Automated Assembly Repair
Highly Automated Assembly Repair for Sustainable Electronics Production
Sustainable electronics production puts as many assemblies as possible from the manufacturing process into use in a functional manner. With a minimum failure rate. At the same time, the demands on production equipment are increasing due to constantly changing parameters. Electronic products should be durable and repairable in case of failure. Rework and repair have long been established - but many electronics manufacturers want even more automation.
There are many causes for rework on electronic assemblies. The following reasons often lead to rework:
- Defect on the component
- Wrong component assembled
- Component assembled in wrong orientation
- Component badly soldered (bridges, open solder joints, ...)
- Component wrongly programmed
- Component is reused (recycling)
- Modification of assembly (redesign)
- Assembly as sample or component(s) are reassembled (prototyping)
- Tests on assembly, e.g. cross exchange (testing)
- Backup of component data from defective assembly (forensics)
- Insertion of more powerful components into the circuit (upgrading)
Mostly, manufacturers or users want to minimize the scrap of PCBs in order to save costs. But aspects such as sustainability are also becoming more important, because avoiding electronic scrap saves money and conserves resources. It is increasingly recognized that qualified rework makes technical and economic sense in order to obtain functional, reliable assemblies again. This requires process know-how and suitable equipment. The trend is toward further automation, as qualified electronics production personnel are becoming harder to find.
Automated repair process
For a long time, component repair was a matter for experts. Extensive measurements had to be carried out before a repair could be considered. Ersa therefore introduced temperature control directly on the component for desoldering and soldering processes at an early stage. In this way, a safe heating process is created right from the start after a target profile is specified – the temperature is tracked to the profile, and the target component is automatically removed. At the same time, the automatic Ersa rework systems precisely place new components on the assembly: Component connections and landing surfaces are recorded with cameras, the target position is calculated, and the new component is precisely positioned by the axis system. Upstream, automated wetting of the components with flux or solder paste is now standard. The system operator simply provides the assembly and new target component and selects the assigned data set to start the autonomous process.
Extensible rework platform
Communication electronics and IT infrastructure rely on increasingly powerful circuit boards with high-quality components – this is where a repair pays off quickly. The HR 600 XL modular rework platform is predestined for this. The processing of large assemblies is designed for board sizes up to 650 x 1,250 mm with the expandable bottom heater and matching PCB holder. By means of matrix heating, the heating surface is adapted to the dimensions of the assembly and the power distribution of the preheating is dimensioned to the application. Exchangeable heating heads allow the system to be adapted – depending on component size and energy requirements. With the largest heating head with 150 x 120 mm effective area and 2,800 W total power, very large components can be desoldered and soldered in and a gentle upgrading process can be carried out.
Functions for residual solder and measurement
Additional functions for automated processes are available for the HR 600 XL platform and can also be retrofitted to existing systems. After desoldering a component, residual solder usually has to be removed. With the “Auto Scavenger” module, there is now a fully integrated functional unit for this purpose – immediately after removing the component, the suction nozzle of the Auto Scavenger is lowered over the board and the residual solder is automatically extracted without contact.
There are also new developments in temperature detection: in addition to the proven temperature sensors (K-type thermocouples), there is now a non-contact sensor (Virtual Thermocouple, or Virtual-TC) to precisely control soldering processes. Usually, optical sensors measure different temperatures – depending on the surface condition. Ersa initially teaches the Virtual-TC the temperature of a reference thermocouple. All subsequent soldering processes on the same assembly are safely run using the non-contact sensor. This is a huge advantage for customers who process many identical assemblies – the repeated application of a thermocouple is no longer necessary. All Ersa rework devices are controlled and operated via the cross-system software platform HRSoft 2. All process parameters are stored centrally and MES interfaces are defined. The path to further automation of rework processes is clearly marked out!
