A PCB test fixture, or test jig, is a piece of equipment that ensures the product is built to specification at the production stage. Using a text fixture is highly recommended because it identifies design flaws early on, preventing these flaws from passing into the manufacturing process.
By holding a workpiece at several points or allowing work-pieces to clamp together, jigs allow users to drill holes, remove material precisely. In other words, a jig is a work-holding device that holds, supports, and locates the workpiece in order to guide one or more tools.
Jigs are tools that hold a cutting tool in place or guide it as it performs a repetitive task like drilling or tapping holes. Fixtures, on the other hand, do not guide a cutting tool, but hold a workpiece steady in a fixed position, orientation, or location.