Different Cutters and Operations of Milling Machine

Types of milling cutters

·         Endmill

·         Face mill

·         Involute gear cutter

·         Woodruff cutter

·         Roughing end mill

·         Hollow mill

·         Fly Mill Cutter

·         Side-and-face cutter

·         Slab mill

·         Dovetail cutter

·         Ball cutter

·         Shell mill

What is the difference between face milling and end milling?

These are two of the most prevailing milling operations, each using different types of cutters –the face mill and the end mill. The variance between face milling and end milling is that an end mill used both the end and the sides of the cutter, whereas face milling is used for horizontal cutting.

1. Endmill

These tools used have a flat bottom but not always. Round and radiuses cutters are also available. End mills are similar to drills in the intellect that they can cut axially. But the favorable of milling lies in the possibility of lateral cutting.   

2. Face mill

The face mills cutter cannot cut axially. Instead, the cutting edges are always situated on the sides of the cutting head. The cutting teeth are refundable carbide inserts.

This makes the life of a tool longer while maintaining a good cutting quality.

3. Ball cutter

Ball cutters, also known as ball mills, have hemispherical cutting tips. The objective is to maintain a corner radius for vertical faces.   

4. Woodruff cutter

Woodruff or keyset/keyway cutters are used to cut key slots into parts, for example, shafts. The cutting tools have teeth upright to the exterior diameter to generate suitable slots for Woodruff keys

5. Roughing end mill

As the name says, these are moderately many end mills with a slight dissimilarity. The roughing end mill has notched teeth. These make the cutting progress faster than with a regular end mill.

The cut bits of metal are littler than ordinary and therefore easier to clear. Multiple teeth come into the junction with the workpiece at the same time. This restores chatter and vibration, which could otherwise be larger because of the serrated teeth.   

6. Involute gear cutter

There is a special cutting tool for milling roller gears. There are separate cutters available to generate gears within a certain number of teeth.

7. Fly cutter

These tools have the same performance as face mills. They comprise a central body that holds either one or two tool bits (double-end fly cutters).

Face mills cutter are better for high-quality cutting. The fly cutters are just cheaper and the cutting bits are often made at the shop by a machinist rather than buying from stores.

8. Hollow mill

Hollow mills are fundamentally against face mills. Here, the workpiece is fed into the internal parts of the mill to generate a cylindrical outcome.   

9. Slab Mill

This kind of cutter is used when you have to remove more amount of material from the workpiece. By using roughing end mills, we obtain a rough surface Roughing finishing end mills are also famous as “ripped” cutters. They are more helpful commercially and are used in various industrial applications.  

10. Woodruff cutter

Woodruff or keyset/keyway cutters are used to cut key slots into parts, for example, shafts. The cutting tools have teeth upright to the exterior diameter to generate suitable slots for Woodruff keys.

11. Thread mill

The name of this tool says everything you need to know about its aim. Thread mills are used for showing tapped holes.

Threading operations are usually carried out on drilling apparatus. Using a thread mill, though, is more fixed and has few limits regarding the environment.

Milling Machine Operation

The different milling machine operation is:

·         Side Milling

·         Plain Milling

·         Face Milling

·         Straddle Milling

·         Gang Milling

·         Angular Milling

·         Profile Milling:

·         Saw Milling

·         End Milling

·         Form Milling

·         Gear Milling

·         Cam Milling

·         Thread Milling

·         Helical Milling

·         Milling Key Ways, Grooves, and Slots

1. Side Milling

It is the machining process that generates a flat vertical surface at the sides of a workpiece. This operation is completed by using a side milling cutter.

2. Plain Milling

It is a Progress of milling plane surfaces keeping the axis of the cutter parallel to the surface being milled. It is also called slab milling or surface milling. A plain milling cutter is used for the plain milling.     

3. Face Milling

This operation makes plane surfaces on the face of the workpiece. This machining operation is done on surfaces that are perpendicular to the axis of the cutter. The operation is achieved by the face milling cutter fixed on the stub arbor of the machine.   

4. Straddle Milling

it is an operation in which two side milling cutters are used to machine two adverse sides of a workpiece simultaneously. The straddle milling process is shown in the figure given below.

5. Angular Milling

It is an operation of milling flat surfaces which are neither Parallel nor upright to the axis of the milling cutter. It is also called angular milling. A single-angle milling cutter is used to perform this process.

6. Gang Milling

It is a machining operation in which two or more milling cutters are used together to perform different milling processes simultaneously. In gang milling, the cutters are fixed on the arbor.

7. Form Milling

It is the operation of machining a special contour (outline) composed of straight lines, curves, or entirely of curves, at a single cut. Formed milling cutters shaped to the contour to be cut are used to complete this operation. This operation is completed by using convex, concave, and corner circular milling cutters.

8. Profile Milling:

This milling process is used to cut a profile on the workpiece.

9. End Milling

It is the operation of generating flat surfaces which may be vertical, horizontal, and at any angle taking the worktable as a reference. End milling cutters are used to complete this process.     

10. Saw Milling

It is a machining operation that is used to generate narrow grooves or slots on the workpiece.

It is also used for dividing the workpiece into two equal or unequal parts.

This milling process is performed by using a saw milling cutter.

The width of the cutter is very less as compared with the width of the workpiece.

11. Milling Key Ways, Grooves, and Slots

This milling process is used to generate key ways, grooves, and slots on the workpiece.

12. Gear Milling

It is the milling process that is used to cut gears on the workpiece. This operation is done by using conceived milling cutters called involute gear cutters.

13. Helical Milling

This milling operation is done to generate objects having a helical design such as helical gears, twisted drills, etc. it is done on the outside of the cylindrical workpiece.

14. Cam Milling

It is a machining operation that is used to make cams. The cams are used to open and close the valves in the I.C. Engines (internal combustion engines).

15. Thread Milling

It is the operation of milling used to cut threads on the cylindrical workpiece.

 

Milling Machine Main Parts and Types with Diagrams

It is a machine that is used to remove metals from the workpiece with the help of a revolving cutter so-called milling cutter. It is used to machine the rough, flat, and irregular surfaces and this is done by feeding the workpiece against a revolving milling cutter.

Main Parts of Milling Machine   

·         In a Milling machine every individual part performs an important task.

·         Some important parts of a Milling machine are as follows:

1. Knee

It is a casting that supports the table and saddle. All gearing mechanism is surrounded inside the knee.

·         It is secure to the column by dovetail ways.

·         The knee is adjusted and supported by a vertical placing screw (elevating screw).

·         The elevating screw is used to adjust the knee up and down by lowering or raising the lever either with the help of a power feed or hand.

2. Column & Base

The column counting base is the main casting that supports all other parts of the milling machine.

·         The column contains an oil tank and a pump that lubricates the spindle.

·         The column rests on the base and the base covers the coolant reservoir and a pump which is used during machining operation that requires coolant.

3. Power Feed Mechanism

It is the knee that covered the power feed mechanism. It is used to control the longitudinal (right and left), crosswise (in and out) and vertical (up and down) feeds.

·         To get the desired rate of feed on the machine, the feed selection lever is located as designated on the feed selection plates.

·         On some universal knee and column milling machines, the feed is obtained by turning the speed selection handle until the wanted rate of feed is designated on the feed dial.

·         Most of the milling machines have a speedy traverse lever which can be engaged when a temporary increase in the speed of the longitudinal, transverse, or vertical feeds is required. For example, this lever would be engaged when the operator is aligning or positioning the work.

4.  Arbor Support

It is a casting with a bearing that supports the outer end of the arbor. It is also helpful in aligning the outer end of the arbor with the spindle.

·         It prevents the springing of the outer end of the arbor during cutting operations.

·         These are generally two types of arbor supports to be used in the milling machine. The first one has a small diameter bearing hole, 1-inch in maximum diameter. And the other one has a large diameter bearing hole, usually up to 23/4 inches.

The arbor supports have an oil reservoir that lubricates the bearing surface. It can be fixed anywhere on the overarm. The arbor supports it,s used only in the horizontal types of milling machine

5. Ram

The hanging arm in the vertical machine is called a ram. One end of the ram straddling on the top of the column and on the other end milling head is attached.

·         The ram can be moved transversally (out and in) on the column by a hand lever.

6. Over Arm / Overhanging Arm

It is a horizontal beam current at the top face of the column. It may be a single casting that slides on the dovetail ways present on the top face of the column.

·         The overarm is used to fasten arbor support. It may contain one or two cylindrical bars which slide through the holes in the column

Types of Milling Machines

1.      Horizontal Milling Machine

2.      Vertical Milling Machine

3.      Knee-Type Milling Machine

4.      Ram-Type Milling Machine

5.      Manufacturing or Bed-Type Milling Machine

6.      Planer-Type Milling Machine

Basically, the milling machines are divided into two types first is a vertical milling machine and the second is a horizontal milling machine. They are further categorized as ram-type, knee-type, manufacturing or planer-type, and bed-type milling machines.

Most of the milling machine categorized above has a self-electric driven motor, power operated, coolant systems table feed, and variable spindle speeds.

1. Horizontal Milling Machine     

In a horizontal milling machine, the axis of revolution of the spindle is horizontal to the table. And due to the axis of the spindle being horizontal, it is called a horizontal milling machine. 

2. Vertical Milling Machine

The milling machine in which the spindle axis is vertical to the table is called a vertical milling machine.     

3. Knee-Type Milling Machine

The milling machine which has a knee-like projection in the middle is called a knee-type milling machine. It is characterized by a vertically adjustable work table resting on a saddle supported by a knee.    

4. Ram-Type Milling Machine

A milling machine that has a ram on the top of the column is called ram type milling machine. Generally, ram is used in vertical milling machines. It can be moved on the column in the transverse direction (i.e. in and out when operated from the knee side).

5. Planer-Type Milling Machine:

The planner milling machine is generally used for facing operations in mass production.

These machines are similar to the bed-type mill machine, except they can be straddled with various cutters and spindle heads the machine.

These cutters in the machines can complete the facing operations simultaneously which is a great function.    

Lathe Machine parts and Their Functions with Diagrams

INTRODUCTION:

In the field of Mechanical Engineering Lathe machine acting an important role in the manufacturing industry. I’m going to discuss the Lathe machine in detail in this article.

·         A lathe is a machine that is used to remove undesired metals from the workpiece to give the wanted shape and size.

·         A lathe machine is an imperative machine that is used in the industry of metalworking.

·         It works on the base of a rotating principle workpiece and a fixed cutting tool.

·         The cutting tool is fed into the workpiece which rotates about its own axis causing the workpiece to form the desired shape.

·         It is also known as” the parents of the entire tool family”.

Description of Lathe Machine

The machine tool that’s used to remove unwanted metals from the workpiece to give the asked shape and size so-called the” Lathe machine“, The lathe machine is also known as a “Center Lathe” because of the two centers between which the job can be held and rotated.

Functions of lathe Machine

The primary function of the Lathe machine is to remove excess material in the form of chips by rotating the workpiece against stationary cutting tools. This is skilled by holding the work strongly and rigidly on the machine and then turning it against the cutting tool that will remove metal from the workpiece. To cut the material correctly the tool should be harder than the material of the object, should be rigidly held on the machine, and should be fed or progressed in a certain way compared to the work.   

Main Parts of lathe Machine  

In a lathe machine, every individual part performs an important task. Some important parts of a lathe machine are as follows:

1.      Bed

2.      Head Stock

3.      Main Spindle

4.      Tail Stock

5.      Lead Screw

6.      Live Center

7.      Dead Center

8.      Carriage

·         Saddle

·         Apron

·         Tool Post

·         Cross slide

·         Compound Rest

·         Compound Slide

9.      Feed Mechanism

·         Belt Feed Mechanism

·         Gear Feed Mechanism

1. Bed

The Bed makes the base of a machine.

It is loaded on the legs of the lathe machine that is bolted to the ground.

It is prepared with cast iron and its top surface is machined exactly and correctly.

2. Head Stock

The headstock is an important part of a lathe machine that is loaded permanently on the inner guide – ways at the left-hand side of the bed.

It consists of the main spindle, a chuck fitted at the spindle nose, a back-gear drive, and an all-gear drive.

3. Main Spindle

The spindle is a hollow cylindrical shaft.

Its face has a standard mouse taper.

It is used to hold the live Centre or collet.

The spindle revolves around main two large bearings contained on the headstock casting.

The face end of the spindle is threaded, which is used to hold the chuck, driving plate, face plate, and catch plate.

It is known as a spindle nose.

4. Tail Stock

A tail stock is located on the inner guide – ways at the right side of the bed opposite to the headstock.

The tail stock body is bored and houses the tail stock spindle.

It tapered holes to obtain the dead Centre or shunk of tools such as a drill or reamer.

Its body is prepared with cast iron.

5. Lead Screw

It is used to transmit power to the carriage through gear and clutch arrangement in the carriage apron.

6. Live Center     

A Live Center is loading on bearings and revolves with the work.

Live centers are used to support or clamp a workpiece.

7. Dead Center   

A dead center may be used to support the workpiece at either the revolving or fixed end of the machine.

Dead centers are usually fully hardened to avoid damage to the important coupling surfaces of the taper and to preserve the 60° angle of the nose.

8. Carriage    

A carriage is located between the headstock and tailstock on the lathe bed guideways.

It can be relocated along the bed either towards or away from the headstock.

It has many parts to support, control, and move the cutting tool.

i. Saddle    

It is H – a shaped casting.

The saddle connects the pair of bed guideways as a bridge.

It fits over the bed and slides along the bed between the headstock and the tailstock.

The saddle can be moved by providing hand feed or automatic feed.

ii. Apron     

The front portion of a carriage calls an apron. It consists of all control keys.

The handle operates the carriage. It has a housing, which has a set of gears and a split nut.

Automatic feed and threading control are on the apron.

iii. Tool Post     

It is located on the top of the compound slide. It is used to hold the tools rigidly.

Tools are chosen according to the type of operation and loaded on the tool post and adjusted to a suitable working position.

There are different types of tool posts, which are as follows.

1.      Single Way / Screw Tool Post

2.      Four-Way Tool Post

3.      Quick Change Tool Post

4.      British Type Tool Post

iv. Cross slide    

It is located on the slides and saddle on the dovetail guide – ways at right angles to the bed guideways.

It brings a compound slide, compound rest, and tool post.

The Cross slide hand wheel is revolved to move it at a right angle to the lathe machine axis.

The cross slide hand wheel proceeds on its rim to enable to give the known amount of feed as accurately as 0.05 mm.

v. Compound Rest     

It is a part that connects to the compound slide and cross slide.

It is loaded on the cross slide by the tongue and groove joint.

The compound rest can be rotated to the required angle while tapers turning.

A top slide called the compound slide is attached to the compound rest by a dovetail joint.

vi. Compound Slide     

A compound slide is a T-shaped rounded slot that is fixed with a cross slide upper surface by two bolts, which is associated with a micrometer sleeve and screw handle with the outer edge of the screw.

Taper turning can be possible by setting the compound slide at half of the required angle.

The slide is only used for short job taper turning.

The automatic feed is not possible in the compound slide.

9. Feed Mechanism

There is a number of mechanisms to make the cross slide and carriage move automatically to change the direction of their movement.

Some important feed mechanisms are as follows:

i. Belt Feed Mechanism   

The belt feed mechanism is commonly used in the oldest lathe machines.

In this, a cone-stepped pulley is used to provide the different types of speed.

To change the speed, a lever is used to slide the belt from one pulley to another.

The belt feed mechanism has a demerit of the belt slipping in the pulley changing process.

ii. Gear Feed Mechanism     

In the gear feed mechanism, the power is transmitted from the spindle to the lead screw or feed rod with the power gear train.

Gear 1 is located at the back side of the spindle and the tumbler bracket contains gears 2, 3, 4, and 5.

A lever controls the bracket. This bracket is pivoted about the axis of the stud gear.

This position of the bracket can be arranged in three different stages namely:

1.      Neutral Position

2.      Forward Position

3.      Reverse Position

4.      Working Principle of lathe machine

Principle

·         A lathe is a machine that use to remove undesired materials from a workpiece in the form of chips with the help of a tool that moves across the workpiece and can be fed deep into the workpiece.

·         When the device is traveled parallel to the workpiece then the cylindrical surface is shaped.

·         If the tool is traveled inclined to the axis then it forms a tapered surface and so known as taper turning.

Working

·         It grips the work between two supports so known as centers.

·         A faceplate or Chuck is used to hold the work.

·         Faceplate or Chuck are loaded on the machine spindle.

·         The cutting tool is held with the help of a Tool post.

·         The movement of the job is revolving around the spindle axis.

·         Against the rotating work, the tool is fed.

·         The tool travels either parallel or in inclination to the work axis.