Time to read: 6 min

Jig-Fixture-CNC-Machining-Beginners

In the manufacturing process of CNC machining, various tools are employed, each with unique capabilities. Among these, jigs and fixtures are two tools that are often confused with each other. This article will clarify the differences and uses of these tools, helping you understand their types, distinctions, and applications in machining.

What is a Jig?

A jig is a device used to secure a workpiece and machine part on a workstation. It is attached to CNC machine tools such as lathe cutting tools, dictating the location and motion of the tools. Essentially, jigs guide the machining tools. Uniquely, when jigs move, the tools remain stationary.

Types of Jigs

Jigs are common in CNC machining and come in various types suited for different operations:

  • Template Jigs: Simple and accurate, these jigs are favored for their precision over speed. They can be fitted over or into the workpiece but are not usually clamped.

  • Angle-Plate Jigs: Ideal for holding parts for drilling at angles relative to their mounting locators.

  • Plate Jigs: Similar to template jigs but with built-in clamps to hold the workpiece.

  • Leaf Jigs: Feature a hinged leaf that allows for easy loading and unloading of parts without completely surrounding the part.

What is a Fixture?

A fixture, or CNC fixture, is another essential tool in CNC machining, known for providing stability, support, and positioning. Like jigs, fixtures secure, support, or mount a workpiece on a CNC machine.

Types of Fixtures

Fixtures are classified based on machining operations, uses, and power sources:

Fixtures Based on CNC Machining Operations
  • Turning Fixtures
  • Milling Fixtures
  • Drilling Fixtures
  • Boring Fixtures
  • Grinding Fixtures

Other fixtures are named after their specific operations, such as honing and lapping fixtures.

Fixtures Based on Their Uses
  • Universal Fixtures
  • Special Fixtures
  • Assembled Fixtures
  • Modular Fixtures
  • Combination Fixtures
Fixtures Based on Their Power Source
  • Manual fixture
  • Pneumatic fixture
  • Hydraulic fixture
  • Electric fixture
  • Magnetic fixture
  • Vacuum fixture

Differences Between a Jig and Fixture

For those new to CNC machining, jigs and fixtures might seem similar and confusing. However, they serve different functions:

Main Function

Jigs guide the cutter to a predefined location on the workpiece, supporting and locating the part. Fixtures only secure, support, and locate the workpiece without guiding the machine part.

Complexity

Jigs are easier to use than fixtures, which require some skill to operate effectively.

Weight

Jigs are lighter than fixtures, which need to withstand significant cutting forces and vibrations.

Attachment to the Machine

Jigs can be held or fixed on the machine table depending on the task. Fixtures require clamping and accessories for optimal performance.

Design

Jigs are more complex in construction compared to fixtures.

Contact with the Tool

Fixtures do not need to contact the machine part, while jigs must touch the tool to set the angle and position accurately.

Why are Jigs and Fixtures Important for Machining?

Both jigs and fixtures play crucial roles in CNC machining due to their advantages:

Application of Jigs and Fixtures

Jigs and fixtures are generally used to secure workpieces and machine parts. Fixtures are suitable for multidimensional operations like turning, milling, and grinding. Jigs are ideal for one-dimensional operations such as counterboring, tapping, drilling, and reaming.

Advantages of Using Jigs and Fixtures

  • Improved Productivity and Efficiency: They reduce machine idle time by eliminating the need for manual alignment of workpieces.
  • Reduced Manufacturing Costs: They increase productivity and quality while lowering manufacturing costs.
  • Enhanced Product Quality: By removing the chance for human error during operation, they improve quality.
  • Ease of Manufacturing Complex and Heavy Tools: They hold the workpiece rigidly, facilitating the manufacturing of complex shapes.
  • Improved Safety: They minimize human involvement, enhancing safety in machining operations.

How to Make Jigs and Fixtures

CNC machining and 3D printing are the primary methods for making jigs and fixtures, depending on complexity, production volume, and manufacturing difficulty.

Design

Before designing jigs and fixtures, consider the component, locating elements, machine type and capacity, loading and unloading arrangements, clamping mechanisms, power and safety devices, clearance between jigs/fixtures and components, and ejecting and fixing arrangements.

Materials Used in Making Jigs and Fixtures

Material selection depends on the application and machining operation requirements and may include steel, cast iron, hardened aluminum, plastics, and bronze.

Manufacturing

Jigs and fixtures can be manufactured through CNC machining or 3D printing, each with its advantages. 3D printing offers design flexibility and cost-effectiveness, while CNC machining provides precision for complex designs.

Conclusion

Understanding the differences and applications of jigs and fixtures is crucial for anyone involved in CNC machining. This article has provided insights into their types, uses, and manufacturing processes, helping you make informed choices for your machining needs.

For any machining projects, Unofactory is a leading CNC machining service provider, focusing on precision parts manufacturing at competitive prices. We also offer jig and fixture manufacturing services.

FAQ

What is the use of jigs and fixtures?

Jigs and fixtures are workholding devices used in machining operations to support and secure workpieces, ensuring smoother manufacturing processes and improved productivity.

What is the difference between a jig and a fixture?

The primary difference lies in their functions. Jigs guide the machine part, such as a cutter, while fixtures secure, support, and stabilize the workpiece without guiding the tool.