Re-work soldering for electronics
Integrated solder extraction saves space on the table
Re-work soldering is the targeted desoldering of a defective component in order to re-solder a new component in its place on the PCB board. The processes involved in re-working vary depending on the type and size of the component. Wired components require different procedures from SMD or BGA components. Safe, reproducible results will be achieved by following the prescribed standards (JEDEC/IPC).
The process of soldering for repair
Broadly, re-work soldering follows these steps.
The defective component is de-soldered without damaging surrounding components. Important: Tool design, heat application.
2. Removing waste solder:
Solder remaining on the PCB board must be completely removed. Stranded wire or a solder suction head with continual vacuum are the tools for this. The surrounding components must not be damaged, which requires skill in the case of closely-packed PCB boards.
Fresh solder is applied to the prepared contact points. Solder paste is the medium of choice, as targeted doses can be applied.
The new component is positioned on the PCB board using a suitable tool. ESD-safe tweezers are particularly suited to this.
New components are soldered in using exactly the right amount of heat. While doing so, it is necessary to hold the component in place with tweezers.
Rework Station Weller WXD 2 Kit
2-channel soldering and desoldering unit with WXDP 120 desoldering iron and WXP 120 soldering iron. Compatible with the intelligent WX system. Power: 2 x 120 W. Compressed air is required for the suction system.
Infrared SMD Rework Station
The station comprises a 650 watt underside heating element for pre-heating and an additional 150 watt infrared heating device. Both single and double-sided PCB boards can be soldered with the station. The system is particularly suited for SMD and BGA work.
Weller Rework Station WXR 3030 Set
All-in-One 420 W system with 3 channels: WXHAP 200 hot air soldering iron plus WXDP 120 desoldering iron and WXP 65 soldering iron. The supply unit contains a compressor for generating compressed air and the necessary vacuum. Automatic tool recognition and power management according to the WX standard.
Rework Station Metcal MFR-1351
Metcal soldering units have unique, wear-free temperature stability. The MFR-1351 set contains the very fine MFR-H1-SC soldering iron and a desoldering iron. The vacuum pump is integrated into the main unit.
Hot air, soldering iron, infrared – which is the best method?
Every method has its pros and cons. For SMD circuit boards, hot air soldering is recommended above all else. For wired components, a soldering iron is more suitable, as heat can be delivered more precisely. Infrared reflow soldering has been proven on the production line, but is not yet established for re-working.
The modern standalone soldering iron is undoubtedly a versatile tool and many different soldering and desoldering tips are available for many different applications. In many cases, tips are quick and easy to change and there are many soldering accessories and spare parts. For professional use, however, a soldering station is usually the preferred choice. Soldering stations offer improved performance, highly controlled temperature settings and the flexibility to allow different soldering irons to be connected as and when needed, eliminating the need for frequent changes of soldering tips. Some offer dual soldering iron capabilities, making them suitable for two users, or one user using two tools. With the use of suitable soldering accessories, similar stations can also be used for desoldering operations, but in many cases, especially when dealing with PCBs with surface-mount devices, dedicated desoldering/rework stations are preferred. These often allow for multiple tools to be used, along with suitable desoldering accessories, such as solder removal devices. Hot air irons are a favourite choice when these miniaturised components are involved, especially when any subsequent reworking is required.