In the measurement equipment industry, I have worked for more than 20 years and often see companies struggle to choose between profile projectors and video measuring machines. On the surface, both are optical devices for 2D inspection, but anyone with real production experience knows their usage scenarios are quite different. Each has its own advantages and limitations.
Profile projectors were among the earliest optical inspection tools I used. Over 20 years ago, when I was supporting a mold factory, I often saw operators check stamped parts with projectors. Small components placed on the stage are magnified dozens of times on the screen, making it quick to spot deformations or burrs. For threads, projectors are equally useful. Screw and lead screw angles are impossible to verify by the naked eye, but magnification makes it clear whether the angle is accurate. Gear manufacturers also rely on projectors, comparing tooth shapes with standards to judge pass or fail, which is more than sufficient for daily inspection. In tool inspection, projectors are indispensable. I have seen cutting edges that looked sharp to the eye but revealed micro chipping under projection magnification. If such tools were used directly in production, surface problems would appear quickly. The intuitive display of a projector solves these pain points well.
As manufacturing advanced, video measuring machines (VMMs) gradually became mainstream. Unlike projectors, they use high-resolution cameras and software to capture and analyze edges. This process is not affected by human judgment, offering better stability and repeatability. A few years ago, I visited a smartphone parts factory where tolerances were within a few microns. Manual checks could not ensure consistency, but with VMMs, dozens of dimensions could be measured at once, and reports were automatically generated. In the PCB industry, where boards are full of tiny pads and holes, projectors cannot handle the complexity, but VMMs make batch inspection easy. In medical devices, I’ve seen them used to check syringes and stents, not only ensuring accuracy but also providing traceable reports required by strict regulations.
Although VMMs offer higher precision and automation, profile projectors are still valuable. Many factories use both. On the shop floor, operators prefer projectors for quick checks—simple, intuitive, and efficient. In quality departments, VMMs are used for final confirmation, ensuring traceable results that meet customer requirements. For example, in one tool factory, workers first used projectors to confirm cutting angles, then used VMMs for final dimensional verification before shipment. This two-step process balanced efficiency and accuracy.
From my decades of experience, I can say there is no single best device. Profile projectors are economical, reliable, and straightforward, ideal for daily checks. VMMs deliver higher precision and automation, fitting for mass production and strict quality systems. For companies, combining both is often the most effective way to maximize measurement value.