On many production lines, the coordinate measuring machine (CMM) plays a vital role in providing accurate measurements of newly produced parts and guaranteeing quality control. And while the most common types of CMM are fixed in place to provide the most detailed possible measurements, there are some jobs that stationary CMMs simply cannot do. In cases such as these, portable, manually operated CMMs are the best way to gather fast, accurate metrology data.
While there are several different kinds of portable CMM, they can generally be divided into two categories: articulated arms, like the ROMER Portable Arm, and laser trackers, like the Leica Laser Tracker. While each has its own particular specialty (articulated arms tend to be more accurate, while laser trackers can measure from a much greater distance), both types of portable CMM offer important metrology services due to their flexibility, speed, and mobility.
Flexibility
Generally speaking, the benefit of portable CMMs can be summed up in this one word. Portable CMMs can handle a wide range of jobs, and can move between different sizes of part, much more easily than their stationary siblings. This is true of parts produced on shop floors that are simply too unwieldy for conventional machines to measure, but it is also true when measuring large finished products (laser trackers, for example, are sometimes used to measure complete aircraft after assembly).
Speed
Portable and stationary CMMs are often compared in terms of accuracy and flexibility, but speed is also, at times, an important consideration when weighing the benefits of different types of CMMs. Because it is manually operated, portable CMM equipment can measure parts much faster than stationary machines, which gives them a real advantage in situations where a quick measurement report is needed. They can also measure an existing part against the CAD blueprint in real time, allowing technicians to immediately catch inconsistencies and errors.
Mobility
Can’t bring the part to the machine? Bring the machine to the part. There are times when high-level metrological data needs to be gathered on a part or product, but it is simply isn’t possible to run it through the CMM. This often occurs when special or custom parts are being made off-site, and metrology data needs to be gathered where production is happening. In cases such as these, portable CMMs can be brought wherever they are needed, and, once calibrated, can gather metrology information onsite, without needing to process the information back at the shop.
While portable CMMs provide a huge net benefit due to their flexibility, lower cost, and lightness, there are still situations in which a conventional stationary CMM is better. Portable CMMs provide measurements that are accurate down to 30 micrometers (70 in the case of laser scanners) — anything smaller than that requires a stationary CMM to provide truly accurate measurements. Every manufacturing business will have its own particular needs when it comes to CMMs, but for many production lines, the speed, efficiency, and flexibility of the portable CMM make it an invaluable tool to have on hand.
