Dinsheim-sur-Bruche is a charming small town in historic Alsace, thirty kilometers from Strasbourg. The town invites visitors to all kinds of tourist activities, including trips to the nearby Vosges Mountains. Hardly anyone would guess that one of France's most innovative manufacturers of photovoltaic systems is located here. And yet it is: Voltec Solar has been producing photovoltaic modules in Dinsheim for more than ten years. In 2009, they installed a 30 MW production line in a 4500 m² facility that previously housed a sawmill. Due to growing demand, the company decided in 2019 to increase annual production capacity to 200 MW - and to invest in greater automation of the production lines along with it.
 

Complete production in-house

Voltec covers almost the entire manufacturing process and divides it into two major areas - the clean room and the back end. In the clean room, all the work is done to create the multi-layer solar panel. This starts with soldering the cells into so-called strings (strips), which are then placed by robots on glass with EVA film. Subsequently, EVA film is also applied to the back, as well as an additional backsheet film. A laminator now bakes everything in a vacuum so that the solar panel is encapsulated and protected. The next steps are the framing and the installation of the junction box.

Says Erick Valdez, engineering project manager: "We do this procedure almost completely automatically. Only some tasks that are difficult to automate are performed by employees. In addition, they help us check that all the work has been done correctly." In general, high quality is the be-all and end-all for Voltec, which is why they carry out a corresponding check after each production step. After assembly, for example, the sun is even simulated by means of a light flash to ensure that the module is generating the correct power. 1 5 For visual inspection, the panels are brought into the test position with a multi-joint arm

New concepts for greater efficiency

Next, the condition of the cells is checked - that is, whether anything has been broken or misplaced. This inspection process and the subsequent loading of the finished solar modules onto pallets used to involve quite a lot of manual effort. In order to increase speed and achieve the required productivity, Voltec had to make the processes more efficient and automate them to a greater extent.
Therefore, they contacted MiniTec: "We were looking for an experienced partner who could support us in our project. Important criteria were also a fast and flexible customer service as well as a high reliability of the equipment. MiniTec convinced us with its great experience in the field of photovoltaics and its good product and service quality," recalls Valdez.

High level of consulting and project expertise

A decision that Valdez did not regret: "The course of the project was very successful right from the start. Stefan Buchem as MiniTec project manager and his team convinced us with their high level of expertise and sensible concepts. We realized that we were dealing with competent people in whose know-how and experience we could trust. That was important, because the task was to design a completely new process. We had an idea, and MiniTec developed possible solutions with us and showed where improvements could be made. We gave them information and questions, and the quality as well as the speed of the answers were really satisfactory."

Check faster

The result was a solution that brought a significant increase in productivity: After checking the condition of the cells, the panels are lifted with a pneumatically driven multi-joint arm, brought into a vertical position and thus presented to an employee - the so-called "visual inspection." The employee compares the information on the control screen with the panel. Depending on the result, the panel is assigned to the appropriate quality level and given a corresponding barcode. Based on the classification, a decision is made whether to proceed to the next step or whether the panel should be sorted out and sent for inspection and repair.

"Classifying the panels in this way is very important for us to make sure we don't send defective panels to our customers," Valdez says. The inspection station is duplicated - while the operator is still busy inspecting one panel, the next panel is already entering the second station and being lifted. Once the inspection of one panel is complete, the operator turns around and can move directly to inspect and classify the next panel without delay. This has virtually doubled the throughput.

Fully automatic palletizing

After classification, the final sealing of the connection ("potting") takes place and the panel is loaded onto a pallet for shipping. Previously, two employees were needed to palletize the finished modules, lifting each module by hand onto the appropriate pallet. Therefore, this process was also very tedious.

Today, palletizing is fully automated with a multi-axis linear gantry. Initially, a robot was also discussed; however, in addition to lower costs, the gantry also had the advantage of a significantly longer reach. In order to test the suitability of the solution in advance, MiniTec first created a digital twin. This was used to realistically simulate and optimize the entire process before the system was implemented.

An effort that has paid off, because the speed of palletizing has also been increased considerably. When running in, the quality class is identified on the basis of the barcode on the panel, the panel is lifted and placed on the associated pallet. A height distance meter informs the gantry of the height of the respective stack - as an indication of when it is full and for precise placement of the module. When the loading capacity is reached, this is indicated by a corresponding light signal on the system and the pallet can be removed for shipping.

Goal achieved - new plans for the future

The MiniTec systems play a major role in significantly reducing the throughput time - today, a solar module is produced every 44 seconds. Erick Valdez: "Here we have advantages not only in terms of speed, because by classifying the panels in several steps, the result is now also much more reliable than before."

And because it is well known that standing still means going backwards, the manager is already thinking about the next measures: "The solar market is growing very quickly, and we are competing with Chinese suppliers. That's why we're continuing to look for ways to improve production and will tackle these as early as next year. MiniTec will of course be involved again; the company has shown itself to be an extremely reliable and competent partner. This is also evident from the short project time of just 4.5 months and the fact that the budget was strictly adhered to. Incidentally, MiniTec systems are already in use in other areas of Voltec, for example, for transporting the solar modules from the clean room to the backend."
Voltec considers itself well prepared for the future. The company specializes in installations with panels for large surfaces: "We are already the largest supplier in this segment in France and we want to further expand our position in the European and international market together with our partner Systovi in the future," says Valdez. The prerequisites for this are good, especially since Voltec places particularly high value on sustainability: "One big difference compared to other suppliers is our low CO2 footprint. We have the smallest CO2 footprint on the market. We want to further improve and expand that. We want to produce the solar panels with the lowest environmental impact!"