With only a single SMT line on which it produces highly specialized drive controllers in tiny batches, Aros electronics in Gothenburg, Sweden, is not the kind of company you would associate with terms like Industry 4.0, digitization and high-level automation. Aros is nevertheless considered a smart factory trailblazer in its home country, because it implements state-of-the-art manufacturing concepts in cooperation with ASM Assembly Systems and its Smart SMT Factory Network.
If you run an electronics manufacturing plant, take a rather skeptical view of the current talk of networked production and don‘t believe that it really applies to your everyday requirements, get in touch with Per-Johan Edgren, manufacturing process manager at Swedish manufacturer Aros electronics AB. He explains his viewpoint in his extremely cordial way: “Whether you call it smart factory or something else, I am always looking for opportunities to meet my customer’s increasingly demanding requirements efficiently and on time. To accomplish this, we have developed a roadmap for our factory‘s development over the coming years. We defined improvement targets, but not the technologies for achieving them. We then showed this roadmap to partners and equipment suppliers and asked them how we can achieve these targets in stages and with minimal disruption of our everyday operations.”
One of the company’s partners is SMT line solution supplier ASM, the maker of DEK printers and Siplace placement machines. Alexander Hagenfeldt, solutions marketing manager at ASM and project manager for the company’s Smart SMT Factory Network, remembers: “At first glance, this kind of inquiry was rather unusual for a producer of small and medium-sized lots. Aros didn‘t just want to buy printing and placement solutions, but was looking for sophisticated networking capabilities and optimized process integration. Fortunately, we were familiar with this type of focus from clients with large high-volume environments. Aros already operated with an extremely high level of flexibility and automation on its line. They wanted to increase their future output capacity exclusively by making improvements and not by adding more machines or lines. In our talks, we realized how progressive their approach was, from the first drawings produced by the development department to the finished product.” The result was an operation that was not only very advanced, but made Aros a part of the Smart SMT Factory Network of reference sites for the Smart #1 SMT Factory that ASM is currently building.
Clearly formulated objectives
Aros electronics AB is a member of Van de Wiele Group, a technology enterprise with sales of almost 400 million euros. The 135 employees bring in 34 million Euros of this amount by developing and manufacturing highly specialized controllers for drive solutions, power electronics and embedded systems for the automotive and mechanical engineering industries. Per-Johan Edgren explains: “Our company has long been known for innovative, high-quality developments. But since the demands on quality, flexibility and speed are getting tougher all the time, particularly in the automotive field, we wanted to become even better.”
The company formulated ambitious goals and developed a roadmap for achieving them. It called for a zero-defect philosophy in addition to a central planning instance, advanced user guidance, and highly automated continuous flow production with minimal manual operations from introducing the new product to packaging it.
Alexander Hagenfeldt of ASM: “I am impressed by the sense of purpose and the speed with which Aros is upgrading its production. Our technicians visit the factory in Gothenburg regularly, and each time they go there something has changed. But the line is always running at full speed.”
Barcodes contain everything
A laser applies a unique ID and barcode to each board that enters the line. The entire line is also equipped with dual asynchronous conveyors, i.e. they operate separately of each other. That way, the plant can run large batches of high-volume products and small lots or single prototypes side-by-side. If an order calls for unusually large boards, the two tracks can be combined to form a single wide conveyor. Shuttles and conveyors ensure that a board does not have to be touched by human hands after it has entered the line. The boards run first through the laser-marking machine before a shuttle transports them to one of two tracks that take them through two DEK printers (one per track), each of which is linked to an ASM ProcessExpert system. Per-Johan Edgren: “We expect the ASM ProcessExpert systems to provide huge benefits. At this time we use them as high-quality 5D SPI quality control systems and to run DFM checks for new products. We are already very impressed by them, and we plan over the medium term to let them control the printers and their process parameters completely autonomously.”
One of the first things that visitors notice is how crowded the plant is. Since floor space is expensive, it must be used as effectively as possible, which is why complex transport systems are used to move the circuit boards around. For example, the two DEK printers and their ASM ProcessExpert system are arranged in a row, with one track using lifts and conveyors to route the boards over the other machines. The SMT line itself is arranged in a U-shape. After the boards have been printed, a lift and shuttle system routes them over a walkway before they enter the placement machines on two tracks.
The placement line consists of six Siplace SX1 machines, five of which are equipped with a flexible CPP head. The end-of-line machine features a TwinHead for large components, connectors and odd shapes. When the boards leave the line, they run on two separate tracks through two ovens before two inline AOI systems perform the quality control. This is followed by special processes like THT, selective soldering, encapsulating, and additional IC tests.
Special software provides transparency
The progress of a circuit board can be tracked not only on the line. Anywhere in the company, users can call up an Aros-developed program that displays the line, its dual conveyors and the boards moving along them with their barcode IDs. Clicking on a board shows additional real-time information about the underlying order as well as all process parameters. The user can even call up for each board the associated SPI images, the placement program, and the reflow oven‘s heat profile. This is made possible because each board is identified before it enters a line component so that its UID can be linked to the process data in the database. Clicking on a machine shows its current settings. “We plan to make this data available to our customers in the foreseeable future. At this time, we use this additional transparency to control and optimize our flexible production,” explains Per-Johan Edgren.
Each side of the line runs with a different setup concept
The company has the ability to produce even the smallest lots efficiently by combining Siplace material flow and setup planning tools with innovative concepts.
One side of each placement machine has a fixed setup with standard components. Operators splice the reels for each feeder as instructed by the ASM Line Monitor. “The whole line features state-of-the-art operator guidance. The Line Monitor shows the operator when and where he or she needs to splice or switch out a feeder in order to keep the line running. Over the coming weeks, we will combine the information from the Line Monitor with the data in our own software. On the active feeder rack in the kitting area, for example, the LEDs tell the operators what to do. And in the THT area, we display instructions on the workstation monitors. I am convinced that such support and guidance tools are an absolute necessity in a complex and high-mix production environment like ours. Without them, you would undoubtedly have lots of mistakes and line stops,” explains Edgren.
On the other side of the line, the remaining components are set up via changeover tables. This combination of fixed and flexible setups minimizes the setup effort and accelerates product changeovers. While the setup is being changed on a machine, the rest of the line can keep running. The machine reads the barcode ID of each board and adjusts the support pins and conveyor rails automatically.
All component logistics and setup family planning operations, the component storage systems, the line-adjacent Siplace Material Tower and the setup preparation procedures are controlled via the Siplace Material Manager and the Siplace Material Setup Assistant. When changeover tables come back from the line, LEDs indicate whether the operator can leave a feeder in place, move it to the active feeder rack, or tear it down and return the components to the material storage area. This saves on trips and minimizes the number of withdrawals and returns from/to the main warehouse.
Process improvements alone deliver huge productivity increases
Aros’s roadmap extends through 2021, but the success of the improvements is already measurable today. For example, the company used to run three shifts, each with eight workers on the shop floor. Today, it runs only two six-hour shifts with four people each while placing 50 percent more components per shift. The company installs between 2 and 2.5 million components per week on roughly 220 active products, many of which are dual-sided.
Per-Johan Edgren: “We could have increased our output by adding more gantries to the Siplace SX machines, but this would only alleviate a few process weaknesses while creating bottlenecks somewhere else. Our goal was to improve flexibility and throughput equally through process integration and automation. We are convinced that we can double our production performance once more. For example, we will install a robot that distributes the boards to the different IC test stations. We will also upgrade our final assembly and packaging operations to a continuous-flow model that operates in tandem with the SMT production. Our goal is to have each board packaged and ready for shipping within 24 hours after it has received its barcode, even with lot sizes of 1.”
SMT Hybrid Packaging, Booth 4-219 + 4-309