Standardized automation concept for industry 4.0
Industrial production places the highest demands on the performance, quality and reliability of the welding machines used. The safety of the operator also plays a decisive role when using the machines and systems. Accordingly, the regulations and requirements that manufacturers must meet are correspondingly high. Welding machines and special systems from DALEX Schweißmaschinen GmbH & Co. KG provide tailor-made solutions that increase productivity and optimise processes, while at the same time ensuring that the machines are designed with safety at work in mind. With extensive measures, the welding experts from Wissen ensure the best possible protection for operators and maintenance personnel.
For more than 100 years DALEX Schweißmaschinen GmbH & Co. KG has been developing and building powerful solutions for resistance welding. In addition to the established standard machines, the knowledgeable manufacturer now concentrates mainly on coordinated special systems, robot cells and high performance welding tools. DALEX has developed the PMS series especially for industrial requirements in spot, projection, longitudinal and transverse seam welding. Due to the modular system, the welding machines can be adapted to complex welding tasks. They are therefore particularly robust, long-lasting and reliable in the challenges of modern metalworking - and protect the user with very high standards.
Recognizing and minimizing risks
"Since the introduction of the European Machinery Directive in 1995, every machine manufacturer is obliged to carry out a conformity assessment and CE marking of its machines that are marketed in the European Economic Area - and DALEX is no exception with our PMS series", explains Dr. Henning Grebe, head of design at DALEX Schweißmaschinen GmbH & Co. KG. An essential mandatory element is the risk assessment of the machines according to DIN EN ISO 12100, in which all potential risks arising from the machine must be identified. "What would be the extent of a damage and how often or how long does the user stay in the endangered area? To what extent is the danger identifiable and can it be avoided? We then constructively minimize the identified risks and take appropriate protective measures," says Dr. Henning Grebe.
For this purpose, DALEX examines and evaluates all the functions of the machines - particularly the safety-related functions of the machine control system - and determines the required performance level (PLr) based on the harmonised standard EN ISO 13849-1. The PLr is then checked on the machine for the solution that has been implemented. The simple formula is: The implemented performance level (PL) must at least correspond to PLr. And the higher the implemented PL, the safer and more reliable the function. DALEX calculates the PL using SISTEMA software, which is published by the DGUV Institute for Occupational Safety and Health.
"In order to conform to the high safety requirements of the Machinery Directive, Performance Level D is the benchmark for the welding drives in the PMS range", says Dr. Henning Grebe.
Efficient and safe solutions for welding drive and control
In order to achieve the high PL, DALEX designs safety-related functions that control endangering movements of the welding drive in two channels, both electrically and pneumatically. For example, the pneumatic welding cylinder movement is controlled by a 5/2-way safety valve block with two position-monitored valves. For quick and easy installation, the entire pneumatic installation is pre-mounted on standardized mounting plates.
On the control side, DALEX consistently uses the fail-safe version of the Simatic S7-1200F in the PMS series. Dr. Henning Grebe explains: "We used to use the LOGO! miniature controller in conjunction with hard-wired safety switchgear. This was not only complex, but also, unfortunately, defective in some places. The Simatic S7-1200F controller is the perfect solution for us. It increases the safety standards and offers us many possibilities for standardisation.
Easy adaptation of the machines - even retrospectively
DALEX was able to standardise the structure of the control cabinets for all machines in the PMS range, which enables series production on mounting plates as with pneumatic installation. The modular design and standardisation has many advantages both in the manufacture of the components and for the user: "If, for example, additional tool functions are required on the machine, these can be integrated in the control cabinet without the need for complex new wiring. For the required safety or standard functions, only additional inputs and outputs of the controller are assigned and the programming of the controller is adapted. In addition, the Profinet fieldbus system used enables simple connection of further decentralized peripherals," says Dr. Henning Grebe.
In addition, all PMS machines are equipped with a Simatic Basic Panel KTP 400 and standardized software. The visualization achieved through this significantly increases efficiency. Both operators and the maintenance and service personnel can easily start up the machine via the panel, select and change the parameterization - i.e. the welding programs - and, if necessary, carry out a quick diagnosis thanks to the plain text messages.
The way to Industry 4.0
"With these extensive measures, we are not only making our welding machines of the PMS series safer, but are also creating links to Industry 4.0", adds Dr. Henning Grebe.
Photo 1: DALEX has developed the PMS series especially for industrial requirements in spot, projection, longitudinal and transverse seam welding. With Performance Level D for the welding drives, the high safety requirements of the Machinery Directive are fulfilled.
Photo 2: The pneumatic welding cylinder movement is controlled via a 5/2-way safety valve block with two position-monitored valves. The two-channel design ensures the high PL.
Photo 3: The Simatic S7-1200F controller raises safety standards and enables DALEX to standardise the design of the control cabinets for all machines in the PMS range.
Photos: DALEX Schweißmaschinen GmbH & Co. KG