Product category:
PCB Assembly Equipment and Tools
News Release from: OK International | Subject: APR-5000-XLS
Edited by the Electronicstalk Editorial
Team on 19 March 2007
Rework system reflows lead-free BGAs
gently
Optimised heating scheme avoids excessive lid temperatures, melting joints outside the rework area, warping of the PCB or distorting the plastic bodies of connectors.
OK International has developed optimised heating for lead-free BGA rework, allowing users of the APR-5000-XLS array package rework system to reflow lead-free BGAs without incurring excessive lid temperatures, remelting soldered joints outside the rework area, warping of the PCB or distorting the plastic bodies of connectors such as RJ45s "Lead-free BGA rework requires new heating algorithms because peak reflow temperatures are close to the maximum lid temperature of 250-260C recommended by IC vendors and the IPC", said Paul Wood, Market Development Manager for OK International
This article was originally published on Electronicstalk on 10 May 2005 at 8.00am (UK)
Related stories
Rework system works within Pb-free windows
OK International's Metcal brand APR-5000-XLS array package rework system for larger PCBs will be demonstrated on Stand G610 at Nepcon UK.
Tools simplify cable connections
OK Industries has two new products to simplify and improve the way technicians wrap and unwrap cable connections.
"The new software-controlled heating scheme allows operators to work within the narrow lead-free process window, and is easy to use requiring no additional training or setup time".
The APR-5000-XLS has a total of six convection heaters for underboard heating, as well as the upper nozzle for focused heating of the device undergoing rework.
The revised heating algorithm now allows selected underboard nozzles to be used simultaneously with the upper heater to apply the desired reflow profile only in the area to be reworked.
Further reading
Tools take the stress out of IDC
Companies looking for safe, ergonomically designed hand tools, that will boost efficiency while remaining cost effective, need to consider the ImpactPlus series of hand tools from OK Industries.
Benchtop solutions come to Brighton
Visitors to OK International's stand at Nepcon can expect to see the latest developments in benchtop technology for hand soldering, optical inspection, fume extraction and array package rework.
This saves operators setting excessive nozzle temperatures.
With conventional BGA rework stations, nozzle temperatures around 300C can be needed to overcome the temperature gradient across the BGA package to reflow interconnects on the underside at a peak temperature between 240 and 260C.
As a result, the IC lid temperature can become high enough to damage the package, the internal interconnects, or the die.
In the new algorithm, the six underboard heaters preheat the entire board to 190C.
The four outer heaters are then turned off, leaving just two underboard heaters directly beneath the rework site turned on.
These operate in combination with the upper heater to reflow the array interconnects using much lower nozzle temperatures than conventional rework stations.
This combined heating from above and below the BGA device reduces the temperature gradient set up across the package.
The peak temperature of the package can then be held below the IPC recommended maximum 260C, as the array interconnects reach a suitable temperature to reflow.
In addition, convection air heating above and below the board enables accurate and responsive temperature control, thereby preventing air temperatures from overshooting the desired target.
Temperature overshoot presents another hazard that can damage sensitive semiconductor devices.
OK International has received US patent approval for its dual zone convection preheater, which will deliver a fast and cost-effective solution for manufacturers seeking to improve productivity and yield when reworking double-sided, lead-free assemblies incorporating area array packages. Request a free brochure from OK International ...
• OK International: contact details and other news
• Email this article to a colleague
• Register for the free Electronicstalk email newsletter
• Electronicstalk Home Page
Search the Pro-Talk network of sites
