Industry 4.0 solutions require highly flexible and modular production machines. A prime example is the CresaLine small parts assembly line manufactured by the Swiss company Credimex, which can be expanded by adding individual processing stations to meet specific customer requirements. Beckhoff's XTS system offers similar flexibility, enabling the connection of the most diverse range of processing modules through software functionality.
“The CresaLine modular automation platform, built by Credimex, a company located in Alpinach, Switzerland, consists of intelligent machining stations that meet the requirements of Industry 4.0 production sequences,” said Roger Schelbert, co-owner and head of motion control technology at Credimex. “The modularity of the machine allows us to efficiently produce different products. One of the biggest advantages is that it allows for the automation of difficult and complex processes that previously required manual execution. Each machining station in the standard system can be used in CresaLine. Therefore, handling and pick-and-place processes, as well as assembly and testing stations, can be integrated as needed. These stations are connected by Beckhoff’s XTS system. A workpiece carrier, 250 mm long and 70 to 90 mm wide, is mounted on its mover. These carriers can handle products of the same size or multiple smaller products. This makes the system very flexible and ideal for the watchmaking and electronics industries, as well as motor manufacturing and medical technology. A particular advantage of this system is its ability to produce batches of a single size and quickly changeover to produce other products.”
Decoupling the conveyor system and the machining station is particularly important in the assembly of small parts.
XTS — Highly flexible in both functionality and layout
The current CresaLine system, consisting of eight stations, uses an XTS magnetic drive flexible conveyor system comprised of nine 250mm-long linear motor modules. These nine 250mm-long movers run on this track as workpiece supports. The CresaLine Starter is only half the size of the CresaLine, but uses the same design. This demonstrates that XTS offers significant flexibility in motion control, not only in replacing mechanical components but also in terms of software functionality. Furthermore, the system configuration can be easily adjusted according to user requirements: specific movers can be applied using either the XTS magnetic plate and encoder system or the customer's own guide rails. Moreover, Credimax implements a linear XTS design in this case, rather than a circular one. Roger Schelbert explains, "A key feature here is that the movers in the CresaLine Starter are lowered at the end of the XTS section and restarted via a three-axis linear system. In larger CresaLine systems, the movers are moved to the opposite XTS conveyor line via a cross-conveyor system. Therefore, the return section can also be used for assembly stations. This allows us to design a very compact system to meet the market demands of small assembly lines."
Roger Schelbert believes that the compact system design is easy to expand: "Thanks to the modularity of the hardware and software, XTS can also be easily configured to achieve other machine layouts. For example, the mover return section under the worktable can be replaced with a cross conveyor or a ring XTS system to integrate more filling and processing stations."
Replace hardware with software functionality
Motion control functions that often require significant hardware costs can now be achieved in a remarkably simple way through software using XTS. Roger Schelbert cited several examples: "The production process can be adjusted according to the added machining stations simply by configuring the software, without any modification to the hardware. In addition, motion and positioning can be precisely controlled, eliminating the need for the hardware components that were previously required. For example, XTS no longer needs to lift the workpiece from the traditional conveyor belt to achieve the positioning accuracy essential for machining. Therefore, much simpler machining stations can be achieved using fewer motion axes."
Especially for the assembly of small parts, many factors play a crucial role in achieving the required precision. Here, even slight vibrations can cause problems, which Roger Schelbert believes is another advantage of XTS: "The transport system operates completely independently, with no mechanical connection to the individual machining stations. This means that there is no vibration, such as that generated by the return motion of the transport robot, that is transmitted to the XTS system and other stations. This has a very positive impact on achieving machining accuracy."
The flexibility of the movers also has positive effects, as Roger Schelbert explains: “First, movers can be specifically designed for a particular application—long or short, large or small—depending on how much space is available for their movement or how many products each mover needs to transport. So far, we have focused on the micro-assembly field, from 500 chips per workpiece carrier to up to 3 or 4 large assemblies. But flexibility also means that each mover can be removed from the transport system and put back in when needed. For example, when necessary, a special mover equipped with a battery-powered camera system drives through the entire process, checking the accuracy of each processing station and saving the offset correction again for maximum accuracy. This is very important if there are large temperature differences, for example, in the morning or at noon.”
Diversity is a prerequisite for achieving Industry 4.0.
Even now, CresaLine already meets the requirements for implementing modern Industry 4.0 solutions. For example, the production efficiency of each process can be tracked at any time because each run is timestamped and stored in a database. The main requirement is a unified, modular machine solution based on individual intelligent machining stations and flexibly connected via XTS. Roger Schelbert explains, “For production with a batch size of 1, we can determine which process steps are required for each item based on the order details. On the one hand, this is achieved by linking the C6920 central controller and CX5020 embedded controller used by each machining module to the customer’s ERP system. On the other hand, the individual controller for each mover, along with the uniquely assigned product, plays a crucial role, as products processed in this way become intelligent and can guide themselves through the assembly process. As I mentioned earlier, another relevant aspect is the camera movers used to calibrate the entire process chain. This information can be directly used to correct the process sequence as early as possible before unacceptable quality defects or excessive defective parts occur.”
The XTS linear conveyor system has a mover return section under the worktable.
Roger Schelbert, co-owner and head of motion control technology at Credimex
He stated, "XTS allows us to design particularly compact machines, thus supporting optimization."
Development within existing product areas.
