Honing Process | Types of Honing Machines

Honing process

It is an abrasive process used for finishing previously machined surface. It is generally used for finishing drilled or bored holes. The tool used in this process is called as hone. Hone is a bonded abrasive stone made in the form of a stick.

The honing tool works the same way as that of the expanding reamer. These honing stones are forced away by mechanical or hydraulic pressure against the surface of the bore. Aluminium oxide, silicon carbide or diamond grains of suitable grit are bonded in resinoid or vitrified bond to form the honing stones. Both internal cylindrical and flat surfaces can be easily finished using the honing process.

There are two types of honing process

Manual honing process

On this process a suitable quantity of coolant is used along with the honing stone hence this process is called as wet process. In this process the hone is continuously rotated and the work piece is moved front and back with the help of hand.

Machine honing

The process of honing can be done on any type of machines such as lathes and drilling machines. Fixed type of machines does not suite the honing process. A portable small drilling machine can also be used for the process of honing by fixing a honing tool head at the place of a drill bit. These small machines will fail to yield accurate results in mass production. So a regular honing machine is to be used in order to obtain a good result. Many types of honing machines are available the most common types are explained below.

Horizontal honing machines

Longer jobs are machined with the help of these machines. These machines carry a horizontal spindle on which honing tool is mounted. On some machines the work piece is mounted on the table and it reciprocates to and fro. The hone rotates about its own axis and also slightly oscillates. This oscillation is controlled mechanically or hydraulically. In some cases the honing tool is mounted on a travelling head is rotated as well as reciprocated.

01 - HORIZONTAL HONING PROCESS - HONING MACHINE

The work piece is held in a horizontal position and rotated about its own axis. This type of machine is meant for very longer jobs. Correct machining sizes are checked with the help of gauges. Two spindles are present in some machines.

Vertical honing machines

In this type of machining process the tool as well as the work piece is held vertically. These machines are available in more spindle types. The work piece is stable and the tool reciprocates. Fixtures are present to hold the work piece in correct position. Hydraulic drives are present in modern machineries to control the tool and the work piece.

01 - VERTICAL HONING PROCESS - TYPE OF HONING MACHINE.

Vertical types of honing machines are generally suitable for shorter jobs. These machines are widely used when compared to that of horizontal honing machines.

Types of Broaching Machines | Different Methods of Broaching

Types of Broaching Machines

Horizontal broaching machine

In this machine, the broach moves in a horizontal direction. A pull type broach is used. The pull type broach removes metal when it is pulled through the work piece. Internal and external broaching are done in this machine. But horizontal broaching machine is mainly used for internal broaching.

01 - HORIZONTAL BROACHING MACHINE - TYPE OF BROACHING MACHINE.

The machine has a base or bed. The base is of the box type construction. The length of the base is slightly more than the length of broaching stroke. The front of the machine has a vertical face. An adapter is fitted to this vertical face. The work piece is located in the adapter. The small end of the broach is inserted through the hole of the work piece. The small end is connected to the pulling head the other end of the broach is supported by the guide.

The pulling head pulls the broach. Normally the pulling head is driven by a hydraulic drive.

When the broach is pulled, it cuts the metal. After the cutting stroke, the pulling head returns back the original position. The broach end is separated from the pulling head. The machined work piece is un loaded.

Keyways, splines, slots, round holes and other internal contours are broached in this machine.

Vertical broaching machine

In a vertical broaching machine, the broach moves in a vertical direction. A push type broach is commonly used. The broach is fitted to a slide. The slide moves vertically along the guide ways of the column.

01 - VERTICAL BROACHING MACHINE - TYPE OF BROACHING MACHINE

The movement of the slide is obtained through a hydraulic drive. The work piece is held in fixture. The fixture is clamped to the worktable. The left side view of the broach is shown in the figure. The broach does not have teeth throughout its entire width. The broach does not have teeth are made of three segments A,B and C. Teeth on the segment A cuts first on the central portion of the work piece. This method of broaching is known as progress broaching. If the width of the work piece is smaller, a single piece broach is sufficient.

Continuous broaching machines

Continuous broaching machines are used for mass production of small parts.

Horizontal continuous broaching machine

01 - CONTINUOUS HORIZONTAL BROACHING - BROACHING TYPES.

The machine has two rotating drums. They are connected by a endless chain. Drive is given to one drum. There are fixtures mounted on the endless chain throughout its length. The work pieces are loaded on the fixtures from one end. The broach is fitted horizontally in the frame of the machine. The work piece moves under the broach. The chain when it comes under broach slides over a rigid support. This gives rigid support to the work piece when broaching takes place. The work piece is unloaded at the other end.

Rotary continuous broaching machine

01 - ROTARY BROACHING  MACHINE - TYPES OF BROACHING MACHINE

Small work pieces are fitted to a rotating table by the help of fixture. Broaches are fitted to a stationary broach holder which is placed at the center of the rotary table. There are three broaches. The table rotates continuously. The work piece moves past the broaches. The third broach is a finishing broach. The other broaches are for rough cutting. After the work pieces leave the finishing broach, they are unloaded. New work pieces are loaded to the fixture. Loading and unloading are done without stopping the rotary table.