Grinding Machine: Definition, Types, Parts, Working & Operations [PDF]

Grinding Machine Definition

A grinding machine or grinder is an industrial power tool that uses an abrasive wheel for cutting or removing the material. It is a process of metal cutting by using a rotating abrasive wheel from the surface of the workpiece. Generally, the grinding is a type of finishing operation to make sure that there is high surface quality, accuracy of the shape and dimension. Grinding machine operation is also carried out for machining extremely hard material.

Working principle of Grinding Machine

The working principle of a grinding machine is quite easy to understand. In a grinding machine, there is an electric motor which supplies power to the grinding wheel with the help of a belt and pulley. So when we start the electric motor, the motor rotates at a certain rpm (150-15000 RPM) with the help of v-belt and cone pulley which in turn rotates the grinding wheel to perform the required operation.

Grinding Machine Types

Rough Grinders

  • Floor or bench grinders
  • Portable grinders
  • Abrasive belt grinders
  • SwingFrame grinders

Precision Grinders

  • Surface Grinders
  • Cylindrical Grinders (Plain, Universal, and Centerless grinders)
  • Tool and Cutter Grinders
  • Internal Grinders (Chucking, Planetary, and Centerless grinders)
  • Special Grinding machine

Floor or bench grinder

A floor or bench grinder is a small type of machine used in labs where a small workpiece needs to be grinded. For example, when we manufacture a single-point cutting tool for a lathe machine we use a floor or bench grinder to manufacture.

➔ BOSCH GWX18V-8N 18V Grinder

Sale
BOSCH GWX18V-8N 18V X-LOCK Brushless 4-1/2 In. Angle Grinder with Slide Switch (Bare Tool),Blue
71 Reviews
BOSCH GWX18V-8N 18V X-LOCK Brushless 4-1/2 In. Angle Grinder with Slide Switch (Bare Tool),Blue
  • ERGONOMIC, ROBUST GRINDER DESIGN: Engineered with…
  • X-LOCK WHEEL CHANGE: Features click-in mounting…
  • TOOL-FREE DISC SWAP: The wheel mounts properly…
  • BRUSHLESS MOTOR: Provides equivalent 8.0 amps of…
  • RESTART PROTECTION: Helps prevent accidental tool…

The Bosch GWX18V-8 is not your average angle grinder. It’s a true champion when it comes to combining convenience, performance, and user comfort. With its clever design and advanced features, this grinder takes your grinding experience to a whole new level. The brushless motor is a powerhouse. It is known for delivering an impressive 8.0 amps of power while maximizing efficiency, so you can keep going without interruptions. But what really sets it apart is the game-changing X-LOCK mount.

Safety is a top priority too, with restart protection, soft-start technology, and overload protection to keep you and the motor safe. The grinder’s spiral bevel gears ensure a smooth transfer of power. The adjustable tool-free guard and updated gearhead mounting collar provide versatility and compatibility with various Bosch guards. And let’s not forget about comfort – the two-position side handle and slim soft-grip design make handling a breeze.

ProsCons
✔️ High Power Disc is hard to find
✔️ Fuel gauge on the tool Better for one time use
✔️ Robust

Specifications of BOSCH GWX18V-8N Grinder

BrandBosch
Voltage18 Volts
Weight‎0.01 ounces
Maximum Rotational Speed‎11000 RPM
Item Dimensions‎4.3 x 11.8 x 5.1 in
MaterialMetal

Portable grinder

As the name indicates it is not fixed at one position. The portable grinder is used for cutting tiles.

➔ Fein 4.5 Inch WSG 8-115 Angle Grinder

Fein 4.5 Inch WSG 8-115 Angle Grinder, Warranty: 6 months
Fein Compact Angle Grinder Tool with 5-8/11' Mounting thread and 5' Grinding Wheel - Solid Metal, 800 W, 11,000 RPM - WSG8-125/72217460090
16 Reviews
Fein Compact Angle Grinder Tool with 5-8/11″ Mounting thread and 5″ Grinding Wheel – Solid Metal, 800 W, 11,000 RPM – WSG8-125/72217460090
  • Up to 30% longer brush service life and more…
  • Solid metal gear head for maximum robustness and…
  • The lightest of its type.
  • H 07 Industrial-strength cable.
  • Best vibration values in its class.

The powerful 800W (6.7A) motor of this grinder not only ensures exceptional performance but also provides a high power reserve. It offers excellent balance, feels lightweight in your hands, and its slim design allows for precise control. Also you will be surprised by how little vibration it produces, reducing fatigue during extended use. The inclusion of a metal gearhead means this grinder can handle tough conditions, and the locking spindle makes changing wheels a breeze.

And let’s not forget about the cord – its H07 rating offers top-notch protection against damage and is known for being the most flexible in the industry. All of these features combine to give you a grinder that not only removes material efficiently but also promises a long and reliable lifespan.

ProsCons
✔️ High Power Ergonomics could be better
✔️ Low Vibration
✔️ Comfortable

Specifications of BOSCH GWX18V-8N Grinder

BrandFein
Voltage120 Volts
Weight‎7.48 ounces
Maximum Rotational Speed‎11000 RPM
Item Dimensions‎11.3 x 2.25 x 2.25 in
MaterialMetal

Abrasive grinder

The abrasive grinder is a similar type of grinder but the only main difference is that abrasive is used while cutting and finishing the job. This is more costly than the floor and portable grinder.

➔ Bucktool Combo 2″ x 42″ Belt Sander 6″ Bench Grinder

Bucktool Combo 2" x 42" Belt Sander 6" Bench Grinder, Knife Sharpener with Large Work Table BG2600 Upgraded Model
Bucktool Combo 2' x 42' Belt Sander 6' Bench Grinder, Knife Sharpener with Large Work Table BG2600 Upgraded Model
1,034 Reviews
Bucktool Combo 2″ x 42″ Belt Sander 6″ Bench Grinder, Knife Sharpener with Large Work Table BG2600 Upgraded Model
  • HIGH EFFICIENCY: This sander meets CSA standards,…
  • MULTI-FUNCTION SANDER: This combo 2″x42″ belt…
  • MULTI-ANGLE SANDING: The belt can tilt from 0 to…
  • EASY TO USE: Equipped with a 6-Inch 60 grit white…
  • TWO WORKTABLES: Equipped with two workbenches for…

This abrasive belt grinder is known for its high efficiency and multi function grinder. The belt of this grinder is able to to tilt between 0-90 degrees making it suitable for wide range of applications. It is also equipped with 6-Inch 60 grit white grinding wheel with tool-free adjustable eye shield which makes it easy to use. If you are looking for heavy duty applications then this grinder will be the best choice due to its sturdy cast iron base with rubber foot.

ProsCons
✔️ Value for money Safety could be improved
✔️ High Power Low motor life
✔️ Well built

Specifications of Bucktool Combo 2″ x 42″ Belt Sander 6″ Bench Grinder

BrandBucktool
Voltage120 Volts
Weight40.1 lbs.
Maximum Rotational Speed‎3450 RPM
Item Dimensions‎24.7 x 19.6 x 12.1 in

SwingFrame Grinder

A swing frame grinder is a complicated type of grinder machine and it is used to work on heavy workpiece.

➔ Rebel SwingFrame Grinder

This grinder is known for its stable and rigid steel construction. The structure is vibration free even at maximum load. The parts are designed in such a way that minimum maintenance is needed.

ProsCons
✔️ High Power Skilled operator is needed
✔️ High cutting wheel speed
✔️ Heavy duty

Specifications of BOSCH GWX18V-8N Grinder

BrandRebel
Power20HP
Weight500kg
Wheel cutting speed63 m/s

Surface Grinder

A surface grinder consists of an abrasive wheel, a chuck (a workpiece holding device), and a rotary table. The chuck is used to hold the material in place while the wheel and object are rotated to produce a smooth finish.

➔ Grizzly G3104 Surface Grinder

Grizzly G3104 Surface Grinder
Grizzly Industrial – Grizzly M618 Surface Grinder, 6 x 18-Inch
  • Here is an excellent surface grinder for grinding…
  • It features heavy cast iron construction quiet…
  • Choose from our selection of grinding wheels and…

This grinder provides the highest precision output for hardened or annealed ferrous metals. The construction is of heavy cast iron which makes it sturdy. Longitudinal slide coolant system is associated with this grinder. You can choose from a variety of grinding wheel when using this grinder.

ProsCons
✔️ High efficiency Requires skilled operation.
✔️ Sturdy machine
✔️ Metallic structure

Specifications of Grizzly G3104 Surface Grinder

BrandGrizzly
Voltage110 Volts
Weight1429 lbs.
Power Source‎‎Corded Electric
Item Dimensions‎45 x 42 x 73 in
MaterialCast Iron

Cylindrical Grinders

A cylindrical grinder is used for shaping the outer surface of a workpiece. These machines accept workpieces in a variety of shapes as long as they can be rotated through a central axis. In a cylindrical grinder, both the workpiece and grinding wheel are simultaneously rotated.

Following are the types of Cylindrical Grinders:

  • Outside diameter grinders
  • Internal diameter grinders
  • Centerless grinders

➔ KUG Cylindrical Grinder 

ProsCons
✔️ Finished spindle Skilled worker is required
✔️ Variable speed
✔️ Advanced Hydrostatic Lubrication System

Specifications of KUG Cylindrical Grinder 

BrandKentusa
Max. Load Between Centers154 LBS
Weight6930 lbs
Coolant Tank26.5 Gal
Item Dimensions110″ x 65″ x 72″

Centerless Grinders

A centerless grinder is a type of cylindrical grinder which uses two rotary wheels to secure the workpiece in place. Unlike a centered grinder, a centerless grinder does not make use of a spindle. The speed of the rotation of the wheels determines at what rate the material is removed.

➔ GT-610 Centerless Grinders

GT-610 Centerless Grinders
ProsCons
✔️ Maintain tight tolerance Skilled workforce is required
✔️ Able to grind multiple parts per cycle
✔️ CE Certified

Specifications of GT-610 Centerless Grinders

BrandGlebar
Work Wheel Power15HP
Weight3,130 lbs.
Power480V, 60Hz, 40A
Machine footprints66” x 54” x 94”

Tool & Cutter Grinders

A tool and cutter grinder makes use of a CNC machine tool with up to 5 axes and multiple grinding wheels. These devices are used for sharpening and producing milling cutters such as drills, endmills, and step tools. It is also widely used for producing the tools needed in woodworking and metal-cutting industries.

Tool and cutter Grinder
Tool & Cutter Grinder
(Source: IndiaMart)

Parts of a Grinding Machine

A grinding machine consists of the following parts:

  • Base or Bed
  • Tables
  • Headstock
  • Tailstock
  • Wheel head
  • Crossfeed
grinding machine diagram

Base or Bed

It is a cast-iron casting resting on the floor and supporting other parts which are mounted on it. The base houses the table drive mechanism and on the top of the base accurately machined guideways are provided at right angles to slide on it.

Table

There are two tables namely a lower table, and an upper table. The lower table provides transverse movement to the workpiece by sliding over the guideways on the bed, which can be moved by hand or power. The upper table is pivoted at its center over the sliding table and it is provided with headstock and tailstock. This can be positioned at any position along the table to hold the workpiece. The upper table can be swiveled and clamped for grinding straight or tapered surfaces.

Head Stock

The headstock is fixed over the bed and it supports the workpiece by means of a dead center and drives it by means of a dog. It may also hold the workpiece in a chuck and drive it.

Tailstock

The tailstock can be adjusted and fixed in any required position to accommodate different lengths of workpiece.

Wheel Head

It consists of a grinding wheel and its driving motor. The wheel head is mounted on a slide at the rear end of the base and moves perpendicularly to the table.

Crossfeed

The grinding wheel can be fed to the workpiece by engagement of the cross feed control lever by hand or power.

Grinding Machine Operations

Surface grinding operation

It is used to make a flat surface. The rotating grinding wheel removes the material from the top surface of the workpiece and gives a flat look.

Cylindrical grinding operation

This type of grinding operation is performed only for cylindrical jobs.

The cylindrical grinding operation are of two types:

  • External cylinder grinding
  • Internal Cylinder grinding

External cylinder grinding operation

When we need to remove the excess material from the outer surface of the workpiece then We performed an external grinding operation when we need to remove excess materials from the outer surface.

Internal cylinder grinding operation

This operation is done for smoothening the internal surface of a hole or any cylindrical workpiece.

Centerless grinding operation

In this type of grinding operation two grinding wheels are fitted parallel with a little 5-10 degree angle. This angle is provided to get a longitudinal motion of the workpiece. A cylindrical rod is inserted between the two grinding wheels. Due to the tilted angle of the workpiece, it is automatically passed through the wheels, and we will get a smooth surface.

Form grinding operation

In this type of grinding process, the grinding wheel is maintained exactly the same shape as the final product. When the job is passing through it, automatically the pre-determined shape is formed on the workpiece.

Wet and Dry grinding operation

Although there are two methods of doing a grinding operation, one is wet grinding and the second one is dry grinding.

Wet grinding

In wet grinding, we spray coolant generally water or any coolant to cool the surface during the grinding operation so that the life of the grinding wheel increases. This will also help to get a fine surface finish.

Dry grinding

In this type of grinding process coolant is not used. Dry grinding is not preferable. In this process, the grinding wheel wear is more due to which we get an uneven surface finish.

Video lecture on Grinding Machine

Source: NPTEL by Dr. D. K. Dwivedi, IIT, Roorkee
Source: NPTEL by Dr. D. K. Dwivedi, IIT, Roorkee

FAQ’s

What is Grinding Machine used for?

A Grinding machine is used to make sure that there is high surface quality, accuracy of the shape and dimension. Grinding machine operation is also carried out for machining extremely hard material.

What is the working principle for Grinding Machine?

A Grinding Machine uses an abrasive product usually a rotating wheel to give shape to a workpiece by removing metal.

Conclusion

We can conclude by saying that the grinding machine has revolutionized the manufacturing industry. It provides high precision, low cost & high precision. With the advancement in technology, it continues to evolve & improve the tools and components.

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