Jigs and Fixtures Types, Differences, Pros & Cons, Applications [PDF]

In this article,we shall study the Definition, Types, Advantages, Disadvantages, Application, and the Difference between Jigs and Fixtures. We have provided a PDF download link for the same.

Welding Jig
Photo By Forster America

Definition of Jig

A jig is a work-holding device that holds, supports, and locates the workpiece and guides one or more tools to perform a specific operation. In other words, this can also be defined as, used for holding the tools and also guiding the cutting tools. The main purpose of a jig is to provide repeatability, accuracy, and interchangeability in the manufacturing of products.

Jigs and Fixtures
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  • It is used in uni-dimensional machining processes like drilling, tapping, and reaming, etc.
  • This system is found to be light and has a complex shape.
  • Gauge blocks are not necessary
  • The cost of jigs is higher.
  • Jigs are not fixed to the machine table until a large operation has to be performed.
Video by MechanicalEI

Definition of Fixture

Fixtures are the work-holding device, which holds, supports, and locates the workpiece but not guides the cutting tool to perform a specific operation. In other words, the fixtures are only the work-holding device that holds, supports, and locates the workpiece in the desired position to perform any operation. The main purpose of the fixtures is to hold and locate the workpiece during any machining operation and to provide repeatability, accuracy, and interchangeability in the manufacturing of products.

Jigs and Fixtures
Photo By Dreamstime
  • Fixtures are used in multi-dimensional machining like millinggrinding, turning, etc.
  • This system found to be heavy in weight, have simple designing.
  • Gauge blocks provided for effective handling and the cost is average.
  • Fixtures are having specific tools that use particularly in the milling machine, shapers and slotting machines.
  • Fixtures are fixed to the machine table.

Combining Jigs and Fixtures to Improve Precision

When manufacturing products, it’s important to achieve a high level of precision so they can work correctly. Jigs and fixtures are two tools that can help with this. By combining them, we can make sure that the various parts of a product are in the right place when they’re assembled. For example, if we’re making a door, we need to drill holes for the knob, latch, and hinges in the correct places. Similarly, when making cabinets or shelves, we need to make sure that the holes for the dovetail cuts or shelves are in the right positions. Without jigs and fixtures, the shelves might not be level, drawers might be wobbly, and doors might not close properly.

Jigs and Fixture for Metalworking and Welding
Photo By The Fabricator

Jigs vs Fixtures

Both the Jigs and Fixtures are used to reduce the nonproductive time of any mass production process. The principle of location or the 3-2-1 principle, CAD tools (like ProE), and FEA tools (like ANSYS) are used for the design of the jigs as well as the fixtures. The jig is used for guiding the cutting tool (like a drill bit), and for doing so, jigs have components like a bush, which comes in contact with the cutting tool.

On the other hand, a fixture never comes into direct contact with the cutting tool. Fixtures assure the position and alignment of the workpieces for getting the required machining operation done.

Jigs and Fixtures
Photo By Dreamstime

Factors to be Considered Before Designing a Jig or Fixture

These are the factors should be considered before designing a jig or fixture

  • Study of the component.
  • Study of locating elements.
  • Type and capacity of the machine
  • Loading and unloading arrangement.
  • Clamping arrangement.
  • Study of power devices for operating and clamping element and also a safety arrangement device.
  • The clearance between a jig and the component.
  • Study of tool guiding, cutter setting elements, rigidity and vibration problems.
  • Fool-proofing arrangement.
  • Study of ejecting devices, table fixing arrangement, and the indexing device.
  • Swarf removal arrangement.
Designing a Jig or Fixture
Photo By Froster America

How to Manufacture Jigs and Fixtures

To manufacture Jigs and Fixtures, the most common process used is CNC machine. This is because the production volume for jigs and fixtures is typically low. However, in some cases, 3D printing is a more suitable process, especially when the geometry of the product is too difficult or costly to machine. It’s worth noting that not all jigs and fixtures need to be made of metal; plastic can be a suitable material that can reduce costs while still meeting performance requirements.

Rapid manufacturing is not meant to replace traditional machine shops, but it can be a valuable tool when used appropriately. For example, it can be useful for producing blanks for jigs and fixtures or for manufacturing less critical parts that don’t require high precision. Protolabs, for example, is capable of maintaining tolerances of ±0.005 in. for CNC machining.

How to Manufacture Jigs and Fixtures

For a small number of parts, we recommend using CNC machining for your most common jigs or fixtures. However, if your part requires a more complex geometry that’s difficult to machine, 3D printing may be a better choice. And if you need to produce a high volume of parts, rapid injection molding can produce between 25 and 10,000+ parts using various engineering-grade thermoplastics.

Types of Jigs and Fixtures

There are several types of Jigs and Fixtures available in the market which are as follows

Types of Jigs

  • Template Jig 
  • Plate Jig 
  • Diameter Jig  
  • Channel Jig 
  • Ring Jig 
  • Box Jig 
  • Leaf Jig 
  • Angle plate Jig 
  • Indexing Jig 
  • Trunnion Jig 
Types of Jigs and Fixtures
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Types of Fixtures

These are some Fixtures available in the market which are as follows

  • Plate fixture
  • Angle plate fixture
  • Vise-jaw fixture
  • Indexing fixture
  • Multistation fixture
  • Profile fixture

Difference between Jigs and Fixtures

ParametersJigsFixtures
Main FunctionJigs are used to guide the movement of cutting tools to predefined locations and support and locate the workpiece.Fixtures are used to secure, support, and locate the workpiece and maintain a predefined orientation.
ComplexityJigs are generally simpler to use than fixtures.Fixtures are complex and may require specific skills and accessories for proper operation.
WeightJigs are typically lighter in weight for easier handling.Fixtures are usually heavier and are designed to withstand cutting forces and vibration.
MountingsJigs are not fixed to the machine table and can be hand-held or clamped in place for heavier work with no additional equipment.Fixtures are typically mounted to the machine table and require blocks or gauges to move the cutting tool correctly.
CNC machining applicationsJigs are commonly used in drilling, boring, reaming, and tapping operations.Fixtures are often used in milling, slotting, shaping, turning, and planning operations.
CostJigs can be more expensive than fixtures.Fixtures are cheaper than Jigs
DesignJigs often have more complex designs than fixtures.Fixture designs are usually simpler.
Contact with cutting toolJigs are exposed to the cutting tool to set the angle and position correctly.Fixtures do not come into direct contact with the cutting tool and are designed to fit specific workpieces.
ConstructionJigs can also be made from a variety of materials, including plastic and wood, in addition to metal.Fixtures are typically made from gray cast iron or steel parts that are welded or bolted together, using standard parts such as bushes and screws.

advantages of Jigs and fixtures

  • It eliminates the setting time required before machining.
  • It increases the machining accuracy and also increases production capacity.
  • Requires less skilled operation.
  • They reduce the production cost.
  • Increases machine and labor utilization.
  • They simplify the work handling.
  • Increases the quality of production in the industry.
  • They enable the quick setting of a tool and the proper positioning of the work.
Jigs and Fixtures
Photo By India Mart

Disadvantages of Jigs and Fixtures

  • Can wear away over time.
  • The high initial set-up costs and time.
  • It uses a lot of material and is bulky.

Applications of Jigs and Fixtures

  • Mass production of automobile parts.
  • Inspection of parts in continuous production in manufacturing industries.
  • Cutting the ingots in the steel plant.
  • In the refrigeration industry.
  • Pump assembling process
  • For drilling the flanges and drilling holes to any required angles.
  • For multi-spindle machining.
  • Jigs used for mass drilling, reaming and tapping.
  • For guiding the tools for machining contours.
  • Fixtures used for milling, mass turning, and grinding operations.
Material of Jigs and Fixtures
Photo By Monika Tools

The Material used for Jigs and Fixtures

Material is used for making Jigs and Fixtures are as following

  • Grey cast iron
  • Hardened steel
  • Carbide 
  • Plastic
  • Epoxy resins
  • Low melt alloy steels
  • Stainless steel
  • Bronze

Conclusion

In conclusion, Jigs and Fixtures are essential tools in manufacturing and production processes. Jigs are used to guide and control the motion of tools, while fixtures are used to hold and support workpieces. Their advantages include improved efficiency, accuracy, and consistency in production. However, their disadvantages include high initial costs and limited flexibility. Overall, the right choice of jigs and fixtures can greatly improve manufacturing productivity and quality.

References

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