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DESIGN AND FABRICATION OF A PRINTING /BLOCK MACHINE
ABSTRACT
Parameters on which clear prints depend were comprehensively investigated. The study revealed that clear print depends on the impressed pressure the working temperature and the gold foil print paper life expectancy. Also, studies were the manner of dependence of these parameters on prints impressed on sheets of varied thickness. The results of this investigation were utilized in the design and fabrication of an operational manual printing machine using gold foil sheet depositors clear prints were impressed on papers during the new machine’s operation.
LIST OF TABLES
TABLE 1 – Experimental determination of pressure for printing
11- Effect of temperature on the sharpness of print.
111 – Description of (components) parts and materials used for them
1v- comparison of cost and properties of materials
LIST OF FIGURES
Description
Figure 1 sketch of alternative A
Figure 2. Sketch of alternative B.
Figure 3 Sketch of alternative C
Figure 4 Isomeric view of hot plate square housing
Figure 5 Isometric view of type holder
Figures 6 &7 load and free body diagram of the crank are (Handle) and rod.
LIST OF SYMBOLS
A – Area
A – Acceleration
D – Maximum shaft diameter
- minimum shaft diameter
- efficiency
k – Thermal conductivity
c – Heat capacity
x – The pressure transmissibility of lever system (press x 1/duration )
t – Time
l – Length of shaft
m – Mass
m – Maximum bearding moment
p – Electric power
q – Quantity of heat
TABLE OF CONTENTS
Title page ii
Letter of transmittal iii
Release iv
Approval page v
Dedication vi
Acknowledgment vii
Abstract viii
List of figures ix
List of tables x
List of symbols xi
Table of contents xii
CHAPTER ONE
- INTRODUCTION 1
- Literature Review And Data Collection 2
- Experimental Determination Of Pressure For Prating 3
- Design Specification 9
CHAPTER TWO
- DESIGN SOLUTIONS 11
- Alternative A press foot printer 11
- Alternative B; crank arm (handle ) 14
- Alternative C; automatic (motorized) printer 17
- Comparison of alternative and choice 20
CHAPTER THREE
- DESIGN SELECTION AND ANALYSIS OF PARTS OF CHOSEN ALTERNATIVE 22
- Theory of design/ design calculation 24
- The design of the shaft (Hollow) 26
CHAPTER FOUR
- CONSTRUCTION OF PROTOTYPE 28
- General 28
- Material Selection 29
- Sequence Of Construction And Assembly 40
CHAPTER FIVE
- TESTING OF PROTOTYPE (TEST–RUN) 40
- Evaluation of machine efficiency 40
- Operator’s Manual 41
- Costing (cost analysis) 42
- Problems Encounter 45
- Conclusion 45
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- Recommendation 46
48
CHAPTER ONE
1.1 INTRODUCTION
Nigeria in recent times lays strong emphasis on mass literacy and indigenous technology. Printed matters are indispensable materials in mass literacy campaigns and the trend towards indigenous technology imposes a severe clamp down on imputed engineering including printing block machinery. Thus the situation is such that makes the acquisition of printing machinery from outside our boards extremely difficult.
Therefore to lessen the economic strain on the mass literacy campaign local production of printing machinery is imperative. It is this fact that rendered integrative to the conception and realization of this low-cost but efficient printing machine based entirely on local technology and resources.
The present machine is very useful in the printing of many items like paperback cards etc. its design and fabrication is expected to motivate and advance the design and fabrication of other machines destined for a similar purpose and based on indigenous technology and resources.
1.2 LITERATURE REVIEW AND DATA COLLECTION
There were no available books in printing in both the state and school libraries that actively dealt with printing technology. The only books available were those on the history of ‘Types’ and trade journals advertising products of foreign companies which were found to be of little or no relevance.
However, a visit to the government printing press allowed us to study the ‘types’ available and the basic operations of the giant printing (Blocking) machine concerning the ‘Types’ from there we were able to establish;
- The effect of temperature on the amount of gold deposited from a sheet (sharpness of print )
- The effect of a lifetime on the gold foil sheet depositor.
- The effect of pressure on the amount of gold deposited from a sheet (sharpness of print )
- The effect of size of ‘types’ on the sharpness of print (amount of gold deposited )
Definition:
Types: These are the characters or alphabets that form the letters.
Print:- This is the mark or impression produced on paper due to the types. Gold foil sheet depositor:- is a thin rectangular cellophane sheet coated with gold compound.
- EXPERIMENTAL DETERMINATION OF PRINTING PRESSURE.
For the print there must be impact force between two surfaces one of which contains the ‘type’ and the other the paper on which the print will be made. The force produces the necessary pressure for printing.
Consider alternative ‘B’ of the possible design solution. Impact force is due to the acceleration of mass of the moveable plate and rail against the stationary letter box located on the element box. The pressure for printing is impact force for a constant surface area
Impact surface area the pressure varies with variation in the impact force. Similarly, the impact force varies with the mass and acceleration. But the mass is constant and equal to the mass of the rail plus the mass of the moveable plate hence only the acceleration varies. Therefore in this experiment effort has been made to determine.
- The pressure required to print clearly on a thin cellophane sheet without perforating it.
- The pressure required to print clearly on paper of average thickness without perforating it
- The pressure required to print on a cardboard sheet such that very sharp prints are obtained by varying the input acceleration
Materials: very light cellophane paper, the paperback of higher education exercise book ceiling sheet (cardboard) silver sheets,
Apparatus: Election-speed printer machine
Definition: The electronic speed printer machine is a motorized electronic motor. It has a device for varying the acceleration the current input can vary hence the heat generated and therefore the temperature varied.
Method: the acceleration is varied keeping the temperature and surface area of impact constant. Already the striking mass is constant. The following values show the accelerations at which the sharpest prints were obtained without perforation of the materials after several trials. The corresponding forces and pressure are also shown.
TABLE 1
| Material | Accel. For the sharpest print without perforation | Mass (m) | Force (ma) | Pressure (ma/a) |
| Cellophane paper | 0.07mls 2 | 35kg | 2.45N | 2.45
0.0972 = 25.24 n/m2 |
| The paperback of higher education notebook | 0.76 mls2 | 35kg | 26.6N | 26.6 = 273.N/M2
0.0972
|
| Ceiling sheet
Cardboard |
2.3 mls2 | 35kg | 80.8n | 80.8 = 831 N/m2
0.0.972 |
- operating temperature 1550c (fixed)
- 0972 = area of foolscap sheet (fixed)
for the heating coil, the heat dissipated is given by H. = 12 Rt where 1 = current passing in ampere R = resistance of the coil in ohms and t = duration time in seconds. It varies directly with temperature which is the measurement of heat hence the determination of:
TABLE 11
EFFECT F TEMP. ON SHARPNESS OF PRINT
| Temp
(0 c) |
Cellophane paper | The paperback of Higher Edu. Book | Ceiling sheet cardboard | Acceleration (m/s2) | Pressure (N/m2 |
| 25 | No print | No print | No print | 0.07 | 25.2 |
| 50 | Slight deposit | No print | No print | 0.07 | 25.2 |
| 155 | Sharp print | No print | No print | 0.07 | 25.2 |
| 200 | No print | 0.07 | 25.2 | ||
| 250 | ShriNon–clear | lear print | No print slight deposit | 0.07 | 25.2 |
| 25 | Slight deposit | No print | No print | 0.76 | 273 |
| 50 | Clear print | Slight print | No print | 0.76 | 273 |
| 155 | Perforation | Sharp print | No print | 0.76 | 273 |
| 200 | Burnshrinesrins | Slight groove | Slight deposit | 273 | |
| 250 | Increased burns | Deeper grooNon-clear | lear print | 0.76 | 273 |
| 25 | Fairly clear print | Slight deposit | Slight deposit | 2.3 | 831.2 |
| 50 | Perforation | Clear print | Non-clear print | 2.3 | 831.2 |
|
155 |
Burns/ shrinks | Sharp print with very deep groove | Sharp print | 2.3 | 831.2 |
| 200 | Increased burns | Perforation begins | Grooving begins | 2.3 | 831.2 |
| 250 | Increased burns | Deeper perforations | Deeper groove | 2.3 | 831.2 |
OBSERVATION:
From Tables 1 and 11 it can be observed that
- The sharpness of print varies directly with the acceleration and hence the operating pressure.
- The sharpness of print varies directly with temp.
- No matter how high the pressure applied at room temp.250c) a sharp print can never be obtained before and even after grooving and consequent perforation occurs.
- By increasing acceleration and decreasing term. Or vice-versa sharpness of prints can be altered provided the temp. Variation does not require a fall below 1550
CONCLUSION:
The sharpness of the print depends on pressure on temp (from about 1500c upwards).
- EFFECT OF LIFETIME ON GOLDEN FOIL DEPOSITION
Gold foil sheet as already defined is a very thin rectangular cellophane sheet coated with a golden compound chemical such that temperature and pressure can be regulated its deposition on paper. From the time of production (coating of gold on cellophane) the coherency of the gold deposit decreases with time until a time when the layers of the compound start peeling off from the sheet by itself. Hence sharpness of the print depends on the lifetime of the coating. This fact was established after observing different life golden sheets used under the same temperature and pressure.
(b) THE EFFECT OF SIZE OF TYPES ON THE SHARPNESS OF PRINT.
Since pressure = force / Area, the same force applied ‘types’ having smaller surface area exerts greater pressure in direct proportion to the ratios of their surface area.
1.4 DESIGN SPECIFICATION
The printing (blocking) machine to be designed must be able to:
- produce sharp print on paper gold-concatenated sheet
- require small effort for operation
- resist failure of excessive effort should be applied.
- Be easily operated by anybody
- Produce as many per unit of time as possible.
- Must be relatively cheap in every respect
- Should be compact and portable
- Should not be too heavy – can easily be moved from one location to another
- The position of the operator in use should be convenient, not tiring
- Should be durable
- should have replaceable parts – using bolts, sc, news, and other forms of assembly rather than welding. Also using components whose forming / manufacturing process is less complex so the user can easily replace damaged parts.
- Manufacture ability – can be manufactured within the limits of available materials and processes in the school workshop and neighboring establishments.
