Types of Jigs and Fixtures

Introduction

Jigs and fixtures play a crucial role in machine tool design. They are specialized tools and devices used in manufacturing processes to ensure accuracy, repeatability, and efficiency. Jigs and fixtures are designed to hold and guide the workpiece during machining operations, such as drilling, milling, grinding, and broaching. They provide support, alignment, and control, making it easier for operators to perform these operations with precision.

In this article, we will explore the different types of jigs and fixtures used in machine tool design, their components, and their applications.

Drilling Jigs

Drilling jigs are used specifically for drilling operations. They are designed to hold the workpiece in place and guide the drill bit accurately. There are several types of drilling jigs:

1. Template jig: This type of jig consists of a template or pattern that guides the drill bit. It is used for repetitive drilling operations.

2. Plate jig: Plate jigs are made of a flat plate with drill bushes. They are used for drilling holes in large workpieces.

3. Leaf jig: Leaf jigs are similar to plate jigs but have flexible leaves that can be adjusted to accommodate different hole sizes.

4. Channel jig: Channel jigs are used for drilling holes in cylindrical workpieces. They have channels that guide the drill bit.

The components of drilling jigs include:

• Drill bushes: These are hardened and ground bushings that guide the drill bit.

• Clamping devices: These devices hold the workpiece securely in place.

• Locating devices: Locating devices ensure accurate positioning of the workpiece.

To use a drilling jig, follow these steps:

1. Secure the workpiece in the jig using clamping devices.

2. Align the drill bit with the drill bush.

3. Start the drilling operation, ensuring that the drill bit remains aligned with the drill bush throughout.

Types of Fixtures

Fixtures are used for various machining operations, including milling, grinding, broaching, and assembly. They are designed to hold the workpiece firmly and accurately during these operations. Here are the different types of fixtures:

1. Milling fixtures: These fixtures are used for milling operations. They hold the workpiece securely and guide the milling cutter.

2. Grinding fixtures: Grinding fixtures are used for grinding operations. They hold the workpiece in the correct position and orientation for grinding.

3. Broaching fixtures: Broaching fixtures are used for broaching operations. They hold the workpiece and guide the broach tool.

4. Assembly fixtures: Assembly fixtures are used for assembling multiple components. They hold the components in the correct position and alignment for assembly.

The components of fixtures include:

• Clamps: Clamps hold the workpiece securely in place.

• Locators: Locators ensure accurate positioning of the workpiece.

• Supports: Supports provide additional stability and support to the workpiece.

Real-world applications of fixtures include:

• Automotive industry: Fixtures are used in the production of car parts, such as engine components and body panels.

• Aerospace industry: Fixtures are used in the manufacturing of aircraft parts, ensuring precision and consistency.

• Electronics industry: Fixtures are used in the assembly of electronic components, ensuring accurate placement and soldering.

Indexing Jig and Fixtures

Indexing jig and fixtures are used when multiple machining operations need to be performed on a workpiece at specific angles or positions. They allow for precise indexing and rotation of the workpiece. The following indexing devices are commonly used:

1. Indexing head: An indexing head is a device that allows for the rotation of the workpiece at specific angles. It is commonly used in milling operations.

2. Indexing table: An indexing table is a circular table with indexing holes or slots. It allows for the accurate positioning and rotation of the workpiece.

3. Indexing fixture: An indexing fixture combines the functions of an indexing head and an indexing table. It allows for both rotation and precise positioning of the workpiece.

Using an indexing jig and fixture involves the following steps:

1. Secure the workpiece in the fixture.

2. Set the desired indexing angle or position.

3. Perform the machining operation.

Conclusion

Jigs and fixtures are essential tools in machine tool design. They provide accuracy, repeatability, and efficiency in various machining operations. Drilling jigs, fixtures for milling, grinding, broaching, and assembly, and indexing jigs and fixtures each have their specific purposes and components. Understanding the different types of jigs and fixtures and their applications can greatly enhance the manufacturing process.

In summary, the key points covered in this article are:

• Jigs and fixtures are important in machine tool design for accuracy and efficiency.

• Drilling jigs are used for drilling operations and have different types and components.

• Fixtures are used for milling, grinding, broaching, and assembly operations and have different types and components.

• Indexing jigs and fixtures allow for precise positioning and rotation of the workpiece.

• Real-world applications of jigs and fixtures include automotive, aerospace, and electronics industries.

By utilizing jigs and fixtures, manufacturers can improve productivity, reduce errors, and achieve consistent results in their machining operations.

Summary

Jigs and fixtures are essential tools in machine tool design. They provide accuracy, repeatability, and efficiency in various machining operations. Drilling jigs, fixtures for milling, grinding, broaching, and assembly, and indexing jigs and fixtures each have their specific purposes and components. Understanding the different types of jigs and fixtures and their applications can greatly enhance the manufacturing process.

Analogy

Imagine you are building a puzzle. The puzzle pieces are the workpiece, and your hands are the jigs and fixtures. Without your hands to hold and guide the puzzle pieces, it would be challenging to assemble the puzzle accurately. Similarly, jigs and fixtures hold and guide the workpiece during machining operations, ensuring precision and efficiency.