What Are Jigs and Fixtures?
Jigs and fixtures are two of the most common types of tooling used during fabrication. They are often confused and used synonymously with one another, but there are some subtle, but distinct differences between the two. Both are important in the production system to achieve high throughput rates, high quality and low cost.
Jigs are utilized to control the location or motion of the cutting tool. One of the most common types of jigs is the drill jig. The drill jig expedites the hole centering process and acts as a guide for the drill or other type of boring device as it engages with the work piece. Drill jigs are commonly lined with hardened bushing so that the cutting tool does not damage the drill jig.
Fixtures are a class of tooling that deals with holding a work piece in a fixed location so that a manufacturing operation can be conducted such as machining, assembly or inspection. Common types include check fixtures and milling fixtures. The difference between a fixture and a jig is that a fixture holds a work piece into place as a numerically controlled cutting tool works on the piece but, unlike a jig, it does not guide the cutting tool. A jig is attached to a workpiece and guides the cutting tool to ensure efficiency, quality, and repeatability.
Why Are Jigs and Fixtures Used?
Jigs and fixture are critical to achieving high throughput, low costs, and repeatable quality. The alternative to jigs and fixtures is having workers manually measure every single cut. Not only is this time consuming, but human error will result in a larger range of variations of each unit of product. More variations will lead to more quality defects and a higher scrap rate.
Fixtures are also critical to automation as the work pieces need to be held in an exact location during fabrication and assembly. If the work piece changes location during the operation, then the robot will not be able to reorient itself and will be misaligned when attempting to perform fabrication and assembly operations.
How Are Jigs and Fixtures Manufactured
There are several ways to fabricate jigs and fixtures and the method chosen will depend on a few different variables including volume, complexity, lead time, product lifecycle stage, stress requirements, and budget.
CNC machining is great for producing highly accurate metal jigs and fixtures that have a low level of complexity. Using metal will cost significantly more, but will offer higher strength, durability and heat resistance than plastic tools.
If a high volume of identical jigs and fixtures is required, then injection molding may be utilized. The lead times and costs will be substantially higher due the time associated with building the mold and, as a result, should only be utilized for high volumes of low-complexity tools, with low stress and heat requirements.
3D printing is increasingly becoming an evermore popular method for fabricating jigs and fixtures. 3D printing can produce highly complex plastic and metal tools. In contrast to injection molding or machining, 3D printing can produce multiple iterations of a jig or fixture design in a matter of hours rather than weeks for a fraction of the cost. This makes 3D printing a great manufacturing method for new product development as multiple design iterations can quickly and cost effectively be designed and produced on-demand.
There are several high-performance 3D printing materials that are excellent for tooling applications such as carbon fiber, fiberglass, polycarbonate, nylon, and ABS. Check out our 3D printing materials guide to learn more.
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