Measuring at High Speed
- Measuring Machines

High-precision, high-speed measurement of tool inserts

Practically everyone has used a product from carbide specialists CERATIZIT at least once in their lives – 90 per cent of all the balls in ballpoint pens come from this company. For the measurement of carbide cutting inserts, CERATIZIT Austria recently began using an automated measuring cell from Blum-Novotest. This system is special in that the measurements are precise down to the last few micrometres – and this even though each measurement takes less than four seconds.

CERATIZIT Austria's facility is located in the picturesque mountains of Reutte in Tyrol, near the town of Füssen and the border to Germany. But there's little of that Alpine cosiness felt in the facility's production halls – here it's all about maximum precision. The company supplies semi-finished carbide blanks and finished products, with the portfolio being broken down into 'preforms', carbide rods and tool inserts. Preforms are made-to-order carbide parts that are preformed and partly ground, and are then processed by the customer. Carbide rods, for example, are semi-finished products that become drilling or milling tools. Lastly, tool inserts are finished products that are used in milling, lathing, punching or drilling tools.

The portfolio of tool inserts covers around 2,700 standard inserts, which can be ordered via a catalogue. In addition to this there are many more special geometric forms that are made-to-order on the basis of customer specifications. In addition to the inserts, the associated tools are also offered. The portfolio includes numerous types of carbide that provide the ideal combination of properties for any purpose.

Until recently, an old automated measurement system was used to measure the many plates, but it was already being put to the limits of its capacity back in 2011. A new measuring cell was sought out that not only could achieve very short throughput times but was also as compact as possible. At Control, the international trade fair for quality assurance, Daniel Scheiber, CERATIZIT's Quality Officer for the Presses Production Line, discovered the flexible Blum-Novotest's BMK measuring and automation concept for the first time. Scheiber had until then never seen such a compact measuring cell that combined automation and measurement from any other manufacturer.

The compact BMK 3 measurement and automation concept from Blum-Novotest GmbH
The compact BMK 3 measurement and automation concept from Blum-Novotest GmbH

With the BMK 3, Blum-Novotest GmbH has developed a flexible measuring and automation concept in the form of a variable, modular, expandable measuring cell that can also perform additional functions such as sorting, labelling and packaging of parts when fitted with appropriate modules. The BMK 3 can be deployed in fields ranging from small-series production, for example as a flexible standalone measuring and testing cell, to fully-integrated process systems for high-capacity serial production. The compact measuring cell can support multiple measuring devices tailored to the purpose at hand and can be combined with a wide range of options. For example, palletisers or even labellers can be integrated. The robot is fitted to the roof of the interior chamber, which enables it to not only reach the entire surface of the cell but also provides it with access to the entire floor surface of the cell interior for the measuring instruments.

"While we already had the BMK 3 successfully in use with a number of customers, CERATIZIT presented two new challenges: the required throughput rate and the high measurement precision, as well as the geometry to be measured," said Peter Mösle, Head of Sales of the business division Measuring and Testing Technology at Blum-Novotest, remembering the first talks. "There aren't any flat surfaces on these tool inserts, the cutting edges are curved. This makes them very difficult to measure using conventional methods – especially not to the precision required in the specifications," added Scheiber. "We very quickly came to the conclusion that we would have to use a high-resolution optical measuring system," continued Mösle. "We had only used camera systems until then to detect positions or geometry, not to measure micrometre-level tolerance values. The required unit throughput time of 3.5 seconds also required us to use a very fast delta robot, which would normally have been used in pick & place machinery in packaging, instead of a conventional robot arm." 

An ultra-fast delta robot featuring a Rapid Prototyping vacuum gripper is used to transport the indexable inserts
An ultra-fast delta robot featuring a Rapid Prototyping vacuum gripper is used to transport the indexable inserts

A concept using two robots was first pursued – a delta robot for handling the inserts and another portal conveyor system for handling the boxes, in which the tool inserts were to be placed. The robot would remove the plates from a transport pallet and place them in the machine on a high-speed rotary bench. This rotary bench would turn the insert under the camera where it would be measured. Finally, the robot would place the insert into a 10-insert box. To ensure a stable process, Blum-Novotest developed a monitoring system that ensured that the boxes would lock into place correctly during stacking.

"It became apparent as early as the design stage that robots would be too expensive and that getting two systems to work together would be too complicated," said Mösle as he remembered the development process. "A changing gripper system was the breakthrough. We now use two different rapid prototyping vacuum grippers to transport the tool inserts and the boxes using the delta robot."The Blum-Novotest measuring cell offers quantifiable advantages – the BMK measures 40 per cent more tool inserts per hour on half the space compared to the old system, and all this at a speed that could not be achieved before. "We were fast before, but now we're measuring what we want – all of the insert's features," explained Daniel Scheiber. "And we can operate the system practically without personnel – the operator just looks in from time to time to fill up empty packaging boxes. Our operators have taken quite a liking to the BLUM system," added Schmid.

"We have a very open and honest relationship with Blum-Novotest, that was clear in the development and optimisation phase," concluded Lothar Schmid. "Our needs were understood right away and met superbly. We've achieved the necessary throughput rate, whilst still achieving maximum measurement precision and a very reliable process. This has provided us with large capacity reserves – and shown us that the vision of integrating measurement into the production process is certainly realistic.“