Chapter 1

1. Chapter 1 Type and functions of jigs and fixture.

2. JIG & FIXTURES • Jig and Fixtures are production-workholding devices used to manufacture duplicate part accurately. • Jig andFixture are so closely related that the terms are sometimes confused or used interchangeably. The differences is in the way the tool is guide to the workpiece. • Jigs – not only holds, locates and support but guides • Fixtures – just only holds, locates and supports

3. TYPES OF JIGS • Divided in general to; • 1) Open jig • 2) Closed jig

4. 1) Open jig • Used for simple operations where work is done • on only one side of the part • Sometimes called clamp jigs • Example; template jigs, plate jigs, table jigs, • sandwich jigs, angle-plate jigs, modified angle- • plate jig

5. Template jig • normally used for accuracy rather than speed • the least expensive and simplest type of jig to use

6. Plate jig • similar to template • difference that plate jigs have built-in clamps to hold the work • sometimes made with legs to raise the jig off the table for large work – table jig

7. Table jig Sandwich jig • form of plate jig with a back plate • ideal for thin or soft parts that could bend/warp in another style of jig

8. Angle-plate jig Modified angle-plate jig • used to hold parts that are machined at right angles to their mounting locators • modified angle-plate used for machining angles other than 90 degrees

9. 2) Closed jig • Used for part that must be machined on more • than one side • Usually totally surround the part and resemble a • box like structure. • Example; box or tumble jigs, channel jig, leaf jigs

10. Box or tumble jig • usually totally surround the part • allows the part to be completely machined on every surface without the need to reposition the work in the jig

11. Channel jig • simplest form of box jig • the work is held between two sides and machined from the third side

12. Leaf jig • small box jigs with a hinged leaf to allow for easier loading and unloading • differences between leaf and box jigs are size & part location, leaf jigs normally smaller and sometimes made not completely surround the part • usually equipped with a handle for easier movement

13. Types of fixtures • The names used determined mainly by how the • tool is built • Because of the increased tool forces, fixtures are • built stronger and heavier than a jig would be for • the same part • Example; plate fixtures, angle-plate fixtures, vise- • jaw fixtures, indexing fixtures, multi-station • fixtures, profiling fixtures.

14. Plate fixture • simplest form of fixture • made from a flat plate that has a variety of clamps and locators to hold and locate the part • useful for most machining operations

15. Angle-plate fixture • variation of plate fixture • part normally machined at right angle to its locator

16. Modified angle-plate fixture

17. Vise-jaw fixture • used for machining small parts • vise jaws are replace with jaws that are formed to fit the part • least expensive fixture type, limited by the sizes of the vises available

18. Q&A

19. Exercise 2 • What is the different between jig and fixtures? • List down 4 type of jig and Fixture with example machining process. • Analyze the following part drawings and operations to be performed and select the best jig or fixture for each. • Mill a slot 250 inch.

20. A jig guides tools in relativity to the work piece, while a fixture holds the work piece itself. Fixtures are naturally more generic than jigs while jigs must be specially designed in order to suit the machining operation and the work piece geometry. • List down 4 type of jig and Fixture with example machining process • Analyze the following part drawings and operations to be performed and select the best jig or fixture for each.