Tuesday, May 22, 2018
Publication Date: 12/1/2011
Archive >  December 2011 Issue >  Electronic Mfg. Products > 

SEHO: New Software Feature Ensures Reliability
System automatically compensates for PCB warpage.
Kreuzwertheim, Germany — SEHO Systems GmbH is introducing a new software function for its selective soldering system — the PowerSelective. The new function ensures even higher process reliability by compensating for product or production-related warpage of the assemblies to be processed.\par \Assemblies to be handled in a selective soldering process often do not show the necessary planarity. This warpage may be due to many reasons such as unsymmetrically loaded components, scoring or tensions resulting from previous thermal and mechanical processes.

Any deformation, however, directly affects the z-coordinates in the subsequent selective soldering process, creating the potential for defective PC boards. To achieve a reliable and reproducible process, particularly critical assemblies require careful consideration on a per-board basis to compensate for any distortion. The new software feature available for the PowerSelective guarantees an automated and reliable procedure.

During program generation for the mini-wave soldering process, the operator specifies all board areas that are mechanically supported and gives a correct z-level. Typically, these areas are at the gripper supports or the edges of a carrier in which the boards are processed. A reference point is defined within this area. In addition, the operator specifies an arbitrary number of points on the soldering side of the assembly.

During operation, a high-precision laser measuring system determines the actual distance of the PCB from the previously defined points prior to soldering. These values and the z-height of the reference point are the basis for a precise calculation for modeling and illustrating an altitude profile for the assembly in process. All points of the soldering program are set off against the modeled value, ensuring that all points are soldered at the optimum height regardless of actual board warpage.

The PCB warpage compensation, together with the automatic PCB alignment based on fiducial recognition, guarantees optimum and highly reproducible xyz positioning, thus going one step further in zero-fault production.

Contact: Seho North America, Inc., 1420 Jamike Drive, Erlanger, KY 41018 859-371-7346 fax: 859-282-6718 E-mail: sehona@sehona.com Web:
http://www.sehona.com or http://www.seho.de

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