There’s no question about it: stencil printing is the most important process in electronics production. It is the root cause of 70 percent of all process errors in the SMT line. Most errors in stencil printing can be eliminated easily if they are recognised in time through inspection of the printing result. This is something the EMS service provider Laudren Electronique based in Brittany attaches great importance to – the French company wanted an integrated 3D-SPI even before this was available on the market. Today, they deploy two Ersa stencil printers of the type VERSAPRINT 2 Ultra3 with precisely this feature.
Many will be familiar with Lorient as the annual venue for the world’s largest Celtic gathering – last year more than 4,500 musicians and 750,000 visitors from all over the world poured into the five port city, with the 50th Interceltic Festival planned for August 2020. Alongside fishing and trade, there is also an industrial base here in this far-flung corner of western France – which is not surprising, since Rennes, the capital of Brittany, is just 150 km away, with the Atlantic metropolis Nantes with its important industrial branches steel, glass, textiles and sugar only a few kilometres further. Laudren Electronique, one of the ten companies forming the Laudren Group and in the business of electronics manufacturing since 1975, specialises in small and medium-sized series of electronic assemblies. The company’s plant in Lanester (Lorient district) has a production area of 7,000 m2 available. Currently, a total of 160 employees are prepared to implement demanding high-tech projects in electronic assemblies – as an EMS full service provider from procurement through production, integration and testing to customer services and logistics. With 40 years of experience behind them, Laudren Electronique produce electronic boards and assemblies for their customers in sectors as varied as energy, defence, transport, aviation, optics and networks, automation and lighting. The Brittany-based company serves customers throughout France and abroad.
The two companies Laudren Electronique and Ersa GmbH have known and valued each other for a good eight years – in 2014, the business contact turned into a real business relationship when an Ersa selective soldering system of the type VERSAFLOW 3/66 was purchased for big boards. The requirement set by the French EMS service provider for a concrete project was: selective soldering technology. This is understandable, since current printed circuit boards are becoming increasingly complex – more and more components need to be placed, high-mix, low-volume is becoming the order of the day for sophisticated assemblies. In this case, an XL board format was also part of the requirement package, which is mastered perfectly by the Ersa machine with maximum 610 x 610 mm. “What could have been more obvious than to call on the technological leader for selective soldering? With Ersa technology, every soldering point can be treated separately – in other words with its own parameters – in order to achieve optimum quality,” explains the process engineer responsible at Laudren Electronique. Following relevant tests, the system was designed with a dual pot system for mixed production, since installation it has been ensuring enhanced productivity and quality in 2-shift operation on the manufacturing line.
Convinced by the performance of both the selective soldering system and Ersa Service, the first inquiry for a stencil printer followed about two years later. The first generation was no longer a simple printer; as a multifunctional system it fulfilled further functions and processes along the production line. At the time, those responsible at Laudren Electronique expressed their interest in integrated 3D-SPI – even though this feature was not available on the market at the time. The French knew, however, that the Ersa development department was working on a project to develop precisely this model ready for the market as quickly as possible. For this reason, those responsible at Laudren Electronique decided to purchase a VERSAPRINT S1 stencil printer, which impressed with superior printing and SPI technology for inline manufacturing. Special features of the S1: 100% Solder-Paste-Inspection (SPI), user-oriented interface in accordance with SEMI standard (SEMI stands for Semiconductor Equipment and Materials International), automatic cleaning of the underside of the stencil, optionally retrofittable features.
Following the launch of the second generation of stencil printers VERSAPRINT 2 in 2018, the premium version of which – Ultra3 – had this desirable 3D-SPI function available, it was not long before the existing S1 were retrofitted at Laudren Electronique. This retrofit was carried out directly at Ersa headquarters in Wertheim am Main – with a machine of the type VERSAPRINT 2 Ultra3 loaned to the Laudren team on an interim basis.
How does the integrated 3D-SPI work? Three-dimensional inspection of the VERSAPRINT 2 reliably detects deviations in the volume of solder paste depot by means of laser triangulation – where a laser beam is projected onto the object to be measured, the light reflected by this is mapped under a triangulation angle on the sensor of the camera and the height information is calculated using the geometry of the lens structure. The image is obtained by moving the measuring device over the printed circuit board and scanning the laser profile. The following characteristics are evaluated: volume, area, height, short-circuit, offset. If the system determines deviations in the solder paste printing to the specifications, a 2D image of the area affected is recorded for better analysis through the operator. In addition, the 3D image can be rotated and enlarged as required for safe, efficient analysis. A further advantage of integrated inspection is the closed loop function for the correction of print offset – this is able to detect offset and correct this automatically depending on the direction of printing.
After the upgraded VERSAPRINT S1 was returned, a few consultations were necessary, partly with regard to optimising the software; everything was working properly. However, the phase of temporarily working with the cutting-edge system on loan had convinced the French to such an extent that Ersa took the system back and Laudren Electronique ordered two VERSAPRINT 2 Ultra3 instead. “The change to the very latest model brought a further increase in reliability as well as greater flexibility through faster processes, because the inspection result is available immediately,” says the process engineer responsible. The company also appreciates the fact that no additional external SPI is required, which saves on valuable production area. Since the machines have been installed and running in 3-shift operation, there has been no need to worry about service and maintenance: five minutes of cleaning time are due per shift, a little grease is needed for the axes every six months, that’s it.
Alongside the good business relationship on the basis of a partnership of trust, Laudren Electronique also highly values the fast response by central Ersa Service. For all their system skills in the wide world of soft soldering, the Brittany-based company really appreciates the fact that the Ersa France team is also familiar with the printing process and has stencil printing expertise that they pass on to their business partner as a real added value. They are also impressed with the flexibility in terms of programming, which is often required for the small and medium-sized batch sizes involved here – which is quickly done, not least thanks to the interface that machine operators can operate in their own language.
SPC data analysis (Statistic Process Control) is also valued as an important tool for the continuous improvement of the manufacturing process: the SPC integrated in VERSAPRINT 2 collects all relevant process data including inspection results, summarises these in a compact way and indicates trends. Thus the data make detailed comparisons over several batches or manufacturing shifts possible and thus the qualification of processes and individual components. Inspection images can be saved as an error image together with data, and error-free printed circuit boards can also be documented completely. A perfect basis for later qualification and analysis of the results achieved. Permanent change and continuous improvement are two sides of the same coin – as soon as there is further demand for further reflow, selective or wave soldering systems at Laudren Electronique, Ersa will be on hand as the No. 1 system supplier to provide support … in France, Europe and the world!