New probe system software

Citation

(2007), "New probe system software", Aircraft Engineering and Aerospace Technology, Vol. 79 No. 5. https://doi.org/10.1108/aeat.2007.12779eab.005

New probe system software

New probe system software

The new generation Blum Software FormControl 3.0 for workpiece- measurement has been introduced for 5-axis, fast-machining control directly in the machining centre, 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.

Five-axis machining

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 (Figures 6 and 7).

Says Blum's Dipl.-Ing. Winfried Weiland: “This new software is very important news for the growing numbers of users in the aerospace and die and mould sectors where there is a strong concentration of 5-axis machining centres. Other manufacturing sectors where 5-axis machining predominate will also stand to benefit from this new software”.

Figure 6 Blum probe TC52 measuring component with new FormControl 3.0 software shown in background for 5-axis machining

Figure 7 Blum-probe incorporating new FormControl 3.0 software system for 5-axis-machining

Aerospace applications

This is particularly true in aerospace work where workpieces may take many hours to produce. If the operator has the possibility of securing direct feedback after the first 10 per cent of cutting time, for instance, a rapid decision can be made as to whether to proceed straight away or, maybe, make some program changes to ensure a perfect outcome even from the first component.

Machining set-ups and measurement with arbitrarily oriented probes are now possible with this system. Blum say 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.

Best-fit

Another great 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.

Virtual collision detection

The possibility of tool collision occurring is a constant concern for many operators as it can have devastating financial consequences and every effort has to be taken to prevent it. It has been routine for such precautions to be taken by operators as part of their CAD/CAM procedures. 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 a welcome addition to any manufacturer's armoury. 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.

Blum are well aware of the relatively high incidence of probe collisions because, says Winfried, as many as 95 per cent of the damaged probes received for repair or replacement are the consequence of such misadventure. This is yet another very good reason why the new software is expected to be much in demand.

Grid function saves time

Considerable savings of time and easier handling of the software will be the major user benefits of this new function. It affords the operator useful graphic support relating to the input of large numbers of measuring points in a display that can be easily read and understood. Until now, every single measuring has had to be selected with a mouse click at each chosen surface point, sometimes involving up to one hundred such points in a small area.

Set-up time reduced from 20min to 3 or even 2min

Now, 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£15, entered and they will all be made by a single click of the mouse. The stored instruction can be readily amended if initial experience suggests more or fewer points are needed for future checks of the workpiece. With this function, a typical 20min of set-up time can reportedly be reduced to 3 or even 2min.

Fault-free results with Automatic Data Interface

Owing to 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. Measured results only take a few seconds to become available and can then be immediately evaluated on- screen before printing out in clear report form, either as a record or for keeping with the job documentation. The entire measuring sequence can be executed with a single mouse command (Figure 8).

Blum consider this to be a very important user benefit because this software will be used by machine tool operators rather than the more highly- specialised and trained laboratory engineers on their measuring equipment.

Figure 8 Blum “ADIF” software system enables automatic data transfer between CNC and PC

FormControl 3.0 has been designed with this in mind so that, with a single mouse click, the operator selects the measuring point on the workpiece and then the ADIF, by another click, will transmit the actual measurement from the PC into the NC. The machine tool operator will not have to select any file, or make a manual file transmission, and does not even need to have the knowledge of how such data transfers are done. Even more important is the high level of safety functionality this system achieves when compared to manual exchanges that might involve the selection of a wrong file for transfer to the machine tool.

There are many parameters that can lead to an incorrect workpiece but they can all be detected with this software, e.g. wrong tool data, wrong tool, wrong cutting parameters; for instance, if cutting too deep or with the wrong spindle speed that would impose strong forces sufficient to cause undue tool deflection.

There are also errors that can be detected by measurement, such as thermal drift during production and other errors that can be detected thanks to the “Best-Fit” method described previously. Of course the system is not meant to actually replace a coordinate measuring machine, but it does offer the supreme advantage of giving immediate feedback of what is being produced and this is especially valuable when it comes to large dies and moulds.

The operator is thus able to make an immediate decision as to whether a re- work needs to be done without the disruption and time delay involved in transferring the workpiece to a coordinate measuring machine.

In summary, Blum's FormControl 3.0 software for contour measurement, previously only available for use in machines of up to 3-axis, can now be applied to 5-axis machining centres to combine the advantages of fast detection of machining errors with the opportunity for immediate rework of the initial set-up. The system also provides for the early identification of problems that might arise from incorrect cutting parameters, wrong tool dimensions or wear and incorrect tool orientation.

Details available from: Blum Novotest Ltd, Tel:+44(0)1543257111, Fax: +44 (0)1543 251746, E-mail: david@blum-novotest.co.uk, Web site: www.blum-novotest.com