\n| Exploded view<\/td>\n | Component separation for assembly<\/td>\n | All layers shown in order: shell, interlining, lining<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Each drawing should use clean outlines with construction lines marking seam positions, fold lines, and measurement points. Avoid shaded renderings or three-dimensional mockups in the tech pack itself. Those belong in a separate design presentation. The tech pack drawings are working documents for pattern makers and sewing line supervisors who need flat, dimensioned views they can measure against.<\/p>\n Every measurement callout on the drawings should specify the target dimension and the tolerance. For example, a bag height callout might read “45 cm plus or minus 0.5 cm.” Without tolerances, the factory has no reference for what constitutes an acceptable variation versus a defect. Tolerances on soft goods like bags typically range from 0.3 cm on small dimensions to 1.0 cm on large dimensions, tighter than apparel because bags have structural requirements that apparel does not.<\/p>\n Measurement Points: What to Specify and How to Call Them Out<\/h2>\nA bag tech pack must capture precise sizing details across multiple dimensions. Incomplete measurement callouts are the most common cause of first-sample deviations, because the factory fills in missing dimensions based on its own assumptions rather than the buyer’s intent.<\/p>\n \n- Height:<\/strong> Measured from the bottom edge to the top opening, excluding handles<\/li>\n
- Width:<\/strong> Measured across the front panel at the widest point<\/li>\n
- Depth (gusset):<\/strong> Measured from front panel to back panel at the side seam<\/li>\n
- Handle drop:<\/strong> From the top of the bag opening to the highest point of the handle loop<\/li>\n
- Strap length:<\/strong> Full length including attachment hardware, measured flat<\/li>\n
- Inside pocket dimensions:<\/strong> Height and width of each internal pocket<\/li>\n
- Zipper length:<\/strong> Measured from tape end to tape end, not just the teeth<\/li>\n
- Logo placement:<\/strong> Distance from top edge and side edge to the logo center point<\/li>\n<\/ul>\n
For each measurement, specify the unit (centimeters for international production), the target value, and the tolerance. A measurement table in the tech pack should list every dimension in a single reference so the factory can check each one against the sample without hunting through drawings.<\/p>\n ![\"Signing](\"https:\/\/tiiocti.com\/wp-content\/uploads\/2026\/04\/preproduction-sample-bags-signing-off-from-sample-to-bulk-example-scaled.jpg\") <\/p>\n
Construction Notes: Stitch Types, SPI, and Edge Treatments<\/h2>\nConstruction notes tell the sewing line exactly how to assemble the bag. This section prevents the most expensive class of errors: bags that look correct but fail in use because the stitching, reinforcement, or edge treatment was wrong.<\/p>\n Panel breakdowns specify which pattern pieces make up the bag and how they join. A typical woven PP moving bag has six panels: front, back, two sides, base, and top flap. The construction note should list each panel, its material specification, and the seam type that joins it to adjacent panels.<\/p>\n Stitch type and stitches per inch (SPI) determine seam strength. The tech pack should specify the stitch type for each seam \u2014 classifications defined in ASTM D6193, Standard Practice for Stitches and Seams<\/a> : lockstitch (301) for general seams, chainstitch (401) for heavy-load seams, or bartack for stress points. SPI counts for heavy-duty bags typically run 7 to 9 SPI, meaning 7 to 9 stitches per inch of seam. Lower SPI means larger stitches and faster sewing but weaker seams. Higher SPI means tighter stitches and stronger seams but slower production and higher needle penetration stress on the material.<\/p>\n \n\n\n| Seam Location<\/th>\n | Stitch Type<\/th>\n | SPI Range<\/th>\n | Thread Spec<\/th>\n<\/tr>\n<\/thead>\n | \n\n| Main body seams<\/td>\n | Lockstitch (301)<\/td>\n | 7 to 9<\/td>\n | Tex 40 bonded nylon<\/td>\n<\/tr>\n | \n| Handle attachment<\/td>\n | Bartack<\/td>\n | Density spec<\/td>\n | Tex 60 bonded nylon<\/td>\n<\/tr>\n | \n| Zipper tape<\/td>\n | Lockstitch (301)<\/td>\n | 8 to 10<\/td>\n | Tex 30 polyester<\/td>\n<\/tr>\n | \n| Base reinforcement<\/td>\n | Chainstitch (401)<\/td>\n | 6 to 8<\/td>\n | Tex 60 bonded nylon<\/td>\n<\/tr>\n | \n| Edge binding<\/td>\n | Lockstitch (301)<\/td>\n | 9 to 11<\/td>\n | Tex 20 polyester<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Edge treatments depend on the material. Woven PP bags typically use folded and topstitched edges or bias tape binding. Oxford and canvas bags may require edge paint, burnish, skive, or turn treatments. The tech pack should specify the treatment for every raw edge on the bag, because unfinished edges fray and delaminate during use. A skive specification tells the sewing line to thin the material at the edge before folding, reducing bulk at seams. A burnish specification smooths the edge of leather or coated materials. Each treatment requires specific equipment and time, and omitting them from the tech pack means the factory may skip them to save time.<\/p>\n Bill of Materials: The Complete Component Inventory<\/h2>\nThe BOM (bill of materials) catalogs every material and component that goes into the bag. A complete BOM allows the factory to source all inputs in parallel, reducing lead time, and enables the buyer to verify material costs and quality at each tier of the supply chain.<\/p>\n \n\n\n| BOM Category<\/th>\n | Typical Items<\/th>\n | Required Data<\/th>\n<\/tr>\n<\/thead>\n | \n\n| Shell material<\/td>\n | Woven PP, Oxford, canvas, jute<\/td>\n | Material, GSM, width, color, supplier<\/td>\n<\/tr>\n | \n| Lining<\/td>\n | PP non-woven, polyester, cotton<\/td>\n | Material, GSM, color<\/td>\n<\/tr>\n | \n| Interlining<\/td>\n | Foam, PE board, non-woven stiffener<\/td>\n | Thickness, density, purpose<\/td>\n<\/tr>\n | \n| Trims<\/td>\n | Webbing, binding, drawcord<\/td>\n | Width, material, color, length per bag<\/td>\n<\/tr>\n | \n| Hardware<\/td>\n | Zippers, sliders, buckles, D-rings<\/td>\n | Brand, size, finish, quantity<\/td>\n<\/tr>\n | \n| Thread<\/td>\n | Bonded nylon, polyester<\/td>\n | Tex size, color, supplier<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Each BOM line item should capture supplier information, minimum order quantities, lead times, and unit cost. For the buyer, this transparency reveals where costs concentrate and where substitution might save money without compromising quality. A BOM that lists only “zipper, black, 60cm” without specifying the brand, tape material, slider type, and pull tab design leaves the factory free to source whatever is cheapest, which may not meet the buyer’s quality standard.<\/p>\n The costing sheet extends the BOM by adding labor, packaging, and freight and waste allowances. A typical bag costing sheet breaks down: material cost (from BOM), cutting and sewing labor (per piece rate), finishing labor (edge treatment, quality inspection), packaging (poly bag, carton, label), and a waste allowance (usually 2 to 5% of material cost). The buyer should review this sheet to understand which cost components are fixed versus variable when negotiating price tiers at different order volumes.<\/p>\n Five Common Errors a Tech Pack Prevents<\/h2>\nWhen a buyer sends a tech pack to a factory, the document prevents five specific categories of manufacturing errors that otherwise occur during sample and production runs.<\/p>\n The first error is dimension ambiguity. Without a tech pack, the factory estimates dimensions from photos or verbal descriptions. A buyer asking for a “large moving bag” may envision 120 liters while the factory produces a 90-liter bag. The tech pack’s measurement table eliminates this gap by specifying exact dimensions with tolerances.<\/p>\n The second error is material substitution. Without a specified material in the BOM, the factory sources the cheapest available option that looks similar. A buyer expecting 120 GSM woven PP may receive 90 GSM material that looks identical but fails under load. The BOM locks the material specification and forces the factory to source to standard.<\/p>\n The third error is seam failure. Without construction notes specifying stitch type and SPI, the sewing line uses whatever method is fastest. A heavy-duty moving bag sewn with 5 SPI lockstitch instead of 8 SPI will fail at the seams when loaded. The construction note prevents this by telling the sewing supervisor exactly what stitch to use where.<\/p>\n The fourth error is hardware mismatch. Zippers, buckles, and D-rings come in hundreds of variants. Without hardware specifications in the BOM, the factory may use a zinc alloy zipper pull when the buyer expected stainless steel, or a 3mm webbing when the buyer expected 5mm. The BOM’s hardware section specifies brand, size, finish, and quantity for every component.<\/p>\n The fifth error is branding placement inconsistency. A logo printed 5cm from the top edge on one bag and 7cm on another looks unprofessional in a retail setting. The tech pack’s logo placement callout specifies the exact distance from reference edges, ensuring every bag in the production run carries the logo in the same position.<\/p>\n ![\"Material](\"https:\/\/tiiocti.com\/wp-content\/uploads\/2026\/04\/preproduction-sample-bags-material-verification-and-reach-co-highlight-scaled.jpg\") <\/p>\n
Working With a Factory: From Tech Pack to Approved Sample<\/h2>\nOnce the tech pack is complete, the workflow from submission to approved sample follows a predictable sequence. The buyer sends the tech pack to the factory, the factory reviews it for manufacturability and returns a quote with material costs and lead time. If the quote is accepted, the factory produces a pre-production sample (PPS) based on the tech pack specifications.<\/p>\n The buyer inspects the PPS against the tech pack. Every measurement is checked, every material is verified against the BOM, and every seam is examined for stitch type and SPI compliance. Discrepancies are documented and sent back as a revision note. The factory produces a revised sample incorporating the changes. Ideally, the second sample is approved and production proceeds.<\/p>\n For buyers working with TIIOCTI, the factory accepts tech packs in PDF or AI format and assigns a dedicated merchandiser to review the specifications. The factory produces pre-production samples within 7 to 10 days of tech pack approval. Buyers sourcing custom moving bags<\/a> or drawstring bags<\/a> can submit tech packs directly for quoting.<\/p>\nFor a structured approach to requesting quotes, see our bag factory RFQ template<\/a> which works alongside the tech pack. And for guidance on evaluating the quotes that come back, our guide on comparing three bag factory quotes<\/a> covers the dimensions to compare.<\/p>\nFrequently Asked Questions<\/h2>\nWhat is a tech pack for bags?<\/h3>\nA tech pack is a technical specification document that tells a bag factory exactly how to produce a bag. It includes technical drawings, measurement tables, construction notes with stitch types and SPI counts, a bill of materials, and quality control parameters. The tech pack serves as the manufacturing contract between buyer and factory.<\/p>\n What drawings should a bag tech pack include?<\/h3>\nA bag tech pack should include front, back, side, base, and inside views at minimum. Complex designs with multiple layers may also need an exploded view showing component separation. Each drawing should use clean outlines with construction lines and dimension callouts with tolerances.<\/p>\n What are construction notes in a bag tech pack?<\/h3>\nConstruction notes specify how the bag is assembled: panel breakdowns, stitch types (lockstitch, chainstitch, bartack), stitches per inch counts, edge treatments (skive, burnish, fold, paint), and reinforcement specifications. They tell the sewing line exactly what to do at each seam.<\/p>\n What should a bag BOM include?<\/h3>\nA bag bill of materials should catalog shell material, lining, interlining, trims, hardware, and thread. Each line item should specify material type, GSM or thickness, dimensions, color, supplier, MOQ, lead time, and unit cost. The BOM enables parallel sourcing and cost transparency.<\/p>\n How does a tech pack prevent manufacturing errors?<\/h3>\nA tech pack prevents dimension ambiguity, material substitution, seam failures from incorrect stitching, hardware mismatches, and branding placement inconsistency. By specifying every detail before production begins, it eliminates the guesswork that leads to sample revisions and production defects.<\/p>\n | | |
![\"Pre-production](\"https:\/\/tiiocti.com\/wp-content\/uploads\/2026\/04\/preproduction-sample-bags-what-is-a-preproduction-sample-detail-scaled.jpg\")
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