solution

Question 1 (60 Marks) The following shows a part program prepared using the MDI method. The part program is loaded to a CNC milling machining center to machine a part of size 50x100x25 mm with the machine coordinate system set up as shown in the figure below (Fig. 1). Relevant tools installed in the CNC machine are given in Table 1 on the next page and some sample G and M codes are also attached to this question paper as Fig. 3 for reference. N0010 G90 N0020 G71 N0030 GOO X-150 Y-150 Z 300 T02 M06 N0040 GOO X50 Y-20 245 N0050 GOL Z-2.5 F1000 N0060 Y 120 F250 S1500 M03 M08 N0070 GOO 245 N0080 Y-20 N0090 G01 Z-4.5 F1000 N0100 Y120 F250 N0110 GOO 245 N0120 Y-20 N0130 G01 Z-6 F1000 NO140 Y120 F350 N0150 GOO Z45 MOS M09 N0160 G00 X-150 Y-150 Z300 T06 M06 N0170 GOO X25 Y50 245 N0180 G01 Z5 F1000 N0190 Z-15 F300 S1200 M03 MOS NO200 Z5 N0220 GOO 245 MOS M09 N0220 X-150 Y-150 Z 300 T02 M06 N0230 GOO X25 Y50 745 NO240 G01 Z5 F1000 NO250 Z-10 F250 S1600 M03 M08 NO260 Z5 NO270 GOO Z45 MOS M09 N0280 Z300 N0290 MOO NO300 M30 (Fig. 1) Table 1. Table of tools installed on the NC machine Tool number I Diameter(mm) 20 2 1 4 5 6 7 8 9 Tool type Flat end mill Flat end mill Flat end mill Drill Drill Drill Ball nose mill Ball nose mill Ball nose mill 16 12 20 16 12 20 16 What is the feed rate and depth of cut used in the finishing out that produces the first feature in the part? (b) What is the purpose of the block N0220? (c) What is the clearance level used in this machining setup. State the block number that involves the last material removal process. What features are being produced in the part after the completion of all the machining operations? Sketch a figure of the resulting part and indicate all critical dimensions and locations of the features with respect to the machine coordinate system.