Selective soldering process robotized by ALNEA
For four years, ALNEA Sp. z.o.o. has been active on the market for dedicated industrial solutions. The industrial selective soldering process has been intensively researched at ALNEA and is thus the most recognized and well-known. Using first-hand experience accumulated during initial implementations of soldering processes, ALNEA concluded that the solutions currently available on the market are obsolete, sometimes with outdated technical features and processing parameters. This means that use is often limited and that the repeatable output parameters and interconnection quality required by IPC standards cannot be guaranteed – especially in the case of lead-free soldering. This led the engineers at ALNEA to create a new, original solution for the requirements of future ALNEA solutions and their end users. In order to achieve the targeted results, ALNEA defined the following 3 areas for improvement:
- Control of the soldering process and parameters
- User interface
- Manipulator (a device for physically moving a soldering set)
Starting point / Task definition:
The first challenge the company had to tackle was that it was not possible to ensure synchronous (simultaneous) control over all process parameters. The above-mentioned process parameters (i.e. procedure and process variables) include heating temperature, heating power, on-line temperature measurement, tin supplying speed and direction, soldering iron head movements (at any time and in any direction). Significant technological restrictions seriously limited the implementation of automated selective soldering. The lack of pre-heating generated some problems for lead-free soldering alloys, as these require higher soldering temperatures and more accurate process control.
The second problem to resolve was a user interface, since process control requires a PLC, HMI-type operator panel and soldering controller. In addition, a robot controller and the corresponding teach pendant are also required when using a soldering robot. Such solutions generate high costs and make it necessary to employ additional professional staff, including a process engineer, control specialist and a robotics specialist.
The third problem was how to sufficiently move the soldering tools. Specifically, this required the following key features: moving tools in distinct planes, distinct (variable) and controlled movement speeds, tool movement with rotation when soldering. Previous solutions based on SCARA robots used with Cartesian coordinates did not allow for these features.
Implementation / Solution:
All three technological problems have been resolved with the new “ALNEA – ZEUS” project using the 6-axis KUKA AGILUS robot. ALNEA – ZEUS is a dedicated soldering controller. In the first application – considered a prototype – the KR 6 R900 sixx model is used. However it is also possible to use an AGILUS with a 706 or 1101 mm range. For applications with lower requirements, the 5-axis AGILUS model can also be used (the 4th robot axis is replaced by an adjustable handle that fixes a soldering iron head to a robot flange).[youtube]Fz-sS_hduOc[/youtube]
In addition, a software package for controlling the soldering process has been loaded into the memory of the KUKA KR C4 compact controller (i.e. the KUKA robot controller with open architecture). Commands controlling the soldering process are accessible at the teach pendant level and are then sent to the ZEUS soldering controller via the Ethernet communication layer. Using company-specific dedicated hardware and software, the ZEUS controller executes control of activities performed by soldering devices: soldering iron head, tin supplying feeder, nitrogen generator and cleaners. The entire solution is implemented without a PLC, and HMI operator panel and does not require any additional communication interface.
- ALNEA ZEUS-100 v.2 soldering controller with ZEUS-100ZK.1 v2 software package
- Soldering devices: tin supplying feeder, soldering iron head, mechanical brush-based cleaner, nitrogen generator
- 6-axis KR 6 R900 sixx robot (KUKA AGILUS)
- KR C4 compact robot controller
- KUKA smartPAD teach pendant
- ALNEA ZEUS-100K.1 v.1 software package (soldering package for KUKA)
The entire ZEUS system can be mounted on industrial process lines or at standalone workplaces. The system can be connected to any external system using PROFINET, EtherNet/IP, PROFIBUS, DeviceNet or EtherCAT.
Results / Benefits:
The ALNEA – ZEUS soldering controller with the KUKA AGILUS robot has unlimited direct access to all process parameters using the teach pendant (KUKA smartPAD), meaning that such implementations do not require a PLC or HMI panel. Additionally, digital inputs and outputs of the robot can be used, for example, to control component transportation (supplying of parts for soldering), positioning handle, protective mask limiting the risk of tin drops outside of the working area, and so on. The unique feature of this solution (compared with other contemporary soldering solutions) is the ability to control all the parameters on the teach pendant. In addition, the process time can be significantly reduced by as much as half (see also video clip). Technical staff needed for such automated soldering process can be also limited (or reduced) to one process engineer with a basic level of training in the following areas: defining soldering process parameters using the robot interface and checking the process parameters during the soldering process.