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Riveting technology as standard or custom solutions

Two riveting processes, as well as various automation levels for flexible production

Joining technology is an essential fabrication ingredient to securely join two components, or to ensure their mobility. This could involve hinges or joints for the automobile or furniture industry, products for medical devices, household devices and the electrical engineering industry – they all need these technologies to produce and also make products with the highest possible precision.


When manufacturing safety relevant, function specific, fixed, mobile, or visually appealing joints, the know-how and "Riveting machinery" product segment of Dunkes GmbH (Kircheim/Teck) provides a variety of options to manufacture riveting connections in various designs.


Starting with manually operated riveting units, wobble riveting, radial riveting, as well as press riveting technologies are available for a variety of requirements. Automation and add-on facilities are available as upgrades, such as rotary indexing tables,  sliding tables, material handling equipment, workpiece pallets, quality monitoring controls, for instance for force-travel logs, rivet height sampling, etc..


An example for this performance range is a riveting cell that is equipped with units for wobble and radial riveting processes. An additional processing unit, and electromechanical lead screw, is used for joining and coining processes. All units are programmed with a common control, and monitored with safety technology.


The advantages of the wobble process are short cycle times and cost-effective riveting units. The radial riveting process is used specifically on high quality, galvanized or surface coated rivets. The cycle times are slightly longer due to the nature of the process.


A benefit for the customer is that both riveting processes, as well as the electromechanical lead screw units, are supplied from a single source. The classic press riveting process is accomplished with pneumatically or mechanically driven riveting machines with automatic rivet feeds. This process in particular that she is extremely high bearing stresses.


Automatic riveting plant with three stations and rotary indexing table

The shown riveting cell is equipped with three stations, including a mechanically indexing rotary table. All units are positioned on a rugged base frame. The rotary index table is designed and configured depending on the task. Loading and unloading can be accomplished manually or fully automatically to reduce idle times.


As a matter of course, the plant is equipped with a two-hand safety control. The individual units are programmed with respect to feeds, force, riveting cycle, etc. using a touchpad. A safety oriented SPS that monitors all safety features works in the background. A light curtain is installed upstream for cycle specific loading and unloading.


The basic equipment of this plant includes a wobble riveting unit with an adjustable head, and a riveting force of 7.5 kN for rivet diameters of up to 7 mm. An additional unit for radial riveting is also height adjustable and has a riveting force of 7.5 kN. Because these are installed on an NC controlled X/Y table, any position can be reached and riveted. The limit position of the dedicated riveting lead screw is controlled with a motorized, adjustable depth stop. This enables precisely reproducible limit position accuracy.


A coining unit with electromechanical stroke lead screw and a press force of 100 kN is available for additional processes, such as part marking. All riveting and press forces are  specified by the control, and compared with actual values.


Due to their modularity, all units can also be conveniently integrated into the customer's custom plants, and can be configured and delivered on short notice as standalone workstations or as modules.


The operator enters process specific parameters such as the riveting force, stroke and XY travels, including the process parameters of the coining station, on the touch panel. The screen can also visualize the status of the respective station, or the entire plant. Fault messages are also accompanied by suggested remedies. Riveting forces can be monitored with the help of a min/max envelope in the force-travel diagram, and can be forwarded for documentation analysis to an external computer or to a printer using a serial RS-232 interface. Up to 800 programs can be stored and retrieved when needed.


Flexible uses

Many applications in the automobile, electrical, EBM and hardware industry, in mechanical engineering and other industries, frequently require additional processing steps during component manufacturing, such as part marking processes involving  coining, engraving, or colour additions, as well as torque inspection, assembly work, etc. Proven components and automation elements are available for these tasks, which can be integrated into the production process flow surrounding the riveting units.


Because of the modular design and the broad variety of control options, the user is assured – starting with competent process consulting – that they will be supplied with properly matched components for an economically and reliably working plant from a single source. Riveting trials are performed with original customer components.


The product line supplied by Dunkes includes riveting machinery for riveting forces from 5 kN 120 kN. Far more than 10,000 supplied units and plans provide a high degree of know-how and production technology expertise. We develop the design and software, and fabricate and assemble all plants in-house. Our in-house service staff ensures subsequent support domestically and internationally. The riveting results are documented in detail, and relied on as the basis for the decision-making process. Consistent design updates of riveting machinery and the pneumatic press product line,  supported by industrial design rights and patents, gives customers the assurance that they will continue to have on-demand access to comprehensive technologies and knowledge bases.

Basic concept of the riveting plant with rotary indexing table configured for wobble and radial rivets. An electromechanical stroke lead screw is incorporated for part marking (coining).

Basic concept of the riveting plant with rotary indexing table configured for wobble and radial rivets. An electromechanical stroke lead screw is
incorporated for part marking (coining).