Scanning and sorting concrete blocks with the BT Master SC

The BT Master SC (Brick & Tile Master for Scanning and Sorting) is the modification development of a successful concrete and heavy clay products inspection system, the BT Master, which has been tested and further developed in some of the most modern production facilities in Europa. As a result, not only concrete blocks can be tested with it, but brick and heavy clay products as well.

The system comprises a scanner unit, an analysis unit and a sorting unit. The scanner unit is positioned above the existing conveyor system, thus requiring no complex conversions. The scanner is fitted with all required cameras, lighting systems and, depending on the design, also with additional components. The BT Master SC scans the ongoing production, creates an image of all blocks and determines their quality and position. The 3D camera can optionally be supplemented for generating a height profile.

The analysis unit is housed in a dust-protected PC cabinet and is therefore optimally suited to the environmental influences in a rough production environment. The modular design and the use of state-of-the-art color cameras is intended to detect anomalies also in stamped surfaces. Quality can be assessed for various error criteria: e.g., for shrink holes, edge breakage, bumps, pollution, cracking and deviation in color and texture.


Three different modules for scanning and / or sorting

Module I is a 2D camera module for optical inspection of the surface and the geometry. It also performs color measurement and consists of a time-tested surface inspection process that is fitted with one or several monochrome or line-scan cameras. The surface is scanned during ongoing production and compared to appropriate reference samples. Additive measurement of brightness and colors enables control of these parameters. Products that show color differences in smaller areas can be detected, as well as products that show slight differences in color. In addition to the quality check, Module I determines the coordinates of every individual product and makes these results available, together with the results of inspection, for final sorting by Module III.

Module II is a new 3D measuring module for precise measuring of wing shape characteristics, warping of the products and other topographical defects. It consists of a high-resolution 3D camera and a high-performance laser that, by a laser cutting process generates a 3D image of the products. The image serves for checking dimensional conformance and angularity. These functions measure length, width and height as well as spatial angles. Inaccuracies in delivery and/or position and perspective distortions are corrected by intelligent software developed in-house, and are accordingly compensated for. This feature supplements the statistics and helps detect serial defects in order to sustainably improve product quality. Length, widths and angles are measured to an accuracy of 0.1 mm and/or 0.5 °, depending on product size. The cycle performance of the 3D module, at full resolution, amounts to approx. 150 products per minute.

Module III performs sorting, using a 5-axes robot. The data generated by Modules I and II are then, by PLC, passed on to the optional robot control, which controls the 5-axes that control the sorting robot. Faulty blocks are recorded and sorted out. In the process, the robot also generates sample blocks that are later separately exhibited for documentation. The blocks sorted out are replaced by appropriate “good” blocks that had previously been placed in readiness. Finally, a product board with 100 % OK blocks is moved onward. At the end, the system, with the same robot, covers the individual layers with a plastic sheeting, labels them and affixes an appropriate identification code to the side of the pallet. The robot is fitted with a vacuum gripper, equipped with a vacuum matrix, to enable gripping of the most diverse block formats (or also, for example, two adjacent blocks together). The gripper vacuum-collects small concrete crumbs, ensuring in this way a stable vacuum.


Shrinkage cavity / hole detection in concrete blocks

A specific example for the special requirements in the area of concrete block production is shrinkage and/or hole detection. In decorative products individual, very small holes may still be acceptable; but if they occur in larger numbers the block must be removed. However, on products that already have a rougher surface or on which less stricter requirements are placed, the number of smaller voids is often irrelevant. Blocks such as these are removed only when the voids are of a certain size.

The Ibea inspection system covers all of these product-specific differences through its comprehensive and flexible configurability. The products to be inspected are transported in layers on boards of up to 2-m thickness. The system is mounted directly on the existing conveyor line, at the end, directly in front of the pallets. The products pass through a line camera, which takes a 2D color image. This is the basis for all inspection tasks based on a change in color or black and white. Simultaneously, a 3D image is created by means of laser cutting. It is the basis for detecting any kind of changes in shape: e.g., shrinkage holes, broken edges, bumps and depressions. The positions of the individual blocks on a board can furthermore be determined and passed on to the robot. Between the inspection system and the industrial robot, which handles the products, a PLC manages, interprets and sends the appropriate color commands send to the robot.

Handling takes place with a 5-axes industrial robot that is able to vacuum-attach to the blocks to be exchanged, precisely pick them up and put them down in the correct position. For this task, a vacuum gripper is used whose chambers can be flexibly controlled. This enables adjustment of the size of the products to be transported. It also enables the robot to sequentially process products of different sizes with various vacuum chambers, without requiring additional setting-up times. It is also possible to use several robots to increase the processing rate.

Special tools were developed for handling special shapes that are unsuitable for handling by a vacuum gripper. These can be installed within a very short time, or even fully automatically, depending on the design. In standard design, products weighing up to 50 kg can be handled quickly and efficiently. However, the handling of considerably higher loads is possible as well. The core task of the industrial robot is to exchange blocks marked as faulty for blocks of high quality. This function enables replacement of an individual block by a new block in less than 10 seconds.


Reference plant for manufacturers of concrete blocks implemented

The inspection system from Ibea enables not only flexible detection of faulty parts, but their allocation to various fault classes as well. The industrial robot is then able to differentiate and handle them in various ways – e.g., in a container with waste or breakage – and to palletize blocks of second-rate quality appropriately higher.

As already described, different products (half blocks) can be treated in one layer. This can also be taken into account for handling. To support accompanying quality control, the robot can also be programmed to remove previously earmarked specific sample blocks from the production and to make them available to quality assurance – without having to interrupt ongoing production. Special horizontally interlocking block shapes (e.g., double-T blocks) can also be handled. Additional functions include removal of two adjacent half blocks and replacement by a whole block, as well as recognition and placement of missing blocks or placement of plastic sheeting with the aid of a fully automatically grasped sheeting-covering process.

The possibilities are virtually unlimited and can be fully adapted to the requirements of individual production lines. The time required for positioning a new layer of products for inspection (e.g., by a board feed system provided by the manufacturer) can partly be utilized by the robot to further optimize the entire process.

Handling by industrial robot can be just as flexibly configured as the inspection system, and the special functions can be activated or deactivated to suit a specific product. Intuitive operation by touch panel, including job and formulation administration reduces the time required for changing between various products. This makes the system also explicitly suitable for production lines on which various products are manufactured in small series. Operators of the plants are, of course, also able to configure new products on their own and combine the handling of special functions to suit their own needs.

The company Ibea has built a reference plant for manufacturer of concrete blocks; this plant has been in operation for some time without problem and has increased production efficiency by 40 %. For this plant, Ibea developed and installed the entire final system, the inspection process and final packaging functions.

Ibea GmbH
Kleine Bahnstr. 8
22525 Hamburg/Germany
+49 68 98 87-0

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