Technical Info

A

• Angular Edge- That cutting edge that is a straight line, forming an angle with the cutter axis. The surface produced by a cutting edge of this type will not be flat as is the case with a helical cutting edge.
• Axial Rake- The angle formed by a plane passing through the axis and a line coinciding with or tangent to the tooth face.
• Axial Runout- The difference between the highest and lowest indicator reading taken at the face of a cutter near the outer diameter.
• Axial angle relief- The angle made by a line tangent to the relieved surface at the end cutting edge and a plane normal to the axis.
• Axial relief- The relief measured in the axial direction between a plane perpendicular to the axis at the cutting edge and the relieved surface. Helps to prevent rubbing as the corner wears.

B

• Back taper- A slight taper resulting in the shank end of the cutting diameter being smaller than the cutting end. This condition aids not only the plunging or drilling condition but also tends to compensate for deflection.
• Ball End- Used to mill die cavities and fillets, round bottom holes and slots

C

• Chamfer- A short relieved flat installed where the periphery and face of a cutter meet. Used to strengthen the otherwise weak corner.
• Chip Breakers- Special geometry of the rake face that causes the chip to curl tightly and break.
• Chip Splitters- Notches in the circumference of a Corn cob style End mill cutter resulting in narrow chips. Suitable for rough machining.
• Core Diameter- The diameter of a cylinder (or cone shape with tapered End mills) tangent to the flutes at the deepest point.
• Counterbore- A recess in a non-end cutting tool to facilitate grinding.
• Clearance- Space created by the removal of additional tool material from behind the relief angle.
• Clearance Angle- The angle formed by the cleared surface and line tangent to the cutting edge.
• Clearance: Primary(1st angle, 5°-9°) - Relief adjacent to the cutting edge.
• Clearance: Secondary(2nd angle, 14°-17°) - Relief adjacent to cutting edge
• Clearance: Tertiary(3rd) - Additional relief clearance provided adjacent to the secondary angle.
• Concave- Small hollow required on the end face of an End mill. This feature is produced by a Dish angle produced on the cutter.
• Convex- An outward projection radius feature on the end face of a Ball mill.
• Concave relief- The relieved surface behind the cutting edge having a concave form. Produced by a grinding wheel set at 90 degrees to the cutter axis.
• Coatings- The use of Titanium coated tools will increase the surface hardness of the tool to near 85 Rc. This will allow for greater tool life at increased cutting speeds & feeds (15 - 25%). Melin offers a varity of coatings that can be found in our coating information section.
• Corner Radius- Conventional end mill with radius ground on the tips of the flutes to help reduce chipping on the tip. For mold applications, radius tools can remove more material faster than ball ends.
• Corner Rounders- Cutters having form ground radius with relieved clearance.
• Cutter Sweep(Runout) - Material removed by the fluting cutter (or grinding wheel) at the end of the flute.
• Cutting Edge(A) - The leading edge of the cutter tooth. The intersection of two finely finished surfaces, generally of an included angle of less than 90 degrees.
• Cutting Edge Angle- The angle formed by the cutting edge and the tool axis.

D

• Differential pitch cutters- A specifically designed variation in the radial spacing of the cutter teeth. This provides a variation in tooth spacing and can be beneficial in reducing chatter. This concept is based on reducing the harmonic effect of the tool contacting the part in an exact moment of vibration.
• Dish Angle- The angle formed by the end cutting edge and a plane perpendicular to the cutter axis. Dish ensures that a flat surface is produced by the cutter.
• Double End- An end mill that has teeth on both ends of the cutter. End mill holders must have sufficient clearance to allow for the use of a double end cutter.
• Drill Point- Multipurpose tool which can be used for drilling, milling, or chamfering.

E

• Entrance Angle- The angle formed by a line through the center of the cutter at 90 to the direction of feed and a radial line through the initial point of contact. As this angle approaches 90 degrees the shock loading is increased.
• Entrance Angle: Ramp-in- Angle or radius value to enter the cutter into the part surface.
• Effective rake- The rake angle influencing chip formation most is that measured normal to the cutting edge. The effective rake angle is greatly affected by the radial and axial rakes only when corner angles are involved.
• Eccentric relief- The relieved surface behind the cutting edge having a convex form. Produced by a type I wheel presented at an angle to the cutter axis.
• End relief- Relief on the end of an end mill. Needed only for plunging cutters and to relieve rubbing as the result of corner wear.

F

• Fillet- The radius at the bottom of the flute, from which core diameter is found.
• Flat relief- The relieved surface behind the cutting edge having a flat surface produced by the face of a cup wheel.
• Flute- Space between cutting teeth providing chip space and regrinding capabilities. The number of cutting edges. Sometimes referred to as "teeth" or "gullet". The number on an end mill will determine the feed rate.
• Flute Length- Length of flutes or grooves. Often used incorrectly to denote cutting length.
• Flutes- Spiral cutting edge on the end mill. 2 and 4 flute end mills are the most commonly used.
• 2-Flute - Allows maximum space for chip ejection. Used for general milling operations.
• 3-Flute - Excellent for slotting. Used for general milling operations.
• 4, 5, 6, and 8 Flute - A greater number of flutes reduces chip load and can improve surface finish, if feed rate remains the same.