Automation under control
- Messkomponenten

BLUM touch probes and laser measuring systems at ALSTO Präzisionsspannwerkzeuge GmbH

When milling wood in state-of-the-art machine tools, the speed of the spindle is, above all, crucial for the machining cycle time. However, extremely fast rotating spindles demand ultra-precise clamping fixtures, as produced by ALSTO Präzisionsspannwerkzeuge GmbH in Burladingen-Hausen/Germany. Key elements for the production of high-precision clamping tools are Blum-Novotest touch probes and laser measuring systems that are employed in several machine tools at ALSTO.

The robust BLUM touch probes have been a member of the ALSTO team since 2013. They are able to demonstrate their full abilities by improving and increasing automation. Since automation ultimately needs to be under control. As a result, measuring in the machine and breakage detection are key features. In the meantime, three of the ten machine tools have been fitted with BLUM measuring systems. Of particular interest is the application in the Doosan MX2600 double spindle turning/milling centre that uses a robot arm: The robot inserts the blanks in the right-hand spindle for machining before subsequently transferring the part to the left-hand spindle which then completes machining. After each handling procedure, the BLUM TC62 touch probe uses BRC radio technology to initially measure whether the part has been inserted into the chuck properly. Further, the dimensions are checked to immediately identify and reject any faulty blanks.

“We used to use the touch probes of another manufacturer but were not fully satisfied with the results. In contrast, the compact BLUM touch probe provides not only top quality but also great value for money,” claims company owner Alexander Alber. “The repeatability of 0.3 μm 2σ is extremely high, which is important if you want to produce high-precision parts in large production runs. With several hundred units a day not being uncommon...“. During the machining and measuring procedures, coolant is sprayed onto the tool at 60 bar. Thanks to the mechanically robust design of the system and the high level of ingress protection (IP68), the touch probe is ideal for the harsh conditions of a machine tool and continues to measure accurately and reliably even when using coolant.

A particular highlight at ALSTO: Measurements performed with the BLUM touch probe enable the compensation of fluctuations in precision at the machining centres, e.g. caused by the machine and the workpiece heating up during machining. For instance, the tolerances achieved in Burladingen-Hausen ensure that cylindrical grinding of the clamping tools is no longer required. When considering hard turning and high-precision turning a replacement for grinding processes, the machine must be able to achieve all the tolerances, accuracies and obtainable surface qualities that are common in grinding. Axis error compensation by the BLUM touch probe for accurate positioning of the axes and digital glass scales combined with analogue measuring systems form the basis for reaching this goal.

BLUM TC54-10 T touch probes are additionally used in several Hardinge turning machines at ALSTO within a climate-controlled environment. Furthermore, the BLUM LaserControl NT-H 3D laser measuring system is used in the Doosan MX2600 double spindle turning/milling centre. The combined system with 3D touch probe is employed for setting and monitoring the complete tool spectrum. The TC76 touch probe with a cube stylus is installed with the high-precision laser measuring system which enables the measurement of all tool types and shapes in a real clamping situation at nominal spindle speed. Last but not least, the BLUM LaserControl Micro Single NT measuring systems, with separate transmitter and receiver, are installed in two Chiron machining centres for breakage detection. The production measurement technology from Blum has completely proven itself in Burladingen-Hausen. And just as impressive is the level of support offered, since the competent BLUM service team is well aware of all the processes and requirements at ALSTO. Moreover, Alexander Alber is fully satisfied with the fast response times from BLUM service. “BLUM helps us stay engaged in a hard-fought market: And by eliminating grinding processes we have been able to reduce run-out errors to a minimum,” Alexander Alber says positively. “Furthermore, without reliable checks, 24/7 operation, as can be achieved with BLUM measuring systems, would not be possible. Above all, BLUM systems have become an indispensable element in terms of optimising our processes.”

Established back in 2006 with just three machines, ALSTO Präzisionsspannwerkzeuge GmbH in Burladingen-Hausen now boasts ten state-of-the-art turning and milling machines. In addition, the number of employees has risen to fifteen. As a supplier of high quality clamping fixtures, its customers include manufacturers from every sector. A main focus is, however, on companies that order woodworking tools. As it is not difficult to machine wood extremely quickly at state-of-the-art CNC machines when the spindle achieves very high speeds. With the speeds commonly encountered there, a high balance quality of the tool holders plays a decisive role. As a general rule, the more precise the clamping fixtures, the longer the life of the tools and the spindle bearings. These high-precision clamping fixtures are at the core of ALSTO’s practice – the company’s products therefore guarantee much higher accuracy than demanded by the market.