Your end product is only as good as the design you start with; you want to be sure that the plan you approve will meet the needs of your project. You want to end up with a functional, easy-to-use inspection fixture. A quality fixture will save you time and money over the life of your project. What are some practical steps to achieving this? How should the fixture shop approach the design phase? Let's take a closer look at this topic.
The Concept
The fixture shop should present the initial concept of the fixture in a way that is easy for you to understand. You should receive both a 2D print and a 3D viewing file. All critical tolerances, including pin sizes, feeler offsets, or location of any variable data points, should be included in the 2D print. The 2D should also show you what part print and part CAD were used for the concept. The concept will also have an area for any open issues the designer has encountered, the most common of which is unmarked or unclear tolerances on the part print.
The 3D view file gives you a visualization of the fixture you are purchasing. You can rotate the view to look at critical areas and turn components on and off. These options will allow you to thoroughly examine the provided concept in a relatively short amount of time.
The Design Review
Once you have looked over the design concept, it may be wise to review it with the designer and program manager. This step is usually done over a virtual conference call but can also be done in person. The value of having a design review is twofold. The first is that the program manager and the designer can explain why they designed the fixture the way they did; this may quickly clarify questions you and your team might have about the concept—getting clear answers as to why an area of trim is checked with a flush block instead of a feeler pin, or why your MMC locators are hand held instead of fixed in the form block.
The second is that everyone will hear what corrections or changes you want to make before the fixture is released for build. Providing this information in a design review can save time and frustration. We have all sent and received emails that did not accomplish their goal. It can be challenging to write an email that delivers feedback in a way that keeps everyone on the same page. By having a design review, the entire team hears the same thing and can ask real-time questions if they are uncertain about anything that was discussed.
The Approval
Once any needed updates are made to the design, the fixture shop should send it back out for final approval. If you are good with the final design, you can release the fixture for build. From that point, all materials should be ordered, and the build of your fixture will begin.
Final Thought
The fixture design is a crucial part of the project. Make sure that the design you're paying for is of a fixture you will want to use for the next 4 to 6 years. Also, remember that the design is part of what you are buying. You should ALWAYS receive an electronic copy of the inspection fixture's 2D print and 3D model. Working with an experienced tool shop will streamline the entire design process. Following these steps and focusing on the critical design components will start your fixture build off on the right foot. Let's talk a little more about the build next week.
By Chris McColley