If you work with expensive workpiece materials or process highly complex components, you know how important it is to get the job done right the first time — machine a part improperly and your productivity and profitability take a beating. There are, however, quantitative measures you can take to effectively manage your scrap and rework as well as improve your machine’s overall performance.
While excessive scrap rates are often the result of poor programming, there are occasions where a part is out of tolerance due to a problem with the machine tool itself. And, should you believe something is amiss with your machine, you can either compensate for the problem through programming or address the issue directly by adjusting the errors out of your machine — with the latter being more efficient.
Recognized by ASME B5 and ISO 230 committees, ballbar calibration tests are a quick, simple and economical way to verify the repeatability and accuracy of your machine, mainly in terms of contouring performance. In as little as 10 minutes, the test can generate substantial quantitative data that can assist you in diagnosing errors. While ballbar testing equipment is available for purchase, we provide ballbar qualification and analysis services through our Optimum Plus program that ensure your machine is operating to factory specifications.
A ballbar, which consists of a telescopic bar with an internal sensor and magnetic ball cup joints at either end, monitors spindle movement as it follows a programmed circular path and compares the test path to a perfect circle. The ballbar data then gets converted into a polar plot of the machine’s true movement, allowing you to identify errors, such as backlash, scale mismatch, lateral play and reversal spikes, within your machine’s axes.
Having this type of motion-related information prior to in-process parts inspection allows you to significantly reduce your shop’s scrap rates and machine downtime. Early error detection via ballbar testing also allows you to effectively plan for any machine maintenance and repairs.
Furthermore, ballbar testing can help you with process optimization. For example, it will monitor your machine at different feed rates so you can determine what rate delivers the best accuracy for a specific cutting application.
While you can perform a ballbar test on your machine at any time, it's best to have one at least every six months as long as everything seems to be running smoothly. And, should your testing results indicate adjustments need to be made, please feel free to contact your nearest Mazak Technology Center for assistance. Also, if you’re purchasing a new machine from us, it’s a good idea to have us perform an initial ballbar plot of your machine so you have a benchmark to refer to in the future.