Though the two terms are used interchangeably, jigs and fixtures are actually very different devices that are mostly used in conjunction with one another. These devices are mostly used in machining operations to help reduce human effort during mass production.

However, in this guide, we’ll focus primarily on different types of fixtures, their purpose, advantages, and what industry relies on them the most.

The Advantages of Fixtures

Fixtures are work-holding devices and locating elements that locate, hold, and support the workpiece in a fixed, proper position during the machining process with respect to the machining tools. The most common type of fixture is the vise jaw found in nearly all workshops. Their main advantages are:

• Increased productivity
• Increased machining accuracy
• High-speed manufacturing process
• Maintained interchangeability
• High clamping rigidity for CNC and turning operations on large parts
• The increased quality level of the finished product

The Most Common Types of Fixtures Used in Manufacturing

Fixtures are specifically designed for applications where the cutting tool can’t be easily guided via different types of jigs. Since they’re used in almost any machining operation based on the precise relationship between the workpiece and the cutting tool, these devices are often identified by the machining tools they’re used on. Below, we differentiate the following types based on fixture design:

Turning Fixtures

They are usually mounted on chucks of the machine spindle during turning operations, like on lathes. Depending on the part that’s being machined, turning fixtures may be equipped with counterweights to balance an unbalanced fixture.

Milling Fixtures

Milling fixtures are usually mounted on machining tables facing the faceplate or the spindle of the milling machine. The workpiece is placed at the base of the fixture and clamped before starting milling operations. However, during operation the cutting tool remains in place while the machining table, alongside the piece, shifts in relation to the cutter.

Boring Fixtures

Boring fixtures incorporate the principles of drill jigs since the boring bar is guided through a pilot bushing, similar to drill bushing. Its main function is to hold the workpiece in the correct position relative to the boring bar. Since they aren’t subject to strong cutting forces, boring fixtures don’t need to be as sturdy.

Grinding Fixtures

There are several different forms of grinding fixtures used in grinding machines to hold, locate, or support workpieces that are subject to grinding operations. Regardless of their form, however, these should have provisions for the supply and exit of coolant.

Tapping Fixtures

These work holding devices are specifically designed to position and secure workpieces for tapping operations — cutting internal threads in drill holes. They’re primarily used on odd-shaped and imbalanced parts, especially in mass production, for drilling, tapping, and reaming.

Indexing Fixtures

These are specifically used for machining parts that must have machined details evenly spaced.

Welding Fixtures

Welding fixtures are designed to hold and support different components intended for welding operations and to prevent any possible distortions in welded structures. The structure of these fixtures has to be rigid and stable, and the clamping elements need to be positioned clear of the welding area.

Duplex Fixtures

Duplex fixtures are designed to facilitate simultaneous machining of two parts at separate machining stations. Depending on the manufacturing needs, these parts can be machined identically or in sequence.

Assembly Fixtures

These are used to hold various parts and components together for assembly purposes. They’re similar to welding fixtures, but instead of hot joining, these are used for mechanical assembly.

Broaching Fixtures

Mostly used with plate fixtures, broaching fixtures are used to hold the workpiece during broaching operations.

In Which Manufacturing Industry Are Fixtures Used the Most?

Fixtures are mainly used in machining but also in any other industry that relies heavily on drilling, grinding, cutting, and assembly, which also includes carpentry and construction.

Summary

Fixtures are work-holding devices designed to help maintain accuracy and repeatability for manufacturing parts on a mass scale. If you want to learn more about jigs and fixtures, visit Reid Supply and their extensive library of guides and technical literature.