Design a drill jig for drilling 4 holes in the following component.

Transcription

1 Design a drill jig for drilling 4 holes in the following component.

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3 Design procedure for Jig a. Selection of Jig A leaf (or) latch jig is selected to accomplish this component. The leaf is hinged on one side of jig body by hinges. b. Selection of bushes [ DDB-5.100] (linear bush) For producing Ф 10mm hole a linear bush is selected with mm range. D1 = 10mm L = 12 D2 = 18 R1 = 2.5 R2 =.8 Diameter with fit d1f7 10mm Hole size d1f7 = Brush size d2h6 = D2 = Jig frame thickness is taken as 12mm

4 c. Selection of locating element For cylindrical shape select V block For base location pin locator is selected From DDB for thr cylindrical profile workpiece 20mm select v block with the above size.

5 Pin locator: Workpiece width = 40mm Select round locating pin at DDB-5.92 with head diameter D = 10mm of 3 numbers. One more pin is selected. For frame thickness 12mm, round pin with following dimensions is selected. H1 = 10mm D = 12mm H2 = 18mm D1 = 10mm

6 d. Selection of clamping element In order to clamp the right hand side of the workpiece pressure pad is selected with dimension of d1 = 40mm [DDB-5.104] screw for pressure pad M20 is selected. To accommodate varying dimensions of width of work, adjustable locator may be selected.

7 e. Design of jig plate Thickness of the plate = 12mm Thickness of hinge = 12mm Length of jig plate = (2 X tp) + Lw + allowance (fp) + locator pin (h2) Tp = thickness of plate = 12mm Lw = length of workpiece = 101m fp = allowance = 9mm h2 = locator pin head = 18mm length of jig plate (or hinge) = (2 X 12) = 152mm Height of jig body =tp + locator head + hw+ clearance + hinge thickness Locator head = 18mm

8 Height of workpiece = = 50mm Clearance (workpiece is assumed as casting)(brittle material) Clearance = drill diameter = 10mm Hinge thickness and plate thickness = 12mm Height of jig body without jig feet = =102mm Hinge is to be fabricated Length = 152mm Thickness = 12mm Quarter turn screw can be used for easy operation

9 f. Selection of jig feet (or) jig button Inorder to place drill jig, jig button should be at the bottom. Dimension h = 5mm [DDB-5.98] Material : case hardened C45 Tensile strength, бu = 520 N/mm2 Hardness = RC Surface finish =.025mm to.05 mm

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11 g. Bill of material Sno No.off Part name workpiece V block adjustable support clamping screw with pressure pad bush V block clamping screw jig feet pin locator

12 Design a drill jig for drilling an oil hole of size 3mm for the given job as in figure.

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14 Design procedure for jig Selection of jig Angle plate jig is selected to do the drilling operations Selection of bushes [ DDB 5-100] L1 = 8mm D1 = 3mm L2 = 6mm D2 = 6mm D3 = 10mm The required fit for bush is d1f7 [DDB 3.9] Tolerance for diameter D1, d1f7 is running fit D1 = D2 = press fit D2h6 from DDB 3.7 = Thickness of jig body = L2 of bush = 6mm

15 c. Jig body (casted body) Base length of jig body may be selected as 3 times the length of the workpiece for better rigidity. Base length Lb = 3 X 35 =105 mm Thickness of jig body = 6mm The working height h2 of the jig body is approximately equal to 1.5 to 2 times outer dia of workpiece. H2 = 2X45 = 90mm Ht = 2tp + h2 (including clearance) + (2X6) + 90 Ht = 102mm

16 Design of locator Specially designed locator can be used for making oil hole. It can be fabricated as follows. L1, L2, L3, L4, d1, d2 are dimensions on the locator. L1 can be equal to thickness of jig plate. L1 = 6mm L2 = L4 = 15 to 20% of length of the work for button clamping. L3= Lw (L2 + L4) d1= inner dia of the workpiece = 25mm d1 should be less than d2 to give clearance = 5mm (assume) inner diameter locator d1=15mm as measured from the diagram.

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18 Selection of clamping Quick acting knob is to be selected for fast clamping of workpieces.

19 Design and draw jig for mild steel component shown in figure to drill 4 holes of 5mm diameter at 70 P.C.D

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21 Design procedure for a jig a. Selection of jig. Template jig is selected. b. Selection of bush Press fit is preferred. Fixed bush is selected, range 5-6mm (DDB 5.100) l1 = 10mm l2 = 7mm d2 = 10mm d1 = 5mm required fit for a bush is d1f7 (DDB 3.9) Hole size of bush d1 = Bush size d2h6 =

22 Thickness of frame work = 7mm which is equal to l2 of bush Material : case hardened C45 Tensile strength бu = 520 N/mm2 Hardness = 229 BHN Surface finish =.025mm to.05mm Bush material- high carbon steel hardening 60 +_ 2 RC

23 c. Selection of locator Nesting locator is selected because vertical cylinder is to be drilled. Size 240X240X60 mm d. Template design (to be fabricated) Size 170X240X60 mm e. Selection of clamping nut (DDB 5.81) M8X1 is selected. f. T- bolt Ф 12X50 is to be fabricated.