Stitch formation, problems

Surgical tapes are intended to minimize necrosis, scar tissue formation, problems of stitch abscesses, and weakened tissues. The problems with surgical tapes are similar to those experienced with traditional skin tapes. These include (1) misaligned wound edges, (2) poor adhesion due to moisture or dirty wounds, and (3) late separation of tapes when hematoma or wound drainage occur. 

The previous topics have been addressed to the review of the occurrence of seam pucker and other surface distortions, and defects caused by needles and fabric feeding systems. The present section wUl review the problems related to stitch formation stitch imbalance, stitch distortion and skipped stitches. 

As seen before, thread breakage may result from overheated needles due to thermal aggression. Also, bad-quality or worn-out needles may cause problems due to excessive friction. Very often the problem lies in the machine. Incorrect threading or defects in the machine thread guides cause the thread to weaken and faU. The correct setting of the synchronisation and distance between needles and loopers, or other stitch formation elements, are also important. 

Other experiments concerning with the formation of voids are presented in Ref. 9. The void formation problem for flows along the tows was also studied in Ref. 20. Several liquids with different properties were injected into unidirectional stitched fiberglass mat. The authors manage to relate the percentage aerial void area for different liquids to a single parameter, the modified capillary number (with the contact angle included), introduced as ... 

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