Jigs and fixtures are essential tools in precision machining and manufacturing processes, primarily designed to enhance operational efficiency, ensure consistent part quality, and reduce production time. Although they serve related purposes, there are distinct functional differences between the two that cater to specific needs within the machining cycle.

Jigs:

A jig is a specialized tool used to guide and control the movement of a cutting tool during a machining process. The primary function of a jig is to accurately position and secure the workpiece while also guiding the cutting tool along a predetermined path. This ensures that the tool performs operations such as drilling, milling, or tapping at the correct angle, depth, and location. Jigs are integral in ensuring repeatability and minimizing human error in high volume production environments.

Functions of Jigs:
Jigs precisely guide the cutting tool to the required location on the workpiece, ensuring consistent and repeatable operations.
By restricting tool movement to specific paths, jigs enhance accuracy in processes that demand high precision.

Jigs reduce setup time and reliance on manual skill, making them ideal for largescale production runs where multiple parts require identical machining.

Fixtures:
In contrast, a fixture is designed primarily to hold the workpiece securely in place during the machining operation. It does not guide the cutting tool but ensures that the workpiece is positioned and maintained in a fixed orientation to ensure precise operations. Fixtures are crucial in applications where the workpiece is large, complex, or requires multiple operations to be performed sequentially. They are commonly used in milling, turning, grinding, and welding processes, where part alignment and stability are paramount.

Functions of Fixtures:
Fixtures hold the workpiece securely, preventing any movement during the machining process, which is critical for ensuring dimensional accuracy. 

Fixtures can be designed to accommodate various workpieces or to support parts undergoing multiple machining processes.

By maintaining consistent part positioning, fixtures help achieve high quality results with minimal variation across production batches.

Difference:

Jigs primarily guide the cutting tool, whereas fixtures are designed to hold the workpiece securely in position.

Jigs tend to be more complex as they involve additional mechanisms for guiding the tool, while fixtures are typically more straightforward, focusing on workpiece stability.

Jigs are predominantly used in operations that require tool movement guidance (e.g., drilling, tapping), while fixtures are more common in processes where workpiece stability is essential (e.g., milling, grinding).

Both jigs and fixtures play a critical role in modern manufacturing, enabling high precision, high volume production with minimized error rates. Their ability to enhance both productivity and accuracy makes them indispensable tools in industries such as aerospace, automotive, electronics, and general manufacturing.