GRATIS REPORT

KWAME NKRUMAH UNIVERSITY OF SCIENCE AND

TECHNOLOGY

MATERIALS/METALLURGICAL ENGINEERING

DEPARTMENT

June – July ,2016

A REPORT ON INDUSTRIAL ATTACHMENT AT GRATIS FOUNDATION HEAD OFFICE – TEMA

BY: ADDO FRANCIS KWAME POLYCARP


A REPORT ON INDUSTRIAL ATTACHMENT

AT GRATIS FOUNDATION

Table of Contents

A REPORT ON INDUSTRIAL ATTACHMENT AT GRATIS FOUNDATION ..................................................... 1

AKNOWLEDGEMENT............................................................................................................................ 2

ABSTRACT.............................................................................................................................................. 3

ABOUT GRATIS FOUNDATION .......................................................................................................... 4

VISION ..................................................................................................................................................... 4

MISSION .................................................................................................................................................. 4

WEEK ONE – METAL MACHINING LAB ........................................................................................... 5

CENTRE LATHE MACHINE ..................................................................................................................... 5 GRINDING MACHINE .............................................................................................................................. 6 DRILLING MACHINE ............................................................................................................................... 7 ROLLER MACHINE ................................................................................................................................... 8 ENGRAVING MACHINE/ PANTOGRAPH .............................................................................................. 9 MAKING A SCREW THREAD FOR A METAL ......................................................................................... 9 MILLING MACHINE ............................................................................................................................... 10

WEEK 2: WELDING AND FABRICATION .........................................................................................12

ARC WELDING..........................................................................................................................................12 OXY – ACETYLENE WELDING...............................................................................................................13

GRINDING MACHINE ......................................................................................................................... 14 BENDING MACHINE ............................................................................................................................15 HYDRAULIC SHEAR MACHINE ....................................................................................................... 16

WEEK THREE: FOUNDRY .................................................................................................................. 17

WEEK FOUR: ENGINEERING DESIGN CENTRE .......................................................................... 18

THE DESIGN PROCESS ...................................................................................................................... 19 DESIGNING WITH AUTOCAD ........................................................................................................... 19

CONCLUSION....................................................................................................................................... 20

REFERENCE ......................................................................................................................................... 20


AKNOWLEDGEMENT

My gratitude first of all goes to the almighty God for his enlightenment

and wisdom upon me during the course of my attachment.

My appreciation also goes to Mr. Emmanuel Asiedu, CEO of GRATIS

Foundation, Mr. Ekow Andoh (officer in – charge of recruitment), Mrs.

Lucy Kpor (Training Officer), Mr. Gabriel Boateng – Appiah (Design

Engineering officer) and all other trainers and apprentices who in

various ways helped in imparting practical knowledge unto me.


ABSTRACT

Industrial attachment is an integral part of student training in the university. I

had my internship at GRATIS foundation. Work at GRATIS starts at 8am and

ends at 5pm. On our first day we were taken through the activities, departments

and general knowledge of GRATIS foundation. The departments are:

Metal machining workshop

Welding and Fabrication workshop

Foundry

Engineering Design Centre

We were divided into four groups of six students each and were expected to

spend one full week in department and after, assigned to another department.


ABOUT GRATIS FOUNDATION

GRATIS Foundation was established in March 1987; initially as Ghana Regional

Appropriate Technology Industrial service (GRATIS), a project to promote

micro – industrial activities. Gratis Foundation is a leader in designing,

manufacturing and selling of precision agro, food processing and sanitation

equipment. Some of their products are

Yam slicer

Fruit washer

Fruit Juice Extractor

Palm fruit digester

Fufu pounding machine

Flour mixer

VISION

To be a Centre of excellence for research and Innovation for

appropriate technology product and services in Africa.

MISSION

To Research, design, develop, manufacture and market appropriate

technology – based products and services for micro, small and

medium enterprises so as to facilitate socio – economic and industrial

development in Ghana and other countries.


WEEK ONE – METAL MACHINING LAB

CENTRE LATHE MACHINE Popularly known as the “mother of machine tools” the lathe is a machine used to

cut screws, bore holes, facing and almost any work on a machine part.

Some of the parts of a centre lathe are

Apron: holds the tool holder

Head stock: contains the chuck, spindle and controls of the machine

Tail stock: used to support work piece when drilling

Tool holder: the tools are placed in them

Roller: a cylindrical bar attached to the revolving center

Revolving center: it is placed in the tail and attached to the roller

Bed: apron sits and slides on it.

Figure 1: centre lathe machine

The various tools used on the lathe also are;

HSS Tool: for machining hard or high carbon

TIP Tool: machining circular parts and also facing

BORING Tool: for boring holes in work


PARTING Tool: for separating or dividing work into two.

Figure 3: HSS tool

Figure 4: TIP tool

Figure 5: PARTING tool

The tip tool was used to smoothen a galvanized imperfectly round part into a

perfect round shape and also reduce to a fixed diameter. The part will be used as

a cutter in a fufu pounding machine.

GRINDING MACHINE

A machine used to smoothen the surface of a work piece.

It has a magnetic stage that is holds work to be machined in place.

Figure 2: Boring tool


It uses a wheel as the cutting tool, usually as a finisher in fabrication works.

It has a bed with a fixture to hold and guide the work piece. I observed the

grinding machine being used to smoothen the surface of an engine part.

Figure 6: Grinding machine

DRILLING MACHINE The machine is used to drill holes in a work piece.

The drill machines were many but we used one of them to drill holes into steel

balls. Theses steel balls are used in mills at mine sites and cement factories as

grinding media. The holes are used to check the size at which the balls become

useless as they wear out. In the process of drilling, the tip of the drill tool was

allowed to generate some amount of heat before drilling through the workpiece,

this was because the balls are made of still which is a very hard and metal.

The drill had three buttons used to operate the drilling.

The anti-clockwise drill button is used to push the drill into the workpiece.

The clockwise drill button is used to remove the drill from the workpiece

in case it gets stuck in the work piece.

The red button on the head part is used to stop the rotation and drilling

action of the tool.


Figure 7: A worker drilling a steel ball

ROLLER MACHINE A machine with three circular iron bars, constructed in such a way that one lies

on two others. It is used to make flat parts or metal sheets circular. I observed as

the roller was used to make straight iron pipes/ tubes circular.

Figure 8: Roller


ENGRAVING MACHINE/ PANTOGRAPH

A machine used to engrave letters, words and lines on a metal plate. It uses a

sharp pointed tool (engraver) to etch the metal and form the desired pattern.

One passes over a small metal with the desired shape and the other point with

the cutting tip engraves the design unto the workpiece.

It was used by an operator to calibrate a piece of metal sheet which would be

used as a measuring tool.

Figure 9: pantograph

MAKING A SCREW THREAD FOR A METAL Threads are grooves that form a spiral in or outside a cylinder and usually used

as fasteners for assembling components.

There are two ways of threading a workpiece.

Internal threading (Tapping): the cutting tool is called a Tap. In this

process a cylindrical tool with cutting teeth arranged in a spiral whose

pitch is equal to that of the screw threads, is simultaneously rotated and


fed into a pre-existing hole. The tap is a solid piece and the tapping

operation is performed on a drill press equipped with a tapping head,

which allows penetration into the hole at a rate that corresponds to the

screw pitch. At the end of the operation, the spindle rotation is reversed so

the tap can be unscrewed from the hole.

External threading (Dicing): the cutting here is called threading die. To cut

an external thread, the die is rotated around the starting cylindrical stock

of the proper diameter, beginning at one end and proceeding to the other

end. The cutting teeth at the opening of the die are tapered so that the

starting depth of cut is less at the beginning of the operation, finally

reaching full thread depth at the trailing side of the die. The pitch of the

threading die teeth determines the pitch of the screw that is being cut.

The pitch of a thread is determined by a thread gauge.

Work is lubricated with palm oil.

Figure 10: threading die

MILLING MACHINE Milling is a machining operation in which a work piece is fed past a rotating

cylindrical tool with multiple cutting edges. The cutting tool in milling is called a

milling cutter and the cutting edges are called teeth.

The knee-and-column milling machine is the machine tool for milling at

GRATIS. It is available as either horizontal or vertical milling machine; the


horizontal type has an arbor which supports the cutter. The arbor is basically a

shaft that is connected to the spindle and supports the cutter.

The milling machine is used to cut screw threads, keyways gears etc.

There are two main classes of milling these are face milling and peripheral

milling. In peripheral milling, the axis of the tool is parallel to the surface being

machined, and the operation is performed by cutting edges on the outside

periphery of the cutter.

In face milling, the axis of the cutter is perpendicular to the surface being milled,

and machining is performed by cutting edges on both the end and outside

periphery of the cutter.

Figure 11: Horizontal milling machine


WEEK 2: WELDING AND FABRICATION

Welding is a materials joining process in which two or more parts are fitted at

their contacting surfaces by a suitable application of heat and/or pressure. In

some welding processes a filler material is added to facilitate coalescence.

We were taken around the welding shop and shown the:

Arc welding equipment

Bending machine

Oxy – acetylene welding equipment

Grinding machine.

Welding at GRATIS is usually done using the fusion process. Fusion-welding

processes use heat to melt the base metals. In many fusion welding operations, a

filler metal is added to the molten pool to facilitate the process and provide bulk

and strength to the welded joint.

The fusion weld is subdivided into 3 groups two of which I witnessed at

GRATIS. These were: arc – welding (AW) and oxyfuel gas welding (OFW).

ARC WELDING Arc welding refers to a group of welding processes in which heating of the

metals is accomplished by an electric arc, some arc welding operations also

apply pressure during the process and most utilize a filler metal.

An electric arc is a discharge of electric current across a gap in a circuit. It is

sustained by the presence of plasma through which current flows. To initiate the

arc in an AW process, the electrode is brought into contact with the work and

then quickly separated from it by a short distance. The electric energy from the

arc thus formed produces temperatures of 5500_C (10,000_F) or higher,

sufficiently hot to melt any metal. A pool of molten metal, consisting of base

metal(s) and filler metal (if used) is formed near the tip of the electrode. In most

arc welding processes, filler metal is added during the operation to increase the

volume and strength of the weld joint. As the electrode is moved along the joint,

the plasma solidifies after it. Movement of the electrode is done by the welder

and one of the difficulties in this process is that, the quality of the weld depends


on the skills of the welder. I was given the chance to try welding some few parts

together using the shielded metal arc welding(SMAW) process and some of the

corrections and observations I made were

The metal parts were made of mild steel, since every electrode has the type

of metal it is used for in Arc welding; I used the mild steel electrode with

specifications (MT – 12E6019).

The voltage set is determined by the type of metal being welded and its

hardness.

The type of joint worked on was the close butt joint.

When welding the electrode should not touch the workpiece, it causes the

electrode to stick unto the work piece and no plasma is formed.

The electrode should not be too far from the workpiece because the

electrode would melt and just pour unto metal joint without actually

joining them together. This gives a poor quality or weak joint/weld.

The electrode is moved very slowly on the workpiece and should not be

passed in reverse.

The specification on the electrode had its meaning. The E represents

electrode, the first two letters represent the tensile strength(in psi), the

third digit indicates the position of the weld(all positions in this case) and

the fourth digit indicates the type of electrode coating and the type of

power supply used.

Figure 12: arc welding process

Other arc welding processes are the metal inert gas welding (MIG) and the

Tungsten inert gas welding (TIG), generally known as the Gas metal arc welding

(GMAW). TIG welding makes use of tungsten as the electrode due to it high


strength, and in the MIG welding other metals such as aluminum, copper etc.

are used but the difference here is that inert gas such as helium or argon are

used to accomplish shielding of the arc.

OXY – ACETYLENE WELDING Oxyacetylene welding (OAW) is a fusion-welding process performed by a high-

temperature flame from combustion of acetylene and oxygen. The flame is

directed by a welding torch. The combination of acetylene and oxygen is highly

flammable and very dangerous to use. Sometimes, a filler metal is used and this

filler has to have a composition similar to the metals being welded, this filler is

also coated with a flux that helps to clean the surfaces and prevent oxidation,

thus creating a better weld joint.

GRINDING MACHINE Unlike the grinding machine in the metal machining lab, the grinding tool in the

welding lab is a small hand – held device, used to polish or smoothen the

surface of a work piece. Other uses are:

To remove weld tackings

To cut metal parts

To smoothen welded surfaces

In cutting the workpiece, the flat large plate is used as the cutting tool and to

grind surfaces, the curved small plate is used.

Some of the techniques I learnt were that:

The guide has to be on always. If the guide is not properly fixed in place,

the machine should not be used since the plate can shatter at any time and

considering the speed of rotation, it can cause serious damages such as

injuries and even death.

The cutting tool should be properly fixed and not wobble to ensure ease of

use and perfect cutting.

Positioning is also important to avoid injuries by the tool or sparks.


Eye protection must be worn always to protect eyes against the sparks.

To avoid mistakes in cutting, the pattern should be drawn with a writing

tool (chalk), and then the grinder is used to mark out slightly the pattern

before being pressed on the work to cut it out.

Figure 13: grinder

BENDING MACHINE Bending machine is a machine that is used to form bends on a work piece while

assembling.

The universal bending machine is what is used at GRATIS foundation.

It consists of a basic machine that can be adjusted to get various angles of bends.

The tools are easily exchanged on a plug – in system and have a programming

that is used in operation.

The programming is displayed on a graphical user interface (GUI) that is

attached to the machine.

To operate it:

The desired angle is set on the GUI

The appropriate tool is fixed

The work piece is positioned and the tool slowly lowered onto the work

piece to bend it to required angle.


HYDRAULIC SHEAR MACHINE A powerful tool that is used for a quick cut– through of work pieces. It is

powered by electricity but can only function with the use of hydrogen gas and a

hydraulic fluid.

It consists of the shear table, work – holding device, upper blade (cutting blade).

To operate, the metal is placed on the table and then the cut length indicated

and placed directly under the upper blade. The force is then set according to the

thickness of the metal to be cut, for a good shear (a thickness of 4mm will be set

at 5mm).


WEEK THREE: FOUNDRY

A foundry is a place where metal castings are made and this was where we were

assigned on our third week.

Casting which is the main work done here, is a method of heating metal into

liquid and then pouring this liquid into prepared molds. There were furnaces

also for drying pieces and those for heating metal parts to high temperatures.

During my time, there was no metal cast but I learnt from a previous week’s

activity when an aluminum cast was made.

The mold which had four slab holes made with fine sand was prepared

The metal was heated to liquid

The molten metal was then poured into the mold and then covered, with the

edges tightly sealed with clay

This is done for a slow cooling that is devoid of imperfections in the grains.

Casting is one of the oldest metal working processes and is usually used for

complex metal works that would be expensive with other methods.


WEEK FOUR: ENGINEERING DESIGN

CENTRE

This was the last department we were assigned to. In this department we were

thought the design process, how to design using auto cad and also how to plan

the costing.

THE DESIGN PROCESS Before a good design can be made there are some steps that are taken by the

designer and other stakeholders involved to ensure a product that is durable and

also competitive on the market. The steps considered are:

Need

Research(internet, industries and text books)

Concept evaluation and testing (sketches and drawing, criteria tables)

Skin design( assembly drawing and dimensions)

CAD work( computer aided design and drafting, modelling, formatting

and assembly)

Manufacturing of prototype

Testing of prototype

Marketing

The above steps need to be followed meticulously and incase of any problem

indicated at any stage, it should be referred back to the right stage for

corrections to be made before being taken unto the market. For engineering

products, trade fairs are usually the best places to exhibit ready products first

going to the products since buyers can at these fairs evaluate and give the right

views of consumers for any corrections to be made. This would make the

products meet the demand of consumers and accrue a lot of profit.

DESIGNING WITH AUTOCAD


We used the Autodesk mechanical 2006 for auto cad tutorial. We designed an

extruder.

The first thing we did was to create a folder for the whole tutorial and also

subfolders for the parts, subassemblies and the main assembly. We then went

through the steps of using the software to

create and edit the design.

Figure 15: FORMATED DESIGN

We then after designing the extruder, made the costing analysis and that is

shown in the figure below.

Figure 16: costing of extruder

Figure 14: 4- VIEW OF EXTRUDER


CONCLUSION

I would say it was a fun experience and I hope to have more of such practical

exposure in the course of my studies. The overall atmosphere was good and very

inviting for us the interns as the workers and workshop apprentices made time

to answer all of our question to the best of their knowledge and gave us great

advices that we can use in our lives as engineers. The sense of time timing as we

had to sign in and out also helped us to feel as though we were part of them and

also made us time conscious so as not be late to work but always punctual. I

would always love to come back.

REFERENCE

Fundamentals of modern manufacturing (4th edition) (Mikell P. Groover)

GRATIS REPORT

Documents

Transcript of GRATIS REPORT