Sensor-controlled EC servo screw-driver - now even better

In the quest to manufacture higher quality products faster and more cost-effectively this unique exhibition will be showcasing a host of innovative solutions and the latest trends in product process optimisation.

In the screw-driving technology section, on stand 311, Hall A1, DEPRAG SCHULZ GMBH u. CO. will be presenting the latest generation of its successful MINIMAT-EC servo screwdrivers.

This 311E series of transducer-controlled screwdrivers, with its AST40 sequence controller, replaces the current EC-Servo system which has been proving its worth over many years in a wide variety of applications. Transducer-controlled screwdriver systems are used anywhere where there is a requirement for maximum process reliability.

With highly sensitive screw assembly tasks such as those classified as category A in VDI Directive 2862, which specifies that where there could be a danger to life and limb, maximum precision is required from the screw-driving systems. They should be equipped with a direct measurement system. Traceability of the assembly results must also be assured. DEPRAG EC-Servo technology meets all these requirements.

Sales manager Jürgen Hierold quoted American inventor Thomas Alva Edison: "If there's a way to do it better - find it".

Explaining, he pointed out: "Our new 311E screwdriver series is a system that we have developed entirely in-house. It incorporates all the experience of EC technology that we have gained in the past, and improves on areas where our users wanted extra functions or general advancements.

The screwdriver series consists of three components: the 311E screwdriver, the sequence controller and a motor cable.

Hierold highlighted the main features: "The system is reliable, flexible and very efficient."

The 311E screwdriver was developed and tested for heavy-duty industrial use. Robust, brushless, high-performance motors with resolver commutation provide reliable power to the screwdriver function.

Signal transmission is fully digital via a single cable to the screwdriver.

"Integrating signal and power transmission fully into a single cable less than 11mm in diameter has enormously simplified handling," Hierold said.

The connection plug to the screwdriver is appropriate for harsh industrial environments. The passively cooled motor control system channels away operating heat directly through an integrated heat sink. Its fanless operation reduces maintenance requirements.

Flexibility, economy, reliability, its data logging and communications capabilities - all these features mean that opting for an EC industrial screwdriver is an easy choice to make.

"When developing the latest generation our engineers considered all these features in minute detail. The new series is particularly distinctive for its many different variants. The controllers are available as single controllers or multi-channel systems for integration with larger control cabinets."

The AST40 accommodates several programming, control and data-logging interfaces. Multiple screw-driving programs (120 via 24V I/O, and virtually unlimited via fieldbus) are available with all standard industrial screw-driving sequence command sets.

The brushless EC motors ensure outstanding dynamics and high peak torques - the ideal combination for industrial screw-driving assembly stations. The power density of the new screwdriver is double that of its predecessor. It means that a screwdriver can achieve maximum torque of 50 Nm with a housing diameter of just 36 millimeters.

Its machine capability index of CmK 1.67 - specified for many applications - is achieved with a tolerance of ±7 percent. The DEPRAG screwdriver is distinctive for its compact size and the modular structure of its components. The only maintenance needed is on the gear module and the drive module. With its modular design any repairs can be made on site by replacing individual sub assemblies.

The new screwdriver generation is available in four models, each with several torque ranges. The range extends from the 311E27 screwdriver (27 mm diameter) for torques starting at 0.2 Nm, to the 311E63 screwdriver (63 mm diameter) for torques up to 500 Nm.

"The range of variants means we can offer a solution for every screw-driving task," Hierold said, "and the prices are attractive too."

"Despite the considerable increase in the range of functions and features, we have been able to keep the prices in line with our current EC servo system."

The industrial screwdriver is controlled by a similarly enhanced sequence controller - the AST40. Not only does it permit free programming of screw-driving processes it can also quickly and easily compile specific user screw-driving programs using the embedded command set as a platform. The control parameters allow the user to fine tune the faster run-down sequence to the particular assembly task.

The TFT display unit is distinctive for its high 800 x 600 pixel resolution, providing good readability for user. The touch screen ensures that process data such as screw-driving results, screw-driving curves and system parameters can be accessed quickly. It is very simple to manipulate the required functions.

And the AST40 can do even more that this: "The AST40 has an integrated web server, which means that it can communicate with a PC without the need for additional software" said Jürgen Hierold, explaining the advantages of the cutting edge DEPRAG control system.

Optional fieldbus interfaces such as PROFINET, PROFIBUS and EtherCAT permit communication between the PLC and the PC for programming, data capture and analysis purposes.

The AST40 stores operating data records for the previous seven working days, regardless of the duty cycle. The data analysis functions are compatible with standards of today's quality management systems.

"All the required quality control data are made available to users," Hierold said, "which means that process reliability can be constantly analysed and optimised."