Automation offers opportunities, especially in grinding and polishing. The participants in the automation event at 3M in Neuss realize this all too well. This initiative of Metaaltechniek, the family wholesaler from Amersfoort specializing in abrasives and grinding tools, was on the program for the second time and could count on the support of 3M and automakers SHL and TFT (Tools for Technology).
A truly working automation solution for grinding? Few of those are still active in the metal industry. After all, the complexity to achieve a working solution is higher than for a welding process, so many grinding robots sit unused in a corner of the company gathering dust. Still, the urgency is high. It is increasingly difficult for companies to find people to do grinding work. So the question is not so much whether we should automate, but rather how and with whom. The three workshops during Metaaltechniek's automation event sought to inform and inspire participants.
For SHL, building an automation solution starts with a visit to the shop floor. How do you work now? What needs to be processed? How large are the series or are they single pieces? What steps need to be completed? What is the required final finish? In addition, an inventory is made of which existing production resources can function well in conjunction with the new machines. The financial picture is also calculated: what is needed and what will it cost? Investments of 250,000 euros are the order of the day for SHL. To spread the investment, it is possible to start with a basic concept and add modules later.
A feasibility study then zooms in on the technology. SHL chooses very solid machines with very high rigidity to work quickly and without vibration. After all, any vibration compromises the result and operational reliability. All forces released during the sanding process are mapped to ensure stable operation. Clamping tools for perfect clamping, special spindles or high-performance belt sanders, cameras for control, AI for error detection and recovery, ultrasonic sensors for measuring[IB1] gaps and tolerances, SHL thinks of everything and provides turnkey solutions. Before the robot is put to the test in practice, it already goes through simulations virtually to have placement problems, bottlenecks and bottlenecks in advance. With more than 3,500 grinding applications delivered, there is a particular amount of experience in house to determine the price per product and the processing time required.
Explicit knowledge of hardware, software, attachments, machines and abrasives is essential, according to 3M. Even the biggest and best automakers do not have all the expertise to do justice to the latest technology. 3M has set up a division specifically for this purpose to gain and share knowledge with automakers such as SHL and TFT. The details seem simple: which grinding belt do we use? But if only after delivery it turns out that a sanding belt does not last 3 hours but 2.5 hours, an entire concept can fall apart. Possibilities and impossibilities can be tested in practice at the 3M CAT center in Neuss. The extensive range of machinery offers many possibilities and is available to 3M customers under certain conditions.
A major advantage of robotic grinding is the reproducible finish and consistent quality. Even if the starting material has large tolerances. To achieve the best results, it is necessary that the abrasives used also have these properties in them: a uniform wear pattern and a finish that remains constant until the end of their service life. 3M's Trizact and Cubitron3 products are therefore ideally suited for use on a robot. The same goes for Scotch Brite products such as Bristle Discs or Unitized wheels. 3M showed how much experience it has in-house with a demonstration of grinding welds and finishing a stainless steel product. In the robot cell is a setup with two abrasive belts and a Scotch Brite Unitized wheel. 3M also has its own hardware, programmers, a test center and an R&D department.
Like SHL, TFT has the entire process of engineering, manufacturing, assembly and testing in-house, as it guarantees flexible and personal cooperation with short lines of communication. TFT's choice, unlike SHL, lies much more with cobot solutions. Flexibility in a production environment is indispensable, especially for smaller series. You don't necessarily have to automate 100% of sanding operations. Automating 50% is also profitable. TFT showed how easy it is to program a cobot, but also that grinding requires different conditions than welding. Delivering continuous, equal power while compensating for unevenness requires a lot. That is why TFT always chooses Doosan cobots that are equipped with force transducers in all axes and are accurate to 0.2 N.
Why a cobot instead of a robot? It works safely with an employee at the same workbench. Compared to the robot, it takes up less space, requires no additional safety measures and requires a lower investment. Programming is also easy to learn. However, the payload of a robot is higher and a programmed robot works completely independently and at higher speed. A demonstration of grinding with a belt sander followed. It indeed turns out to be child's play to get the cobot to work. You place the head of the cobot at a number of points on the workpiece, the positions are stored and the machine follows the programmed line. For fine-tuning the settings, experience of the grinding process is helpful. We played a bit with belt speeds, height setting and pressure, just until we were satisfied with the result. Then we changed the spindle and went into eccentric rotary grinding on another workpiece. Dynabrade's machines are specially designed for mounting on a cobot.
'Together towards the perfect finish' is Metaaltechniek's slogan. Choosing the right partners is essential for a successful end result. The manufacturing industry is making strides in automation. We will have to. But how fascinating and instructive it is to work with it.
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