PIA Automation's compact CGM rotary indexing tables needed an upgrade. Their fixed profiles neither allowed for alterations nor performance improvements. Having collaborated with Pilz for 15 years, the upgrade was once again entrusted to the automation experts headquartered in Osterfield.
Combining Pilz's PMCprotego S safety card with the existing motion solution improved safety as a first step, but it didn't increase productivity as expected. An alternative control and safety solution was needed. This led Pilz to implement the PMCprimo motion control system with integrated drives at PIA Automation: this system handled equipment automation, including motion management of multiple servo axes. A single electronic spindle could flexibly combine up to 32 axes with a cycle time of 1 millisecond (or longer cycles with more axes) to complete simple CNC tasks. Some commonly used functions (such as cam functions) were stored as function blocks. These extremely short cycle times were achieved because the PMCprimo C motion control card provided a high-performance, real-time EtherCAT master interface.
Another factor contributing to increased productivity and efficiency is Pilz's PMCprimo motion control system, which features an integrated development environment compliant with IEC 61131-3 for programmable logic controllers (PLCs) used for application development in industrial automation. Customers and users do not require a single-user license; they can download the software directly from the manufacturer and begin programming immediately.
Combining performance, flexibility and security
The cam disk function of the electric servo drive is electronically implemented. While traditional systems make it nearly impossible to change operating conditions, Pilz's drive technology maximizes flexibility: operators simply select different programs based on the required curve profile, and the system can quickly execute new tasks. PIA Automation's new CGM rotary indexing table is a fully automated servo-controlled machine with multifunctionality and modularity. The inserts are driven and moved purely electromechanically. One drive shaft controls the movement of the rotary indexing table, and two other drive shafts control the vertical and horizontal strokes respectively. "The machine assembles components into mechanical products adorned with filigree, such as microswitches, plugs, or razor parts, through 16 stations. Components are transported via conveyors, workpiece carriers, vibrating conveyors, and handling devices," explains Stefan Unger. The rotary motion of the indexing table is decoupled from the movement of the inserted object, injecting optimal flexibility into time-consuming or routine processes.
The highest precision is especially required when assembling very small parts. When using the emergency stop function or opening the safety door during operation, the shaft must maintain its mechanical cohesion and operate asynchronously at all times. Simply allowing the shaft to stop uncontrollably due to inertia will cause serious damage to the workpiece clamping device.
Replacing hardware with simulation
The PMCprimoDriveP motion control system and three PMCprotego S safety cards for motion monitoring are responsible for the overall motion and safety management of the servo axes.
PMCprotego D servo amplifiers typically have two option slots: one for a motion control card and the other for a security card. PIA's CGM machines use three PMCprotego D servo amplifiers, each equipped with one PMCprotego S security card. One of the servo amplifiers is also equipped with a PMCprimo C motion control card.
This solution electronically simulates a traditional mechanical cam disc; PMCprimoC receives corresponding data from a higher-level control system. A virtual axis that can move within a range of 0 to 360 degrees replaces the main spindle. The mechanical axes are synchronized with this virtual axis: for example, the rotary indexing table moves between 0 and 90 degrees (in one-degree increments), the vertical axis moves between 90 and 180 degrees, and the horizontal axis moves between 180 and 360 degrees.
If intervention is made without authorization or the emergency stop button is pressed, the system will react within milliseconds. Monitoring by the safety card ensures that the three axes are braked in unison by the electronic master station, maintaining their mechanical cohesion at all times. Releasing the emergency stop button and pressing the reset button allows the system to resume operation from its stopped position without first approaching the initial position.
The PMCprotego S plug-in safety card includes functions such as Safe Torque Off (STO), Safe Deceleration, Safe Operation Stop (according to EN 61800-5-2), and Safe Stop. These safety functions are designed to achieve performance levels of PL e and below, regardless of the type of motor and encoder used.
Give users more freedom
In summary, the upgrade to the CGM rotary indexing table has been invaluable for PIA Automation: the rotary indexing table now boasts nearly a 50% increase in cycles per minute, significantly improved reusability and technical availability, and the automated machine is well-suited for production with short run times. Shorter changeover times optimize processing time, and with only three servo motors and electric grippers, energy consumption is relatively low.
“Pilz worked closely with our engineering department to manage and implement the entire upgrade process, contributing significantly through advice, hands-on experience, and extensive expertise. The solution provided by Pilz was impressive because, in addition to integrating the EtherCAT master and PROFINET slave, it connects to a more advanced system to record spindle runtime,” said Stefan Unger of PIA Automation with admiration.
