Work Holding. Manufacturing Tooling 4. Work Holding Principles. Nageswara Rao Posinasetti

Size: px

Start display at page:

Download "Work Holding. Manufacturing Tooling 4. Work Holding Principles. Nageswara Rao Posinasetti"

Clifford Page
6 years ago
Views:

1 Manufacturing Tooling 4. Work Holding Principles Nageswara Rao Posinasetti Work Holding Work holder includes all devices that hold, grip, or chuck a work piece to perform a manufacturing operation. February 5, 2008 Nageswara Rao Posinasetti 2 February 5, 2008 Nageswara Rao Posinasetti 3 1

2 February 5, 2008 Nageswara Rao Posinasetti 4 February 5, 2008 Nageswara Rao Posinasetti 5 February 5, 2008 Nageswara Rao Posinasetti 6 2

3 February 5, 2008 Nageswara Rao Posinasetti 7 Purpose & Function of Work Holder Location Clamping Support Cutting forces Safety February 5, 2008 Nageswara Rao Posinasetti 8 General Considerations Physical characteristics of the workpiece Degree of precision Strength and stiffness of workpiece Production requirements Safety requirements Standard work holders February 5, 2008 Nageswara Rao Posinasetti 9 3

4 Locating Principles Work piece surfaces Flat surfaces Cylindrical surfaces Irregular surfaces Types of location February 5, 2008 Nageswara Rao Posinasetti 10 Plane Location February 5, 2008 Nageswara Rao Posinasetti 11 Concentric Location February 5, 2008 Nageswara Rao Posinasetti 12 4

5 Radial Location February 5, 2008 Nageswara Rao Posinasetti 13 Combined Location February 5, 2008 Nageswara Rao Posinasetti 14 Degrees of Freedom February 5, 2008 Nageswara Rao Posinasetti 15 5

6 3-2-1 Method of Location February 5, 2008 Nageswara Rao Posinasetti Method of Location February 5, 2008 Nageswara Rao Posinasetti 17 February 5, 2008 Nageswara Rao Posinasetti 18 6

7 February 5, 2008 Nageswara Rao Posinasetti 19 Concentric Location February 5, 2008 Nageswara Rao Posinasetti 20 February 5, 2008 Nageswara Rao Posinasetti 21 7

8 Basic Locating Rules Position and Number of Locators Redundant Locators Locational tolerances Fool proofing February 5, 2008 Nageswara Rao Posinasetti 22 When more than one locator is placed on a surface, they should be distributed as far apart as possible on the surface When more than one locator is placed on a surface (plane), they should be distributed as far apart as possible on the surface. This would help in placing the workpiece on locators without much skill. Also the clamping forces would not be able to shift the workpiece from such locators. A blank with irregular surface (such as sand casting) would be better located on such distributed locators. February 5, 2008 Nageswara Rao Posinasetti 23 When more than one locator is placed on a surface, they should be distributed as far apart as possible on the surface Machining forces would not be able to disturb the equilibrium of the workpiece in the fixture with properly distributed locators. Wear of any locator contributes less to the inaccuracy of location if the locators are placed far apart. February 5, 2008 Nageswara Rao Posinasetti 24 8

9 While selecting the surface for the largest locators, consideration should be given to the largest area of the workpiece. The two locators should be placed on the surface with the next largest area and the single locator on the surface with the least surface area. February 5, 2008 Nageswara Rao Posinasetti 25 February 5, 2008 Nageswara Rao Posinasetti 26 February 5, 2008 Nageswara Rao Posinasetti 27 9

10 Redundant Locator February 5, 2008 Nageswara Rao Posinasetti 28 To prevent incorrect loading February 5, 2008 Nageswara Rao Posinasetti 29 To prevent incorrect loading February 5, 2008 Nageswara Rao Posinasetti 30 10

11 To prevent incorrect loading February 5, 2008 Nageswara Rao Posinasetti 31 Basic types of Locators External locators Fixed Adjustable Threaded locators Spring pressure locators Equalizing locators Integral locators Assembled locators February 5, 2008 Nageswara Rao Posinasetti 32 Integral locators February 5, 2008 Nageswara Rao Posinasetti 33 11

12 Assembled locators February 5, 2008 Nageswara Rao Posinasetti 34 Basic types of Locators Locating pins V-locators Locating nests Adjustable locators February 5, 2008 Nageswara Rao Posinasetti 35 Locating pins February 5, 2008 Nageswara Rao Posinasetti 36 12

13 Locator 0.5 in (Jergens) February 5, 2008 Nageswara Rao Posinasetti 37 February 5, 2008 Nageswara Rao Posinasetti 38 February 5, 2008 Nageswara Rao Posinasetti 39 13

14 February 5, 2008 Nageswara Rao Posinasetti 40 February 5, 2008 Nageswara Rao Posinasetti 41 February 5, 2008 Nageswara Rao Posinasetti 42 14

15 V-locator error? C" C' α O February 5, 2008 Nageswara Rao Posinasetti 43 V-locator error? February 5, 2008 Nageswara Rao Posinasetti 44 Adjustable Locators February 5, 2008 Nageswara Rao Posinasetti 45 15

16 Support surfaces Select a surface where there is maximum likelihood for the part to deflect under the action of clamping and cutting forces. Support areas selected should not disturb the location of the workpiece in any manner nor displace the locators while providing the support. Support areas selected should not interfere with the loading and unloading of the component into the work holding fixture. February 5, 2008 Nageswara Rao Posinasetti 46 February 5, 2008 Nageswara Rao Posinasetti 47 Adjustable Supports Adjustable locators positioned beneath the workpiece Threaded Spring Equalizers February 5, 2008 Nageswara Rao Posinasetti 48 16

17 February 5, 2008 Nageswara Rao Posinasetti 49 February 5, 2008 Nageswara Rao Posinasetti 50 February 5, 2008 Nageswara Rao Posinasetti 51 17

18 February 5, 2008 Nageswara Rao Posinasetti 52 Internal Locators Use holes or bored diameters February 5, 2008 Nageswara Rao Posinasetti 53 February 5, 2008 Nageswara Rao Posinasetti 54 18

19 February 5, 2008 Nageswara Rao Posinasetti 55 Pin locators Plain Shouldered Undersized ( to ) Prevent jamming February 5, 2008 Nageswara Rao Posinasetti 56 February 5, 2008 Nageswara Rao Posinasetti 57 19

20 February 5, 2008 Nageswara Rao Posinasetti 58 Radial location Diamond Pin February 5, 2008 Nageswara Rao Posinasetti 59 February 5, 2008 Nageswara Rao Posinasetti 60 20

21 February 5, 2008 Nageswara Rao Posinasetti 61 February 5, 2008 Nageswara Rao Posinasetti 62 February 5, 2008 Nageswara Rao Posinasetti 63 21

22 February 5, 2008 Nageswara Rao Posinasetti 64 Chip and Burr Problems Make locators easy to clean Small and hard Open jigs Make them self cleaning Edge relief around locators wipers Protect them February 5, 2008 Nageswara Rao Posinasetti 65 February 5, 2008 Nageswara Rao Posinasetti 66 22

23 February 5, 2008 Nageswara Rao Posinasetti 67 February 5, 2008 Nageswara Rao Posinasetti 68 February 5, 2008 Nageswara Rao Posinasetti 69 23

24 February 5, 2008 Nageswara Rao Posinasetti 70 February 5, 2008 Nageswara Rao Posinasetti 71 February 5, 2008 Nageswara Rao Posinasetti 72 24

25 February 5, 2008 Nageswara Rao Posinasetti 73 February 5, 2008 Nageswara Rao Posinasetti 74 February 5, 2008 Nageswara Rao Posinasetti 75 25

26 February 5, 2008 Nageswara Rao Posinasetti 76 February 5, 2008 Nageswara Rao Posinasetti 77 February 5, 2008 Nageswara Rao Posinasetti 78 26

The best of both worlds

The best of both worlds CoroMill 210 the ultimate roughing cutter for modern machining techniques Use CoroMill 210 for plunge milling to mill away large volumes of metal or for high feed milling of flat