Grinding Machine Grinding Machine process

1.Grinding Machine ?

Ans:- Grinding is a material removal process accomplished by    abrasive particles that are contained in a bonded grinding wheel rotating at very high surface speeds. The rotating grinding wheel consists of many cutting teeth ( abrasive particles ) and the work is fed relative to the rotating grinding wheel to accomplish material removal.

2.Types Of Grinding Machine

Ans:-

1.  Rough Grinders

a.  Floor Standard Grinders

b.  Clench Grinders

c.   Portable Grinders

d.  Abrasive belt Grinders

e.  Swing Frame Grinders

2.  Precision Grinders

a.  Cylindrical Grinders

        i.  Centre Type Plain Grinders

        ii.  Center Type Universal Grinders

        iii.  Centerless Grinders

b.  Internal Grinders

       i.   Chucking Type Grinders

       ii.   Planetary Type  Grinders

       iii.   Centerless Grinders

 

c. Surface Grinders

   i.Reciprocating table-horizontal spindle

   ii.Rotary table-horizontal spindle

   iii.Reciprocating table-vertical spindle

   iv.Rotary table-vertical spindle

d. Tool end cutter grinders

E.Special Grinders

3.Surface Grinding Machines?

Ans:- Surface grinding machines are used primarily to grind flat surfaces. However  formed,  irregular  surfaces  can  be produced on some types of surface grinders by use of a formed wheel.

Four basic types of surface grinding machines are:

1.  Horizontal spindle and reciprocating table

2.  Vertical spindle and reciprocating table

3.  Horizontal spindle and rotary table

4.  Vertical spindle and rotary table

4.Abrasives

Ans:- Abrasives are hard substance which are used as cutting edges in the grinding wheel. Small abrasive particles called abrasive grains are used in grinding Wheels.

Abrasives Are classified into Two Types

1.  Natural Abrasives

2.  Artificial Abrasives

a.  Aluminium oxide

b.  Silicon Carbide

5.Bond And Various Types Of Bonds?

Ans:- In order to give an effective and continuous cutting action, it is necessary That the grains of abrasive material should be firmly together to form a series of cutting edges. Bond is an adhesive substance used to hold abrasive grains together in the grinding Wheel.

The Following are the various types of bonds.

a.  Vitrified bond (V)

b.  Silicate bond (S)

c.   Resinoid bond (B)

d.  Rubber bond (R)

e.  Shellac bond (E)

f. Oxy-chloride bond (O)

6.Standard Marking System?

Ans:- The Indian standard Institution (IS 551-1954) has specified a standard system of marking the grinding wheels. According to this system the following elements are represented in a definite order.

•  Abrasive

•  Grain Size or grit

•  Grade

•  Structure

•  Bond

Example of a wheel specification:

•  51   A         36       L          5          V         40

• 51  Manufacturer’s symbol indicating type of abrasive A    Abrasive (aluminium oxide)

•  36  Grain size(medium) L        Grade(medium)

•  5    Structure(dense)

•  V   Bond(vitrified)

•  40Manufacture symbol (suffix) optionally

7. SPECIFICATION OF GRINDING WHEELS

Ans:-

•   Standard wheel markings

•   Diameter of the wheel

•   Bore diameter of the wheel

•   Thickness of the wheel

•   Type of the wheel

8.Selection Of Grinding Wheels

Ans:- In selecting a grinding wheel, the following factors are considered:

Constant Factors

1.  Properties of the material to be ground i.e., its hardness, toughness, strength etc.

2. The amount of stock to be removed.

3. Area of contact of the wheel with the workpiece.

4. Type of grinding machine and its condition.

Variable Factors

1. Wheel speed and work speed.

2. Dimensional accuracy required.

3. Type of grinding to be done.

4. Quality of surface Finish required.

5. Speed and feed of the wheel.

6. Method of grinding i.e., wet or dry

 

9.Mounting Wheels

Ans:-

•  Examine for any obvious surface defects

•  Test wheel for cracks by suspending by its centre and tapping with a light bar. It should give a clear ring sound.

•  Examine the lead bush for burrs

•  After mounting, run the wheel for some minutes without load and without standing near.

 

10.Dressing Of Grinding Wheel ?

Ans:- Remove loading and breaks away the glazed surface so that sharp abrasive particle are again presented to work

11.Truing Of Grinding Wheels ?

Ans:- It is the process of changing the shape of the grinding wheels as it becomes worn form an original shape owing to the breaking away of the bond.

12.Balancing Of Grinding Wheels?

Ans:- Grinding wheels rotate at high speeds. The weight should be evenly distributed throughout the body of the wheel. The imbalance of the wheel will develop a high unbalanced centrifugal force.

13. Diamond wheels?

Ans:- These wheels are also made in almost similar shapes as of Aluminum oxide or silicon carbide wheels. They are also provided with the central hole for being mounted on a spindle.