CTE 3763 Exam 2 Study GuideSeams & Edge TreatmentsSeam line- the stitched line if a seam, parallel to and always a specific distance from the raw edge of the fabric- important for grain, fit, allowanceSeam allowance- the narrow width of fabric between the seam line and the cut edge of the fabric- lowers cost if smaller (5/8 of an inch)Seam types: fabrication, functional, aestheticdepends on: seam location- arm seam line gets more stress, intended use of garment, styling, equipment usedInfluences: appearance, durability, comfort, ease of alterationASTM International- total uniformity, rigid, scientific6 seam classes, 4 major:•Superimposed •Lapped•Bound•FlatSeam specifications very important because we are a very global world Specifications use two uppercase letters that identify seam class, followed by a lowercase letter or letters that identify seam typeSuperimposed seams- SS, also known as plain seam•Most used seam class•The cut edges of the fabric layers are stacked on top of one another to form a booked seam ready for stitching•When found on inside of garment usually pressed open flat- busted or butterfliedLapped seams- LS•Has the most variations, NOT most widely used•Formed by overlapping the seam allowances of two or more plies of fabric and sewing them together•Specialized- jeans, men’s dress shirts, leather•Flat- fell seams, more casual in appearance•Ensuring the seam will lay right•Can only be used on straight edge Bound seams- BS•Made by encasing the raw edges of seam with fabric strips•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•Binding the edges, very aesthetic•Use on raw edges, often necklines, details•Not used on structural seams, used on edgesFlat seams- FS, also known as butt or exposed seams •Join fabric plies by butting the raw edges together and securing them with a 600-class cover stitch or a zig-zag stitch•Look same on both sides•No seam allowances- economical•Very inexpensive, less fabric used•Less bulky, exposed seams•Almost never used on wovens•Advantage of using with knits- they curl, avoid bulky seamsOrnamental stitching- OS•Can be just a top stitch fully decorative added to seam•Can be functional, keep garment flat while creating a decorative top stitch•Dressmaker details Edge Finish Stitching- EF•Stitch seam and finish edge at the same time•Economical- saves time, fabric•Explosion of knits, no seam allowance•Stitches applied to finish an edge or for ornamental purpose•Prevent raveling of woven fabrics•Keep the edges of lightweight to medium-weight knit fabrics from curling OS and EF technically don’t join fabric togetherFrench seam- “a seam within a seam”- high-end couture seam, quality indicator, inner beauty, ex. sheer top Seam Performance- seam strength is affected by type and width of seam, strength and tendency of the fabric to ravel, characteristic of stitchesdepends on hot it is stitched, pressed, and finished, fit, fabric, care of garmentSeam quality defects:•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 Finish should not add bulk to a seam, a variety of finishes are used in the industry•Plain Finish- when a plain seam is left untreated, garments that will be fully lined •Clean Finish- turned over the seam allowance and stitched, neatly finish edges inside the garment, raw edge of seam or hem allowance folded under once and stitched- add bulk•Pinked Finish- edge cut with a sawtooth blade, generally only opaque fabrics are pinked because serrations show through sheer fabrics, inexpensive non-bulky edge finish•Bound Finish- covering the raw edges of each ply with a folded ribbon tape or bias binding •Overcast Finish- a series of loose, slanting hand stitches placed to encircle the saw edge of each seam allowanceBias seam- forms horizontal softness, most often in skirtsEdge Finishes- methods other than hems include:•Facings•Cut-on facings•Bias strip 1. Shaped or Separate Facing:•Fabric pieces shaped identically to the garment edges they face•Should be cut on the same grain as the garment piece they face•Ideal for shaped necklines, hems & sleeveless armholes as they conform to any shape•Shaped facings are sewn on not folded back•Require less fabric than extended facings because separate pieces are laid out to better advantage2. Extended Facing:•Simplest type of facing•Require least labor & add the least bulk to garment•Used less than shaped facing due to more fabric usage•Can only be used on straight edges3. Bias Facing: •Narrow, bias strips of fabric used to face raw edges•Form a neat, inconspicuous facing- approx. 1/2” wide•Require little fabric•Most cost efficient•Useful for sheer fabrics•Low in bulk•Not suited for intricately shaped edgesSeam Quality DefectsRestitched Seams/ Broken Stitches•Where a "splice" occurs on the stitch line. If this occurs on Topstitching, then the seam does not appear to be 1st quality merchandise. •Caused by 1) thread breaks or thread run-out during sewing; or 2) cut or broken stitches during a subsequent treatment of the finished product (i.e., stone washing).•How to minimize: use a better quality sewing thread, proper machine maintenance, correct material handling techniquesSkipped Stitches•Where the stitch length is inconsistent, possibly appearing as double the normal stitch length; or where you can see that the threads in the stitch are not properly connected together. •Caused by the stitch forming device in the sewing machine missing the thread loop during stitch formation causing a defective stitch. On looper type stitches, this will allow the stitch to unravel causing seam failure.•How to minimize: same as aboveOpen Seam- Seam Failure- Stitch •Where the threads in the seam have ruptured leaving a hole in the stitch-line.•Caused by 1) Improper stitch for application; 2)Inadequate thread strength for seam; 3) Not enough stitches per inch.•Minimize: better quality thread, proper size thread, check for stitch cracking in knitsOpen Seam- Seam Failure- Fabric•Where the stitch line is still intact but the yarns in the fabric have ruptured.•Minimize: reinforce stress points with bartacks,
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