Recognize seam classes LS SS BS FS EF from graphic images and written description 02 26 2014 EXAM 2 SEAMS Influences Appearance durability comfort ease of alteration choice depends on seam location intended use of garment styling factors equipment available for production ASTM International identifications written into specifications by Using 2 uppercase letters that id the seam class Followed by lowercase letter or letters that identify the seam LAPPED SEAMS type o i e 301 stitchtype SSae 2 seam type o More than 100 variations Formed by overlapping the seam allowances of two or more plies of fabric and sewing them together with the fabric plies extending in opposite directions usually more casual than SS because they always have some form of topstitching uses special purposes rain gear because they are more waterproof Underwear sportswear because they are less bulky than SS Always hace a form of topstitching Largest seam class contains 102 versions of LS FLAT FEEL SEAMS formed by sewing face side up lapping one layer over the other o MOST COMMON OF LS o Strong durable used in jeans shirts work clothing pajamas o Prevent raveling cause all raw edges are enclosed o Bulky rigid in heavy fabrics o Difficult to alter o Can be used only on straight or fairly straight edges SUPERIMPOSED SEAMS MOST COMMON USED SEAM CLASS o 301SSa most common seam class Usually created by superimposing fabric plies or stacking them on top of one another with edges even and sewing them together near the edge forms a booked seam Most major structural seams and many minor detail seams are superimposed Plain SS are created by superimposing fabric plies or stacking them on top of one another with edges even and sewing them together near the edge o Most used seam class o Most common seam is the 301SSa o Butterfly or busted o BOUND SEAMS binding fabric strips Made by encasing the raw edges ONLY at edges of a seam with With increased use of safety stitches or serging and the growing use of knit fabrics that do not ravel the use of bound seams has decreased used to cover and finish raw edges necklines armholes hems seam allowances FLAT SEAMS butt seam or exposed seam Look the same on both sides joins fabric plies whose raw or sometimes folded edges are abutted or sometimes slightly lapped and sewn together The joining stitches are typically 600 class cover stitches although zigzag or bottom over stitches may be used o remember 600 class extensively used by manufactures of knit garments to cover raw edges and prevent raveling o ONLY on KNITS o Least bulk o ORNAMENTAL STITCHING EDGE FINISHES A series of stitches applied to finish an edge they do not join fabric together for ornamental purpose Do not join fabrics together as do seams Any stitching that finishes a raw edge without attaching a separate piece of fabric qualifies as EF Prevent raveling of woven fabrics Very economical found on knits Herms are the most common EF stitching Recognize common seam names from graphic images and written description o Recognize seam finishes from graphic images and written description Recognize seam defects from graphic images and written description MATCHING SEAMS LS lapped seam always have topstitching used on jeans more casual only on straight edge BS bound seam NOT for structural seams Used for binding raw edges Necklines armholes collars SS superimposed seam plain seam MAJORITY OF ALL SEAMS FS flat seam ONLY used on KNITS Least bulk very economical fabric usage EF edge finish MATCHING 1 Seam allowance b 2 garment d 3 raw edges c 4 seam a the narrow width of fabric between the seam line and the cut edge of the fabric a hole in the seam cause not by broken stitches but by not stitching both seams allowances deeply enough the stitched line of a seam parallel to and always a specified distance from the raw edge of the fabric SEAM PERFORMANCE Seam strength is affected by Type and width of seam Strength and tendency of the fabric to ravel Characteristics of the stitches Depends on how it is stitched pressed finished fit care of garment fabric COMMON SEAM QUALITY DEFECTS INCLUDE Unraveling caused by a broken or skipped stitch Restitched seams reflecting a splice where a thread broke or ran out during construction A ropy hem caused by poor operator handling or too much pressure on the presser foot SEAM FINISHES Finish should not add bulk to the seam A variety of finishes are used in the industry Edge finish stitching EF a series of stitches that finish and edge They include hems most seam finishes and other sewn finished for raw edges 1 PLAIN FINISH When a plain seam is left untreated garments that will be fully lined 2 CLEAN FINISH turned and stitched finish Turned over the seam allowance once and stitched o a clean finish for medium and light weight fabrics o Costly labor because it requires 4 passes thru a sewing maching 1 Sewing the seam 2 Butterflying the seam allowances 3 Stitching thru the folded edge of one of the seam allowances 4 Stitching thru the folder edge of the remaining seam allowance 3 PINKED FINISH o produced by a power machine equipped with a special disk to give a saw toothed edge or with pinking shears o inexpensive nonbulky o done on opaque rather than sheer fabrics because serrations show through o rarely used to finish seam allowances because overedging has been found to be more effective o 4 BOUND FINISH binding o Covering the raw edges of each ply with a folded ribbon tape Good for finishing seams and unlines jackets or or bias binding coats Designer and expensive o Best bindings are nonraveling nonbulky and comfortable and match coordinate with color of fabric o Designers use them decoratively to finish outer garment edges i e necklines armholes front and back opening edges and the lower edges of the garment and seams o Common for reversible garments because bindings look the same from both sides o 5 OVERCAST FINISH o A series of loose slanting hand stitches placed to encircle the raw edge of each seam allowance o most common single ply finish in ready to wear o Overedging is the machine version of it o 6 DOUBLE STITCHED FINISH MATCHING SEAM FINISHES A Overcast serged finish B Bound finish C Clean finish D Pinked finish BIAS SEAM Forms horizontal softness Mostly often found in skirts tue bias is a 45 degree angle to the lengthwise and crosswise grains of woven fabrics When a garment is cut on the bias it usually refers to te true bias o It is the most stretchy part of a woven fabric its stretch is
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