Investment in selective soldering line - 02/2020

Due to the continuing trend towards miniaturization of assemblies, more and more products are being developed from the classic THT layout to the reflowable SMT assembly. What remains are a few THT components that have to be soldered in after the reflow process because they are not available in SMT form or are disproportionately more expensive than the corresponding wired component. Most of these are components with special shapes or temperature-sensitive elements. THT manufacturing is therefore considered labor intensive and quality critical. The subjective influence by the employee is too great.

Leesys has faced these challenges and invested in a selective soldering line with a maximum of options for the variance and flexibility of the assemblies to be assembled, while adhering to the set quality goals.

Requirements for the new selective soldering system:

  • Selective soldering line with the statement: Industry 4.0!
  • Cycle time minimization
  • Process stability
  • Implementation of special requirements:

             o finepitch connector
             o Processing high components 120 mm top and 60 mm bottom
             o Reduction of assembly handling

  • Create production flexibility through chaotic assembly / soldering
  • Reduction of maintenance times
  • Easy to use
  • Automated frame handling to minimize operator influence
  • Control of component assembly at the workplace through the use of a vision system
  • Traceability in THT assembly / soldering on assembly level


Clever Claus never stops learning!


selective soldering line "Clever Claus"

At the heart of the new selective soldering line is the placement control system "Clever Claus". The system is used at Leesys as an interactive assembly workstation for THT components.

After registering, the employee receives the individual information about the assembly process on the touch screen or by projection directly on the work surface. For a smooth workflow, the employee places or assembles the components in the places provided. The “Clever Claus” recognizes the individual steps and checks them for correctness; in the event of errors, the employee receives an audiovisual message and the assembly can only be continued once the error has been rectified. In parallel to quality control, the system documents every single work step in the background.

The “Clever Claus” constantly looks over the shoulder of the employees at work, follows every step of the process practically according to the four eyes principle and confirms when the work process is completed with zero errors. However, the point is not to control the employee, but to relieve him and at the same time ensure quality. Through the combination of database management, high-resolution camera technology and intelligent image processing algorithms, the "Clever Claus" manages to check items for their quality up to one millimeter.

"The system is very user-friendly and is easy to program," explains Sebastian Worch, who, as a production technician at Leesys, sees three advantages in working with the "Clever Claus": The training period has been extremely shortened, the placement quality has increased significantly and the error rate dropped significantly. When assembling it goes to zero, because if a component with the wrong polarity is used or a component is installed at an angle, the knowing colleague will report.

The finished assemblies receive a checkpoint at the line entrance after completion of the assembly and a line exit when leaving the soldering system. These checkpoints are assigned to the assemblies and enable traceability via the Manufacturing Execution System (MES).

The new selective soldering line at Leesys consists of:

  • Selective soldering system from Kurtz / Ersa with fixed frame transport for flexibly adjustable soldering frames for soldering individual circuits, panels or carriers
  • Automated frame circulation system from Pacha for the connection between the soldering machine and the placement area
  • Pacha assembly table with detachable set-up table for realizing external set-up
  • Assembly control system from Optimum as an assembly aid for manual assembly to identify assembly errors before soldering and to minimize rework
  • Manufacturing Execution System (MES) represents the interface between all line components and thus enables traceability at assembly level

Process flow:

  • The assemblies to be processed are scanned at the assembly table and married to the rotating frame.
  • The in-house part number is determined from the MES and the associated assembly program started.
  • The guided assembly begins.
  • Only after the complete assembly has been completed can the soldering frame be released by the operator

            o The scope of control also includes soldering aids such as hold-down devices
            o Center supports and their position.

  • To optimize cycle times and reduce costs, chaotic assembly within one armor is possible (the soldering programs must contain the same nozzles).
  • The processed assemblies are given a checkpoint line entrance after completion of the assembly and a line exit when leaving the soldering system.
  • These checkpoints are assigned to the assemblies and enable traceability via the MES.

Key data selective soldering system:

  • Manufacturer: Kurtz / Ersa
  • Type: VersaFlow VF455VF Selective
  • Processes are carried out in parallel by separating flux application, pre-heating and soldering
  • Selective fluxer for the targeted application of flux
  • 2 pre-heaters, each with one convection and one radiant heater
  • 2 soldering jars with:

            o An overtop convection heater to maintain temperature during soldering
            o One 3-axis system each, which can move fully independently or electrically coupled
            o A set-up control to check the nozzle geometry and the drainage behavior
            o Automatic solder nozzle activation to increase the nozzle life

  • Conversion of a crucible as a mini flash possible (selective soldering can be combined with wave soldering)
  • Warp measurement to adjust the Z heights
  • Fiducial detection for X and Y correction


Key data handling system:

  • Transport of the soldering frames to the placement position on the placement table and automatic removal of these when the placement is complete
  • Turning station enables additional assembly tables to be retrofitted
  • 2 buffer stations to increase the utilization of the soldering system
  • Circuit system with lifting and lowering station with return transport through the cooling section
  • Automatic return transport

Key data of the optical placement control system:

  • Manufacturer: Optimum
  • Type: Clever Claus