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Location
&
Locating Devices
Prof. Ms. Amruta A. Rane
Assistant Professor,
DJSCE, University of Mumbai,
Mumbai.
Location System
• The location refers to the establishment of a desired relationship between the
workpiece and the jigs or...
The Six Degrees of Freedom
• Figure shows a body that is free in space.
• A body in this condition had six degrees of free...
The Choice of Location System
• The requirements of the location system depend upon workpiece before
operation and the ope...
The Choice of Location System
• When there is choice of location points the most effective location system must
be selecte...
Location Principles
• Workpiece Requisites: Dimensional requirements of the workpiece stated on
component drawing.
• Face ...
Location Principles
• Accuracy: Location should be done on most accurate surface of the workpiece.
• A machined surface is...
Location Principles
• Constraints: Location should prevent linear and rotary motion of the workpiece
along and around the ...
Location Principles
• Motion economy: Location should facilitate easy and quick loading of the
workpiece in the fixture.
•...
Location Principles
• Redundant Location: A redundant location is said to exist when two locators are
attempting to constr...
Location Principles: Redundant Location
Redundant Location
• We can only location workpiece effectively on one machined su...
Location Principles: Redundant Location
• The workpiece is located over two pins.
• The purpose of pin 2 is to prevent rot...
Location Principles: Foolproofing
• Foolproofing: The location system should positively prevent wrong loading of the
workp...
Locating Methods
Locating Methods
• Locators are made separate from the fixture or jig body.
• Made from casehardened steel accurately grou...
Location from Plane Surface
Location from Plane surface
There are three most common types of locating points
• Buttons
• Pins
• Pads
Location from Plane surface: Buttons
• Buttons are round and have either a flat head or
a crowned head.
• They are made of...
Location from Plane surface: Buttons
Buttons are termed as –
• Rest buttons
• Stop buttons
Location from Plane surface: Button Positioning
• Installation of the button in the fixture body is
done with press fit in...
Location from Plane surface: Buttons
• The buttons have interference fit / press fit with
the hole in the fixture.
• The s...
Location from Plane surface: Buttons
• For the flat buttons, H can be
selected from 1/3 D to 4/3 D (5 to
25mm).
• L = ½ (D...
Location from Plane surface: Buttons
Location from Plane surface: Threaded Buttons
• A threaded shank buttons are also used.
• They are installed in a tapped h...
Location from Plane surface: Hollow Buttons
• Hollow buttons are fastened by separate screws.
• The screw head is counters...
Location from Plane surface: Hollow Buttons
Location from Plane surface: Pins
• A pin is a cylindrical component that is contacted on its side.
• Height of the pin is...
Location from Plane surface: Pins
Location from Plane surface: Pads
• Pads are usually flat components made from steel and heat treated to similar
hardness ...
Location from Plane surface: Pads
• Dowel pins are used to secure the position of the pads. Since screws are not
capable o...
Location from Plane surface
• A machined surface can be better located by pads having a flat surface.
• For large componen...
Location from Cylinder: Dowel Pins
• Dowels are used for permanent assembly
of two parts with significant precision.
• Two...
Location from Cylinder: Dowel Pins
Location from Cylinder: Dowel Pins
• Dowel pin holes are drilled through so
that the pin can be taken out.
• The recommend...
Location from Cylinder: Dowel Pins
Location from Cylinder
• It is necessary to use two dowel pins to ensure that the workpiece is completely
constrained.
• I...
Location from Plane surface
• A plane surface can be located from 3 points
on the plane surface.
• A rough, unmachined sur...
Location from Plane surface
• 3 pins can define the plane but they can’t provide adequate support to the
workpiece during ...
Location from Plane surface
Adjustable Support
Location from Plane surface
• For locating very rough, uneven surfaces adjustable locating pads are used.
• Castings and f...
Location from Plane surface
• Sometimes adjustable support is provided at inaccessible place since it is difficult
to reac...
Location from Plane surface
• Square and rectangular workpieces can be located by replacing one of the
locating pads by an...
Location from Plane surface
• For small workpieces location pads are not necessary.
• The fixture body itself is machined ...
Location from Plane surface
• Ample recess is provided in the corners so that burr on the workpiece corners,
dirt or swarf...
Location from Profile
Location from Profile
• A sighting plate is provided for simple components where appearance is
important.
• It is slightly...
Location from Profile
• The profile of a workpiece can also be located by confining the profile with
cylindrical locating ...
Location from Profile
• The profile of the workpiece can be located
by providing pocket or nest around the
profile of the ...
Location from Cylinder
Location from Cylinder
• It is most common and convenient form of
location.
• When the cylinder is located on its axis and...
Location from Cylinder
• The seating surface of the locator should be
recessed to provide space for dirt or
workpiece burr...
Location from Cylinder
Circular locators types –
• Inside locators
• Outside locators
Problems with cylindrical locators -...
Location from Cylinder: Jamming
• Jamming is result of a friction.
• The amount of clearance, the length of the engagement...
Location from Cylinder: Jamming
• The part has entered the locator over a short length “L”, the length of
engagement.
• If...
Location from Cylinder: Jamming
• The length of the locator should be small to prevent jamming of the workpiece.
• A long ...
Location from Cylinder: Jamming
• For the length of engagement L, there exist two critical values L1 and L2, which can
be ...
Location from Cylinder
Location Post
Location from Cylinder
Locating post
• They are used for anchoring clamping studs.
• Location post is secured to the base ...
Location from Cylinder: Jamming
• The jamming of the workpiece on the locating post can also be prevented by
providing spe...
Location from Cylinder
• Location pot is used for locating a cylinder on outside diameter.
• They have lead at entry point...
Location from Cylinder
• When we use two holes in workpiece for location, we must take into account variation in
centre di...
Location from Cylinder
• A location pin is positioned as far away as possible from the principal locator in
order to minim...
Location from Cylinder
Conical Location
• Used to locate rough machined surfaces of castings and forgings.
• They locate t...
Location from Cylinder
Vee (V) Location:
• Used to locate cylindrical surfaces from
outside.
• 2 “V” locators are used for...
Location from Cylinder
• Adjustable V Block – for more accurate location, to take care of size of workpiece.
• Adjustable ...
Location from Cylinder
Inclined V:
• When a sliding V locator is used, a small downward clamping force can be
introduced b...
Location from Cylinder
• A swinging eyebolt is used when a V plate has to be withdrawn quickly.
Quick action V locator
Location from Cylinder
• When a cylindrical workpiece is located by a V block, the centre would always lie
on the centre l...
Location from Cylinder
• If V block axis is horizontal, the variation in the diameter of the workpiece would
lead to error...
Summary
1. Location must be related to the dimensional requirements stated on the
component / workpiece drawing.
2. It is ...
Summary
Locating Methods: Plane surfaces
1. A reasonably flat surface can be located by three pins of equal height having
...
Summary
Locating Methods: Profile
1. A profile can be located approximately by aligning it with a slightly bigger sighting...
Summary
Locating Methods: Cylinder
1. Spigots used for locating bores should have ample lead for easy entry and their
leng...
References
1. Jig and Fixture Design Manual, Erik K. Henrikson, Industrail Press.
2. Jigs and Fixture, P.H. Joshi, THM.
3....
Thank You!
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Location and locating devices used in jigs and fixtures

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Jigs and Fixtures: Workpiece location principles, Different types of locating devices

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Location and locating devices used in jigs and fixtures

  1. 1. Location & Locating Devices Prof. Ms. Amruta A. Rane Assistant Professor, DJSCE, University of Mumbai, Mumbai.
  2. 2. Location System • The location refers to the establishment of a desired relationship between the workpiece and the jigs or fixture. • Correctness of location directly influences the accuracy of the finished product. • The location system in conjunction with the clamping system should completely constrain the workpiece or eliminate as many of the six degrees of freedom as in necessary for operation to be completed with required accuracy.
  3. 3. The Six Degrees of Freedom • Figure shows a body that is free in space. • A body in this condition had six degrees of freedom, three of these are freedoms of translation and three are freedoms of rotation.
  4. 4. The Choice of Location System • The requirements of the location system depend upon workpiece before operation and the operation being performed.
  5. 5. The Choice of Location System • When there is choice of location points the most effective location system must be selected.
  6. 6. Location Principles • Workpiece Requisites: Dimensional requirements of the workpiece stated on component drawing. • Face A should be used as datum, so that hole will always be at distance D from face A irrespective of the variation in length L. • Location should be w.r.t. face A. Location and Workpiece Dimensions
  7. 7. Location Principles • Accuracy: Location should be done on most accurate surface of the workpiece. • A machined surface is preferable to an unmachined one. • When more than one machined surfaces are available, locate on the most accurate surface. • The φ80 has tolerance of 0.05 and φ40 has tolerance of 0.1 so the workpiece can be located most accurately from outside diameter φ110. • Location from φ40 bore would be less accurate than location from φ80. Accuracy of Location surfaces
  8. 8. Location Principles • Constraints: Location should prevent linear and rotary motion of the workpiece along and around the three major axes X, Y and Z. Six Degrees of Freedom
  9. 9. Location Principles • Motion economy: Location should facilitate easy and quick loading of the workpiece in the fixture. • Parallel locators are preferable to those placed at right angles. • If we drill hole B first and use it for location while drilling hole C, it is possible to load the workpiece on both the locators in hole A and B in one motion as both the locators would be parallel. Motion Economy in Location
  10. 10. Location Principles • Redundant Location: A redundant location is said to exist when two locators are attempting to constrain one freedom from two location points. • Redundant locators must be avoided. • The distance between surface A and B would vary according to the process capability. • We can only locate effectively on surface A or B. Redundant Location
  11. 11. Location Principles: Redundant Location Redundant Location • We can only location workpiece effectively on one machined surface. • Inaccurate location can result in bending, dimensional error, flatness error, distortion. • We can only locate effectively on surface A or B. • The clamping force would distort the workpiece and distorted part would spring back to its original position when the workpiece is unclamped. • Redundant location will also occur if the workpiece is located from two concentric cylinders or between two fixed V-locators. • Redundant location can be prevented by providing an adjustable support. Workpiece Distortion due to Redundant Location Adjustable Support
  12. 12. Location Principles: Redundant Location • The workpiece is located over two pins. • The purpose of pin 2 is to prevent rotation about pin 1 but the system is such that both the pins are attempting to constrain the workpiece along X-X. Redundant Location
  13. 13. Location Principles: Foolproofing • Foolproofing: The location system should positively prevent wrong loading of the workpiece by foolproofing. • It would be impossible to load the workpiece wrongly due to the foolproofing pin. Foolproofing
  14. 14. Locating Methods
  15. 15. Locating Methods • Locators are made separate from the fixture or jig body. • Made from casehardened steel accurately ground to size. • A workpiece can be located from: i. Plane surface ii. Profile iii.Cylindrical surface
  16. 16. Location from Plane Surface
  17. 17. Location from Plane surface There are three most common types of locating points • Buttons • Pins • Pads
  18. 18. Location from Plane surface: Buttons • Buttons are round and have either a flat head or a crowned head. • They are made of steel. • Usually alloy steel, low grade tool steel hardened to 40-45 RC, low carbon steel (AISI 1113) hardened to 53-57 RC. • Ground after heat treatment to have precise dimensions • Flat buttons are used against machined surfaces only. • When the plane is defined by three buttons, they are surface ground across their faces after installation. • Crowned buttons are used for unmachined surfaces. However they do not provide a well- defined bearing area.
  19. 19. Location from Plane surface: Buttons Buttons are termed as – • Rest buttons • Stop buttons
  20. 20. Location from Plane surface: Button Positioning • Installation of the button in the fixture body is done with press fit in a cylindrical bore (reamed or precision bored). • The shank ends with 30o chamfer. • Spot facing is done around the hole to provide the seating for the head of the buttons • Hole is chamfered to ensure good seating. • Undercut is provided under the head.
  21. 21. Location from Plane surface: Buttons • The buttons have interference fit / press fit with the hole in the fixture. • The shanks on the buttons are supplied with standardised tolerances, resulting in oversize ranging from 0.03 to 0.04mm. • Rest and stop buttons are commercially available in standardised dimensions.
  22. 22. Location from Plane surface: Buttons • For the flat buttons, H can be selected from 1/3 D to 4/3 D (5 to 25mm). • L = ½ (D + H) • B = ¾ (D – 3) • For the crowned buttons, H can be selected from1/3 D to D. • R = 3/2 D • B = ¾ D • L = ¾ D
  23. 23. Location from Plane surface: Buttons
  24. 24. Location from Plane surface: Threaded Buttons • A threaded shank buttons are also used. • They are installed in a tapped hole. • This practice is not recommended as screw thread requires clearance and is less accurate with respect to location and direction.
  25. 25. Location from Plane surface: Hollow Buttons • Hollow buttons are fastened by separate screws. • The screw head is countersunk safely below the face of the button.
  26. 26. Location from Plane surface: Hollow Buttons
  27. 27. Location from Plane surface: Pins • A pin is a cylindrical component that is contacted on its side. • Height of the pin is not a critical dimension. • Buttons can be substituted for pins, but pins can not be substituted for buttons. • Installed by press fit. • With or without a shank of a reduced diameter. • Used for a nest. • They are used as side stops and for locating in holes. • Pins can be used on unmachined surfaces. • Pins as side stop should be used only on shallow parts with light side loads.
  28. 28. Location from Plane surface: Pins
  29. 29. Location from Plane surface: Pads • Pads are usually flat components made from steel and heat treated to similar hardness levels. • They are ground flat and parallel. • They are used as base locators in cases where rest buttons do not provide sufficient bearing area. • Pads are placed at locations not easily accessible by the operator. Hence, the edges and corners of a pad are usually not rounded or chamfered as the edges on rest buttons. They are lightly polishes to make them smooth to touch. • Pads are fastened by means of screws with countersunk heads.
  30. 30. Location from Plane surface: Pads • Dowel pins are used to secure the position of the pads. Since screws are not capable of precision location.
  31. 31. Location from Plane surface • A machined surface can be better located by pads having a flat surface. • For large components the pads can be screwed to the body of the fixture as shown in figure. • Due to use of locating pads only seats for the pads need to be machined instead of entire body of the large fixture which saves machining time. Location Pads for Large Fixtures
  32. 32. Location from Cylinder: Dowel Pins • Dowels are used for permanent assembly of two parts with significant precision. • Two dowel pins are required for locating a component and they are placed as far as possible. Standard Dowel Pins
  33. 33. Location from Cylinder: Dowel Pins
  34. 34. Location from Cylinder: Dowel Pins • Dowel pin holes are drilled through so that the pin can be taken out. • The recommended bearing length of a dowel pin in each part is 1 ½ to 2 times the diameter of the pin. • Dowel pins are cylindrical or tapered. • The straight type is available in unhardened and hardened form. • The fit of the dowel pin can be a press fit in each part. • Tapered pins are easily taken out by the application of light pressure or a blow on the small end. • Dowel pins are extensively used in the construction of built-up fixture bodies. Standard Dowel Pins
  35. 35. Location from Cylinder: Dowel Pins
  36. 36. Location from Cylinder • It is necessary to use two dowel pins to ensure that the workpiece is completely constrained. • If we use only one dowel pin P, plate B can pivot around P. • The dowels P and Q should be placed as far a possible. Use of Dowels
  37. 37. Location from Plane surface • A plane surface can be located from 3 points on the plane surface. • A rough, unmachined surface can be located with three location pads having point contact. • Three location pins having spherical surfaces at locating points can be used. • The pins should be placed as widely as possible for more accurate location. • The height is adjusted to make the workpiece surface parallel to the baseplate. • An adjustable support with locking nut can be used. Adjustable Support for Rectangular Workpieces
  38. 38. Location from Plane surface • 3 pins can define the plane but they can’t provide adequate support to the workpiece during machining operation. • Additional adjustable supports are necessary to prevent distortion and vibrations in workpiece during clamping and machining. • The number of additional supports would depend on the shape, size and strength of the workpiece. • The bolt with hex nut Adjustable Support
  39. 39. Location from Plane surface Adjustable Support
  40. 40. Location from Plane surface • For locating very rough, uneven surfaces adjustable locating pads are used. • Castings and forgings are located by adjustable screw pads. Adjustable Locators
  41. 41. Location from Plane surface • Sometimes adjustable support is provided at inaccessible place since it is difficult to reach a support which is in recess or is distant from an operator. • inclined surface on wedge pin raises the pad when the wedge pin is pushed forward by height adjusting screw. • When the adjusting screw is withdrawn the return spring pushes the wedge pin towards the right and the pad slides down by gravity. • Pad is locked in position by clamping screw. • The retaining screw prevents the pad from being pushed out of the housing by the spring.
  42. 42. Location from Plane surface • Square and rectangular workpieces can be located by replacing one of the locating pads by an equalising rocker. • The rocker provides support at two points “R”. It provides itself to suit the surface to be located. • It provides contact at four points without contradicting the three-point location of the plane. • The pivot pin of the rocker acts as a single point complementing the pother two points “F” in defining the plane. Equalising Rocker Location
  43. 43. Location from Plane surface • For small workpieces location pads are not necessary. • The fixture body itself is machined suitably to provide locating surface.
  44. 44. Location from Plane surface • Ample recess is provided in the corners so that burr on the workpiece corners, dirt or swarf do not obstruct proper location through positive contact of the workpiece with locating surface.
  45. 45. Location from Profile
  46. 46. Location from Profile • A sighting plate is provided for simple components where appearance is important. • It is slightly bigger than the workpiece. • The workpiece is placed on the plate in such a way that there is equal margin on all the sides. Sighting location
  47. 47. Location from Profile • The profile of a workpiece can also be located by confining the profile with cylindrical locating pins. Profile location by pins
  48. 48. Location from Profile • The profile of the workpiece can be located by providing pocket or nest around the profile of the workpiece. • The inside profile of the nest matches with the outside of the workpiece. • The height of the nest should be lesser than the workpiece to ease unloading. • A partial nest can be used. Location nests
  49. 49. Location from Cylinder
  50. 50. Location from Cylinder • It is most common and convenient form of location. • When the cylinder is located on its axis and base, it can only rotate about its axis. All other motions are constrained. • Clamping from top prevents linear motion along Y-Y axis. Cylindrical locator
  51. 51. Location from Cylinder • The seating surface of the locator should be recessed to provide space for dirt or workpiece burr. • There should be ample chamfer or radius at the entry point so that the components can be loaded quickly. • The chamfer is called “lead”. • The locator itself is located in fixture by a concentric diameter generally made press fit in the fixture body. • The cylinder is best location shape because a cylindrical locator is least difficult to produce and eliminates five of the six degrees of freedom. Cylindrical locator
  52. 52. Location from Cylinder Circular locators types – • Inside locators • Outside locators Problems with cylindrical locators - • Jamming • Clearance
  53. 53. Location from Cylinder: Jamming • Jamming is result of a friction. • The amount of clearance, the length of the engagement and steadiness of the hand of the operator are reason for jamming. • Jamming occurs when part has entered short distance into the inside locator or around an inside locator. • A workpiece is likely to be tilted to the axis of the location post during quick loading.
  54. 54. Location from Cylinder: Jamming • The part has entered the locator over a short length “L”, the length of engagement. • If the part is slightly tilted, then one side of the leading edge comes in contact with the inside of the locator and is caught up by the friction resulting in jamming. • The locator has dia. W. • The workpiece has dia. (W-C), where “C” is clearance.
  55. 55. Location from Cylinder: Jamming • The length of the locator should be small to prevent jamming of the workpiece. • A long lead aligns the axis of the workpiece with locating post. • If the locator is long and lead is short, the workpiece would get jammed on the post. • Long location posts are used for fragile workpieces since locator provides support to the workpieces. • Long locators are relieved i.e. made undersize in central portion. Prevention of jamming
  56. 56. Location from Cylinder: Jamming • For the length of engagement L, there exist two critical values L1 and L2, which can be calculated. • The distance between L1 and L2 is where jamming possible and likely to occur. • This area can be completely eliminated by providing a relief-groove on the locator over a length of at least from L1 to L2. • L1 = 0.02 D • L2 = 0.12 D • L3 = 1.7 (D)1/2 • d = 0.97 D
  57. 57. Location from Cylinder Location Post
  58. 58. Location from Cylinder Locating post • They are used for anchoring clamping studs. • Location post is secured to the base otherwise it will be pulled out by clamping force. • The post is secured by retainer nut or a grub screw. • C washer is used. Locators subjected to axial pull
  59. 59. Location from Cylinder: Jamming • The jamming of the workpiece on the locating post can also be prevented by providing special lead at the entry point. Jamming prevention lead
  60. 60. Location from Cylinder • Location pot is used for locating a cylinder on outside diameter. • They have lead at entry point and central portion is relieved in case of long pots.
  61. 61. Location from Cylinder • When we use two holes in workpiece for location, we must take into account variation in centre distance of the two holes. • The variation is taken care of by making one of the two location pins diamond shaped. • Out of the two holes, the accurate one should be used for principal cylindrical location with full pin. • The diamond shaped pin is used to constrain pivoting of the workpiece around the principal locator. • The locating surface of a diamond pin is usually less than 8% of a full cylindrical pin. Diamond Pin Application
  62. 62. Location from Cylinder • A location pin is positioned as far away as possible from the principal locator in order to minimise the angular error.
  63. 63. Location from Cylinder Conical Location • Used to locate rough machined surfaces of castings and forgings. • They locate the workpiece from hole or shaft. • Similar to location posts and pots. • Centralization • A conical locator is considered as superior as it has a capacity to accommodate a slight variation in the hole diameter of the component without affecting the accuracy of location. Conical Locators
  64. 64. Location from Cylinder Vee (V) Location: • Used to locate cylindrical surfaces from outside. • 2 “V” locators are used for accurate location. • A “V” locator can be adjusted quickly by using a cam for adjustment. • Return spring is provided to bring back the V locator to its original position. • Fixed V blocks are used for approximate location. • Fixed V Blocks are attached to fixture body by screws and dowelled to prevent shifting during operation. Fixed V locator
  65. 65. Location from Cylinder • Adjustable V Block – for more accurate location, to take care of size of workpiece. • Adjustable along the axis of “V”. • Guide plate is provided to guide and to constrain movement along the axis of V. • The side of V face is sometimes inclined slightly to provide downward clamping force. Screw adjusted V locator
  66. 66. Location from Cylinder Inclined V: • When a sliding V locator is used, a small downward clamping force can be introduced by inclining the sides of the V. Inclined V
  67. 67. Location from Cylinder • A swinging eyebolt is used when a V plate has to be withdrawn quickly. Quick action V locator
  68. 68. Location from Cylinder • When a cylindrical workpiece is located by a V block, the centre would always lie on the centre line of V. • For drilling vertical holes in round bars, the V block should be placed in such a way that its centre line is vertical. Suitable position of V for drilling vertical hole
  69. 69. Location from Cylinder • If V block axis is horizontal, the variation in the diameter of the workpiece would lead to errors. • Hole would be eccentric or offset in undersize and oversize bar. Unsuitable position of V for drilling vertical hole
  70. 70. Summary 1. Location must be related to the dimensional requirements stated on the component / workpiece drawing. 2. It is preferable to use a more accurately machined surface than a less accurate surface for location. 3. The workpiece should be prevented from moving along and rotating around the X, Y and Z axes. 4. Location system should facilitate easy and quick loading and unloading of the workpiece and aim at motion economy. 5. Redundant locators must be avoided. 6. Location system should positively prevent wrong loading of the workpiece by foolproofing.
  71. 71. Summary Locating Methods: Plane surfaces 1. A reasonably flat surface can be located by three pins of equal height having spherical surfaces at the location points. 2. A rough, uneven or tapered plane surface should be located by adjustable location pins having spherical ends. 3. Additional adjustable supports are necessary to prevents vibrations or distortion of the workpiece machining operation. 4. A machined surface can be located by pads having flat surface. 5. There should be ample clearance for burr or dirt to ensure proper seating of the workpiece surfaces. 6. A cube can be prevented from linear movement and rotation around axes X, Y and Z by six location pads.
  72. 72. Summary Locating Methods: Profile 1. A profile can be located approximately by aligning it with a slightly bigger sighting plate. 2. Locating pins can also be used to locate a profile or cylindrical workpieces. 3. Variations in workpiece sizes from batch to batch can be taken care of by using eccentric locators whose eccentricity can be set to suit the batch. 4. Workpiece with little variation can be located precisely with nesting plates with suitable provision for unloading or ejection.
  73. 73. Summary Locating Methods: Cylinder 1. Spigots used for locating bores should have ample lead for easy entry and their length should be short to prevent jamming of the workpiece. 2. Long locators for fragile workpieces should be relieved at the centre. 3. Location posts which are also use for clamping should be retained a nut or a grub screw. 4. When two location pins are used, less important one should be made diamond- shaped. The main cylindrical pin should be longer than the diamond pin in order to facilitate easy loading of the workpiece. 5. Rough cored holes and bosses are located on conical locators which often have integral clamping arrangement and drill bush. 6. Fixed V blocks are used to locate approximately the outside surface of the cylinder. 7. For precise location, adjustable guided V block is necessary. The V block can be adjusted by a screw or a cam. 8. V blocks should be positioned in such a way that the variation in the workpiece would not affect the location for the operation.
  74. 74. References 1. Jig and Fixture Design Manual, Erik K. Henrikson, Industrail Press. 2. Jigs and Fixture, P.H. Joshi, THM. 3. An introduction to jig and tool Design, M.H.A. – Kempster, III Ed.Pub ELBS.
  75. 75. Thank You!

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