A bag tech pack is the document that specifies a design precisely enough for a production floor to build it without guessing. It contains technical drawings, a dimension schedule with tolerances, a bill of materials, construction and assembly notes, and branding and packing specifications. It drives production because it is the single authority every stage refers to: patterns are cut from it, materials are ordered from it, and finished units are inspected against it.
This article explains how to create a bag tech pack that actually drives production, what each section should contain, how to write tolerances so that pass or fail is objective, and the omissions that cause the most expensive mistakes. It is written for designers, brand owners and sourcing managers who need a specification a manufacturing partner can execute rather than interpret.
The tech pack is not a formality attached to a design; it is the design in a form that survives contact with production. A sketch communicates intent to a person looking at it. A tech pack communicates intent to a cutting table, a sewing line and an inspection bench, none of which can ask a follow-up question. The effort spent making it unambiguous is repaid the first time a run repeats without redevelopment.
Programme parameters at a glance
| Parameter | Commitment |
|---|---|
| Minimum order quantity | 500 pieces per style / colourway |
| Sampling lead time | 6–10 working days (12–15 days for complex constructions) |
| Bulk production lead time | 35–50 days after sample approval |
| Inspection standard | AQL 2.5 (ISO 2859-1), single sampling, general level II |
| Incoterms | FOB Xiamen — EXW, CIF and DDP available on request |
| Payment terms | T/T 30% deposit / 70% before shipment; L/C at sight for container loads |
| Verified production floor space | 4,950 m² (SGS-verified) |
| Team | 137 staff across 7 production lines |
| Equipment | 149 machines including computerised saddle-stitch and edge-painting units |
| Monthly capacity | 200,000 pieces |
| Entity | Founded 2014; principal has worked in bag development since 2004 |
What a Tech Pack Is and Why It Drives Production
A tech pack is the connective tissue of a bag programme. It sits between the design idea and the physical run, and it is consulted at every stage. When it is complete, decisions are made once, in one place, and every stage inherits them. When it is incomplete, decisions are made repeatedly, in different places, and drift creeps in.
| Stage | How the tech pack is used | What it prevents |
|---|---|---|
| Pattern-making | Panels are graded and shaped from the drawings and dimensions | Panels that do not fit or that yield poorly |
| Material purchasing | Leather, lining, thread and hardware are ordered from the bill of materials | Wrong material or component substitution |
| Cutting | Panel placement and grain direction follow the specification | Mismatched panels and inconsistent grain |
| Assembly | Sequence, seam types and stitch density are set by construction notes | Seams that vary between units |
| Finishing | Edge treatment and interior fit-out follow the finishing specification | Inconsistent edges and lining |
| Inspection | Units are checked against the dimension schedule and tolerances | Subjective judgements and disputes |
| Reorder | A repeat run inherits the specification without redevelopment | Reinventing the design at every order |
The reorder row is the commercial case for a good pack. Every decision captured in the pack is a decision that does not have to be made again, so the second run, the third and the tenth all start from the specification rather than from a blank page. Over the life of a style, the pack is the difference between a product and a series of related one-offs.
The Core Sections of a Bag Tech Pack
A complete pack is organised into sections so that each reader finds what they need without scanning the whole document. A pattern-maker reads the drawings and dimensions; a purchasing officer reads the bill of materials; a line supervisor reads the construction notes. The sections overlap deliberately where a single fact serves more than one reader.
- Cover sheet with the style name, code, revision number, date and the person who approved the current version.
- Design intent, with reference images or a mood board, so the reader understands the concept behind the specification.
- Technical drawings: front, back, side, top and interior views, from an external view and from a sectioned view where helpful.
- Dimension schedule listing every critical measurement with a nominal value and a stated tolerance.
- Bill of materials naming every leather, lining, reinforcement, thread and hardware item by part code, finish and supplier reference.
- Construction notes describing the assembly sequence, seam types, stitch density and reinforcement placement.
- Finishing specification covering edge treatment, lining specification and interior fit-out.
- Branding and packing specification giving logo position, label placement and carton configuration.
The revision number on the cover sheet is not decoration. Over a development cycle a pack changes, and production must build to the current version rather than to a superseded one. Naming the version, dating it and recording who approved it removes the most common source of specification drift between buyer and producer.
Technical Drawings, Dimensions and Tolerances
The drawings and dimension schedule are the heart of the pack, because they define the bag's form in measurable terms. Drawings communicate shape and proportion; the schedule makes the important measurements checkable. Together they replace the phrase 'the same as the sample' with a numeric target that survives the sample being lost, worn or mislaid.
| Measurement | Nominal example | Typical tolerance | Why it is controlled |
|---|---|---|---|
| Overall width | 320 mm | ± 2 mm | Determines how the bag reads against its market |
| Overall height | 240 mm | ± 2 mm | Affects proportion and internal capacity |
| Depth or gusset | 120 mm | ± 2 mm | Governs volume and how the bag sits when loaded |
| Strap drop | 540 mm | ± 5 mm | Sets where the bag hangs on the body |
| Handle drop | 110 mm | ± 3 mm | Determines carry comfort for a handheld format |
| Zip length | 280 mm | ± 3 mm | Controls opening and the fit of the closure |
| Logo position | 90 mm from top edge, centred | ± 2 mm | Protects brand presentation consistency |
Tolerances should be realistic as well as tight. A tolerance wider than a customer would notice is a missed opportunity to control quality; a tolerance tighter than the material can hold, such as demanding a naturally variable leather meet a machining-level tolerance, guarantees rejection and wastes material. Tolerances are best set by material class: leather forgives less precision than a die-cut panel, and soft linings move more than firm ones.
The Bill of Materials and Hardware Schedule
The bill of materials is the pack's purchasing document. It lists everything the bag consumes, named precisely enough that nothing has to be chosen on the floor. Hardware deserves particular care, because it is the category most prone to silent substitution: a zip that is functionally similar but visually different will undo an otherwise faithful run.
The discipline is to name components by part number and finish rather than by description. 'A gold zip of about 28 cm' invites interpretation; a part number and finish does not. Where a component may need to be sourced from more than one place, the pack should name both options and confirm that they are visually and functionally interchangeable — and that any change is approved by a physical sample rather than accepted as a written equivalent.
Construction and Assembly Notes
Construction notes describe how the bag is built, in the order it is built. They exist because the same set of panels can be assembled in more than one way, and the ways are not equally strong or equally clean. The notes fix the sequence, the seam types and the points of reinforcement, so assembly does not depend on the preference of whoever happens to be at the machine.
- Assembly sequence, stated as numbered steps from sub-assembly through closing and turning.
- Seam type at each join, distinguishing plain seams, lapped seams and any bound or piped treatment.
- Stitch density in stitches per inch, agreed per material and held through the run.
- Reinforcement placement, naming where interlining or backing is added and how far it extends.
- Skiving instructions, defining where leather is thinned and to what thickness.
- Hardware setting method, whether by press, setter or hand, and the sequence in which items are fitted.
- Any hand-finishing steps, with the standard the finish must meet rather than a description of the process.
Stitch density deserves a note of its own because it is where construction meets strength. The value is agreed for each material: too coarse and a seam is weak and visually loose, too fine and the leather can perforate along the line and tear under load. Because the value is material-specific, it is recorded in the pack against the material rather than as a single number for the whole bag.
Branding, Labelling and Packaging Specification
Branding is specified in the pack with the same rigour as construction, because a logo in the wrong place or at the wrong depth is more visible than many structural faults. Labelling and packaging belong in the same section, since they are the brand's last controlled touchpoints before the customer opens the box.
| Element | What the pack specifies | Common pitfall if omitted |
|---|---|---|
| Logo placement | Process, position and dimensions on the pattern | Logo drifts between units and runs |
| Deboss or foil | Depth, temperature range and finish | Inconsistent depth or a weak impression |
| Interior label | Material, size, position and content | Label placed by eye or missing |
| Care or origin labels | Content, language and position | Compliance information absent |
| Dust bag and wrap | Material, size and branding | Unboxing inconsistent with the brand |
| Carton | Dimensions, count per carton and labelling | Packing does not protect or identify goods |
| Unit packing method | Stuffing and hardware protection | Transit damage presenting as a defect |
Packing is included in the tech pack not because it is manufacturing, but because it is a specification like any other. A carton configuration agreed in the pack protects the product and speeds receiving, while one left to chance creates damage that the customer experiences as poor quality. Labelling also carries compliance content for many markets, which is easier to manage when it is specified once than reconstructed at each shipment.
Common Tech Pack Mistakes and How to Fix Them
Most tech pack failures are recurring and predictable. Naming them in advance is often enough to avoid them, because each mistake has a simple, structural fix that belongs in the document rather than in a conversation.
| Mistake | Consequence | Fix |
|---|---|---|
| No tolerances | Pass or fail becomes a matter of opinion | Add a nominal value and tolerance to every critical measurement |
| Components described, not numbered | Silent substitution during production | Name every item by part code and finish |
| Drawings without a construction view | The interior and seams are left to interpretation | Add interior and sectioned views to the drawing set |
| No revision control | Production builds to a superseded version | Number, date and sign each revision on the cover sheet |
| Ambiguous material reference | Lot variation reads as a defect | Name the tannery or supplier reference and the colour target |
| Branding as an afterthought | Logo placement drifts across the run | Mark branding on the pattern and confirm it on the sample |
| Packing left unspecified | Transit damage and inconsistent unboxing | Add a packing and carton specification to the pack |
The thread running through these fixes is precision. A tech pack works when every reader reaches the same conclusion from it, and the failures above are all cases where two reasonable readers could disagree. Writing for the least-informed reader on the floor, rather than for a design colleague who shares context, is the habit that produces a pack that drives production.
How the Tech Pack Travels Through Production
A tech pack is only useful if it is present where the work happens. The specification should follow the bag through every stage, so that the reference the designer used is also the reference the line uses. In practice this means the pack is not filed away after sampling; it is maintained, versioned and made available at cutting, assembly, finishing and inspection.
| Production point | Pack content on hand | Check performed |
|---|---|---|
| Sample build | Full pack, current revision | Sample judged against drawings and dimensions |
| Material order | Bill of materials and hardware schedule | Components ordered to part code and finish |
| Cutting | Patterns and dimension schedule | Panels cut to shape and placement rules |
| Assembly | Construction and assembly notes | Sequence and stitch density followed |
| Finishing | Finishing and branding specification | Edge treatment and logo placement to standard |
| Inspection | Full pack with tolerances | Units checked objectively against the schedule |
| Reorder | Retained frozen pack | Repeat run raised without redevelopment |
When the pack travels properly, the finished run is a physical record of the document. Where it does not, the pack becomes a development artefact that describes what was meant rather than what was made. Keeping it current is light work during a run and decisive for the run that follows.
Turn your design into a production-ready tech pack
Send your sketches, reference bag and target specification to service@junyuanbags.com, or message the programme team on WhatsApp at +86 177 5002 0688. We will review your pack against production requirements and highlight what to add before sampling begins.
Frequently Asked Questions
What is a bag tech pack?
A bag tech pack is the document that specifies a design precisely enough for production to build it without guessing. It contains technical drawings, a dimension schedule with tolerances, a bill of materials, construction and assembly notes, and branding and packing specifications. It is the single authority every stage refers to, which is why a complete pack lets a design sample once and then repeat reliably.
What should a bag tech pack contain?
A complete pack has a cover sheet with revision control, a design intent section, technical drawings from multiple views, a dimension schedule with nominal values and tolerances, a bill of materials naming every component by part code, construction and assembly notes, a finishing specification, and a branding and packing specification. Each section serves a specific reader on the production floor.
Why is a tech pack important for bag production?
Because it converts a design into instructions that survive contact with production. A sketch communicates intent to a person; a tech pack communicates intent to a cutting table, a sewing line and an inspection bench, none of which can ask a follow-up question. A complete pack means decisions are made once, in one place, and inherited by every stage rather than remade each time.
How detailed should tolerances be in a bag tech pack?
Tolerances should be realistic as well as tight. Every critical measurement needs a nominal value and a tolerance so that pass or fail is objective. Set them by material class: leather forgives less precision than a die-cut panel, and soft linings move more than firm ones. A tolerance wider than a customer would notice is a missed control, and one tighter than the material allows guarantees rejection.
What is the difference between a tech pack and a specification sheet?
A specification sheet usually lists materials and key measurements, while a tech pack is a complete engineering file. The pack adds technical drawings, construction and assembly notes, hardware part numbers with finishes, branding and packing specifications, and revision control. The specification sheet answers what the bag is made of; the tech pack also answers how it is built and how it is checked.
How do I write a bill of materials for a bag?
List every item the bag consumes and name it precisely enough that nothing has to be chosen on the floor. For hardware, name each zip, lock, ring, buckle and foot by part number and plated finish rather than by description, because hardware is the category most prone to silent substitution. Where two components are interchangeable, name both and confirm that any change is approved by a physical sample.
Why do bag tech packs need revision numbers?
Because a pack changes during development, and production must build to the current version rather than a superseded one. Naming the revision number, dating it and recording who approved it removes the most common source of specification drift between buyer and producer. Without revision control, a run can be built faithfully to a version the brand has already replaced, and nobody notices until units arrive.
How does a tech pack prevent manufacturing mistakes?
It prevents them by removing ambiguity before work begins. Panels are cut from the drawings, materials are ordered from the bill of materials, seams follow the construction notes and units are inspected against the dimension schedule. Each of those replaces a judgement call with a specification, and a judgement call made on the production floor is exactly where avoidable variation enters a run.
Should branding be included in the tech pack?
Yes, branding belongs in the pack with the same rigour as construction. A logo in the wrong place or at the wrong depth is more visible than many structural faults, so the process, position and dimensions are marked on the pattern and confirmed on the sample. Labelling and packing specifications sit in the same section, as they are the brand's last controlled touchpoints before the customer opens the box.
What is construction notes in a tech pack?
Construction notes describe how the bag is built, in the order it is built. They state the assembly sequence, the seam type at each join, stitch density in stitches per inch, reinforcement placement, skiving instructions and the hardware setting method. They exist because the same panels can be assembled in more than one way, and not all ways are equally strong or equally clean.
How does a tech pack help with reorders?
A reorder inherits the pack rather than rebuilding it. Because patterns, bill of materials, construction notes and tolerances are already specified, a repeat run can be raised without redevelopment, which makes it faster and cheaper than the first order. Every decision captured in the pack is a decision that does not have to be made again, and over the life of a style that is its main commercial value.
Can I create a tech pack without a design background?
You can assemble the content, but the construction and tolerance sections benefit from technical input, which a production partner can supply. The practical route is to provide the design intent, reference images and target measurements, then work with a technical partner to complete the drawings, bill of materials and construction notes. A pack built collaboratively is usually more complete than one written in isolation.
What is the difference between a development sample and a production sample?
A development sample is built to prove the design and is made from available development stock. A production or pre-production sample is built from the actual production materials, which is why it can reveal lot-based differences such as a shade shift or a firmer hand. Where the pre-production sample matches the approved reference, the run can proceed with confidence; where it differs, the difference is resolved before bulk begins.
How precise do bag measurements need to be?
Precise enough that a reasonable deviation is detectable and a reasonable tolerance is stated. Overall dimensions are often held to a couple of millimetres, strap drops to about five, and logo position to about two, depending on material and construction. The numbers matter less than the fact that they are written down, because a stated tolerance makes inspection objective rather than a matter of opinion.
Who uses a bag tech pack on the production floor?
Different sections serve different readers. A pattern-maker uses the drawings and dimension schedule, a purchasing officer uses the bill of materials, a line supervisor uses the construction notes, a finishing hand uses the finishing and branding specification, and an inspector uses the tolerances. The pack overlaps deliberately where a single fact serves more than one reader.
What happens if a tech pack is incomplete?
The missing decisions get made anyway, but on the production floor, where they cost more and are harder to reverse. An absent tolerance becomes a judgement call, an unnumbered component invites substitution and an unspecified packing method becomes a risk in transit. Incompleteness does not save work; it defers the work to a stage where correcting it requires remaking samples or cutting new panels.