Milling Cutter- Types Of Milling Cutter used For Machining
Milling Cutter- Types Of Milling Cutter used for Milling Operations
Milling cutters are classified into different categories depending on different criteria as described below :
According to the Construction of Milling Cutter
(a) Solid milling cutter
(b) Inserted teeth cutter
(c) Tipped solid cutter
Solid cutter consists of teeth integral with the cutter body, in tipped cutter, teeth are made of cemented carbide or satellite, teeth are brazed to steel cutter body called shank. Inserted teeth cutter are larger in diameter, teeth of hard material are
inserted and secured in the shank.
According to Relief Characteristics of the Cutter Teeth
(a) Profile relieved cutter
(b) Form relieved cutter
In case of profile relieved cutter, a relief to cutting edges is provided by grinding a narrow land at their back. In case of form relieved cutters a curved relief is provided at the back of the cutting edges.
According to Method of Mounting the Cutters
(a) Arbor type
(b) Facing cutter
(c) Shank cutter
Arbor type cutters have a central hole and keyways for their mounting on arbor. Milling Shank type cutters are provided with straight or tapered shanks inserted into the spindle nose and clamped there. Facing type milling cutter are used to produce flat surfaces. These are balled or attached to the spindle nose or the face of a short arbor (stub arbor).
According to Direction of Rotation of the Cutter
(a) Right hand rotational cutter
(b) Left hand rotational cutter
A right hand rotational cutter rotates in an anticlockwise direction when viewed from end of the spindle while left hand rotational cutter rotates in a clockwise direction.
According to the Direction of Helix of the Cutter Teeth
(a) Parallel straight teeth
(b) Right hand helical
(c) Left hand helical
(d) Alternate helical teeth
Parallel or straight teeth cutter consists of teeth parallel to axis of rotation of the cutter with zero helix angle. In case of right hand and left hand helical teeth cutters, teeth cut at an angle to the axis of rotation of the cutter. Teeth have opposite inclination in both the cutters. Alternate helical teeth cutter has alternate teeth of right hand and left hand helical teeth cutters.
According to Purpose of Use of the Cutter
(a) Standard milling cutter
(b) Special milling cutter
Special milling cutters are designed to perform special operations which may be combination of several conventional operations.
Standard milling cutters are the conventional cutters which are classified as given below.
Plain Milling Cutters
These cutters are cylindrical in shape having teeth on their circumference. These are used to produce flat surfaces parallel to axis of rotation. Plain milling cutter is shown in Figure . Depending upon the size and applications plain milling cutters are categorized as light duty, heavy duty and helical plain milling cutters.
Side Milling Cutters
Side milling cutters are used to remove metals from the side of workpiece. These cutters have teeth on the periphery and on its sides. These are further categorized as plain side milling cutters having straight circumferential teeth. Staggered teeth side milling cutters having alternate teeth with opposite helix angle providing more chip space. Half side milling cutters have straight or helical teeth on its circumference and on its one side only. Circumferential teeth do the actual cutting of metal while side teeth do the finishing work. Interlocking side milling cutter has teeth of two half side milling cutter which are made to interlock to form one unit.
Metal Slitting Saw
These cutters are like plain or side milling cutters having very small width. These are used for parting off or slotting operations. Metal slitting saw is shown in Figure . It is of two types. If teeth of this saw resembles with plain milling cutter, it is called plain milling slitting saw. If its teeth matches with staggered teeth side milling cutter, it is called staggered teeth slitting saw.
Angle Milling Cutter
These cutters have conical surfaces with cutting edges over them. These are used to machine angles other than 90o. Two types of angle milling cutters are available single angle milling cutter and double angle milling cutter.
End mills are used for cutting slots, small holes and light milling operations. These cutters have teeth on their end as well as an periphery. The cutting teeth may be straight or helical. Depending upon the shape of their shank, these are categorized as discussed below.
Taper Shank Mill
Taper shank mill have tapered shank.
Straight Shank Mill
Straight shank mill having straight shank.
Shell End Mills
These are normally used for face milling operation. Cutters of different sizes can be accommodated on a single common shank.
‘T’ Slot Milling Cutters
These are the special form of milling cutters used to produce „T‟ shaped slots in the workpiece. These have cutting edges on their periphery and both sides.
Fly Cutter Milling
Fly cutters are the simplest form of cutters used to make contoured surfaces. These cutters are the single cutting point cutting tools.
Formed cutters may have different types of profile on their cutting edges which can generate different types of profile on the workpieces. Depending upon tooth profile and their capabilities formed cutters are categorized as given below.
Convex Milling Cutters
These cutters have profile outwards at their circumference and used to generate concave semicircular surface on the workpiece.
Concave Milling Cutters
These milling cutters have teeth profile curve in words on their circumference. These are used to generate convex semicircular surfaces.
Corner Rounding Milling Cutters
These cutters have teeth curved inwards. These milling cutters are used to form contours of quarter circle. These are main used in making round corners and round edges of the workpiece.
These cutters are used in making gears on milling machine. Gear cutting is an operation which cannot be done otherwise. These cutter have shape of the teeth which are to be reproduced on the gear blank. Different gear cutters are used to make teeth with invalute profile or cycloidal profile. A gear cutter is used to cut a range of gear size with a fixed tooth profile.
Thread Milling Cutter
These cutters are designated to mill threads of specific form and size on the workpiece. These cutters may be with parallel shank of tapered shank and mainly used to make worms.
Top and Reamer Cutter
Top and reamer cutters are the cutters of double angle type, these are normally used to make grooves and flutes in taps or reamers. Taps and
reamers are used as thread cutting tools for softer material workpieces.