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Safety Concept in Custom Machine Building
Safely Changing Robot Tools - Application Report on Synergies in Robotics and Safety Solutions

 

How the company HS Automation, a specialist for robot integration in custom machine building, utilizes the synergies of the two companies Robot System Products and Safety System Products for safe tool changes.

 
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Complete Solutions in Custom Machine Building

 

As a provider of complete solutions in custom machine building, our customers come from the automotive, food, or chemical industries, meaning that the variety of realized projects is steadily growing. Almost daily, new, customized automation systems are planned, developed, and manufactured.

 

Rising Safety Requirements when Using Robots

 

Through the use of multi-axis robot systems, greater flexibility has been made possible in recent years, not only at HS Automation but across the entire automation industry.

This opens up new avenues in the automation of applications because, unlike other systems, a robot can handle multiple tasks. In order to fully utilize the flexibility and cycle time of the robot, automatic tool changes are performed in many cases. This allows a single robot to take over multiple tasks within the process chain.

It was precisely this request that a TIER-1 supplier brought to HS Automation. However, new possibilities often go hand in hand with new hazards. These are described in the safety standard EN ISO 10218-2, published in 2011. Here, the user receives detailed assistance in order to fulfill the requirements of the Machinery Directive even in systems with robot systems. Among other things, the requirements for technical protective measures on tool changer systems are specified. Accordingly, the tool changer system must not open even in the event of a power supply failure, e.g., pneumatics, since dropping the tool plate along with the tools could cause serious personal injury and property damage.

The changer systems from RSP are therefore built in such a way that they can absorb all dynamic forces even in the event of a loss of power supply, without losing the tool. However, it must also be ensured that the changer system is completely closed before the robot begins to move. Here too, the tool changer from RSP offers the decisive advantage.

 
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The Patented TrueConnectTM Locking Process

 

The inherently safe mechanical design is engineered in such a way that the electrical contacts on the inside of the changer only close and provide feedback when the changer system is mechanically locked in a safe state. This also protects the contacts from wear and dirt. In the "TrueConnect" locking process, developed and patented by RSP, the tool plate and tool changer are docked via a ball system.

In this process, the tool changer is automatically centered in specially machined cavities on the tool plate. As a result, dynamic forces are absorbed and slight misalignments are corrected, guaranteeing a very high repeatability and reliability with minimal signs of wear. Mixing up the tools is defined as a further hazard in EN ISO 10218-2. This repeatedly leads to misuse, as tools are rearranged manually.

Together with the partner company SSP – Safety System Products, an opportunity was created to also monitor the end position of the tool in the tool stand in a safety-oriented manner.

 

Safety Sensor Comes from SSP

 

For this purpose, HS Automation utilized the SAFIX safety sensor. This sensor stands out not only due to its compact design but also makes use of state-of-the-art RFID technology. With its high coding level according to EN ISO 14119, it also offers high tamper protection. Once taught to an actuator, the sensor can only be actuated by that specific actuator. Thus, the tool stand from SSP not only checks whether a tool is present but additionally verifies whether the correct tool is located in the corresponding stand. This function is decoupled from the robot, which significantly reduces the mechanical stress on the components and the programming effort.

Another challenge was the tight space conditions, as the tool stand is located close to the safety fence of the robot cell and is therefore difficult for the robot to approach. When picking up and placing down the tool, the robot must therefore navigate around the tool stand at an angle of 90°. However, with the RSP tool stand, even this requirement should not pose a problem. Thanks to the 3-point mounting with tapered pins and a guide pin that prevents tilting, the tool can be placed down and picked up safely and without vibrations. The non-contact safety sensor SAFIX can be approached by the actuator not only from the front but also from the side, enabling entirely new application possibilities. Available in 3 different versions with a choice of low or high coding levels according to EN ISO 14119, it offers high tamper protection.

 

More about the SAFIX Product

 

SAFIX can be connected in series up to 80 times without any significant increase in response time, allowing it to be integrated into systems with the highest safety level PL e according to ISO 13849-1. The OSSD signals also allow for the detection of cross-circuits. Via an 8-pin M8 connector, SAFIX can be easily connected and thus perfectly integrated into the existing environment. Diagnostics are user-friendly via a three-color LED display, enabling quick maintenance and commissioning. Thanks to two different actuators, standard or very narrow, SAFIX can be mounted quickly and easily on a wide variety of applications, whether it is a hinged door, a lifting gate, or a standard industrial aluminum profile.

 
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