DJJ10022 MECHANICAL WORKSHOP PRACTICE 1 (V2) (WELDING) DEPARTMENT OF MECHANICAL ENGINEERING POLITEKNIK SULTAN MIZAN ZAINAL ABIDIN MOHAMAD NAZMI BIN NORDIN JOHAR BIN ITAM ISMAIL KEMENTERIAN PENDIDIKAN TINGGI JABATAN PENDIDIKAN POLITEKNIK DAN KOLEJ KOMUNITI
DJJ10022-MECHANICAL WORKSHOP PRACTICE 1 (V2) (WELDING) MOHAMAD NAZMI BIN NORDIN JOHAR BIN ITAM ISMAIL DEPARTMENT OF MECHANICAL ENGINEERING, PSMZA
DEPARTMENT OF MECHANICAL ENGINEERING, PSMZA FIRST PUBLISH LEARNING MODULE, 2018 © MOHAMAD NAZMI BIN NORDIN, MOHD SAILUDDIN BIN MAMAT & JOHAR BIN ITAM ISMAIL SECOND PUBLISH LEARNING MODULE, 2023 © MOHAMAD NAZMI BIN NORDIN & JOHAR BIN ITAM ISMAIL SESI I 2023/2024 ALL RIGHTS RESERVED. NO PART OF THIS BOOK (ARTICLE, ILLUSTRATION, AND CONTENT) MAY BE REPRODUCED OR USED IN ANY FORM OR BY ANY MEANS, ELECTRONIC OR MECHANICAL INCLUDING PHOTOCOPYING, RECORDING OR OTHERWISE WITHOUT THE PRIOR PERMISSION OF THE AUTHOR. THIS LEARNING MODULE EDITION IS PUBLISHED WITHOUT ANY ASSESSMENT OR EDITING PROCESS. THE QUALITY OF THIS EDITION WILL BE IMPROVED FROM TIME TO TIME BASED ON FEEDBACKS RECEIVED FROM LEARNING ACTIVITIES. WRITER MOHAMAD NAZMI BIN NORDIN PUBLISH AND PRINTED BY: Department Of Mechanical Engineering Politeknik Sultan Mizan Zainal Abidin KM. 8, Jalan Paka 23000 Dungun Terengganu Tel : 09-8400800 Fax : 09-8458781 EMAIL : [email protected] EDITOR JOHAR BIN ITAM ISMAIL
DEPARTMENT OF MECHANICAL ENGINEERING, PSMZA eNotes: DJJ10022 - Mechanical Workshop Practice 1 (V2) (Welding) First Edition 2023 eISBN 978-976-0047-51-5 eNotes - DJJ10022-Mechanical Workshop Practice 1 (V2) (Welding) is a general references and readings especially to lecturers and students of polytechnics and colleges Malaysian community to apply best practices in method implementation online teaching and learning. eNotes - DJJ10022-Mechanical Workshop Practice 1 (V2) (Welding) adalah sebagai rujukan dan bacaan umum terutama kepada pensyarah dan pelajar politeknik dan kolej komuniti Malaysia bagi mengaplikasikan amalan terbaik dalam perlaksanaan kaedah pengajaran dan pembelajaran atas talian.
DEPARTMENT OF MECHANICAL ENGINEERING, PSMZA IN THE NAME OF ALLAH, THE MOST GRACIOUS AND MERCIFUL. ALL PRAISES TO ALLAH S.W.T FOR HIS GREAT LOVING KINDNESS AND BLESSING, THIS BOOK IS SUCCESSFULLY PUBLISHED. THE AUTHOR WOULD LIKE TO EXPRESS DEEPEST APPRECIATION TO ALL THOSE WHO PROVIDED THE POSSIBILITY IN PUBLISHING THIS BOOK ESPECIALLY FRIENDS AND COLLEAGUES. MANY THANKS ALSO GO TO THE MECHANICAL ENGINEERING DEPARTMENT ADMINISTRATION TEAM FOR THE SUPPORT AND GUIDANCE THROUGHOUT THE PROCESS OF COMPLETING THIS BOOK. THE AUTHOR HOPE THAT THIS BOOK WILL HELP STUDENTS TO DO THE PRACTICAL WORKS IN THIS COURSE SUCCESSFULLY BASED ON THE CONCEPT OF WELDING APPLICATION. HOPEFULLY STUDENTS AND LECTURES CAN GIVE FEEDBACKS TO IMPROVE THE QUALITY OF THIS PRACTICAL TASK ASSESSMENT BOOK. THANK YOU. PREFACE
I would like to express my gratitude to the author of this welding module for extending the invitation to review their work. Congratulations to the authors who have skilfully demonstrated their experience and expertise in the field of mechanical engineering, resulting in the successful completion of the welding module for workshop practice. This module serves as an invaluable resource by imparting fundamental knowledge of welding technology. Its significance is particularly for lecturers and students seeking to apply the best welding practices. The module's organization is commendable, presenting information in a simple yet compact manner, ensuring ease of comprehension and implementation for students engaged in welding activities. Emphasis on workshop safety is crucial, and this module equips students with the requisite knowledge to maintain a safe working environment during welding tasks. Despite being primarily an instructional module, the presentation and meticulous preparation of the content contribute to its appeal for readers. I am confident that the publication of this module will greatly benefit students and lecturers alike, especially those new to the field of welding technology. My hope is that this resource will be maximally utilized by academics, facilitating an enhanced understanding of welding practices. In conclusion, this module stands as a valuable contribution to the field and promises to be an effective tool for knowledge acquisition and application. Regards Ts. Dr. Mohd Hanif bin Harun Lecturer, Faculty of Technology and Mechanical Engineering, Universiti Teknikal Malaysia Melaka REVIEW & COMMENTATOR
DEPARTMENT OF MECHANICAL ENGINEERING, PSMZA ABSTRACT This book is designed to assist student in performing practical task in Mechanical Workshop Practice 1 lab. Mechanical Workshop Practice 1 exposes the students to welding, machining, and fitting which involve the use of arc and gas welding machine, lathe machine, drilling machine, grinding, hand tools, marking out tools, measuring and testing tools. Students are also taught to emphasize on safety procedures and cleanliness in the workshop.
CONTENTST A B L E O F 11 A R C W E L D I N G 10 I N T R O D U C T I O N 18 O X Y A C E T Y L E N E W E L D I N G 22 W E L D I N G P R O J E C T 30 W O R K S H O P R E P O R T 33 R U B R I C 35 R E F E R E N C E S
WORKSHOP DRESS
SAFETY RULES AND UNSAFE PRACTICES GENERAL SAFETY RULES
INTRODUCTION Welding is a fabrication process whereby two or more parts are fused together by means of heat, pressure or both forming a join as the parts cool. Welding is usually used on metals and thermoplastics but can also be used on wood.
1.0 ARC WELDING Arc welding is one of several fusion processes for joining metals. By applying intense heat, metal at the joint between two parts is melted and caused to intermix - directly, or more commonly, with an intermediate molten filler metal. Upon cooling and solidification, a metallurgical bond is created. Since the joining is an intermixture of metals, the final weldment potentially has the same strength properties as the metal of the parts. This is in sharp contrast to non-fusion processes of joining (i.e. soldering, brazing etc.) in which the mechanical and physical properties of the base materials cannot be duplicated at the joint. In arc welding, the intense heat needed to melt metal is produced by an electric arc. The arc is formed between the actual work and an electrode (stick or wire) that is manually or mechanically guided along the joint. The electrode can either be a rod with the purpose of simply carrying the current between the tip and the work. Or, it may be a specially prepared rod or wire that not only conducts the current but also melts and supplies filler metal to the joint. Most welding in the manufacture of steel products uses the second type of electrode. 1.0.1 BASIC WELDING CIRCUIT The basic arc-welding circuit is illustrated in Fig. 1. An AC or DC power source, fitted with whatever controls may be needed, is connected by a work cable to the workpiece and by a "hot" cable to an electrode holder of some type, which makes an electrical contact with the welding electrode. An arc is created across the gap when the energized circuit and the electrode tip touches the workpiece and is withdrawn, yet still with in close contact. The arc produces a temperature of about 6500ºF at the tip. This heat melts both the base metal and the electrode, producing a pool of molten metal sometimes called a "crater." The crater solidifies behind the electrode as it is moved along the joint. The result is a fusion bond.
Figure 1: Arc Welding Circuit 1.0.2 ARC SHIELDING However, joining metals requires more than moving an electrode along a joint. Metals at high temperatures tend to react chemically with elements in the air - oxygen and nitrogen. When metal in the molten pool comes into contact with air, oxides and nitrides form which destroy the strength and toughness of the weld joint. Therefore, many arc-welding processes provide some means of covering the arc and the molten pool with a protective shield of gas, vapor, or slag. This is called arc shielding. This shielding prevents or minimizes contact of the molten metal with air. Shielding also may improve the weld. An example is a granular flux, which actually adds deoxidizers to the weld. Figure 2 illustrates the shielding of the welding arc and molten pool with a Stick electrode. The extruded covering on the filler metal rod, provides a shielding gas at the point of contact while the slag protects the fresh weld from the air. The arc itself is a very complex phenomenon. In-depth understanding of the physics of the arc is of little value to the welder, but some knowledge of its general characteristics can be useful.
Figure 2: The Shielding of The Welding Arc and Molten Pool. 1.0.3 NATURE OF THE ARC An arc is an electric current flowing between two electrodes through an ionized column of gas. A negatively charged cathode and a positively charged anode create the intense heat of the welding arc. Negative and positive ions are bounced off of each other in the plasma column at an accelerated rate. In welding, the arc not only provides the heat needed to melt the electrode and the base metal, but under certain conditions must also supply the means to transport the molten metal from the tip of the electrode to the work. Several mechanisms for metal transfer exist. Two (of many) examples include: 1. Surface Tension Transfer® - a drop of molten metal touches the molten metal pool and is drawn into it by surface tension 2. Spray Arc - the drop is ejected from the molten metal at the electrode tip by an electric pinch propelling it to the molten pool (great for overhead welding)
If an electrode is consumable, the tip melts under the heat of the arc and molten droplets are detached and transported to the work through the arc column. Any arc welding system in which the electrode is melted off to become part of the weld is described as metal-arc. In carbon or tungsten (TIG) welding there are no molten droplets to be forced across the gap and onto the work. Filler metal is melted into the joint from a separate rod or wire. More of the heat developed by the arc is transferred to the weld pool with consumable electrodes. This produces higher thermal efficiencies and narrower heat-affected zones. Since there must be an ionized path to conduct electricity across a gap, the mere switching on of the welding current with an electrically cold electrode posed over it will not start the arc. The arc must be ignited. This is caused by either supplying an initial voltage high enough to cause a discharge or by touching the electrode to the work and then withdrawing it as the contact area becomes heated. Arc welding may be done with direct current (DC) with the electrode either positive or negative or alternating current (AC). The choice of current and polarity depends on the process, the type of electrode, the arc atmosphere, and the metal being welded. 1.0.4 ARC WELDING DEFECTS Welding Defects can be defined as the irregularities formed in the given weld metal due to wrong welding process or incorrect welding patterns, etc. The defect may differ from the desired weld bead shape, size, and intended quality. Welding defects may occur either outside or inside the weld metal. Some of the defects may be allowed if the defects are under permissible limits but other defects such as cracks are never accepted.
External Welding Defects: 1. Weld Crack This is the most unwanted defect of all the other welding defects. Welding cracks can be present at the surface, inside of the weld material or at the heat affected zones. Figure 3(a): Weld Crack Causes of Weld Crack: 1. Poor ductility of the given base metal. 2. The presence of residual stress can cause a crack on the weld metal. 3. The rigidity of the joint which makes it difficult to expand or contract the metals. 4. If there is high content on sulfur and carbon then also the cracks may appear. 5. Using hydrogen as a shielding gas while welding ferrous materials. 2. Undercut When the base of metal melts away from the weld zone, then a groove is formed in the shape of a notch, then this type of defect is known as Undercut. It reduces the fatigue strength of the joint. Figure 3(b): Undercut
Causes of Undercut: 1. If the arc voltage is very high then this defect may occur. 2. If we use the wrong electrode or if the angle of the electrode is wrong, then also the defect may form. 3. Using a large electrode is also not advisable. 4. High electrode speed is also one of the reasons for this defect. 3. Spatter When some metal drops are expelled from the weld and remain stuck to the surface, then this defect is known as Spatter. Figure 3(c): Spatter Causes Of Spatter: 1. High Welding current can cause this defect. 2. The longer the arc the more chances of getting this defect. 3. Incorrect polarity. 4. Improper gas shielded may also cause this defect. 4. Porosity Porosity in the condition in which the gas or small bubbles gets trapped in the welded zone.
Causes of Porosity: 1. It occurs when the electrode is not coated properly. 2. Using a longer arc may also increase its chances. 3. Increased welding currents. 4. Rust or oil on the welding surface. 5. Overlap When the weld face extends beyond the weld toe, then this defect occurs. In this condition the weld metal rolls and forms an angle less than 90 degrees. Figure 3(e): Overlap Causes of Overlap: 1. Improper welding technique. 2. By using large electrodes this defect may occur. 3. High welding current Figure 3(d): Porosity
2.0 OXY ACETYLENE Oxy- acetylene welding is one of the oldest welding processes. Its use has declined somewhat in popularity in recent years, but it is still widely used for welding pipes and tubes, as well as for repair work. Oxy-acetylene welding does not require electricity and is typically used for maintenance, in body shops, and in the repair of small parts where other welding processes are too expensive. Oxy-acetylene welding can be used to join iron, steel, cast iron, copper, brass, aluminum, bronze and other metals. Often, dissimilar metals such as steel and cast iron, brass and steel, copper and iron, and brass and cast iron can be joined with oxy- acetylene welding. Oxyacetylene welding equipment can also be used for preheating, cutting metal, case hardening, annealing, soldering and brazing. Oxy-acetylene welding uses the heat from the combustion of a mixture of oxygen and acetylene (the fuel gas) to fuse base metals and filler metal together. This mixture produces flame temperatures in the range of 5800°F to 6300°F, which can be used to weld a variety of metals. Oxy-acetylene welding processes are used with or without filler rod/metal. If filler rod/ metal is not used in the joint, the weld is autogenous. An autogenous weld is a fusion weld made without filler rod/metal. Figure 4: Oxy Acetylene Gas Welding Equipment
2.0.1 FLAME ADJUSTMENT Three types of flame adjustment can be obtained when using the gas welding plant. It is essential that the operator learns to recognise the three types of flame because incorrect flame setting could lead to weld problems or failure of the weld. 1. Neutral Flame A neutral flame is produced when acetylene and oxygen burn in the proper proportions. It is made up of a distinct and clearly defined incandescent cone or jet surrounded by a faint secondary flame or envelope. The length of the inner cone should be between three to five times its own widths. The flame desired is what may be termed as a ‘gentle’ or ‘soft flame’, not a ‘harsh flame’. A harsh flame increases the agitation of the molten metal and causes metal to be forced over unfused areas. Temperature 3000 °C – uses the following. Fusion welding of: i. mild steel and alloys ii. cast iron iii. aluminum and alloys iv. stainless steel All heating applications and cutting pre-heating flames. Figure 5: Neutral Flame
2. Carburizing Flame This flame is produced when there is an excess of acetylene and can be readily recognized by a luminous intermediate cone or ‘feather’ around the inner cone caused by unburnt particles of carbon which are burnt and disappear as they reach the outer edge of the feather. The carburizing flame has an excess of carbon and will add carbon to the surface of the material. It is also sometimes referred to as a ‘reducing flame’. A reducing flame is one that, because of its need for oxygen, will reduce oxides such as iron oxide. The temperature of the carburizing flame is lower than that of the neutral flame. It causes mild steel to seemingly sweat or look greasy. (This is brought about by the unburnt particles of carbon in the flame reacting on the steel’s surface and lowering the melting point of the steel before it melts to any depth). Temperature 2800 °C – uses the following. Fusion welding high carbon steels. Figure 6: Carburizing Flame 3. Oxidizing Flame This flame is produced when there is an excess of oxygen in the flame, so named because of its oxidizing effect on the molten metal. The effect of too much oxygen is to decrease the length and width of the outer envelope and to shorten the inner cone. It is very harmful in certain welding applications, such as the welding of mild steel, aluminums and stainless steels. When welding mild steel excess oxygen can be detected by the intense sparking of the melted metal and the appearance of a whitish scum. Temperature 3300 °C – uses the following. Fusion welding of brass, bronze and zinc die castings.
Figure 7: Oxidizing Flame This Oxyacetylene weld troubleshooting guide is easy to use. Simply find the problem in the table of contents on the left or match one of our many illustrations to the problem. Often acetylene welding issues occur when one of the basics weren’t performed properly. 2.0.2 OXY ACETYLENE WELDING DEFECTS This includes: i. only weld bare metal with all paints, oils and rust removed ii. fit metal parts before welding iii. a welding jig table might be needed to secure the project iv. firm clamping in position v. selection of correct gas pressure based on tip selection vi. right speed of travel Type of defect in a gas welding: i. Lack of penetration ii. Lack of fusion iii. Poor appearance iv. Undercut v. Porosity vi. Crack in weld Figure 8: Gas Welding Defect
TITLE : ARC WELDING NO. OF PROJECT : W 01 COURSE : DJJ10022 - MECHANICAL WORKSHOP PRACTICE 1 PROGRAM : DKM, DAD & DTP SEMESTER : ONE (1) 1.0 COURSE LEARNING OUTCOMES Upon completion of this workshop, students should be able to: 1. Perform fitting, machining, and welding works according to Standard Operating Procedures (SOP). 2. Demonstrate the awareness of social responsibility and safety in practical work procedures and practices. 3. Demonstrate an understanding of professional ethics, responsibilities and norms of engineering practices according to the workshop safety regulation. 2.0 OBJECTIVES 1. Follow the safety procedures while operating the arc welding machine. 2. Weld straight bead with correct electrode and amperage selection. (refer to figure 1) 3. Weld a close squire butt joint with straight, smooth and convex bead in flat position throughout the joint. (refer to figure 2) 4. Weld the corner joint with straight convex beads surface in flat position throughout the joint. (refer to figure 3) 5. Keep the workshop clean and safety. WELDING PROJECT
3.0 APPARATUS/EQUIPMENT 1. Arc welding equipment 2. Face shield 3. Chipping hammer 4. Plier 5. Wire brush 6. Electrode E6013 (φ2.6mm or 3.25mm) 7. Leather hand glove 4.0 MATERIAL Mild steel flat bar (100mm x 50mm x 3mm) 5.0 SAFETY PRECAUTION The following recommendation details the standard behavior for all personnel working within in a workshop: 1. Before any work is carried out in the workshop, permission must be obtained from lectures. 2. Wear safety devices such as wearing safety glasses, glove, face protection, earplugs and others. 3. Work areas and equipment are to be thoroughly cleaned after use. 4. If last to leave workshop, make sure all equipment are turn off. 6.0 PROCEDURES 6.1 Straight Beads 1. Cut the mild steel flat bar to the specified size. 2. Clean the surface and sharp edge of the work piece. 3. Prepare the arc welding equipment and make sure all the cable is tightly installed. 4. Switch on the welding machine and set the alternate current within 70A to 120A. 5. Put the work piece on the work bench on the flat position. 6. Strike the arc either using tapping method or scratching method. 7. Weld from left to right. Move the electrode using drag travel technique.
8. Set the electrode angle at 70° to 80° to the weld movement and 90° to the work piece side. 9. Weld with uniform angle and travel speed during the weld pass. 10. Keep the arc length between 2mm to 3mm and is uniform throughout the weld pass. 11. Repeat the process (7 to 10) for next weld pass until all part completely welded. 12. After completion, strike weld area with chipping hammer and remove remaining slag with wire brush. Figure 1: Straight Line Welding 6.2 Close Butt Joint 1.Cut the mild steel flat bar to the specified size 2.Clean the surface and sharp edge of the work piece 3.Prepare the arc welding equipment and make sure all the cable is tightly installed. 4. Switch on the welding machine and set the alternate current within 70A to 120A. 5. Put the work piece on the work bench on the flat position and tack together. 6.Weld from left to right. Move the electrode using drag travel technique. 7.Set the electrode angle at 70° to 80° to the weld movement and 90° to the work piece side. 8. Weld with uniform angle and travel speed during the weld pass. 9. Keep the arc length between 2mm to 3mm and is uniform throughout the weld pass. 10. After completion, strike weld area with chipping hammer and remove remaining slag with wire brush.
6.3 Open Corner Joint 1.Cut the mild steel flat bar to the specified size. 2.Clean the surface and sharp edge of the work piece. Prepare the arc welding equipment and make sure all the cable is tightly installed. 3. Switch on the welding machine and set the alternate current within 70A to 120A. 4. Put the work piece on the work bench on the flat position and tack together. (refer to figure 3) 5. Weld from left to right. Move the electrode using drag travel technique. 6. Set the electrode angle at 70° to 80° to the weld movement and 90° to the work piece side. 7. 8.Weld with uniform angle and travel speed during the weld pass. Keep the arc length between 2mm to 3mm and is uniform throughout the weld pass. 9. After completion, strike weld area with chipping hammer and remove remaining slag with wire brush. 10. Figure 2 : Close Butt Joint Figure 3: Open Corner Joint
TITLE : OXY ACETYLENE WELDING NO. OF PROJECT : W 02 COURSE : DJJ10022 - MECHANICAL WORKSHOP PRACTICE 1 PROGRAM : DKM, DAD & DTP SEMESTER : ONE (1) 1.0 COURSE LEARNING OUTCOMES Upon completion of this workshop, students should be able to: 1. Perform fitting, machining, and welding works according to Standard Operating Procedures (SOP). 2. Demonstrate the awareness of social responsibility and safety in practical work procedures and practices. 3. Demonstrate an understanding of professional ethics, responsibilities and norms of engineering practices according to the workshop safety regulation. 2.0 OBJECTIVES 1. Follow the safety procedures while operating the oxy acetylene welding. 2. Start and adjust flame for different types of oxy acetylene welding gas. 3. Select proper filler rods and use them to get continuous and uniform beads. 4. Weld close square butt joint in flat position throughout the joint. (refer to figure 4) 5. Weld an open corner joint in flat position throughout the joint. (refer to figure 5)
3.0 APPARATUS/EQUIPMENT 1. Oxy-acetylene gas welding equipment 2. Goggle or face shield 3. Spark lighter 4. Plier 5. Wire brush 4.0 MATERIAL Mild steel flat bar (100mm x 50mm x 1.5mm) 5.0 SAFETY PRECAUTION The following recommendation details the standard behavior for all personnel working within in a workshop: 1. Before any work is carried out in the workshop, permission must be obtained from lectures. 2. Wear safety devices such as wearing safety glasses, glove, face protection, earplugs and others. 3. Work areas and equipment are to be thoroughly cleaned after use. 4. If last to leave workshop, make sure all equipment are turn off. 6.0 PROCEDURES 6.1 Close Square Butt Joint 1. Clean the surface of the work piece with wire brush. 2. Prepare the gas welding equipment. 3. Open the cylinder valve and set the acetylene regulator at 0.5 bar and for oxygen at 1.5 bar. 4. Make sure the work piece is underlay to provide air space at the bottom of the welded work piece. 5. Ignite and adjust the flame until producing oxidation flame. 6. Determine the angle of welding torch between 60° to 70°.
7. Heat the work piece surface for preheat purpose to avoid the work piece from warp. 8. Begin the welding work with forward welding technique. 9. Heat the work piece at one point until melt and move the welding torch to get enough molten weld pool. 10. Dip the molten weld pool to get the penetration. 11. To get good penetration, control the molten weld pool so that it’s not too wide or too small. 12. Make sure the distance between inner cone flame and molten weld pool is within 2mm to 4mm. 13. After completion, clean the work piece with wire brush. Figure 4 : Close Square Butt Joint 6.2 Open Corner Joint 1. Clean the surface of the work piece with wire brush. 2. Prepare the gas welding equipment. 3. Open the cylinder valve and set the acetylene regulator at 0.5 bar and for oxygen at 1.5 bar. 4. Make sure the work piece is underlay to provide air space at the bottom of the welded work piece. 5. Ignite and adjust the flame until producing oxidation flame. 6. Determine the angle of welding torch between 60° to 70°. 7. Heat the work piece surface for preheat purpose to avoid the work piece from warp. 8. Begin the welding work with forward welding technique. 9. Heat the work piece at one point until melt and move the welding torch to get enough molten weld pool.
10. Dip the molten weld pool to get the penetration. 11. To get good penetration, control the molten weld pool so that it’s not too wide or too small. 12. Make sure the distance between inner cone flame and molten weld pool is within 2mm to 4mm. 13. After completion, clean the work piece with wire brush. Figure 5: Open Corner Joint
NAME: ____________________________________________________ MATRIX NO: ______________________________________________ CLASS: ___________________________________________________ SUBMISSION DATE: ______________________________________ EXAMINER: _______________________________________________ 1.0 TOOL EQUIPMENT: WORKSHOP REPORT APPARATUS/MATERIAL USED DRAW THE APPARATUS/MATERIAL
2.0 PROCEDURE: ARC WELDING GAS WELDING
3.0 RESULT: 4.0 DISCUSSION:
SKILL/ ASPECTS EXCELLENT 5 VERY GOOD 4 GOOD 3 FAIR 2 UNSATISFA CTORY 1 Tool Equipment All the required equipments are listed with diagram and their funtions are stated. Most of the required equipmen ts are listed with diagram but no function is stated. Some of the required equipments are listed with diagram. Some of the required equipment s are listed. The writer does not state and list down the materials & equipment in report writing Procedure Easy to follow steps which are logical and adequately detailed Easy to follow steps which are logical and nearly detailed Most of the steps are understand able; some lack detail or are confusing Some of the steps are understand able; most are confusing and lack detail Not sequential, most steps are missing or are confusing RUBRIC ASSESMENT: REPORT (10%) [DP1]
SKILL/ ASPECTS EXCELLENT 5 VERY GOOD 4 GOOD 3 FAIR 2 UNSATISFA CTORY 1 Result Student able to display 100% data correctly for the exercise given in the lab sheet, neatly complete and totally accurate. Student able to display 80% data correctly for the exercise given in the lab sheet Student able to display 50% data correctly for the exercise given in the lab sheet Student able to display 30% data correctly for the exercise given in the lab sheet The writer does not stating the work result in report writing Discussion Construct discussion is related with observation and the explaination is detailed Construct discussion is related with observatio n and the explainati on is nearly detailed Construct disscussion is related with observation Construct discussion is lack related with observatio n there has a little/ no relationship between discussion with the observation . RUBRIC ASSESMENT: REPORT MEASURE (10%) [DP2, DP4]
Bryan Trandem (2009). Welding Complete. USA: Creative Publishing International, Inc. B.J Moniz and R.T. Miller(2010). Welding Skills Fourth Edition. American Technical Publishers. Orland Park, Illinois. Larry Jeffus (2009). Welding Principle And Application.USA: Delmar, 5 Maxwell NY. REFERENCES