Shaping & Constructing Textile Products
Pattern Pieces and Marking Out
Before any fabric is cut, a designer or pattern cutter produces a set of pattern pieces. Each piece represents one component of the finished product — a front bodice, a sleeve, a collar — and includes a seam allowance (typically 1.5 cm in commercial garment production) beyond the stitch line. Pattern pieces also carry a grain line — an arrow indicating how the piece must align with the fabric's warp threads to ensure the finished garment hangs correctly. Cutting a piece off-grain causes the garment to twist in wear.
Marking out transfers the pattern information onto the fabric before cutting. Common methods include tailor's chalk (temporarily marks the stitching lines and dart positions on fabric; brushes away cleanly), tracing wheel and dressmaker's carbon paper (transfers markings through multiple layers simultaneously) and tailor's tacks (small loops of thread through the pattern and fabric layers, removed once the pieces are separated). Accurate marking out is essential: incorrect positioning wastes expensive fabric and produces ill-fitting products.
Cutting Methods
Several cutting methods are used depending on scale of production, fabric type and required accuracy:
- Fabric shears — long-bladed scissors specifically designed for cutting fabric; the blade angle allows the lower blade to remain flat on the cutting table. Using general-purpose scissors blunts them quickly and causes frayed or inaccurate edges. For small-scale or one-off production.
- Rotary cutter — a circular rolling blade mounted in a handle, used with a self-healing cutting mat. Allows fast, accurate cutting of straight lines and gentle curves through multiple layers of fabric simultaneously. Widely used in home dressmaking and small batch production, particularly for quilting.
- Laser cutter — uses a focused laser beam to cut fabric with extreme precision under computer control. Seals the edges of synthetic fabrics as it cuts, preventing fraying. Capable of cutting intricate patterns and lace designs impossible to achieve with hand tools. Used in commercial production and design studios; high capital cost limits use to larger operations.
- Die cutting — a shaped metal blade (the die) pressed through multiple layers of fabric to cut identical shapes repeatedly and rapidly. Used in mass production for components such as pocket linings, labels and shoe uppers. Extremely fast and consistent but requires a custom die for each shape, so only economical at high volumes.
A laser cutter automatically seals the edges of synthetic fabrics as it cuts, eliminating the need for separate edge finishing on polyester or nylon. This is a major time and cost advantage in commercial production — one process does two jobs simultaneously.
Seams and Construction Techniques
A seam is a line of stitching joining two or more fabric pieces. Choosing the correct seam type for the application is a key technical decision:
- Plain seam (open seam) — the most common seam: two fabric pieces placed right sides together, stitched along the seam allowance, then opened out flat and pressed. Simple to sew but requires separate edge finishing to prevent fraying. Used in most garment construction.
- French seam — encloses the raw edges completely within a folded seam, producing a neat finish with no visible raw edges on the inside. Made in two stages: first sewn wrong sides together, then trimmed and turned before a second line of stitching encloses everything. Suitable for fine, sheer fabrics such as silk chiffon where a raw edge would show through or fray badly.
- Flat fell seam (run-and-fell seam) — a very strong, flat double-stitched seam where one seam allowance is trimmed, folded over the other and stitched down. Produces two visible lines of stitching on the outside. Used on denim jeans and workwear because it is durable and lies flat under stress.
- Overlocked seam — an overlocker (serger) machine simultaneously trims the seam allowance, wraps thread around the cut edge and stitches the seam in one pass. Produces a neat, stretchy edge finish ideal for knit fabrics and jersey garments. Almost all commercially produced T-shirts use overlocked seams.
Although machine stitching dominates commercial production for speed, hand stitching techniques retain an important role in quality garment construction and alteration. Running stitch is the simplest hand stitch — thread passes in and out of the fabric in a straight line — used for gathering and basting (temporary holding). Backstitch is the strongest hand stitch, with each new stitch overlapping the end of the previous one, producing a near-continuous line; it is used where machine stitching is impractical, such as inside a narrow cuff or on couture pieces. Slip stitch joins a folded edge to a flat fabric almost invisibly, used for hems and lining attachment. Pad stitch is used in tailoring to anchor a felt or linen interlining to a jacket lapel, building up the characteristic roll of a bespoke suit.
Edge Finishing
Woven fabrics fray when cut, so raw seam allowances and hem edges must be finished to prevent the weave unravelling in use. Common finishing techniques include:
- Pinking shears — scissors with a zigzag blade that cut a serrated edge, slowing fraying on fabrics that do not fray excessively. Quick but not permanent.
- Zigzag stitch — a machine stitch applied along the raw edge, encasing the threads so they cannot unravel. The most widely used finishing technique in domestic sewing.
- Overlocking — as described above; wraps thread around the cut edge for a very neat, professional finish that also allows a small degree of stretch.
- Binding — a strip of bias-cut fabric (or tape) folded over and stitched around the raw edge, enclosing it completely. Produces a decorative finish used on necklines, armholes and quilt edges.
The flat fell seam is the seam of choice for denim jeans because it is sewn twice (giving double the strength), lies flat (comfortable against the skin on inner thigh seams under pressure) and encloses all raw edges (preventing fraying through repeated washing).
The domestic sewing machine drives a needle carrying the upper thread through the fabric; a hook mechanism in the bobbin case catches the upper thread and loops it around the bobbin (lower) thread, forming a lockstitch. Tension must be balanced between upper and lower threads: uneven tension causes loops or puckering. A presser foot holds the fabric flat against the feed dogs (toothed grips beneath the needle plate) that advance the fabric at a controlled rate. Different presser feet are used for different tasks: a standard presser foot for straight stitching, a zipper foot for inserting zips, a buttonhole foot for automatic four-step buttonholes, and a walking foot for quilting multiple layers evenly. Pressing (using an iron at appropriate heat for the fibre) is a critical step between construction stages: it sets seams, flattens dart bulk and ensures accurate alignment of the next component.