Anna University Model Question Paper BE VI sem Mechanical DESIGN OF JIGS, FIXTURES AND PRESS TOOLS

ANNA UNIVERSITY, CHENNAI 25

MODEL QUESTION PAPER

B.E. MECHANICAL ENGINEERING, VI SEMESTER

ME339 – DESIGN OF JIGS, FIXTURES AND PRESS TOOLS

TIME – 3 Hours                                                                    MAXIMUM : 100 Marks

PART – A                     (10 x 2 = 20 Marks)

1. When is a diamond-pin used for locations?
2. Sketch a quick acting clamp.
3. What is the difference between a jig and a fixture?.
4. What is meant by fool proofing in the design of a jig?
5. What is the purpose of a setting block in a fixture?.
6. What are modular fixtures?
7. Distinguish between blanking and piercing.
8. Mention the significance of center of pressure as applied to

Press tool design.

1. What is the purpose of shear angle on a punch or die?
2.  What causes spring back in bending?

PART – B                        (5 x 16 = 80 Marks)

1. A cup shown in Figure 1 is to be produced using a suitable drawing die.

(i)    Find the size of the blank and the number of draws required.     (4)

(ii)  Sketch (without dimensions) the sectional front view of punch

and die assembly and name the parts                                             (6)

(iii) Sketch the punch and die separately and indicate their

dimensions.                                                                                         (6)

1. a) (i) Explain the 3-2-1 locating concept using pins, with suitable sketches.

Indicate where the clamping forces are to be applied. Is this locating

concept limited to rectangular work pieces?                                       (7)

(ii) Sketch a simple vise that can be used for clamping work pieces.

The fixed jaw, moving jaw and guidway are to be clearly indicated

and a parts-list is also to be given. Also indicate how will you fix the

vice on the table of a milling machine.                                              (9)

( OR )

12.b) (i) Sketch  and explain V-type locating device having fixed-V and movable-V locator. Give details of guiding the movable-V locator.  Give also an example of a component for which this type of locator can be used.                                            (8)

(ii) Sketch a strap type clamp for clamping a rectangular block. Give a parts list. Assuming that a milling operation is going to be performed on the block, compare the directions of tool force and clamping force.                                                                            (8)

13. a)  (i) Design and sketch a drill jig to drill the 20 mm hole in the component shown in Figure 2.                                                     (12)

(ii) Discuss briefly the location and clamping arrangements used in your design.             (4)

( OR )

b)  (i)  Design and sketch a drill jig to drill the 10 mm hole in the component shown in Figure 3, assuming that this is the last operation to be performed.         (12)

(ii)  Discuss the location and clamping method employed in your

design                                                                                                     (4)

14. a) (i) A key way of 16 mm width, 6 mm depth and 45 mm long is to be milled on a 50 mm diameter shaft 150 mm long, at the middle of its length. Sketch a suitable fixture and indicate all the parts, if the operation is to be done using a vertical milling machine.                                                                                                                (12)

State how the cutter will be set before milling                                  (4)

( OR )

b) (i)  Explain with suitable sketch, how a fixture could be designed to  broach a keyway in a gear blank.                                                                                              (8)

(ii)  Two plates are to be held at right angles to fabricate a L-shaped component by gas welding. Suggest a suitable fixture.                                                   (8)

15. a) (i)  Explain briefly the function of the following parts applied to press working.

• Pilots
• Stock stop
• Knockout rod                                                                        (6)

(ii) Sketch a suitable press tool to manufacture square component

40 mm side having a central square hole 20 mm side, the

material thickness being 1.5 mm.                                                   (10)

( OR )

b) The component shown in Figure 4 is to be manufactured using a

progressive die.

(i)   Develop and sketch a suitable strip layout                                  (6)

(ii)    Sketch the punches and dies of the progressive die,

indicating how the stock is fed.                                                    (10)