FVC: Fagor Volumetric Compensation
Last modified 31-05-2011
To achieve the required accuracy on most demanding parts.
Machining imperfections on a part may be caused by several factors: some are design related, others are related to machine kinematics, mounting, etc. Usually the best way to avoid or minimize this type of errors is by properly designing the machine. However, this is not always possible or is not economically feasible. Particularly for mid-size to large machines, the increase in rigidity may be unfeasible beyond a certain limit or it may just be too expensive.
Since some time now, there are compensations at the CNC’s for most common errors such as leadscrew pitch, cross compensation, etc. that may be enough for small or large machines whose machining quality requirement is not too high.
But, in industries like aerospace, the machining requirements make classic compensation tools insufficient because they do not take into consideration the machine’s kinematics and other effects due to the relationship between axes.
Dynamic compensation while machining for maximum accuracy
That’s why the classic error compensation tools must be completed with other more advanced ones that adapt to the different designs of the machine with particular kinematics.
When focusing on the problems that one of the machine axes might have, we could find errors having to do with axis quadrature, rotational errors caused by leadscrew torsion and translational errors.
Extending the study to the whole machine, its volume is represented by the X, Y and Z axes. The interaction of the axes increases the possibility of error to 21. FAGOR AUTOMATION in cooperation with the German company AFM (known provider of solutions in the mobile measuring technology area), has developed in their equipment the volumetric compensation feature that takes uses those 21 error tables and compensates them dynamically while machining in order to obtain highly accurate parts.
Applying this feature results in more than 50% increase in volumetric accuracy of the machine while obtaining the tolerances required by most demanding parts.
Talleres Aratz, located in Vitoria-Gasteiz (Basque Country – Spain), is one of the companies that is already applying this new feature very successfully. This company has recently installed in its shop a new machine equipped with a Fagor CNC that offers this innovative volumetric compensation technology.
Talleres ARATZ exports 70% of their production to countries like USA, Australia, Norway and China among others and is dedicated to machining special high accuracy parts working in such demanding fields as:
- Aerospace: making their own tooling and prototypes.
- Hydroelectric: manufacturing turbines, large shells, injectors, etc.
- Manufacturing of special machines.
- Special machining services.
In Mr. Karlos Balsategui, production manager of Talleres Aratz: “On an expanding market like aerospace, opportunities and demands go hand in hand. The more than 30 years of machining experience of Talleres Aratz together with the advantages offered by Fagor’s volumetric compensation will allow us maintain our competitiveness in this sector, so important to us”.