The Rework Experience – First in Germany & UK

For the first time the Rework Experience was run in Germany at one of the Europe’s most popular exhibitions with supported from Global SMT. SMT Hybrid Packaging was held between 26-28th April in Nuremberg, Germany, come and meet the team on Stand 406 Hall 7. We also ran the Rework Experience in the UK at National Electronics Week a couple of weeks before

What is the Rework Experience?

We have been creating different Experience features over the years including Cleaning, Conformal Coating, Package on Package Assembly, Lead-Free, Automatic Inspection and now it’s time for the Rework Experience to take centre stage. Basically the Experience concept provides a source of information practical demonstrations and in this case a rework competition with cash prizes of 300 Euro, 200 Euro & 100 Euro

IPC have been successfully running the Hand Soldering Competition for many years testing the skills of the best in the world which will also be featured in Germany Stand 500 Hall 7. Your author has competed in the hand soldering competition in the past, with fair soldering quality but ran out of time to complete the test board.

We believed that the next logical step was to hold a fine pitch and area array rework event based around specific components and dedicated board design. With the support of IPC & NPL we have created an interesting and informative concept which will of course develop in the coming years with more advanced products, components and processes

The aim of the challenge is to rework and repair one board which features four components. The rework operations are conducted in line with accepted standards like IPC 7711/7721 and meet the inspection criteria in IPC 610 class 3. The competitors time will be taken for step 1 & 3. The following steps in the competition will be undertaken

1. Competitor will assemble and solder the components to the board
2. The board will be inspected
3. Competitor will remove components from the board and redress the pads
4. The board will then be inspected

Each participant is provided with one board and one of each of the following companies to assemble to the board:

• Plastic Quad Flat Pack (160 pins)
• Plastic Ball Grid Array (361 pins)
• Chip Scale Package (48 pins)
• Quad Flat No Lead (40 pins)

Although there are multiple footprints for each component on the board only one footprint per device may be used during the challenge. Each component is soldered to one set of pads, the parts removed and the site redressed/prepared for possible component replacement

The image above shows the board and component footprints being used in the Rework Experience competition

The following are methods used in the industry to solder or rework these parts. The methods in a company may vary but it is always worth trying new techniques to enhance skills and possibly improve the process. During the experience these techniques should be available for contestants to use

Plastic Quad Flat Pack
Individual leads are soldered manually with wire and a soldering iron
Leads are drag soldered using liquid flux, solder wire and iron
Dip solder paste is used on the leads or paste printed to the board joints are reflowed with IR or convection

Plastic Ball Grid Array & Chip Scale Package
Solder paste is applied to the substrate, component placed & reflowed
Flux gel is applied to the PCB or solder spheres, component placed & reflowed
BGA is dipped into dip solder paste, placed & reflowed
Print paste with plastic or metal stencil, place part and reflow

Rework of QFN devices often use a mini stencil to print standard lead-free paste on to the package terminations before placing the part and reflowing in place

Quad Flat No Lead
Solder paste is applied to the substrate, component placed & reflowed
Solder paste is printed on to QFN, component placed & reflowed
Solder paste is printed on to QFN & reflowed. Gel flux on QFN pads, placed & reflowed

Example of the assessment sheet used to record methods used and the results obtained

Pre Show Experience Webinar

During our pre show webinar “Area Array Rework Repair Failures Causes Cures” which included over 100 engineers we conducted a survey on rework and the issues industry face. You can watch the Rework Experience video and obtain a copy of the slides presented Click Here