to the cutting edge of the tool. Face :  It is the surface of the tool where the chip slides along the top of this surface. Base :  Base is a bearing surface of the tool. This base is held in a tool holder or it is directly clamped in the tool post. Heel :  Heel is an intersection to the flank and base of the cutting tool. It is a curved portion at the bottom of the tool .

5. Nose:   This is a point where the base cutting edge and the side cutting edge gets intersected. Cutting edges:   It is a face edge on the face of the tool that removes the material from the work piece. There are two cutting edges as side cutting edge and end cutting edge, where the side cutting edge is major cutting edge and the end cutting edge is minor cutting edge. Tool angles:   Tool angle splay a vital role in the tool cutting action. The tool that comes with proper angles will reduce failures as tool breaking due to high work forces on the work piece. The metal cutting is done more efficiently with generation of little heat. Noise radius:   The nose radius will provide long life and also good surface finish with it sharp point on the nose. It has high stress and leaves in its path of cut. Longer nose radius will give raise to chatter.

6. Angles of Single Point Cutting Tool 1.Side Cutting Edge Angle: The angle between side cutting edge and the side of the tool shank is called side cutting edge angle. 2.End Cutting Edge Angle: The angle between the end cutting edge and a line perpendicular to the shank of the tool shank is called end cutting edge angle .

7. Angles of Single Point Cutting Tool . Side Relief Angle: The angle between the portion of the side flank immediately below the side cutting edge and a line perpendicular to the base of the tool . Side Rake Angle: The angle between the face of the tool and a line parallel to the base of the tool measured on plane perpendicular to the base and the side edge.

8. Angles of Single Point Cutting Tool End Relief Angle: The angle between the end flank and the line perpendicular to the base of the tool is called end relief angle. Back Rake Angle: The angle between the face of the tool and line perpendicular to the base of the tool measures on perpendicular plane through the side cutting edge.

9. Multipoint cutting tool Multi-point cutting tools are those that have two or more chip producing edges on a common body. Tool rotation then achieves the cut. Multi-point cutting tools include milling cutters, end mills, drills, reamers, and taps. The number of cutting edges may vary from around four (in milling cutter) to hundreds (in grinding wheel ).

10. Machines with multipoint cutting tools A  milling machine  cuts metal as the workpiece is fed against a rotating cutting tool called a milling cutter . Milling machines cut flat surfaces, grooves, shoulders, inclined surfaces, dovetails, and T-slots. Milling machines are available in a variety of designs that can be classified as the following: (1) standard knee-and-column machines, including the horizontal and the vertical types; (2) bed-type or manufacturing machines; and (3) machines designed for special milling jobs.

11. Broaching  is a machining method in which a series of cutting teeth each remove a portion of stock as the cutting tool ( broach ) moves past or through the work piece. Combining both roughing and finishing in one operation. Broaching removes stock to precise tolerance faster than any other known metal cutting process.

12. Tool wear and failure Interaction between tool & chip. Cutting forces. Temperature increase during cutting. Effect of tool wear— Tool wear changes tool shape, decrease efficacy. Tool wear induce loss of dimensional accuracy, loss of surface finish. It increases power consumption.

13. Classification of tool wear  Flank wear Crater wear on tool face Chipping Breakage Loss of hardness at high temperature

14. Single Point Cutting Tool Multi Point Cutting Tool These cutting tools contain only one main cutting edge. Multi point cutting tools contains more than one up to hundreds of cutting edges. While machining with single point cutting tool, only one main cutting edge continuously remains in contact with work piece . While machining with multi point cutting tool, more than one cutting edge simultaneously engage in material removal action in a pass. Chip load per tooth is usually high. Due to presence of multiple cutting edges, effective chip load per tooth reduces. Since one cutting edge continuously remains in contact with the work piece , so rate of rise in tool temperature is high. Due to successive engagement and disengagement, heat in cutter dissipates when it is not in contact with workpiece . Consequently rate of rise in tool temperature is low. In case of unplanned breakage of cutting edge, entire process is required to pause until the broken tool is replaced by a new one. If one cutting edge breaks, cutting action can be continued using other cutting edges without much problem. Design and fabrication of single point cutting tools are comparatively easy. Design and fabrication of multi point cutting tools are quite difficult. Usually single point cutting tools are given low feed rate, so Material Removal Rate (MRR) and thus productivity are low. Higher feed rate can be employed with multi point cutting tool, which increases MRR and productivity. So machining operation becomes economic.

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