Deadline and cost pressures are especially great in high-volume SMT production environments where space-saving machines are needed that churn out large numbers of units without production interruptions and continuous requests for operator assists. Hardware from ASMPT has been optimized specifically for such environments.
The numbers are impressive: In the high-end consumer products segment, circuit boards worth up to 80,000 euros leave the SMT production line every hour. Anyone familiar with these figures knows how expensive even a short production interruption can be, how important every discarded component or module is, and how important it is to maintain a consistently high level of performance. Accordingly, being able to assemble and optimize each production line in accordance with the factory’s specific requirements matters more than ever. Fortunately, the extensive portfolio of market leader ASMPT offers everything that’s needed to do this.
Since it takes place at the very beginning of the line and is particularly sensitive to disturbances and interfering factors, the solder paste printing process plays a particularly important role in high-volume SMT production. A modern printer must work quickly and precisely while taking up as little space as possible on the shop floor. This is where ASMPT’s DEK TQ printing platform sets new standards. Thanks to its wet-printing accuracy of up to ±17.0 microns with a process stability of 2 Cpk, it can apply solder paste deposits for 0201m components that a barely larger than a coarse peppercorn. And it achieves the impressive values in a core cycle of five seconds, all in a footprint of only 1.0 by 1.3 meters (DEK TQ). Especially convenient is its ability to be positioned back-to-back in groups of two, which doubles the line’s printing capacity without adding to its length. A new off-belt print clamping process, an innovative print head and drive and the pneumatic full-surface stencil clamping system are just a few of the DEK TQ’s highlights.
DEK TQ solder paste printers are optimized for uninterrupted production. With a 22-meter fabric roll and a seven-liter detergent tank, they can run for more than twelve hours, i.e. a complete shift, without operator intervention. And the pivot design ensures coplanary contact with the stencil underside for maximum cleaning quality. Also important for long assist-free operation for as long as possible is its ability to clean selectively, which reduces the cleaning agent consumption significantly. The agent is applied via a dispenser from above, but only in the area of the circuit board being processed.
Also minimizing manual assists is the optional paste management system with an automatic paste dispenser, integrated paste height control, and individually configurable warning and stop thresholds. Another highly useful option for non-stop production is the Dual Access Cover, a laterally movable hood that makes it possible to replace the paste cartridge while the machine continues to operate.
Manufacturers who want to automate their production even further can opt for the Smart Pin Support, which places support pins with 4-mm and 12-mm diameters automatically based on programmed commands. After placing the pins, the system automatically verifies their height and position to prevent them from damaging the entire module because a single pin is slightly elevated, for example as a result of contamination on the table.
“We view the solder paste printing process, as well as the entire SMT production, as a systemic whole,” explains Rick Goldsmith, Director Product Management Printing Solutions at ASMPT. “It is therefore only logical that we also offer process-supporting products such as stencils, squeegees, solder paste, cleaning fabrics, solutions, cloths, gloves, sprays, spatulas, and paste nozzles – all tested and meeting the highest quality standards.”
While the paste printing process forms the basis of the production flow, it is also the most susceptible step and thus responsible for 60 percent of all production errors. This is caused by a whole range of variables, such as the stencil design and material, the solder paste type, or the cleaning cycles. In addition, more scrap is often the consequence of advancing miniaturization, which leads to ever finer pads, whose distances are also getting smaller and smaller, especially in fine-pitch applications – to as little as 50 microns. “At the beginning of a shift, the temperature and humidity are different than at the end,” says Jérôme Rousval, Product Manager Process Solutions at ASMPT. “Even this small difference has an impact on process stability, which is why it is so important to check the quality of each circuit board after it has been printed. This lets you prevent defective products from being processed further and incurring additional costs.”
To prevent such problems, most SMT factories install a Process Lens optical SPI system from ASMPT in the second position on the line. It measures each pad and detects even the smallest deviations and trends. What makes this possible is a DLP chip with up to 20 million individually controllable micromirrors that checks the pads for volume, height, area, shape, and position. To keep an inspection this thorough from slowing down the line, the system was optimized for maximum throughput. It first identifies relevant areas on the PCB via a 2D scan and then measures them in 3D, thus achieving up to 80 percent fewer false positives compared to conventional SPIs. With a software-selectable resolution of up to 10 microns, even the measurements of 0201m pads are precise and reliable. Despite all this, the Process Lens HD operates up to 70 percent faster than conventional devices. The dual-track conveyor of the Process Lens also contributes to the SPI system’s high throughput rate.
The great performance reserves of the Process Lens even leave room for additional measurements without increasing the overall production time. These include contaminant detection or the mixed mode of the Process Lens HD platform, in which both solder paste deposits and adhesive dots are examined. The Process Lens HD is also one of the few SPI systems on the market where the measurement resolution can be controlled via software.
“In high-volume manufacturing, every centimeter counts,” explains Petra Klein-Gunnewigk, Senior Product Manager Placement Solutions at ASMPT. “The quantities of electronic components in products are rising continuously. For example, a high-end smartphone today contains almost twice as many components as it did ten years ago, and a similar trend is emerging in the automotive sector. On the other hand, the available production space is limited, which means that significantly more components must be assembled per hour in the same physical area.”
Delivering maximum throughput without sacrificing quality, all in a compact footprint, is one of the main goals of ASMPT’s SIPLACE TX placement platform. A speed of 96,000 cph (with two placement heads) in an area of only 1 by 2.23 meters speaks for itself. The machine features non-contact placements and minimum placement forces down to 0.5 N. To ensure that the quality does not suffer even at the highest throughput rates, the SIPLACE TX platform is equipped with an intelligent vision system. The new high-resolution PCB camera handles even the smallest structures, such as fiducials or data matrix codes with 50-micron line widths, with ease. In addition, it is possible to inspect the PCB before and after assembly, and components can be checked for faults and their position before they get picked up.
The component cameras take a separate picture of each component and feature capabilities such as component-specific lighting settings, Pin1 and tombstone detection, and barcode reading for traceability. The machine can process components ranging from 0.12 mm × 0.12 mm to 200 mm × 110 mm. Three different head variants are available:
80 8-mm tape feeder slots ensure an efficient material supply. The Glue Feeder and the Linear Dipping Unit are also available as options, and connecting many third-party feeders is no problem. To check the components, the CRDL Measurement Feeder is available.
A new feature for the non-stop supply of components from trays is the SIPLACE Tray Unit, which increases the machine’s footprint only minimally thanks to its compact design. It features 30 tray shelves in the main storage area plus 12 shelves in its cache section. The unit accommodates trays measuring up to 355 mm × 275 mm or alternatively two JEDEC trays on each level. The cache ensures speedy tray changeovers. An RFID tag on each tray shelf and an LED for each level ensure clear identification.
“At ASMPT, we view every SMT production as a specific, integrative system that must always be optimized for maximum ROI,” concludes Klein-Gunnewigk. “As part of our open automation concept, we leave it up to each customer to decide to what extent they want to automate, for example by adding AIVs in the material supply area, installing buffers in automated storage systems, or streamlining their waste disposal. Together with the customer, we develop a concept that can also include third-party systems thanks to our open interfaces – a configuration that ensures a future-proof investment for the customer.”
