Kurtz Ersa Magazine

Let it REFLOW!

Let it REFLOW!

Energy-efficient reflow soldering with Ersa HOTFLOW

Multi-track transport system for different PCB widths
Multi-track transport for different PCB widths

Since 1987, Ersa has been developing, producing and distributing SMD reflow soldering systems, making it one of the pioneers of this technology. In the early days, the first machines started at 2.5 m overall length, a 5-metre machine was considered a “monster”. Since they were introduced more than 30 years ago, Ersa reflow systems have been defining the industrial standard – the current HOTFLOW systems score with a perfectly balanced mix of process reliability, throughput and low operating costs.

As long ago as 1993, the ERS 460 N2 was the first reflow soldering machine to be delivered under nitrogen atmosphere – thus preventing oxidation and achieving significantly improved soldering quality. Then the first big change in heating technology occurred. Although infrared emitters offered a high energy transmission rate, their disadvantage was that differently sized components particularly with dark-coloured housing absorbed more heat than the environment. This resulted in large differences in temperature on the PCB. In other words, even more powerful systems were required for the dynamically expanding SMD technology. Thus in 1994 the Ersa HOTFLOW series was created, which relied on recirculating heating zones with changeable nozzles.

Further generations followed the successful model: HOTFLOW 2 with faster wear part replacement and increased machine availability, HOTFLOW 3 (2008) with further enhanced energy efficiency and increased maintenance friendliness, HOTFLOW 4 in 2013 with energy consumption reduced even further, intelligent nitrogen control and flexible grip-transport system. The technology of the original machine lives on in the HOTFLOW reflow soldering systems version still used today, although this has been revised and had flow optimised multiple times. The HOTFLOW 4 uses directly controlled fan motors for the first time in a reflow system, leading to energy savings of more than 50 percent despite the lengthened process zone. Whereas initially mesh belts were solely used for transporting the flat assemblies, more than 90 percent of all reflow systems had adjustable pin chain transport systems by the mid-1990s.


A quadruple chain transportation system was developed for a well-known Nordic mobile phone manufacturer, with every individual track adjustable in terms of both width and speed. Maximum throughput despite small footprint and maximum energy efficiency were the requirements set at the time. Ersa promptly delivered – not just then, but umpteen times ever since.


Quick and easy servicing through excellent accessibility and connections through quick couplings
Quick and easy servicing through excellent accessibility and connections through quick couplings

The development of the personal computer led to a further leap in technology in the 1990s. Up to 1992 only a very few reflow soldering systems had a PC with user interface – the breakthrough in price and performance led to a positive explosion in the development of user-friendly software. Saving soldering profiles became the norm – the 1995 software was already able to calculate and adapt soldering profiles independently. This development has continued until today, and represents an important, if not the decisive, factor for an increasing number of potential customers.

Reflow soldering systems in Zhuhai from 2013

As well as presenting the HOTFLOW 4, Ersa achieved a further milestone with its reflow soldering system division in summer 2013: production of the HOTFLOW 3 series begins in the Kurtz Ersa plant in Zhuhai. “As experienced mechanical engineers, we copied our final assembly line from Germany and set it up in Zhuhai. Frames and panels are produced locally, but all the important components such as drives, guides, chains or fans are provided on a weekly basis in accordance with the Zhuhai production schedule,” explains Ersa General Sales Manager Rainer Krauss. Today, Ersa produces six different models of the HOTFLOW 3 series with between 14 and 26 heating zones there, all of which are designed to maximum production output per square metre of footprint and minimise error rates as well as the overall costs per printed circuit board produced.

Where does the leading technology stand today? Ersa has produced and delivered around 5,000 reflow soldering systems to date – with the Zhuhai plant having already contributed around 600 machines for the Asian market. In the meantime, the Ersa team produces more than 250 HOTFLOW 3 machines per year in Zhuhai as well as more than 100 machines of the HOTFLOW 4 series in Wertheim, all of which score with outstanding performance all down the line – high soldering quality, optimum process control, maximum machine availability – and a top energy balance, which means intelligently controlled energy and nitrogen consumption. Technology and electronics manufacturing remain an exciting field – to be continued with innovative solutions!


Summer 2013: The production of the HOTFLOW 3 series begins in the Kurtz Ersa plant in Zhuhai
Summer 2013: The production of the HOTFLOW 3 series begins in the Kurtz Ersa plant in Zhuhai

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