Process Planning & Cost Estimation Unit - 5 Important Questions Based on Previous year board exam question paper

UNIT –  5, Machining time calculation           Scheme : MSubject : Process Planning & Cost Estimation

NOTE : 1. The highlighted Questions are asked more than two times in the Board Exam

              2. These Questions are collected from Board Examination Question Papers.

2/3 Marks questions

1.     List the principle elements of metal machining.

2.     Define cutting speed. Give the various factors on which the cutting speed depends.

3.     Define tool approach and tool over travel/

4.     Define feed. What are the factors influencing for the selection of feed?

5.     The handle of a gauge of 30mm diameter has 80mm length. It is to be knurled in lathe. Find the machining time for knurling the handle, if the cutting speed is 20m/min and the feed is 0.3mm per rev.

6.     Define setup time and machining time

7.     A shaft of 35 mm diameter is turned at a cutting speed of 50 m/min. determine the speed of the shaft.

8.     Differentiate between feed and depth of cut.

9.     A CI flange 400mm outer diameter has a bore of 120mm. this is to be faced on a lathe. Calculate the machining time to face the part, given the feed 0.8mm/rev and cutting speed 30m/min.

10.  Briefly explain the procedure for assigning cutting variables

11.  A CI flange 300mm outer diameter has a bore of 100mm. this is to be faced on a lathe. Calculate the machining time to face the part, given the feed 0.8mm/rev and cutting speed 30m/min.

 

10 marks questions

1.     Estimate the machining time required on the shaper to complete one cut on a block 600 x 900 mm. if the cutting speed is 6m per min. the return time to cutting raio is 1:4 and the feed is 3mm per stroke. The clearance at each end is 75mm and neglect widthwise allowance

2.     A 63.5mm diameter plain milling cutter having 6 teeth is used to ace mill operation in an aluminium block of 180mm long and 30mm wide. The spindle speed is 1500rpm and the feed is 0.125mm per tooth per revolution. Find the cutting time

3.     Estimate the machining time required on the shaper to complete one cut on a plate 500 x 900 mm. if the cutting speed is 6m per min. the return time to cutting ratio is 1:3 and the feed is 2mm per stroke. The clearance at each end is 70mm and widthwise allowance may be taken as 25mm.

4.     A slot 25mm deep is to be cut through a work piece 200mm long with the help of a HSS side and face cutter whose diameter is 150mm and that has 10 teeth. The cutting speed is 50m/min and feed is 0.25mm/tooth. Determine (i) table feed in mm/min. (ii) total cutter travel and (iii) time required to machine slot.

5.     Calculate the time taken for shaping a CI block 500mm long and 400mm wide in a single cut. Feed is taken to be 1.5mm per stroke and cutting speed is 10m/min. the return time to cutting time time ratio is 3:5. Assume length wise and width wise clearance 25mm each.

6.     A 200 x 50mm CI surface is to be faced on a milling machine with a cutter having a diameter of 100mm and 16 teeth. If the cutting speed and feed are 50m/min and 50mm/min respectively. Determine the milling time, rpm of the cutter and feed per tooth.

7.   A flat is to be cut of a round brass bar 50 mm in diameter. The depth of cut is 19mm. the diameter of cutter is 100mm. cutting speed is 50m/min with a feed of 0.2mm tooth. Find the milling time, if the cutter has 8 teeth.

8. A machine bed is to be planed in two cuts on a planning machine. It takes 10 seconds in forward stroke and 4 seconds in return stroke. Find out the time required to plane the bed width 600mm. assume the feed as 2 mm/stroke.