A 2,000-piece order of satin evening dresses came back with every third garment showing a 3 cm gap between the zipper tape and the seam allowance. The tech pack specified the zipper length and the seam allowance, but not the stitch density on the zipper attachment. That omission cost the buyer a full rework cycle and a 6-week delay. This is the pattern: most quality failures in China-based womenswear production trace back to a spec that was incomplete, not to a factory that was careless. The fix is a checklist that forces every measurable detail onto the tech pack before you commit to a run.
What a Tech Pack Must Carry Before You Send It
A tech pack that omits a single dimension can turn a production run into a negotiation. The most common omission is the finished garment measurement for critical points like the bust, waist, and hip, stated as a tolerance range, for example 84 cm ± 1 cm at the bust. Without that range, the factory grades to its own standard, and you discover the discrepancy at final inspection. Specify every measurement that affects fit and silhouette, and include the grading rules for sizes S through XL. One concrete detail: a size run that grades the bust by 4 cm per size will fit differently than one that grades by 5 cm, and the difference shows up in the shoulders and armholes.
State the grade.
List the thread weight and type. A polyester core-spun thread in Tex 30 is not interchangeable with a cotton-wrapped poly in Tex 40, and the difference affects seam strength and needle holes on lightweight fabrics. Specify the needle size. A 75/11 needle on a 20-denier chiffon leaves a visible hole; an 80/12 does not. Include the stitch type and SPI (stitches per inch). A 12 SPI lockstitch on a side seam of a woven dress will unravel if a single thread breaks; a 14 SPI will hold. These are not optional details. They are the difference between a garment that survives a wash test and one that fails.
Fabric and Material Specifications
State the fabric composition, weight, and finish. "100% polyester chiffon" is not a spec. "100% polyester, 75D, 30g/m², calendared finish, hand-feel soft, no stretch" is a spec. The difference is that the first allows the factory to source a 90D fabric that is 20% heavier and has a stiffer hand, and you will not know until the bulk fabric arrives. For knits, specify the gauge, yarn count, and stretch percentage. A single jersey in 30S/1 at 180g/m² with 20% stretch in the width will behave differently in cutting than the same weight in 32S/1 with 15% stretch. For blended fabrics, state the exact blend ratio. "Poly-cotton blend" can mean 65/35 or 50/50, and the dyeing behavior and shrinkage differ.
Include a swatch or a Pantone reference for color, but do not rely on the swatch alone. A Pantone code for the lab dips and a physical swatch for the final bulk approval gives you two points of control. Specify the color fastness requirement: Grade 4 for washing, Grade 3-4 for rubbing. If you do not state this, the factory will use the cheapest dye that meets the visual match, and the color will bleed in the first wash. For prints, specify the repeat size, the registration tolerance (typically 0.5 mm), and the print method (rotary, digital, or screen). A digital print on a 100% polyester satin will have a different hand and color saturation than a screen print, and the cost difference is significant.
Trims and Accessories
The trim list is where most tech packs get vague. "Zipper" is not a spec. "YKK #3 nylon coil zipper, 18 cm, auto-lock slider, matching tape color" is a spec. Specify the brand, the size, the length, the slider type, and the color. For buttons, state the material, diameter, hole count, and color. A 15mm resin button with 2 holes is not the same as a 15mm resin button with 4 holes, and the sewing operation differs. For interlining, specify the weight and the fusible temperature. A 25g/m² fusible interlining applied at 130°C will bond correctly; the same interlining applied at 110°C will delaminate after one wash. Include the care label content, the wash care symbols, and the brand label dimensions. These are not afterthoughts; they are part of the garment.
Construction Details and Stitching
The construction sheet is the section where you prevent the zipper gap problem. Specify the seam type for every seam on the garment. A French seam on a chiffon blouse requires a different operation than a serged seam, and the cost and labor differ. State the seam allowance. A 1 cm seam allowance on a lightweight woven is standard, but a 0.6 cm allowance on a French seam is tighter and requires more precision. Specify the hem type and width. A 2 cm double-turned hem on a skirt will look different than a 1 cm rolled hem, and the drape changes. Include the topstitching details: the distance from the edge, the stitch length, and the thread color. A topstitch at 0.5 cm from the edge in a contrasting thread is a design detail; a topstitch at 0.3 cm in a matching thread is a construction detail. State which it is.
For closures, specify the attachment method. A zipper can be set in with a lapped seam, a centered seam, or an exposed seam, and each requires a different pattern and operation. For elastic, specify the width, the stretch percentage, and the recovery. A 2.5 cm elastic with 50% stretch and 90% recovery will hold its shape after 20 washes; a 2 cm elastic with 40% stretch and 80% recovery will not. Include the bartack placements. A bartack at the top and bottom of a pocket opening prevents tearing; without it, the pocket will fail under stress. These details are the difference between a garment that looks right and a garment that is right.
Measurement Points and Tolerances
The measurement chart is the core of the tech pack, and it is the section where a single missing point can cause a full inspection failure. List every measurement point on the garment, and for each, give the base size measurement and the tolerance. Common points for a woven dress: bust, waist, hip, hem sweep, total length, shoulder width, armhole depth, sleeve length, and neck drop. For each, state the measurement method. "Bust: measure 2 cm below the armhole, straight across, from seam to seam, with the garment flat and relaxed." The method matters because two inspectors can measure the same point differently if the method is not specified.
Set tolerances based on the fabric and the fit. A woven fabric with no stretch can hold a ±1 cm tolerance at the bust; a knit with 20% stretch may need ±2 cm because the fabric moves. For critical fit points like the waist on a fitted dress, tighten the tolerance to ±0.5 cm. For less critical points like the hem sweep, ±1.5 cm may be acceptable. State the grading increments. If the base size is M with a 88 cm bust, and the grade is 4 cm per size, then S is 84 cm, L is 92 cm, and XL is 96 cm. List these explicitly. A factory that grades by its own standard may use a 5 cm grade, and the fit will be off. Include the tolerance for each size, not just the base. The tolerance for a size S may be ±0.8 cm while the tolerance for a size XL is ±1.2 cm, because larger garments have more variance.
Labeling, Packaging, and Shipping
Specify the label placement and content. A care label sewn into the side seam at the waist is standard, but a brand label at the center back neck is a design choice. State the label material. A woven label with a damask weave and a heat-cut edge will not itch; a satin label with a straight-cut edge will. For packaging, specify the folding method. A dress folded with tissue paper between layers and packed in a polybag will arrive without creases; a dress folded without tissue will have set-in wrinkles that require re-pressing. Specify the carton dimensions and the packing quantity. A carton that holds 30 dresses at 0.06 m³ is standard, but if the dresses are bulky, the carton may need to be larger, and the shipping cost changes. Include the shipping mark requirements: the carton size, the PO number, the style number, the color, the size ratio, and the gross weight. These details prevent delays at customs and at your warehouse.
The Pre-Production Sample and Its Role
The pre-production sample (PPS) is the physical version of the tech pack. It is the point where every spec is tested. When you receive the PPS, measure it against the tech pack, point by point. Use the same measurement methods specified in the tech pack. If the bust is 86 cm and the spec is 84 cm ± 1 cm, the sample passes. If it is 87 cm, it fails, and you request a revision. Check the construction details: the seam allowances, the stitch density, the hem width, the topstitching distance. Check the trims: the zipper length, the button size, the label placement. Check the fabric: the weight, the hand, the color match. Check the fit: put the sample on a fit model or a mannequin of the correct size, and assess the silhouette, the drape, and the ease. Do not approve the PPS until every point matches the tech pack. The PPS is your last point of control before bulk production. If you approve a sample with a deviation, the factory will produce the entire run to that deviation, and you will have no recourse.
Final Inspection and the AQL Standard
The final inspection uses the Acceptable Quality Limit (AQL) standard, typically AQL 2.5 for major defects and AQL 4.0 for minor defects. The inspector pulls a random sample from the bulk, based on the lot size and the AQL level. For a lot of 2,000 pieces, the sample size at AQL 2.5 is 125 pieces. The inspector checks each piece against the tech pack and the approved PPS. A major defect is a stain larger than 2 mm, a seam that is skipped or broken, a measurement that is out of tolerance, a wrong color, or a missing trim. A minor defect is a loose thread, a slightly crooked label, or a small fabric flaw that does not affect wearability. If the number of major defects in the sample exceeds the acceptance number (7 for a sample of 125 at AQL 2.5), the lot fails, and you can reject the shipment or require rework.
The inspection must be against the tech pack, not against the inspector’s general standard. If the tech pack specifies a 14 SPI stitch density, and the inspector counts 12 SPI, that is a defect, even if the seam looks fine. The tech pack is the contract. The inspection is the enforcement. Keep a copy of the approved tech pack and the PPS at the inspection site, and refer to them constantly. If the factory disputes a defect, point to the spec in the tech pack. The conversation ends there.
Common Failures and Their Tracing
The most common failure is a measurement out of tolerance, and it traces back to a tech pack that did not specify the measurement method or the tolerance for every size. The second most common is a color mismatch, and it traces back to a tech pack that relied on a physical swatch without a Pantone reference, or that did not specify the color fastness grade. The third is a construction failure, like a skipped stitch or a weak seam, and it traces back to a tech pack that did not specify the stitch type, the SPI, or the thread weight. The fourth is a trim failure, like a zipper that breaks or a button that falls off, and it traces back to a tech pack that said "zipper" instead of "YKK #3 nylon coil, 18 cm, auto-lock slider." The pattern is consistent: the defect is predictable, and the prevention is in the tech pack.
The 14-point checklist is not a formality. It is the tool that forces you to write down every detail before production starts, so that the factory has no room to interpret, and you have no surprises at inspection. The checklist is: 1) flat sketch with front and back, 2) fabric spec with composition, weight, and finish, 3) color spec with Pantone and fastness, 4) trim list with brand, size, and type, 5) construction sheet with seam types and allowances, 6) stitch details with type, SPI, and thread, 7) measurement chart with points, methods, and tolerances, 8) grading rules for all sizes, 9) label placement and content, 10) packaging method and carton specs, 11) shipping marks and PO details, 12) care instructions and wash symbols, 13) PPS approval against tech pack, 14) final inspection against tech pack and PPS. Run every tech pack through this list before you send it. The time you spend on the checklist is the time you save on rework and delays.
How to Work with a Clothing Manufacturer on Tech Packs
The relationship with a clothing manufacturer is a dialogue, not a handoff. A tech pack is not a document you send and forget. It is a living spec that the factory will question, and you must be prepared to answer. When the factory’s pattern maker reviews your tech pack, they will flag details that are unclear or that conflict with their production capabilities. For example, if you specify a French seam on a curved armhole, the pattern maker may note that the curve is too tight for a clean French seam, and suggest a serged finish instead. That is a conversation, not a failure. The factory is telling you that your spec, as written, will produce a poor result, and they are offering a correction. Listen to that feedback, but do not accept it blindly. Ask for a sample of the suggested alternative, and compare it to your original intent. The goal is a garment that meets your quality standard, not a spec that is easy for the factory to produce.
The tech pack also sets the basis for cost. Every detail in the tech pack affects the price. A 14 SPI stitch density takes longer to sew than a 10 SPI, and the labor cost is higher. A YKK zipper costs more than a generic zipper. A French seam takes more time than a serged seam. When you send the tech pack, expect the factory to come back with a price that reflects the details. If the price is higher than you expected, do not ask the factory to cut costs without specifying what to cut. "Can you make it cheaper?" is not a useful question. "If we change the French seam to a serged seam and reduce the SPI to 12, what is the new price?" is a useful question. You control the cost by controlling the spec, and the tech pack is the spec.
The Iterative Process of Tech Pack Development
What to send us
If the specifications above match what you are sourcing, send your tech pack to Orange Sea Clothing. If the pack is not written yet, sketches and a reference sample are enough to start — sample development covers the design review, fabric and trim sourcing, pattern making and the first prototype, so you see fit and construction before you commit to a production run.
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