Many bdtronic systems are custom-made products. Continuous monitoring and control circuits ensure process reliability. In addition to conveying capacity, fill level monitoring and temperature control in the material container, this also includes regular dosing needle monitoring. Here, bdtronic relies on sensor technology components from Captron in Olching near Munich. "When it comes to sensor technology, expertise, accuracy and innovative solutions are crucial," says Martin Kraus, Head of Materials Management at bdtronic, explaining the more than 25 years of cooperation with Captron. "Here, the solutions are not off-the-shelf, but are developed individually. That's what makes the collaboration so special."

Avoid errors, simplify processes
bdtronic, formerly known as Bartec Dispensing Technology, is now a global supplier of one- and two-component dispensing systems and equipment. The company designs and builds manual to fully automatic systems. In the initial phase, the integration of sensors into the dispensing systems was still complex. Custom brackets had to be manufactured and many different components had to be harmonized. The vibrations of the systems meant that the sensors became misaligned after a while and no longer worked accurately. Time-consuming readjustments were necessary in order to be able to work with lasting precision. This is where the collaboration with Captron comes in: "We get to the bottom of the respective requirement and develop a suitable solution based on this," explains Reinhard Bellm, company founder and managing partner at Captron. "Our idea was to develop a one-piece system in a flat design that enables easier installation, greater accuracy and more process reliability." This solution has now proven itself on the market.

Accuracy first and foremost
Captron's solution is based on its TCP measurement technology for industrial robots. A total of up to 200 bdtronic systems are equipped with ORL2 sensors every year. The closed measuring unit is characterized by a particularly flat design. Two laser light barriers are integrated into the sensor, which create a correction field like a kind of coordinate system. This enables precise, three-dimensional needle measurement. The principle: a robot moves the potting needle into the laser cross from above as part of a reference run. The routine can then be used to determine whether the tool tip is positioned correctly. In addition to the position, the sensor also checks the condition of the needle: if the robot is at the so-called zero point of the light barriers, the measuring unit can measure the length of the dispensing needle based on the robot's traversing speed as it plunges in. This process also determines whether the needle is bent or dirty.

"If dosing systems are used in adhesive processing, the curing times in particular are a potential risk: adhesive tends to cure quickly in the air, which can leave unwanted residues on the dosing needle," explains Martin Kraus from bdtronic. "Regular checks must be carried out to ensure that the needle is clean and ready for use."

The customer software used evaluates data for regular analyses and statistics in continuous monitoring and control loops. If the needle is not positioned correctly, the sensor reports the error directly to the system. This reacts without manual support. There is also an error message if a needle has been inserted incorrectly so that the operator can intervene. This ensures process reliability and reduces the system's error rate.

Systems with multiple potting
Parallel to the closed system based on the ORL2 models, another open solution was developed at the same time, which is also used at bdtronic. While the dosing needle is inserted into the ORL2 measuring unit from above and can only be moved within a limited measuring field, the OGLW2 model is open at the side. Some of bdtronic's end customers work with dispensing systems that cast several parts at the same time and therefore have a battery of dispensing needles. Using the open system, several needles can be measured directly one after the other as they pass through - which is not possible in a closed system. The laser light barriers are integrated into a raised optical structure of the sensor for this purpose. The recesses between the lasers prevent the other needles from colliding with the housing while a dispensing needle is being measured. Here too, the one-piece structure milled from solid material ensures optimum mechanical stability.

The fully automatic process saves the system operators time. Instead of constantly checking the settings of the dispensing robots manually and carrying out re-measurements, the system automatically runs through the measuring system after a certain number of splices and decides whether all settings are correct and the dispensing process can be resumed. Potential faults are automatically reported by optical or acoustic signals. This does not lead to higher productivity and at the same time reduces the error rate in production. pb

As a modern, medium-sized manufacturer of capacitive and optical sensors, Captron Electronic GmbH has been shaping the future of human-machine and machine-machine interaction since 1983 - with complete sensor systems and customized special sensors according to customer-specific adaptations. As a global manufacturer, Captron develops, manufactures and supplies small and medium-sized companies as well as large corporations in a wide range of industries and applications. This applies to both series production and project business. In addition to the German company headquarters in Bavaria, Captron operates further company locations in China and the USA as well as sales partners around the globe.