I. Raw Material Stage: Cotton → Cotton Yarn → Denim Fabric
1. Cotton Harvesting & Spinning
Conventional jeans use ring-spun cotton yarn, while high-end selvedge denim adopts vintage shuttle spinning.
· Cotton is cleaned, carded and drawn to produce roving yarn.
· Roving yarn is twisted into coarse count cotton yarn (7s, 10s and 14s coarse yarns are widely used for denim for thickness and durability).
· Two types of yarn are separated: warp yarn (blue) and weft yarn (white/grey).
2. Warp Yarn Dyeing (Core Process for Denim Blue)
Only vertical warp yarns are dyed while horizontal weft yarns remain undyed to create gradient wash effects:
· Raw yarn is sized for reinforcement to prevent breakage during weaving.
· Yarn is repeatedly dipped, padded and oxidized with indigo dye (dip in indigo → air-dry for oxidation, repeated 6–12 times; more cycles result in deeper shades).
· Surface loose dye is rinsed off and yarn is dried to form dark blue warp yarns, with weft yarns retaining natural off-white.
3. Weaving (Conventional Denim / Selvedge Denim)
Vintage shuttle looms weave twill fabric (classic 3/1 right-hand twill):
· Blue vertical warp yarns interlace with white horizontal weft yarns to form the unique twill texture of denim.
· Narrow high-end looms weave red edging on both fabric sides, known as selvedge.
· Freshly woven raw fabric is called grey fabric, which is stiff and dull in color.
4. Pre-Shrinking & Setting (Critical Step for Shrinkage Control)
Grey fabric undergoes high-temperature washing and steam pre-shrinking to release latent fabric shrinkage in advance.
· Standard denim requires post-wash shrinkage ≤3%. Pants made from unpre-shrunk fabric will shrink significantly after laundering.
II. Cutting Workshop: Fabric → Cut Components
1. Marker Making & Spreading
Computerised markers are generated for sizes XS–XXL to maximise fabric utilisation.
· Dozens of fabric layers are laid flat and aligned during spreading.
2. Cutting
CNC cutters or manual knives cut along marker lines to separate all components: Front panels, back panels, waistband, fly, pocket facing, pocket bag, belt loops, crotch patch, side seam patch, etc.
· All cut pieces from one single pair are bundled with matching numbers to avoid size mixing.
3. Auxiliary Material Preparation
All accessories are prepared simultaneously: Brass tack buttons, metal zippers, rivets, leather patches, woven labels, care labels, sewing thread, pocket lining, fusible interfacing for reinforcement.
III. Sewing Workshop: Cut Components → Unwashed Raw Denim Semi-Finished Pants
Assembly is completed on a production line following fixed sequences:
1. Pocket Construction Front slash pockets and back patch pockets are sewn, with bartacks at pocket openings for reinforcement; metal rivets are fastened on back pockets to prevent tearing.
2. Front & Back Panel Assembly Inner crotch and outer side seams are stitched with denim-specific double-needle chain stitches for superior tensile strength and resistance to thread breakage.
3. Fly & Zipper Sewing Zippers are installed with fly facings, and prominent topstitching creates the signature heavy denim stitching.
4. Waistband Making & Belt Loop Attachment Waistbands are shaped with fusible interfacing, and evenly spaced belt loops are sewn on.
5. Waist Closing & Button Installation Waistbands are attached to pant bodies; buttonholes are punched, followed by pressing brass tack buttons and front pocket rivets. (Zippers, buttons, rivets, and other hardware are attached to the jeans)
6. Hemming & Full Stitching Inspection Pant hems are double-stitched; workers inspect missing stitches, skipped stitches and fabric holes to obtain unwashed raw denim semi-finished pants.
IV. Washing Process (The Soul of Jeans – Determines Fit, Color & Texture)
Stiff raw jeans are treated with chemicals and abrasion to achieve vintage, distressed, whisker and faded effects, ranging from light to heavy wash treatments:
1. Desizing Sizing agents left from weaving are removed to soften fabric and enable color fading and distressing.
2. Standard Stone Wash Pants tumble with industrial pumice stones/rubber stones in washing drums for friction fading and overall lightening.
3. Enzyme Wash (Bio-Wash) Cellulase enzymes erode indigo pigment on fabric surfaces for soft, even fading; this process is applied to 80% of jeans on the market.
4. Special Hand Distressing (Manual Operations)
· Whiskers: Hand sanding on the upper thigh to create natural faded crease marks
· Honeycombs: Abrasive texturing under back pockets for honeycomb patterns
· Spray Monkey Wash: Localised spraying of potassium permanganate solution for rapid partial bleaching
· Rips, holes, fraying, patchwork & Snow Wash (white speckles formed by permanganate spraying)
1. Neutralisation for Color Fixing & Softening Treatment Acid-base neutralisation locks color; silicone oil soaking softens fabric and eliminates stiffness.
2. Drying & Shaping Low-temperature drying followed by tension pressing to restore original pant silhouette.
V. Finishing & Packing: Washed Jeans → Finished Goods Shipment
1. Ironing & Shaping
Steam pressing machines smooth seams, waistbands and hems to lock in the pant fit.
2. Full Inspection
Each pair is checked for color variation, holes, broken threads, loose buttons, stains and size deviation; defective products are reworked or scrapped.
3. Tagging & Packing
Attach leather patches, woven labels and care labels, hang swing tags, cover with dust bags and fold into plastic pouches.
4. Carton & Warehousing
Cartons are packed according to size ratios, labelled externally, then dispatched to brand stores or warehouses.
Concise Core Production Chain of a Pair of Jeans
Cotton Spinning → Indigo Yarn Dyeing → Shuttle Weaving of Denim → Pre-Shrinking & Cutting → Assembly Line Sewing of Raw Semi-Finished Pants → Distressing Wash (Enzyme / Stone / Hand Sanding) → Ironing & Inspection → Tagging, Packing & Delivery