Home-Work Problems

 

Problem 1. A drilling operation is to be carried out using a 1/4 in.-diameter high speed steel(HSS)drill. The work  material is a machineable grade of aluminium. Recommended cutting speed is 400 surface feet per minute and recommended feed rate is 0.003 ipr. Convert these recommendations into machine tool speed and feed:rpm and ipm respectively.  (Ans. 6111 rpm, 18.33 in./min)

Problem 2. The same work material in the problem one is to be millied with a 3/4 inch. diameter four flute end milling cutter .Recommendations are :cutting speed =400 fpm and feed=0.003 ipt. Convert these values to rpm and ipm. (2037 rpm, 24.44 in./min)

Problem 3.  A cast-iron  workpiece is to be fce millied on an NC machine using cemented carbide inserts. The cutter has 16 teeth and is 5 in. diameter. The recommended cutting speedis 250 fpm. Recommended feed is 0.002 ipt. Convert these to rpm and ipm for use by the machine tool. (191 rpm, 6.11 in./ min.)

Problem 4. A part program is to be written to drill the holes in the workpart of Figure below on page 220. The part is 3/8 inch thick.

(a) Define the X and Y axes for the job.
(b) Write the part program manuscript(manual part programming) using the word address format and an absolute position format and an absolute position system. The words must be specified for the particular NC drill press are n-,x-,y- and m-words. The speed and feed are manually set by the operater.

Problem 5. Solve Problem 4. except that the feed and speed specifications must be included in the program(n-,x-,y-,s- and m-words must be given.) Assume that the tool material is HSS and the work material is Aluminium so that the cutting condiyions are dtermined by Problem1.

Problem 6. Solve Problem 4 expcept use the tab sequentional format rather than the word address format.

Problem 7. Solve Problem 5 except use the tab sequentional format.

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