Cory´s Cutter Corner - November 2016
Anatomy of an Engraving Cutter - Part II
While there is a seemingly infinite number of cutter sizes and shapes, engraving tools fall into two basic categories – conical and parallel.
Have an angled cutting edge and produce a “vee” shaped, flat-bottomed cut.
Have a straight cutting edge that is parallel to the cutter’s axis of rotation and produce a cut with straight walls and a flat bottom. The width of the cut can be as large as the diameter of the shaft (i.e. 11/64” = 4.6mm parallel tool can be made to cut up to 4.2mm wide).
Cutting Angle and Overall Angle
The cutting angle is the angle formed between the cutter’s axis of rotation and its cutting edge. (ie 22 degrees.) For a standard plastic laminate cutting angle. This determines the “V” shape of the groove produced by conical cutters.
The overall angle is double the cutting angle (ie 44 degrees.)
Clearance Angle or Back Angle
The clearance angle refers to the angle of the cutting edge with respect to the face of the cutter. This angle allows for chip clearance, determines how fine the cutting edge is and is selected on material properties.
The tip angle is the angle at the tip of the cutter. Sometimes called the tip-off. Determines the width of the flat at the bottom of the cut.
Tip-off or Tip Width
The tip-off refers to the flat on the tip of an engraving cutter that determines how wide the cutter will cut. When we refer to tip width or tip size, we are describing the width the cutter produces at the bottom of the cut.
End Clearance Angle
The end clearance angle is the angle on the back side of the tip that provide clearance for the tip.
Tip widths are most accurately measured by doubling the dimension from the cutters centerline to the cutting edge. In the sharpening process, material is removed from the back of the tool to provide clearance, therefore the dimension across the tip will be smaller then the cut produced. For example, a 0.75mm cutter for flexible engravingstock will only measure about 0.5mm.