Sep 7, 2022
Image of manufacturing tools for fixture design

Key Takeaways:

  • Fixtures and jigs offer support to work pieces during manufacturing, ensuring a steady output.
  • The support and rigidity of design fixtures make them a necessary feature in all manufacturing operations.
  • There are six degrees of freedom in fixture design. An accurately designed fixture restricts the degrees of freedom.
  • Following the industry best practices ensures your fixture design is of high quality and can compete with other manufacturers.

There is no one-size-fits-all answer when it comes to fixture design for manufacturing. What works for one company may not work for another. However, there are a few best practices that have proven successful time and time again in this industry. In this blog post, we’ll take a look at some of the most common practices and how they can benefit your business.

What Are Fixtures and Jigs?

Fixtures are devices that hold, support, and locate workpieces during a manufacturing operation. Fixtures offer a means to reference the workpiece and support during a machining operation. Fixtures with the added feature of guiding the tool during manufacturing are called jigs. The following industrial products are characterized as fixtures:

  • Grinding Fixtures
  • Milling Fixtures
  • Welding Fixtures

Why Design and Build Fixtures

Fixture design and build are essential to the success of any manufacturing process. The fixture must provide adequate support, rigidity, and accessibility to the workpiece. The following are some reasons why fixture design and build is essential:

  • To reduce setup time
  • To improve accuracy
  • To reduce scrap rates

Design Basics of Jigs and Fixtures

Understanding how degrees of freedom work is key to understanding the design basics of manufacturing jigs and fixtures. The number of degrees of freedom (DOF) is the minimum number of independent coordinates that can specify the body’s position. In fixture design, there are six DOF:

  • Three linear dimensions
  • Three angular dimensions

The X, Y, and Z axes are the three linear dimensions. The three angular dimensions are A, B, and C axes. An adequately designed fixture restricts the degrees of freedom to ensure the part is locked in position, but not so precisely that the part is overconstrained.

Parts become overconstrained when redundant forces do the same job, resulting in counterproductivity. A four-legged chair is an excellent example of over-constraint. A chair’s four legs are redundant and only serve to make the chair more difficult to move.

One important fixture design consideration is ensuring enough space around the part for tooling clearance. This is especially important when designing fixtures for CNC machining because the cutting tools need a certain amount of space to avoid collisions. Fixture designers must also consider the part’s size and weight when designing the fixture.

For example, a large and heavy part will require a sturdier fixture than a small and light part. Additionally, fixture designers must consider how easy loading and unloading the parts from the fixture will be.

Successful fixture design engineers incorporate human-centric designs into their plans. The engineers often consider the following calculations:

  • How do you mount the fixture?
  • What is the operator’s reach?
  • What safety clearances does the fixture require?

After taking these calculations into consideration, the designer can create a model of the fixture using computer-aided design (CAD) software. This software allows designers to create a three-dimensional (3D) fixture model, which is then forwarded to the manufacturer for production.

When manufacturing fixtures, it is essential to use accurate machining methods. The most common type of CNC machine used for fixture manufacturing is a milling machine. Milling machines use rotary cutting tools to remove material from workpieces.

Learn more about how gibs and fixtures work with machine tools.

Manufacturing Best Practices for Fixtures

You can build both jigs and fixtures using metals and plastic. It is essential to use the most suitable materials for your specific application.

For example, if you need a fixture that can handle high temperatures, you will want to select a material that can withstand those conditions.

Some of the most common materials used in fixture design and manufacturing include aluminum, brass, stainless steel, and tool steel.

To ensure accuracy during the fixture manufacturing process, it is essential to use quality control methods.

These tools help manufacturers verify that fixtures are produced within the specified tolerances. The three most common precision measurement tools are calipers, micrometers, and optical comparators.

Ribs and fillets increase the fixture’s strength while helping distribute stress evenly. When designing a fixture, it is essential to consider how these features will affect the part’s overall strength and durability.

Experts also use springs to ease ejection and help with die clearance. Springs are a vital part of the fixture design process and should be carefully considered.

3D printing of jigs and fixtures is a newer technology becoming more prevalent in designing fixtures and manufacturing. This technology offers many benefits over traditional methods, such as increased accuracy and shorter lead times.

Once you get your hands on the prototype, your goal is to ensure it matches the precise manufacturing needs. You need to ensure the fixture meets the dimensional accuracy required for providing able support to the product.

Expert manufacturers suggest verifying the fixture’s dimensional accuracy with coordinate measuring machines (CMM). This process is essential to ensure that the fixture meets the required tolerances.

It is also essential to consider the type of surface finish required for the application. Achieving the correct surface finish can be critical for some applications.

There are many other factors to consider when designing and manufacturing a fixture. These are just a few of the most important ones. With careful consideration, you can develop a fixture that will help streamline your manufacturing process and produce high-quality parts.

Detroit, MI, is known for its manufacturing prowess, and for a good reason. The city has a long history of producing high-quality goods that are both durable and accurate. If you’re looking to get a piece of that action, the experts at Cav tool can help. We adhere to top-of-the-line fixture design and manufacturing processes that will ensure your product is of the best quality possible. Get a free custom quote now and see how we can help you take your business to the next level.