Avoiding Voids
How to avoid Voids!
The causes of voiding are numerous – they begin with the choice of soldering paste, but are also dependant on the surfaces of the printed circuit boards, the component parts and the process control in the reflow system. Leading soldering experts met up in early October at Ersa in Wertheim, to experience the next technological step in reflow soldering systems LIVE.
As Europe’s largest manufacturer of soldering systems, Ersa has intensively engaged with the topic “void reduction in reflow soldering” – the result: a system with which the soldering experts in Wertheim are breaking new ground. Before the participants tackled the theory plus “hands-on” practice, they spent an evening in Hasloch learning about the 235-year history of Kurtz Ersa from small beginnings to today’s high-tech and component supplying group, in the Hammermuseum, in the form of numerous documents, exhibits, historical pictures and replicas. And directly next door with the water-powered iron hammer, the last one still in operation in the Spessart region. During the forging demonstration in which the hammer reached a power of impact of over 1,000 kg, there was general agreement that all voids had been completely eliminated. This was undoubtedly one of the highlights of an evening which ended with dinner in the manor house.
Exciting technology presentation
The next day’s programme began with a company presentation before the eagerly awaited technology presentation, “Reduce to the optimum – Voids in reflow soldering!“ commenced. Two Ersa engineers presented the test series and test set-ups and showed before-and-after X-rays of void reduction. The construction: The entire system operates without expensive, technically-elaborate vacuum chambers or pressure tanks, requires neither air locks nor other appliances – and can therefore be ideally operated as an inline reflow system. Nor need higher operating costs be anticipated as no high-maintenance additional power units and no other mechanical appliances are required.
Then came the hands-on demonstration: circuit boards were printed with the Versaprint soldering paste printer. After that, the components were placed on the boards. In the next step, the boards were soldered and finally tested for voids in the Viscom x-ray apparatus – the result: approx. 34% void ratio. After that, the printed board assemblies were subjected to a reflow temperature profile and the void reduction turned on in the liquidus of the soldering paste. The next measurement was taken after cooling: The void ratio had been reduced to a sensational 5%, and even, in three cases, to almost zero. The whole procedure was repeatedly re-run – the result each time: reduction of the voids to between 5% and 0 %! The specialist public was very enthusiastic and encouraged Ersa to manufacture industrial series machines on the basis of the familiar Ersa reflow soldering machines. The upshot? The question of “How to avoid Voids“ is answered by Ersa with the Ersa Hotflow reflow soldering machine, Voidflow model!
