Full 5-axis on-machine measurement software
Blum Software FormControl 3.0 for workpiece-measurement has been introduced for 5-axis, fast-machining control directly on machining centres, eliminating the need for time-consuming resetting of the workpiece on a separate measuring machine. Re-work is done within the initial set-up, thereby not only saving further time-consuming alignment of the workpiece, but also increasing essential accuracy.
With the introduction of the new 3.0 Version of Blum's FormControl software, Blum systems users can, for the first time, now carry out full 5-axis measurements of whole workpieces on their machine tools.
Machining set-ups and measurement with arbitrarily oriented probes are now possible with this system. Blum says that, while it would clearly have been easier to produce software for the calibration of the probe at fewer positions and requiring more steps in the process, users can specify any probe positions they like; there are now no limitations in this respect.
Another innovation is the automatic compensation of setting errors, thermal drifts and errors that may arise when changing probes. This mathematical method of working has been in use for many years on coordinate measuring machines, using the probe to find the orientation of the workpiece and the precise orientation of any angle. Now all of this measuring work can be done on the machine itself. In this way, many machine errors are avoided, including those that might occur after hours of continuous running when the spindle will be warm and measurements are subsequently taken after it has stopped and cooled.
'Best-Fit' is particularly useful with FormControl because, when measuring, it must assume that any workpiece to be measured is fixed exactly as defined by the CAD model. Unfortunately, clamping errors or deviations of the axis alignment are all too likely to exist. A reliable result for the measuring operation can only be made if the deviations caused by manufacturing errors can be separated from these positional errors. Best-Fit does this by a process known as, 'rigid body transformation', whereby the algorithm calculates the translation and rotation needed in order to minimise such deviations.
The opportunity to employ a probe system with its own built-in virtual collision detection system between probe or spindle and workpiece on the machine will be welcome. The software can easily provide a model of the probe and spindle-head so that potential collisions can be foreseen and the operator alerted and hence avoid such costly events.
With the grid function, a square or rectangle can be defined and the number of desired measuring points in both x and y directions, say 7 x 15, entered and they will all be made by a single click of the mouse. The stored instruction can be amended if initial experience suggests more or fewer points are needed for future checks of the workpiece. With this function, a typical 20 minutes of set-up time can be reduced to three or even two minutes.
With Automatic Data Interface (ADIF) the measuring results are instantly available and, because no manual data generation of measurements or their transmission is involved, these results are fault-free.
Author: Andrew Allcock