Product category:
Electronics Manufacturing Materials and Consumables
News Release from: Tecan | Subject: PCB rework stencils
Edited by the Electronicstalk Editorial
Team on 07 October 2004
Stencils ensure accurate rework
A new range of PCB rework stencils ensures accurate and repeatable printed results for single component footprints such as QFPs, PLCCs, BGAs, uBGAs and surface-mount connectors.
PCB rework stencils that ensure accurate and repeatable printed results, for single component footprints such as QFPs, PLCCs, BGAs, uBGAs and surface-mount connectors, are now available from Tecan, along with a range of associated accessories The precision stencils mimic the footprint and aperture sizes corresponding to both the device requirements and the original stencil used in production
This article was originally published on Electronicstalk on 24 Oct 2000 at 8.00am (UK)
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In combination with a rework station, alignment is simple, resulting in a controlled "right first time" process.
Offering optimum reliability and consistent printed results, the rework stencils are both strong and rigid to ensure positive gasketting with the PCB surface.
The compact designs include minimal stencil projection beyond the image to be printed thereby enabling use in all situations, especially high-density component areas.
Further reading
Mini rework stencils save time and money
Mini stencils from Tecan Stencils ensure accurate repeatable paste deposits are produced when replacing components such as QFPs, PLCCs and BGAs during PCB rework operations.
Prototype micro metal parts in five days
A five-day prototype service has been launched by Tecan, offering design engineers cost-effective small sheet metal parts for a vast array of applications.
Accurately folded edges and run-on/run-off areas ensure effective paste roll and containment without causing interference to other components on the populated PCB.
In addition to the provision of specialised rework stencils, the company provides personalised help and advice to overcome the most demanding needs.
Other rework solutions include dip transfer plates, BGA reballing stencils, direct component printing stencils and reflow reflector shields.
Dip transfer plates enable the accurate application of precise flux volumes to the lower quartile of the solder balls of ball grid array (BGA) components, thereby eliminating excessive flux contamination on the underside of the reflowed component.
BGA reballing stencils offer advantages in two areas.
First, to ensure the precise registration of new solder spheres onto pre-printed flux deposits, and secondly, in the form of the thicker stencils necessary for printing solder paste onto the BGA itself to create new solder sphere terminations.
For depositing paste onto the pads of the BGA device itself, where the printed device will be picked and placed onto the printed circuit board (PCB) and subsequently reflowed, direct component printing stencils are used.
During reflow, the company's reflow reflector shields provide critical protection for heat sensitive components on densely populated PCBs, where an adjacent device is to be reworked/reflowed.
The reflow shields are custom-made to fit over leaded components such as connectors, crystal oscillators, switches, inductors and capacitors, during reflow.
In the reflow oven the shield reflects heat energy, thereby preventing damage to the component body, while simultaneously allowing conducted heat from the bottom of the PCB to reflow the solder paste effectively, ensuring a good joint every time.
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