the main Geometric Parameters of Reamer in Boring, Reaming and Broaching
Reaming is one of the most important processes in manufacturing. It is used to finish and utilize existing holes to create precise and standard size holes. Reamers are used to impart desired accuracy and finish to the hole. Reamers come in various shapes and sizes, which are specified according to the hole to be machined. The main geometric parameters of reamer include the number of flutes, flute angle, profile shape, clearance angle, rake angle, chamfer angle and cutting edge angle.
Number of Flutes: Reamers are available with two to six flutes. This number generally increases as the diameter of the reamer increases. A large number of flutes will result in a better finish and increased material removal. But too many flutes can reduce cutting edge life. The flutes directed towards the center of the hole are helpful in chip evacuation.
Flute angle: This is the angle between the flutes and the axis of the reamer. It is not necessary to use the same angle for all reamers, but there are general guidelines for use. The flute angle of a reamer should be between 10 and 25 degrees to ensure that the cutting edges are kept sharp.
Profile shape: This refers to the cross-sectional shape of the flutes. Reamers are available with round, square, triangular and trapezoidal flutes. The square shaped flutes are most commonly used as they provide better guidance and support to the cutting edges.
Clearance Angle: This is the angle which helps in controlling the cutting forces. It is the angle between the cutting-edge chamfer and the flank of the cutting tool. This angle should be between 7 and 15 degrees, as it prevents the cutting edge from rubbing against the work-piece. A high clearance angle will reduce the cutting forces and increase tool life.
Rake angle: This is the angle between the cutting edge and the work-piece surface. It is the angle which determines the cutting force. The rake should be between 5 and 15 degrees so that the cutting force is distributed properly. If the rake angle is too low, the cutting forces will be high and can reduce tool life.
Chamfer angle: This is the angle between the cutting edge and the flank surface. It should be between 5 and 15 degrees to ensure that the tool does not rub against the work-piece. If the chamfer angle is too low, the cutting forces will be large and wear-resistant properties will be reduced.
Cutting Edge Angle: This is the angle between the cutting edge and the flank surface. This is important for the cutting performance of the reamer. The cutting edge should be at an angle between 90 and 120 degrees for maximum performance. A lower angle can cause too much wear on the cutting edge and reduce tool life.
The main geometric parameters of reamer play an important role in order to produce accurate and repeatable results in reaming operations. The correct selection and combination of these parameters will ensure a efficient and productive machining process.
