surface grinding report

8/10/2019 Surface Grinding Report

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TITLE: UNIVERSAL SURFACE GRINDING

INTRODUCTION

Surface grinding is used to produce a smooth finish on flat surfaces. It is a widely used

abrasive machining process in which a spinning wheel covered in rough particles (grinding

wheel) cuts chips of metallic or non-metallic substance from a work piece, making a face of it

flat or smooth.

Surface grinding is the most common of the grinding operations. It is a finishing process that

uses a rotating abrasive wheel to smooth the flat surface of metallic or non-metallic materials

to give them a more refined look or to attain a desired surface for a functional purpose.

The surface grinder is composed of an abrasive wheel, a work holding device known

as a chuck, and a reciprocating or rotary table. The chuck holds the material in place while it

is being worked on. It can do this one of two ways: ferromagnetic pieces are held in place by

a magnetic chuck, while non-ferromagnetic and non-metallic pieces are held in place by

vacuum or mechanical means. A machine vies (made from ferromagnetic steel or cast iron)

placed on the magnetic chuck can be used to hold non-ferromagnetic work pieces if only a

magnetic chuck is available.

Factors to consider in surface grinding are the material of the grinding wheel and the

material of the piece being worked on.

Typical work piece materials include cast iron and mild steel. These two materials

don't tend to clog the grinding wheel while being processed. Other materials are aluminium,


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stainless steel, brass and some plastics. When grinding at high temperatures, the material

tends to become weakened and is more inclined to corrode. This can also result in a loss of

magnetism in materials where this is applicable.

The grinding wheel is not limited to a cylindrical shape and can have a myriad of

options that are useful in transferring different geometries to the object being worked on.

Straight wheels can be dressed by the operator to produce custom geometries. When surface

grinding an object, one must keep in mind that the shape of the wheel will be transferred to

the material of the object like a mirror image.

Spark out is a term used when precision values are sought and literally means "until

the sparks are out (no more)". It involves passing the work piece under the wheel, without

resetting the depth of cut, more than once and generally multiple times. This ensures that any

inconsistencies in the machine or work piece are eliminated.

TYPES OF SURFACE GRINDERS

1. Horizontal-spindle (peripheral) surface grinders.

2.

Vertical-spindle (wheel-face) grinders.3. Disc grinders and double-disc grinders.

THE BENEFITS OF SURFACE GRINDING ARE

You can grind very hard or abrasive materials

High degree of dimensionalaccuracy

Produces surface textures of very high finish

Tooling is less expensive

Work holding is easier because of magnetic chuck

Can be done automatically


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1. Horizontal-spindle (peripheral) surface

Grinders.

The periphery (flat edge) of the wheel is in contact with the work piece, producing the

flat surface. Peripheral grinding is used in high-precision work on simple flat surfaces; tapers

or angled surfaces; slots; flat surfaces next to shoulders; recessed surfaces; and profiles.

2. Vertical-spindle (wheel-face) grinders

The face of a wheel (cup, cylinder, disc, or segmental wheel) is used on the flat surface.

Wheel-face grinding is often used for fast material removal, but some machines can

accomplish high-precision work. The work piece is held on a reciprocating table, which can

be varied according to the task, or a rotary-table machine, with continuous or indexed


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rotation. Indexing allows loading or unloading one station while grinding operations are

being performed on another.

3. Disc grinders and double-disc grinders

Disc grinding is similar to surface grinding, but with a larger contact area between disc and

work piece. Disc grinders are available in both vertical and horizontal spindle types. Double

disc grinders work both sides of a work piece simultaneously. Disc grinders are capable of

achieving especially fine tolerances.

Aluminium oxide, silicon carbide, diamond, and cubic boron nitride (CBN) are four

commonly used abrasive materials for the surface of the grinding wheels. Of these materials,

aluminium oxide is the most common. Because of cost, diamond and CBN grinding wheels

are generally made with a core of less expensive material surrounded by a layer of diamond

or CBN. Diamond and CBN wheels are very hard and are capable of economically grinding

materials, such as ceramics and carbides, that cannot be ground by aluminium oxide or

silicon carbide wheels.

As with any grinding operation, the condition of the wheel is extremely important. Grindingdressers are used to maintain the condition of the wheel, these may be table mounted or

mounted in the wheel head where they can be readily applied.


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OBJECTIVE

1.

Know how to grind the surface of a metal object.

2. Know about the function of the universal surface grinding machine.

3.

Understand the functioned the type of tools used in the universal surface grinding

machine.

4. Knowing method about how the work

SAFETY PRECAUTION

1. Wear a goggle before start the works.

2.

Wear safety shoes.

3. Avoid wear jewellery while using this surface grinding machine.

4. Make sure the machine is safe before use.

5.

Use appropriate machine speed.

6. Switching off the machine after use.

7. Make sure the machine is used with safety switch and another switch lock.

SAFETY PRECAUTIONS DURING RUN MACHINE

Wear appropriate safety glasses. In addition, use the eye shield on the grinder, when

provided.

Ensure that the grinder has a start/stop button within easy reach of the operator.

Check the grinding wheel before mounting it. Make sure it is properly maintained and

in good working order.

Follow the manufacturer's instructions for mounting grinding wheels.

Keep face of the wheel evenly dressed.

Ensure that the wheel guard covers at least one half of the grinding wheel.

File off any burrs on the surface of work that is placed on the magnetic chuck.

Clean the magnetic chuck with a cloth and then wipe with the palm of your hand.


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Place a piece of paper slightly larger than workpiece in the centre of chuck.

Position work on the paper and turn on the power to the magnetic chuck.

Check that the magnetic chuck has been turned on by trying to remove work from the

chuck.

Check that the wheel clears the work before starting the grinder.

Run a new grinding wheel for about one minute before engaging the wheel into the

work.

Stand to one side of the wheel before starting the grinder.

Turn off coolant before stopping the wheel to avoid creating an out-of-balance

condition.

Keep the working surface clear of scraps, tools and materials.

Keep the floor around the grinder clean and free of oil and grease.


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Universal surface grinding

machine

- Used to produce the

smooth finish and flat

surface of the work piece.

VernierCalliper

- Used to measure the

diameter and the length

of work piece.

Goggle

- To protect the eyes from

dust, including iron.

PROCEDURE:

1. Surface grinding machine was started

2. The speed, angle of rotation, height of table and etc has been setting.

3. The work piece has been clamp tightly to avoid it flew away.

4. The movement of the magnetize table was set.

5.

The machine started to feed the work piece.

6. The grinded shouldnt very big or else the work piece will be damaged.

7. Make sure the surface object doesnt had any rust strain after it has been grinded


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EQUIPMENT

A surface grinder is a machine tool used to provide precision ground surfaces, either

to a critical size or for the surface finish.

The typical precision of a surface grinder depends on the type and usage, however +/-

0.002 mm (+/- 0.0001") should be achievable on most surface grinders.

The machine consists of a table that traverses both longitudinally and across the face

of the wheel. The longitudinal feed is usually powered by hydraulics, as may the cross feed,

however any mixture of hand, electrical or hydraulic may be used depending on the ultimate

usage of the machine (i.e.: production, workshop, cost). The grinding wheel rotates in the

spindle head and is also adjustable for height, by any of the methods described previously.

Modern surface grinders are semi-automated, depth of cut and spark-out may be preset as to

the number of passes and, once set up, the machining process requires very little operator

intervention.

Depending on the workpiece material, the work is generally held by the use of a

magnetic chuck. This may be either an electromagnetic chuck, or a manually operated,permanent magnet type chuck; both types are shown in the first image.

The machine has provision for the application of coolant as well as the extraction of metal

dust (metal and grinding particles).


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PROCEDURE FOR USE SURFACE GRINDER

The first step in using the surface grinder, is to make sure that the material you wish

to shape can be used in the grinder. Soft materials such as aluminum or brass will clop up the

abrasive wheel and stop it from performing effectively, and it will then have to be cleaned.

This process is explained in the Maintenance section. The maximum size of a material that

the grinder can machine is 18 long by 8 wide by 6 high. The next step is to make sure the

material is secured. This is done by use of a vice, and then by engaging the magnetic clamp.

Once the material is secure, it must be manually positioned under the abrasive wheel. This is

done by turning the longitude and latitude wheels located on the front of the grinder. The

abrasive wheel itself can be moved slightly to get the material in the perfect position. Then

the machine may be started. It should reach maximum speed before you try to use it for the

safety reasons mentioned before. If the wheel is working properly, then the hydraulic table

can be activated which will then begin to oscillate under the wheel, cross-feeding towards or

away from you as required. The automated speed and direction of the tables oscillations can

be set as required, or manually used when very precise work needs to be done. If needed, a

lubricant may be used to speed up or facilitate the grinding process. For this machine

Cutwell 45 is used. It is delivered via a tube beside the wheel, and falls onto the material

being used. The excess fluid is then drained into the reservoir.

CLEANING

A wire wheel mounted to a utility grinding machine is used for cleaning operations

such as removing rust, paint, or dirt from metal objects. If the utility grinding machine on

which the wire wheel is to be mounted is equipped with wheel guards and tool rests, these

parts should be removed or swung out of the way so that the objects to be cleaned can be

brought against the wheel without interference.

To clean objects with a wire wheel, place the object firmly against the wire wheel.

Work the object back and forth across the face of the wheel until all traces of rust, paint, or


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dirt are removed. Avoid excessive pressure against the face of the wire wheel to prevent

spreading the steel wires. Keep the point of contact below the center of the wheel to avoid

kickback of the workpiece.

LUBRICATION

Lubricants are sometimes used to cool the workpiece and wheel, lubricate the

interface, and remove swarf (chips). It must be applied directly to the cutting area to ensure

that the fluid is not carried away by the grinding wheel. Common lubricants include water-

soluble chemical fluids, water soluble oils, synthetic oils, and petroleum-based oils. The type

of lubrication used depends on the workpiece material and is outlined in the table below.

Types of lubricants used for grinding based on workpiece material

Workpiece material Lubricant

Aluminium heavy duty oil

Brass Light duty oil

Cast iron Heavy duty emulsifiable oil, light duty chemical and synthetic oil

Mild steel Heavy duty water-soluble oil

Stainless steel Heavy duty emulsifiable oil, heavy duty chemical and synthetic oil

Plastics Water-soluble oil, dry, heavy duty emulsifiable oil, light duty chemical and

synthetic oil

EFFECTS ON WORK MATERIAL PORPERTIES

The high temperatures encountered at the ground surface create residual stresses and a

thin martensitic layer may form on the part surface; this decreases the fatigue strength. In

ferromagnetic materials, if the temperature of the surface is raised beyond the Curie

temperature then it may lose some magnetic properties. Finally, the surface may be more

susceptible to corrosion.


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THINGS YOU SHOULD AVOID DOING

Do not run a grinding wheel faster than the speed recommended on the wheel.

Do not clean the magnetic chuck or mount or remove work until the wheel has

completely stopped.

Do not grind material for which wheel is not designed.

Do not grind without proper ventilation.

Do not start the machine until the wheel guard is in place.

Do not stand directly in front of a grinding wheel when starting a grinder.

Do not apply work too quickly to a cold wheel or disk.

Do not jam work into the wheel.

Do not reach above or around a moving wheel.

EXAMPLES OF FINISHED PRODUCT OF SURFACE GRINDER


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DISCUSSION

Surface finish is an important index of machinability or grind ability because the

performance and the service life of the ground component are often affected by its surface

finish, nature and extent of residual stresses and presence of superficial or sub superficial

micro cracks. The roughness of a ground component is mainly influenced by size of abrasive

grain, dressing conditions, feed rate, spark-out time and cooling conditions. The analysis of

the results obtained with the conventional cutting fluid application system and with the MQL

technique indicates that the application of cutting fluid by MQL technique led to satisfactory

results in comparison to the conventional system, due to the more efficient penetration of the

fluid into the cutting region.

CONCLUSION

Surface grinding is an abrasive machining process in which the grinding wheel

removes material from the plain flat surfaces of the work piece. In surface grinding, the

spindle position is either horizontal or vertical, and the relative motion of the work piece isachieved either by reciprocating the work piece past the wheel or by rotating it.

REFERENCES

Tool and Manufacturing Engineers Handbook (TMEH), 4th edition, Volume 1, Machining.

Society of Manufacturing Engineers, 1983

Todd, Robert H.; Allen, Dell K.; Alting, Leo (1994), Manufacturing Processes Reference

Guide.

surface grinding report

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