Tech Packs for Apparel: What Chinese Factories Expect

A tech pack for apparel is the technical document package a Chinese factory uses to pattern, sample, cost, and produce your garment: technical flat sketches, a measurement spec with tolerances, a graded size chart, a bill of materials, construction details, artwork files, and packing instructions. Missing any of these means the factory fills the gaps with its own assumptions — and you pay for it in extra sample rounds.

A sharp 8–12 page document with real numbers beats a bloated file of mood images. Precise flats, POMs, and fabric specs in the first pages mean the costing team quotes the real garment rather than a padded guess.

This is one of the steps where a sourcing partner earns its keep — not by doing design work, but by reviewing the pack against what factory costing and sample rooms actually ask for before ambiguity becomes a wrong sample.

What pages must an apparel tech pack include?

A complete pack answers every question a pattern maker, sample room, merchandiser, and QC team will ask. Most Chinese factories work fastest with these pages, in this order:

Page · What it carries · Who uses it

• Cover / style summary: Style number, name, season, size range, target price band, contact · Merchandiser, costing
• Technical flats: Front, back, and detail views; black-and-white line drawings · Pattern maker, sample room
• Colorways: Each colorway on flats with Pantone or swatch references · Fabric sourcing, dyeing
• Measurement spec: POM table with tolerances for the base size · Pattern maker, QC
• Graded size chart: Specs for every size in the range · Pattern maker, QC
• Bill of materials: Every fabric, trim, label, thread, packing material · Sourcing, costing, warehouse
• Construction details: Seam types, stitch types, SPI, seam allowances, bar tacks · Sewing line, QC
• Artwork and print: Vector files, placement, dimensions, colors per component · Print/embroidery unit
• Labels and packaging: Label content and placement, folding, polybag, carton rules · Finishing, packing

The cover page sets context the costing team needs: season and delivery window tell them which production slot to check, and the target price band tells them whether to propose premium or standard trims.

Factories read flats as instructions, not illustrations. Fashion sketches and Canva mockups are not flats. A technical flat shows the garment laid flat — proportions, pocket shapes, rib placements, collar construction — in clean black line, with detail callouts zooming in on anything ambiguous at full view: a pocket bag, a drawcord exit, a binding finish.

What goes on the measurement spec page?

The measurement spec is where most tech packs fail, and it is the page factory QC teams live on: each row is a point of measure (POM), and each column records the spec value for the base size plus the allowed tolerance.

Two rules separate usable spec sheets from decoration:

• One unit system only. Pick centimeters or inches and commit. Mixing units is one of the most common causes of wrong samples, and factories will not guess which system applies to which row.
• Every POM gets a tolerance. A measurement without a tolerance is not a specification; it is a suggestion. When a tolerance is missing, the factory either assumes the tightest possible one (and prices in a higher reject allowance) or the loosest (and your fit drifts in bulk).

Tolerances should be realistic. Specifying ±0.25 cm on every measurement looks rigorous, but most factories cannot hold it across bulk sewing — keep tolerances tight on fit-critical points (chest, waist, hip, body length) and looser on styling details (pocket placement, print position).

One detail that saves weeks: describe where each measurement is taken, not just the number. "Chest width" measured 2.5 cm below the armhole can differ by a centimeter from the same garment measured at the armhole itself. A one-line POM definition per row removes an entire category of disputes.

How should size grading be documented?

Grading scales the approved base size up and down the size range. The pack should include a full graded size chart — spec values for every size — not just grade increments.

Grade from the approved base size, never from a sample that still has unresolved fit corrections. If the size medium fit sample is revised but the graded chart still uses pre-revision specs, every size in the range inherits the old error.

The factory needs the finished chart — their pattern maker cuts marker sets directly from it. Check it like an auditor: do the increments stay consistent across the range, do proportions stay sane at the extremes (2XS, 3XL), and does the smallest size still fit the design intent?

What belongs in the bill of materials?

The BOM lists every component that goes into one garment and one packed unit — nothing travels with the garment unless it is on this list. That includes fabric (composition, weight in GSM, weave or knit type, width, color reference), every trim (buttons, zippers, drawcords, eyelets, ribbing), thread (type and color per component), labels (main, size, care, country of origin), hangtags, polybags, and carton materials.

For each line item, factories need: supplier or source status (nominated supplier vs factory-sourced), unit, consumption per garment or per size, and the colorway mapping. Consumption drives the fabric order — understated consumption means fabric shortages mid-production, and reordered fabric can come from a different dye lot.

A common trap: changing the fabric after sample approval without updating the BOM and measurement table. A heavier GSM shrinks and drapes differently; if the specs still describe the old fabric, the bulk fit will not match the approved sample. Any material change resets the relevant spec values — update the pack, version it, and resend.

Fabric specs should read like engineering data, not poetry. "Soft premium cotton" is not a specification; the sample room cannot source it. "100% cotton, single jersey, 180 GSM" can be sourced, costed, and tested. The same applies to finishes: brushed, enzyme-washed, and silicone-softened are three different garments, and the dye house needs the one you approved, by name and by lab dip.

How detailed must construction and stitching specs be?

Detailed enough that a sewing line supervisor can read them without calling your merchandiser. That means, for every seam: the seam type, the stitch class, stitches per inch (SPI), seam allowance, and any reinforcement.

Stitch classes follow the industry standard ASTM D6193 classification, and using the class numbers instead of nicknames prevents translation loss. The classes are:

Class · Stitch range · Typical use

• 100: 101–111 · Single-thread chainstitch (temporary seams)
• 200: 201–209 · Hand and hand-effect stitches
• 300: 301–312 · Lockstitch — most woven garment seams
• 400: 401–410 · Multi-thread chainstitch — denim, sportswear
• 500: 501–516 · Overlock/overedge — knit seams, edge finishing
• 600: 602–612 · Coverstitch/flatlock — hems, activewear

You do not need to memorize these numbers; the reference exists precisely so your pack can cite them. Writing "Class 401 chainstitch, 8 SPI, 1 cm seam allowance" on the side seam is unambiguous in any language. Writing "strong stitching" is a Rorschach test.

Beyond stitching, the construction page should cover seam allowances where they matter (armholes, crotch curves, collars), bar tack locations (pocket corners, belt loops, drawcord exits), hemming method, and assembly order if the garment has an unusual sequence. Finishing details like pressing standards and thread trimming belong here too — what counts as "clean" varies between factories.

What artwork and print files do factories need?

Vector files with the exact placement measured from a fixed point on the garment — not from "about here." A placement described as "center chest" can land anywhere in a 5 cm radius; "top of graphic 8 cm below the back neck seam, 28 cm wide" lands in one place.

For each graphic, the pack should state the decoration method (screen print, embroidery, sublimation, heat transfer, DTG), the vector file version, the Pantone references per ink or thread color, and the dimensions. If the print scales with garment size, say so and give the scaling rule; if it stays fixed across the size run, say that too. Factories consistently flag this as one of the most-asked clarifying questions when it is omitted.

Embroidery needs stitch counts and density in addition to artwork; puff print, foil, and flock need wash-fastness limits stated, since some decorative techniques do not survive industrial laundering. If the garment will be washed after decoration — enzyme wash, garment dye — that goes in the construction notes, because decoration and washing interact.

Do Chinese factories accept digital samples instead of physical ones?

Increasingly, yes — for the early rounds. Tools like CLO 3D and Browzwear let technical designers simulate drape, fit, and colorways on screen before any fabric is cut. Brands and factories report that digital sampling rounds cut sample lead times and physical sample counts substantially. But digital has limits, and Chinese factories are explicit about them.

Round · Digital sample enough? · Why

• Proto / concept review: Usually · Silhouette, proportion, and design intent read well in 3D
• Fit review: Often, with caveats · Drape simulation is good but fabric hand-feel, stretch recovery, and rib behavior still need a body
• Decoration review: Sometimes · Print placement and color accuracy depend on calibrated digital fabrics; ink and thread colors need physical confirmation
• PP / pre-production approval: Rarely · Shrinkage, seam strength, wash behavior, and colorfastness cannot be approved from a screen

The practical workflow most China-based programs use: 3D for proto and early fit to kill bad ideas cheaply, physical samples for fit confirmation and PP approval. When a factory offers a digital sample, ask what is digitally accurate in their setup — the fabric physics model, the avatar, the color calibration — and what still needs a physical check.

None of this removes the need for a complete tech pack. If anything, digital sampling raises the bar: the 3D model is only as accurate as the spec data fed into it.

How do you control revisions once sampling starts?

Every comment round produces changes, and every change needs a version number, a date, and a change log — or both sides end up approving different documents. The working method that holds up:

• Version the whole pack, not just the changed page. Tech pack v1.2 replaces v1.1 in full. Partial page swaps across email threads are how factories sew from stale specs.
• Keep a change log table at the front: version, date, what changed, who approved. This is also the audit trail your quality control process will reference during inspections.
• Mark changes visibly on the pages themselves — cloud the revised POMs or highlight the changed BOM lines — so the pattern maker spots them without re-reading the whole document.
• Freeze the pack at PP approval. After the pre-production sample is signed, changes go through a formal deviation request, not a casual WeChat message. Post-PP changes are the single most reliable way to get bulk that does not match the approved sample.

Plan 2–3 sampling rounds per style and pad timelines around Chinese public holidays, when factories and their suppliers shut down and nothing moves.

Which tech pack mistakes cause the most delays?

Factory merchandisers keep seeing the same failures. Ranked by the damage they do:

Mistake · What goes wrong

• Sending a mockup instead of a tech pack: The factory cannot cost, pattern, or sample from it; the project stalls at the first email
• Design language instead of factory language: "Premium feel" with no GSM, composition, or finish forces the factory to guess materials
• No tolerances on measurements: QC has no standard to inspect against; bulk fit disputes have no reference document
• Changing fabric after sample approval: Shrinkage, drape, and fit shift; the approved sample no longer predicts bulk
• Approving by photo only: Shrinkage, seam strength, and hand-feel need physical checks; photo approval hides them
• Leaving packing specs to the end: Carton ratios, barcodes, and polybag rules surface too late and miss the shipping window

Notice the pattern: every one of these is a missing decision pushed onto the factory. Chinese factories are excellent at executing specifications; they are not mind readers. Before you send, do a cold read of your own pack and count the sentences a stranger could interpret two ways. Each one is a future sample round.

Tech pack FAQ for brands sourcing from China

How long should a tech pack be?

As long as it takes to be complete — usually 8–15 pages for a standard cut-and-sew garment, more for technical outerwear. Length is not the metric; ambiguity is. A factory would rather receive a tight 10 pages with real numbers than 40 pages of inspiration images and vague notes.

Can I send a tech pack as an Excel file?

Yes — many factories prefer Excel for the measurement spec and BOM, because the data drops straight into their costing and pattern systems. PDF is standard for flats and construction pages. What matters is editable data where data belongs (measurements, BOM lines) and locked visuals where visuals belong (flats, artwork).

Do I need a tech pack for a simple T-shirt?

Yes. Even a basic tee needs fabric specs, a graded size chart, stitching details, and label placement. Simple garments go wrong in simple ways — wrong GSM, missing size labels, hem curling — and only the tech pack prevents those errors.

What is a lab dip, and does it belong in the tech pack?

A lab dip is a small dyed fabric swatch the dye house produces for your color approval before bulk dyeing. The approved lab dip reference number belongs on the colorway page, next to the Pantone reference. Without it, the factory has no approved standard to dye against.

Who owns the tech pack — the brand or the factory?

The brand owns the design intent and the original document; the factory typically owns the pattern derived from it. Keep your version controlled on your side, and confirm in writing which document governs if the factory keeps its own internal spec sheet. When those two disagree in a QC dispute, the one both parties signed wins.

The 10-minute pre-send rule

Read your finished pack once, top to bottom, with this checklist. If it passes, send it; if not, fix it before the factory reads it.

1. Every page has the style number, version number, and date.
2. Every measurement has one unit system and a tolerance.
3. Every BOM line has a spec, not an adjective.
4. Every artwork has a vector file, placement from a fixed point, and a scaling rule.
5. Every construction note names a stitch class or seam type, not "strong" or "neat."
6. Packing specs are in the pack, not in a later email.
7. The change log shows what moved since the last version.

A tech pack is a contract written in numbers. Brands that treat it that way get faster quotes, fewer sample rounds, and bulk production that matches the approved sample. If you want a second pair of eyes on your pack before it goes to a factory — checking that the specs say what you think they say — write to hi@cnally.com. Reviewing packs against factory reality is part of what our product sourcing work covers, and catching a missing tolerance on paper is always cheaper than catching it in bulk.