BLUM production metrology at toolcraft
- Messkomponenten

Measuring systems for precise tool and workpiece measurement with a robot arm

toolcraft, based in the German municipality of Georgensgmünd, develops and builds robotic cells for a wide range of applications – from polishing to milling. Always on board: Blum-Novotest measuring systems for precise tool and workpiece measurement with the robot arm.

“We have extensive experience working with robotics and also know a great deal about software thanks to unicam,” explains department manager Thomas Wieland. “We consolidate this knowledge to develop special solutions for the complex challenges of our customers”. A good example of these requirements is a production line consisting of five 5-axis grinding machines and just as many robotic cells. They are used to grind and polish full ceramic clasps with illuminated gear knob that are fitted on the gearshift lever of current BMW luxury models. Machining these components present a multitude of challenges. For example, the flat yet curved shape of the clasp is difficult to clamp and polishing the ceramic surface is a demanding task.

The toolcraft cells are equipped with high-precision Stäubli robot arms with a specially developed felt tool rotating on a high-speed spindle. The clasps – of which there are eight variants – are always clamped in pairs in specially adapted vacuum zero-point holders and machined one after the other. Since the felt wears quickly despite applying a polishing paste and sometimes even becomes detached from the carrier disc, toolcraft employs BLUM’s Z-Nano tool setting probe in the robotic cells to determine the thickness of the felt – and thus the position of the tool – prior to each polishing cycle. Once a certain wear limit has been reached, the robot takes a new piece of felt from a magazine. The tolerances that need to be maintained are extremely tight and have been reduced to five hundredths of a millimetre on the free-form surface. This is the reason why Z-Nano probes are also employed in the grinding machines during the preceding grinding process in order to measure the mounted points precisely. It was important for toolcraft to be able to carry out grinding and polishing unmanned – and they have succeeded in doing this. All the machines – five grinding machines and five polishing robots – can be operated by just one person. This would not be possible without the BLUM tool setting probes.

A current project in a large machining cell also demands a high level of accuracy: The new LC50-DIGILOG laser measuring system from BLUM is mounted in a corner of the working area to monitor more than 60 different tools that are used during machining. The system performs a tool breakage check before each tool change and precisely measures the individual cutting edges of the tools at critical machining points. In addition, the BLUM laser provides very reliable and exact information about the position of the tool and its length, which makes it possible to work precisely with a robot arm. The LC50-DIGILOG is perfectly suited for harsh environments, as it activates the sealing units of the laser optics during processing to prevent any dust from penetrating and guarantees reliable measurements even in very dirty applications.
A further challenge of this project is the material block, whose weight is reduced from 1,300 kg to just over 200 kg during the machining stage. It is removed from the robotic cell between two machining steps and then set up again and remeasured. The robotic cell uses the TC63-10 modular touch probe, which is attached to the tip of the robot like a tool and sends data to the machine using BRC radio transmission technology. The switching signal of this touch probe is also generated opto-electronically and thus wear-free, which guarantees constant measuring accuracy over many years. As in many other BLUM touch probes, the TC63-10 features the high-precision shark360 measuring mechanism with a face gear comprising 72 teeth. 

The BLUM touch probes and laser measuring systems, which have been working precisely and reliable for many years, have proven their worth in Georgensgmünd. Thomas Wieland concludes positively: “This deserves a huge amount of praise as almost all of our sixty 5-axis machining centres are equipped with a BLUM laser measuring system, and each new machining centre is fitted with a touch probe. And we shouldn’t forget to mention the tool setting probes in the grinding and polishing machines either. toolcraft has developed an excellent reputation among its customers, which is based on our innovative strength and quality standards. BLUM measuring systems have played a major role in this, as they are flexible, reliable and accurate – just like we are.”