INSTRUCTION: This paper consists of FOUR (4) structured questions. Answer ALL questions.

Transcription

1 INSTRUCTION: This paper consists of FOUR (4) structured questions. Answer ALL questions. ARAHAN : Bahagian ini mengandungi EMPAT (4) soalan struktur. Jawab semua soalan. QUESTION 1 SOALAN 1 C1 (a) Name the parts with label A, B, C, D and E as shown in figure 1a. Namakan bahagian yang berlabel A, B, C, D dan E dalam gambarajah 1a. A E B C D Figure 1a / Rajah 1a (b) Determine the correct reading of the micrometer and vernier caliper as shown in figure 1b(i) and figure 1b(ii). Berdasarkan bacaan di bawah, tentukan bacaan bagi mikrometer dan angkup vernier. i. Figure 1b(i) / Rajah 1b(i) Figure 1b(ii) / Rajah 1b(ii) 2 SULIT

2 C3 (c) i. State FOUR (4) methods of holding a drill bit. i Nyatakan EMPAT (4) kaedah memegang mata alat gerudi. Sketch and label the main parts of a twist drill bit. [4 marks] [4 markah] Lakarkan dan labelkan bahagian utama mata alat gerudi pintal. Explain SIX (6) steps of marking out before drilling. Terangkan ENAM (6) langkah menanda sebelum menggerudi. [6mark] [6 markah] QUESTION 2 SOALAN 2 (a) Explain briefly the lathe machine operations stated below: Terangkan secara ringkas operasi operasi mesin larik berikut: i. Facing Menampang Knurling Membunga / melorek i Turning Melarik iv. Parting Membahagi v. Drilling Menggerudi [10 marks] [10 markah] 3 SULIT

3 C3 (b) i. Explain the basic principles of x, y and z axis movement of a milling machine using a labeled diagram. Dengan bantuan gambarajah berlabel, terangkan prinsip asas arah pergerakan paksi x,y dan z sebuah mesin pengisar. [9 marks] [9 markah] Calculate the feed rate in millimeters per minute for a 75 mm diameter, six-tooth helical carbide milling cutter during machining a cast-iron work piece (CS 60). Use the value of chip per tooth, CPT, as Hitungkan kadar suapan dalam millimeter per minit bagi pemotong mata alat peraut heliks 6 gigi yang berdiameter 75mm untuk memotong bahan kerja besi tuang (CS60). Ambil nilai CPT = [6 marks] [6 markah] QUESTION 3 SOALAN 3 (a) i. Describe the method to measure tooth thickness using a gear tooth vernier calliper. Perihalkan kaedah untuk mengukur ketebalan gigi gear menggunakan angkup gigi gear. [3 marks] [3 markah] Explain the basic principles of Computer Numerical Control (CNC). Terangkan prinsip asas Kawalan Berangka Berkomputer (CNC). [4 marks] [4 markah] 4 SULIT

4 C4 (b) A spur gear has Pitch Diameter (PD) of 84 mm and 24 teeth. Determine: Satu gear taji mempunyai diameter pic 84 mm dan 24 gigi. Tentukan: i. Module (M) Modul (M) Circular Pitch (CP) Pic Membulat i Addendum (A) Addendum (A) iv. Dedendum (D) Dedendum (D) v. Outer Diameter (OD) [10 marks] Diameter Luaran (OD) [10 markah] C5 (c) Build a G code program to produce the object below using Computer Numerical Control (CNC). Bina satu aturcara G kod untuk menghasilkan objek di bawah menggunakan mesin Kawalan Berangka Berkomputer (CNC). Figure 3c / Rajah 3c 5 SULIT

5 Information about this program: / Maklumat berkenaan program ini: QUESTION 4 SOALAN 4 Interpolation : Linear / Interpolasi : Linear Coordinate : Incremental / Koordinat : Menambah Feed rate : 250 mm/minute / Kadar suapan : 250 mm/minit Process start/end : At point 0 / Process mula/tamat : Pada titik 0 [8 marks] [8 markah] C1 (a) Figure 4a shows a welding set arrangement. Name the parts labeled with P, Q, R, S, and T. Gambarajah 4a menunjukkan sambungan kimpalan arka. Namakan bahagian yang berlebel P, Q, R, S dan T. P R Q S T Figure 4a / Rajah 4a (b) i. Explain the differences between Gas Metal Arc Welding (GMAW) and Gas Tungsten Arc Welding (GTAW). Terangkan perbezaan antara kimpalan logam berperisai gas (GMAW) dan kimpalan tungsten berperisai gas (GTAW). Explain distortion mechanism in welding and how to minimize it. Terangkan mekanisma herotan di dalam kimpalan dan bagaimana untuk meminimumkannya. 6 SULIT

6 C3 (c) T-joint is one of the common joining methods in an engineering workshop. Explain on how this welding process is carried out using arc welding. Sambungan kembi 'T' merupakan salah satu jenis sambungan kimpalan yang biasa dilakukan dalam bengkel kejuruteraan. Terangkan bagaimana proses kimpalan ini dilakukan dengan menggunakan kimpalan arka. [10 marks] [10markah] SOALAN TAMAT 7 SULIT