Press Release



(Press Release, April 2010)

Automatic regulation of feed bowl amplitude

Even miniature screws do not step out of line


Miniaturization: New generation of feeding machines delivers top processing reliability

The tide of ever smaller, ever lighter electronics cannot be stopped. Whether a mobile phone on your wrist or an electronic controller for the petrol saving start-stop-system in vehicles, the demand on engineers is always the same: Maximized potential in electronics for minimum weight and size. In all areas of industry the answer is miniaturization. This creates another challenging task for automation experts. Every day in industrial production millions of screws are assembled and of course even the tiniest of screws must be analyzed for the utmost processing reliability.

Screw joints are again in style and screwdriving technology is currently experiencing an upturn. In times of shortage of resources and environmentalism, system designers must stay abreast of new demands: Devices should be repairable and recyclable. Although reworking is almost impossible with other joining technologies such as gluing and laser welding, this is just one of the advantages of screw joints: A screw can be removed without damaging the joined parts. Therefore screwdriving technology is becoming ever more significant in assembly applications.

The trend of miniaturization is also seen in the screws themselves which are getting smaller and smaller. However miniature screws set higher demands on the assembly system technique, making it more complicated: Tiny screws are difficult to handle manually and consequently the use of an automated screw feeding and handling system offers greater efficiency and processing reliability. At the AUTOMATICA 2010 trade fair which takes place in Munich, Germany in June, the screwdriving and automation specialist DEPRAG SCHULZ GMBH & CO. KG is presenting the new generation of screw feeding machines: the series 6. The machine fulfills all requirements of a precise and reliable feeding cycle and separation of screws, even miniature-screws.

For many years DEPRAG has been a specialist for vibration drives to transport screws, threaded pins, bolts, rivets, nuts, washers, O-rings and other small parts. The vibratory drive feeder functions as follows: A vibratory magnet beneath the feed bowl is connected to alternating current, a spring set and an integrated regulating device. These cause a micro directional, high frequency, wave-movement in the bowl which transports the parts around the bowls spiral.

In traditional feeding systems it is generally the difference with the feed rate, which causes the most problems during screwfeeding. Besides temperature differences in the feed-system or its surroundings, it is predominantly the continuously changing fill level in the feed bowl and the subsequent changes in volume, which alter the feed rate. Result: The components are not presented reliably and cannot be supplied within the required machine cycle time. Up to now technical difficulties attributable to altering volumes in the feed bowl could only be solved with great expense and effort. Part hoppers and fill level sensors have to be added in order to maintain a constant volume of parts in the feed bowl

DEPRAG's main aim when developing the new generation of screw feeders was to combat the issue of the fluctuating feed rate. The following measures were taken, resulting in improved function and processing reliability: A measurement transducer reads the vibratory amplitude in the vibratory bowl and the series 6 screw feeder automatically regulates itself independently from the fill level and ambient temperature! Sales manager Jürgen Hierold emphasizes: “With our series 6 screw feeder the screws are always transported in time and at the same speed to the separator.”

Miniaturization presents a difficulty for traditional screw feeders. If the subject feed parts are very small, the feed bowl contains more individual parts, which in turn influences the volume. In order to achieve functionality, a relatively high oscillation amplitude must be generated. The individual screw on the other hand is very small and therefore very light. Under heavy oscillation it becomes too active in the bowl and this impedes the ability of the feed system to bring the screw to the point of separation in sequence with the assembly cycle. In this case too, automatic control of the oscillation amplitude is the ideal solution. Whether in complex automated production within stationary assembly systems or applied manually with hand held screwdrivers, the series 6 screw feeders reliably “blow-feed” every screw for assembly without fluctuation in the feed rate.

The new generation of machines also has other notable advantages. The Series 6 screwfeeding machine operates user-specific, i.e. it can be adapted to the individual speed of the worker. In contrast to standard feeding systems, where a change of operator preference parameters can only be carried out by electrical technicians, a RFID-Interface-System (Radio Frequency Identification) enables up to 10 workers to be registered to the machine controller by the operator's chip. Their specific personal parameters, entered once in the convenient display, are instantly called up at the start of the shift. So, once an Operator has been identified by his chip, the personal preferences are activated. The screw feeder then works within the operator's rhythm. The Result: The team's atmosphere is positive, no one feels held back by their colleagues and no one feels overburdened. Acceptance of the feeder system as a part of the team increases efficiency.

Improved functional processing reliability and increased user-friendliness through innovation and redesign of their existing product families are DEPRAG SCHULZ GMBH & CO. KG's answers to the growing demands of the industry for mass-production. The longstanding expertise in the field of feeding technology is embodied in the various advantages of the new screw feeder. The respective controller has also been thoroughly modernized. The machine parameters can easily be altered on the display and keypad. Feed bowl run-time, air push, new cycle delay or minimum screwdriver run time can be simply changed by the operator in the clearly defined menu with a two line text display. Soft start is also an option: In this case the optimum acceleration (ramp-up-rate) of the vibration intensity is automatically calculated by the machine.

Additional diagnosis functions, via sensor technology, are optionally accessible Troubleshooting messages, available in several languages, clearly appear in plain text. When the feed bowl is empty the message “fill level” is shown on the display. If a screw has been shot through incorrectly then the error message “screw presence control” appears. Part- and daily counters, as well as the measurement of assembly time, add to the processing reliability.

Operation start up of the new screw feeders has also been simplified. A duration test simulating the customer's serial production is carried out before delivery of every machine. The customer's specific operation procedure is accurately recreated. If, for example, 12 screws should be fed, then the assembly process needs to pause for work piece exchange and restarted thereafter; these specifications are pre-programmed into the controller by DEPRAG. This approach saves the customer time and money and increases reliability for the relevant application.

Additionally, all individual machine settings are saved to a file at DEPRAG, so that if service consultation is ever required the relevant data is immediately available.

Particularly, when the screw feeder is to be integrated into a production system, then the series 6 feeder has several advantages over competitive products.. The integrated sequence controller already includes a range of important functions: It can control and monitor several periphery devices such as valves and the feed bowl fill-level, as well as the screw-inlet or screw presence feature via the integrated interfaces. The customer no longer needs to spend time and effort programming a production system controller (PLC). Processing reliability is assured from the moment the first screw is “blow-fed” during the comprehensive factory test period.

There are now four separate start inputs available for the necessary screw distributors. Screw transportation can thereby be instructed more easily and adapted to applications via the system's PLC. Simple programming on the customer's PLC (only an impulse signal) is all that is needed. There is no more incorrect connection of periphery devices due to the use of a new permanent anti-short-circuit power pack, which can be used worldwide for all devices from 85 to 264 V and 47 to 63 Hz. Finally, the look of the new Series 6 feeder is impressive, with clear lines and angles. Each system comes with a robust outer housing that is insensitive to dirt. The sound-proof housing also ensures a quiet operating noise.

With this new generation of the optimized Screwfeeder Series 6DEPRAG has launched a product with top processing reliability and a wide range of standardized functions at a low price/performance ratio, states Bernd March, the Manager of DEPRAG's Mechatronics R & D Department.

DEPRAG SCHULZ GMBH & CO. KG, headquartered in Amberg, Bavaria, is represented with 600 employees in over 50 countries. For many decades DEPRAG engineers have been delivering innovative automation concepts and offer full service solutions for nearly all industries. DEPRAG not only supplies systems integrators with innovative screwdriving- and feeding technology, but also offers comprehensive solutions for automation. A “One Stop Shop”company, which assume full responsibility, is an advantage to any client especially when considering service and maintenance requirements.

Press Contact:

Dagmar Dübbelde
Carl-Schulz-Platz 1
D-92224 Amberg
Tel: 09621 371-343
Fax: 09621 371-199

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