Today, so much emphasis is placed on accuracy of equipment used for inspection and reverse engineering jobs and for good reason. Without it, your data would not be usable. Many companies claim accuracy of sub one thousandth of an inch, or 0.001”, with laser scan data and even less with contact measurement. That sounds great! Yet, when a client is over concerned with accuracy, they seem to forget to look closely at the setup. We at Rasmus Engineering Services have spent thousands of hours on clients’ jobsites each year measuring large objects. We can safely say, we’ve seen a thing or two with portable measurement devices. Some good, some very bad! That being said, we have learned some valuable tips and tricks on how to get good setups and calibrations in the field. Some key details include measuring on a flat plate, a climate controlled environment, with a workpiece that is securely clamped down. Most people tend to fall short in these areas, causing accuracy and repeatability to become a moving target!
Let’s look at this from a math standpoint. Say you have a heavy object that will not fit on the table. Most likely you would place the equipment on some form of instrument stand. Seems logical, right?! Now let’s assume our measuring equipment accuracy is .001”, and the portable stand being used for the equipment is unsecured and has an accuracy of .002”. Due to size and weight, the part being measured is unsecured and has an accuracy of .0005”. Due to all the variables, this super accurate machine can now only calibrate to an accuracy of .003”. Because of all the differing factors, your project accuracy will, at best, be .0035”. This is why most portable measuring equipment is not living up to the standards claimed by the manufacturer. When we use portable equipment while in a real world, working environment, we need to spend more time on set-up and less time talking about accuracy of the equipment.
The picture above represents an example of a machine witnessed while onsite. What customer would want their job completed with a setup like this! If you would like more help on portable set-up, or would like the service group that has accuracy down to a science, contact Rasmus Engineering Services today!