EKRA is part of the ASYS Group since 2005. The specialists for screen and stencil printing provide solutions for applications in the area of SMT, hybrid thick film and advanced packaging. The Portfolio ranges from manual laboratory printers to fully automatic inline systems and complete customer-specific production lines. Based on the broad and versatile product portfolio, EKRA became an hounoured industry partner for printing solutions of any kind.
According to Torsten Vegelahn, product manager at EKRA, the company is on the right track into the future with developments for future technologies, such as electric mobility, the interaction of green energy, solar cells, hydrogen and fuel cells, and the present topic 5G. The requirements for a modern SMT line are increasingly shifting towards availability and greater autonomy. Especially now during Corona times, when many companies for security reasons have split their workforce, it became an enormous advantage for the production, if the line operates with a few operators and hand movements only. Required are production facilities that can operate without interruptions, around the clock in shifts. Here at EKRA, further steps on the way to a smart and autonomous factory.
SERIO on the way to autonomy
The EKRA stencil printing systems are on the way to a new level of autonomy. The aim is to enable these machines to carry out various task like almost independently changeovers without requiring significant operator intervention. The machine simply calls the operator to the right place at the right time, a permanent presence is not necessary. This is another essential step on the way to autonomous/ smart factory. EKRA has been able to build on these competences for 6 years, so the company has a long experience in the field of autonomous machines. The following features underline this once again:
- various print formats up to 610 x 510 mm with constant cycle times
- iQUESS squeegee quick-exchange system
- Paste height control with automatic verification of the process
- Multiclamp with roller transport
- Scalability and expandability with numerous other options
- Product changover in less than 2 minutes
- NPI in under 10 minutes without Gerber data
Two features of the EKRA printers should be emphasized here as the driver for this autonomy: on the one hand, the fully automatic setting, verification and removal of pins with the APS system, and on the other hand the complete integration of the iSET system, which ensures product changeover and traceability through RFID.
In the SERIO printing system the smart Option APS (Automatic Pin Set) can be integrated. APS not just simply places and removes pins, it furthermore takes care about verifying the propper position during the production cycle. APS uses the build in camera system to verify correct pin position. APS is also directly linked to the MES system, so that processes can be automatically started and constantly monitored. The MES, for example, triggers a product change, the new product is automatically loaded. The support pins are automatically cleared with APS, the transport width is adapted to the new product. The system then automatically sets pins again, checks their position and rearranges them if necessary. Before the printing process is started, the setup is checked, which has now been made smart thanks to RFID technology. This results in a consistent process that can be carried out without further operator intervention.
Furthermore, EKRA print experts enable setup control by means of RFID in their systems. This means setup control now can be started at the push of a button, making verification process faster, easier and safer. With this solution EKRA lays the foundation for machine-material communication and thus the basis for the next level of autonomy: when machines make independent decisions.
The setup components are tagged and then mounted in the machine. The setup control is then started with the lid closed. All components are scanned and compared with the loaded production program – if everything is correct, production can start immediately. Setup control is carried out automatically and simply, thus errors are effectively avoided. The RFID communication is performed in such a way that only those tags are recorded that are located in the process area.
Setup control via RFID synchronized the flow of materials and information, by providing elements with a certain intelligence. The communication of components and machine thus not only enables the identification during the setup, but also the data exchange for further traceability aspects. With the help of RFID tags on the squeegee and on the stencil, the system know for example how many printing cycles have already been run and preventively indicates their exchange before any loss of quality occurs.
This together with the already mentioned capabilities enables the machine to work independently. This autonomy is supported by a paste dispenser with double cartridge, which guarantees a very long paste availability and reduces the machine interventions to a minimum, as well as the iROCS ability to provide stencil cleaning with a 17 m long paper roll. Both allow a continuous operation of up to 8 hours without operator intervention. The operator is supported by the SIMPLEX system, the well-known intuitive machine interface, which is enthusiastically accepted by the customers.
Process integration – EKRA’s core competence
Within the HYCON division, the screen printing experts of EKRA focus on special applications. They accompany the entire development process, starting from the first idea to the conception and to the realization with specialized expert knowledge.
One application which currently picks up speed again is printing functional layer for fuel cells. The production of hydrogen through electrolytic separation of water by means of electrical power is a promising method of storing energy. This energy might initially be generated by wind or solar power. The hydrogen can then be easily transported and used everywhere – in combination with atmospheric oxygen, the fuel cell emits electricity and water.
In fuel cell technology, a main distinction is made between high temperature fuel cells (SOFC – Solid Oxide Fuel Cells) and low temperature fuel cells (PEMFC – Polymer Electrolyte Membrane Fuel Cells).
Polymer Electrolyte Membrane or Proton Exchange Membrane Fuel Cells are mainly used in areas of electromobility where their low-temperature starting capability and dynamic power control can be used particularly well. They are known as low-temperature cells because their operating temperature is below 100°C, in contrast to solid-oxide fuel cells (SOFC).
Solid oxide fuel cells or high-temperature fuel cells are widely used for power and heat supply in buildings or as decentralized mini power plants. Due to the high operating temperatures ranging from 600 to 1000 °C, commercially available gases such as natural gas or biogas can be used instead of pure hydrogen. The resulting waste heat can be utilized for heating or hot water preparation, whereby the modules have a high overall energy efficiency.
Since a single layer of a fuel cell is usually about 0.7 Volt voltage, these layers are stacked, creating so-called stacks which then generate sufficient usable voltage.
With 0,7 Volt the voltage of a single layer fuel cell is comparably low. To reach higher values multiple layers are stacked. These stacks generated sufficient voltage for a vast use of applications.
The manufacturing process of the individual membrane and its subsequent stacking to form a powerful fuel cell module (stack) requires specific process know-how. Individual process steps are linked to form a powerful overall concept. As an established supplier for production automation, ASYS combines expertise in material logistics, stencil printing, laser technology and customer-specific assembly solutions with reliability and precision.
In regards to the production of both systems, SOFC and PEMFC, EKRA supports with expertise. When it comes to the high quality requirements of such systems, EKRA displays longstanding process experience.
In the anode-based concept, the SOFC is based on an oxide ceramic, for which ASYS can offer solutions for processing in both fired and unfired state. The materials used can be easily put into a paste form, so that all active elements and possible support layers can be applied by screen printing. By using different screen and process parameters, different materials are applied via an ASYS/EKRA printing machine. Thus the correct layer thickness and accurate deposit shape are under full control. The sealing of high temperature cells, both on the MEA and the bipolar plat, consists of temperature-stable material. Even this can be applied as a paste by screen-printing.
Proven Turnkey Solutions
ASYS can implement a whole series of process steps in the processing of the membrane electrode assembly (MEA):
- The process can be executed in reel to reel
- by laser cutting the membrane is precisely tailored, a clear marking can also be realised in this step
- membrane printing is an established machine concept at ASYS originating from the solar sector
- Firing or sintering is carried out in standalone or inline systems that are integrated into automation solutions
- the printing control is done via integrated Inspection systems (3D inspection) or weight control
- ASYS can draw on field-experience when it comes to material logistics for transport and storage
Noteworthy to mention is EKRA’s competence in traceability, which is supported by proven interfaces and software solutions such as PULSE.
For the production of PEMFC ASYS provides the equipment for the efficient production of the bipolar plates. During forming and welding of the bipolar plates, the planarity of the thin metal plates must above all be guaranteed in order to achieve a reliable gas sealing.
With the bipolar plate ASYS can also implement a whole series of process steps:
- Laser welding and the leak test of bipolar plates. There are stacks of cut sheets for anode and cathode side fed, automatically aligned by means of an optical systems , fixed and welded
- In stack assembly, stacks of Bipolar plates are connected to subplates, screwed or clamped
- In gasket printing, sealing materials can be applied using the screen printing process, uniform layer thicknesses can be achieved with ± 5 μm tolerance. Four bipolar plates can be processed at the same time with a cycle time of three seconds
- The gas diffusion layer (GDL) is coated by contact printing with a special coating method and subsequent inspection
- For transport and storage ASYS can rely on experience in Material Logistics
A selection of screen-printable sealing materials is available, which can be applied with the corresponding ASYS/EKRA printing machines in the shortest possible time in a uniform layer thickness. During stacking, the MEA and bipolar plate must be precisely aligned with each other in order to avoid leaks and to use the introduced fuel gases as fully as possible.
At laboratory status, tests have already been carried out on the surface printing of the porous gas diffusion layers (GDL) with catalyst material. The difficulty is the ink, in which the catalyst material isdispersed and which must remain on the substrate’s surface while not penetrating into the porous substrate structure. This can only be achieved via special drying methods. For an automated solution of these processes, above all the problems of substrate fixation during printing has to be solved, since standard concepts, like vacuum or clamping, are not available with the flexible and highly porous substrates. Furthermore, the complex drying cycles must be integrated into the machine, which requires a high degree of material reconciliation.
Lukas Sänger, Product Manager HYCON & SOLAR:
“Green energy solutions are the future. We strengthen this product range since years and look back on a lot of experience in the special printing sector. We know what matters now and in the future.”
Franz Plachy, Business Developer Hybrid & Special:
“We turn niches into markets. Thanks to our well-founded consulting and solution competence, we are optimally positioned for every topic.”
Torsten Vegelahn, Product Manager SERIO:
“With our developments we are on the best way into the future. We are prepared for future technologies, and already offer solutions that make a difference today.”