Analysis of Tool Geometry of Single Point Miranda Tool with Pointed Tip

Analysis of Tool Geometry of Single Point Miranda Tool with Pointed Tip

To find and compare the cutting forces of a single point Miranda tool with pointed tip for a solid cylindrical job with materials wood and MS.

Bhavya Ramakrishnan

Mechanical Design

D.Y. Patil College of Engineering, Akurdi, Pune, India 411044

Abstract In this paper, we find the cutting tool force and other parameters of a single point Miranda tool with a pointed tip. We analyse the heat generated and stresses produced in the Miranda tool for both cases of the job (wood and MS)

KeywordsMiranda tool; tool geometry; cutting force; semi circular tip; pointed tip

1. INTRODUCTION

   We have a simple tool room production lathe, with parallel cone pulley drive and back gears, which has parallel jaw bench vice and a lever clamp on the tool carriage with a compound rest (fixture) tool post. We take a simple turning operation where the MS/ wooden cylindrical job is mounted on the headstock using a 3 piece chuck and a chalk method is used for centering the job using the tailstock dead center and analyse and compare the parameters produced analytically.

2. ASSUMPTIONS

   1. Chip area is either rectangular or triangular for simplicity purposes and is assumed to be equal to area of contact.

   2. Assuming countershaft speed is the same as motor speed which is 1500 rpm.

   3. Depth of cut is assumed 1 mm and chip thickness is assumed 0.2mm/rev.

3. PROBLEM STATEMENT

   Lathe – Simple tool room electric motor driven cone pulley belt drive and countershaft lathe with tool carriage along bed o f

   length 135 – 180 cm using a manual wheel, with a cross slide

   lever handle for motion across the bed, where tool post (which can swivel the whole tool diagonally using a tool post slide) is mounted on the carriage with a simple bench vice double plate lever clamp.

   Operation – Turning Motion of Job – Rotary

   Material of Job – MS or wood

   Dimensions of Job – Cylindrical solid with 50mm diameet r and 60 mm height

   Motion of cutting tool – Orthogonal forward translation Type of cutting tool – 1. Miranda single point MS Dimensions of cutting tool – 13 cm x 1 cm x 1 cm

   Manual Feed f= 1.04 mm/rev

   Feed rate F = f*N = 300 × 1.04 mm/min = 5.2 mm/s Motor speed – 1500 rpm (standard)

   Rake angle a – (single point) arctan[(D1 – D2)/(2×60)] = 27.5 degrees

   Cutting speed – pi*50*N/1000 = 47 m/min = 0.78 m/s Spindle speed N – 300 rpm

   Countershaft speed – 1500 rpm

   Pulleys Diameters 75 mm and 15 mm (open belt) Pulley speed (big) = 15/75 * 1500 = 300 rpm Depth of cut d – 1mm

   `Volume of cut in 1 pass of job length (rectangular cross section chip area) = 9236.28 mm^3

   Volume of cut in 1 pass of job length (triangular cross section chip area) = 4618.14 mm^3

   Area of chip (rectangular) = t*d = 1*0.2 = 0.2 mm^2 Area of chip (tringular) = t*d = 1*0.2*0.5 = 0.1 mm^2 Cutting chip thickness t = 0.2 mm/rev

   Feed = sq.root(0.2^2 + 1^2) = 1.04 mm (approx) Cutting force Fc = Kc. Achip(rectangular)

   = 2000*0.2 (MS)

   = 400 N

   Cutting force Fc = Kc. Achip(triangular)

   = 2000*0.1 (MS)

   = 200 N

   Cutting force Fc = Kc. Achip(rectangular)

   = 500*0.2(wood)

   = 100 N

   Cutting force Fc = Kc. Achip(triangular)

   = 500*0.1 (wood)

   = 50 N

   Shear Force Sc = Fc/2

   = 200 N (rectangular MS)

   = 100 N (triangular MS)

   = 50 N (rectangular wood)

   = 25 N (triangular wood)

   Heat Generated Q = Sc. Vc – 0.3*Sc.Vc

   =0.7*Sc*Vc

   = 200 N * 0.78 * 0.7(rectangular MS) = 109.2 W

   = 100 N* 0.78 * 0.7 (triangular MS) = 54.6 W

   = 50 N * 0.78 * 0.7(rectangular wood) = 27.3 W

   = 25 N * 0.78 * 0.7(triangular wood) = 13.65 W

   Heat Generated (W)	Chip Area Triangle	Chip Area Rectangle
   Job Material (wood)	13.65	27.3
   Job Material (MS)	54.6	109.2

4. TABLES

   9

5. ACKNOWLEDGMENT

   I would like to thank my colleagues and professors at my university (Mumbai and Pune) for taking the time to teach me.

6. REFERENCES

1. S. K. Hajra Choudhury, A.K. Hajra Choudhury, and Nirjhar Roy,

   Elements of Workshop Technology Vol.2., pg 53- 182, 397-451

2. R.S. Khurmi, J.K. Gupta, Theory of Machines, pg.309.