Custom Automatic Bottom Folding Cartons
Pre-glued, line-ready cartons that ship KDF and lock into shape on squaring. Built for automated cartoners and high-mix lines, they deliver faster erecting, lower labor, and consistent quality—without sacrificing brand finish or sustainability.
- Faster, steadier runs: Auto-locking base for stable CPM on vertical/horizontal cartoners; magazine-feed bundles.
- Stronger base, cleaner close: Crash-lock bottom + RTE/STE tops with optional dust flaps and tamper evidence.
- Engineered specs: SBS/FBB/CRB, 250–500 gsm; crease-to-cut tolerance ±0.3–0.5 mm; side-seam PVA/hot-melt.
- Brand-true finishes: Offset/Digital/UV; AQ/UV coats; matte/gloss/soft-touch; foil, emboss/deboss; window patching (PET/RPET/cellulose).
- Sized to fit: Standard S/M/L or full custom L × W × H (defined by opening orientation).
- Sustainability options: FSC fibers, recycled content, film-light builds, clear on-pack disposal notes.
- Lead time & MOQ: Typical 1,000–3,000 MOQ; ~12–25 days after approvals (finishes/windows may add).
- Industries: FMCG, pharma/healthcare, electronics/components, e-commerce kitting.
What Is an Auto-Bottom (Crash-Lock) Carton?
An auto-bottom—also called a crash-lock bottom (CLB)—is a pre-glued folding carton that ships KDF (knocked down flat) and locks into shape instantly when squared. The base forms a rigid structure without hand-tucking, so your team (or a cartoner) can erect and load at speed with minimal manual handling. Pair the base with RTE (Reverse Tuck End) or STE (Straight Tuck End) tops and optional dust flaps to suit your filling, coding, and sealing steps.
3-Step workflow
- Square the KDF blank → geometry snaps true.
- Base auto-locks → rigid bottom forms.
- Load, close RTE/STE top → code/label → case pack.
Spec snippet
- Board (paperboard): SBS/FBB/CRB 250–500 gsm
- Adhesive: side-seam PVA or hot-melt; pre-glued crash-lock base
- Dimensions: L × W × H (defined by opening orientation)
- Delivery: KDF; bundled for magazine feeding
Auto-Bottom vs. Snap-Lock vs. Standard Tuck End
Pick by speed, labor, and line fit.
| Feature | Auto-Bottom (CLB) | Snap-Lock / 1-2-3 Bottom | Standard Tuck (RTE/STE) |
|---|---|---|---|
| Erecting speed | Fastest (pop-open) | Medium (manual tucks) | Medium–fast (needs gluing/closing) |
| Labor reliance | Low | Medium | Medium |
| Automation fit | Excellent (vertical/horizontal cartoners) | Limited–Medium | Good with gluer/cartoner |
| Base rigidity | High | High (if glued well) | Medium |
| Unit cost | $$ | $–$$ | $–$$ |
| Best for | High-velocity, stable CPM | Mid-volume, mixed styles | Cost-sensitive, simple packs |
Rule of thumb
If uptime and CPM matter most → Auto-Bottom. If conversion cost is #1 and hand-work is acceptable → Standard Tuck. For mixed programs → Snap-Lock.
Automation & Line Compatibility
Engineered for vertical/horizontal cartoners with magazine feed or pick-and-place.
Line-ready parameters (typical ranges, size-dependent)
- Erecting rate: up to 120–240 cpm
- Tolerances: crease-to-cut ±0.3–0.5 mm; glue flap width ≥10–12 mm
- Adhesives: PVA/hot-melt; define dwell time per board/finish
- Magazine pack: bundle size & strap tension matched to your hopper
Integration notes
- Reserve flat code/label panels; add datamatrix/lot zones on STE where needed.
- Provide fit sheets and CAD so your OEM can dial in guides, squaring plates, and suction cups.
Top Closures & Security
Choose tops by operator access, print area, and security.
- RTE (Reverse Tuck End): fast hand close; good for high-mix lines.
- STE (Straight Tuck End): clean front face; ideal for code windows, clearances, and shelf display.
- Dust flaps: reduce ingress and add edge integrity.
- Tamper-evident elements: tear strips, security labels, VOID tape, perforated tabs.
- Pharma options: braille panel, pharmacode/GS1 zones, proof-of-opening labels.
Materials & Calipers (Paperboard)
Select board for strength, print, and regulatory needs.
| Board | Look/Use | Typical Range |
|---|---|---|
| SBS (Solid Bleached Sulfate) | Premium white, color-critical print (cosmetics/pharma) | 300–450 gsm |
| FBB (GC1/GC2) | Stiffer multi-ply; great stiffness-to-weight | 300–450 gsm |
| CRB (Coated Recycled Board) | Value with recycled content | 350–500 gsm |
Functional finishes
Anti-scuff varnish, moisture-tolerant coatings, oil-resist where needed. For food/pharma, align with contact/labeling requirements.
Printing & Surface Finishes
Keep art brand-true and line-durable.
- Printing: Offset for detail; Digital for short runs/versions; UV for fast cure & rub-resistance.
- Color control: Pantone for brand hues; drawdowns on actual stock/finish.
- Coatings/films: AQ/UV for protection; matte/gloss/soft-touch laminations for tactile stories (balance with recyclability).
- Decor: foil (logo/borders), emboss/deboss, spot UV (logo highlights).
- Window patching: PET/RPET or cellulose film; align with knife/crease to avoid tear.
Structural Reinforcements & Add-Ons
- Crash-panel geometry: tune panel width for base rigidity.
- Internal features: paperboard inserts, tabs, retainers, or dividers to stop product shift.
- Usability: tear strips, hang holes, finger notches, reclose labels.
- Security: tamper seals, serialized stickers; anti-sweep tabs for small SKUs.
Sizes: Standard & Custom (L × W × H)
Use opening orientation to define L/W/H. Offer stocked “S/M/L” plus full custom.
Common stocked sizes (mm)
- Small: 80 × 60 × 100
- Medium: 120 × 80 × 200
- Large: 200 × 150 × 300
(Custom dimensions on request; inch equivalents optional.)
Sizing quick tips
- Add fit clearance for liners/inserts (1–2 mm each side).
- Keep COG centered; avoid port/hinge pressure.
- Reserve 5–10 mm headspace for top closure & printing tolerances.
Engineering Specs & Tolerances
Recommended starting points
- Crease bead width: matched to caliper; avoid fiber crack at scores.
- Cut/score tolerance: ±0.3–0.5 mm; registration ≤0.2 mm for tight art.
- Glue: side-seam length ≥15 mm where possible; clean squeeze-out control.
- Grain direction: align with height for squaring stability and shelf stand-up.
Documentation to share
Knife/crease map, glue diagram, grain orientation, code/label zones.
Testing & QA (System-Level)
Validate carton + product + shipper as a system.
- Carton tests: bond strength (peel/shear), opening/closing cycles, squaring stability.
- Transit tests: drop/vibration/compression in the outer shipper; check scuffing on printed faces.
- Line simulation: erect/load at target CPM; watch for fishtails, mis-squares, and magazine doubles.
- Aesthetics: rub/abrasion on edges; color delta on live stock; soft-touch mar tests.
Industry Applications
FMCG — high SKU velocity; CLB + RTE for operator speed; anti-scuff coats for conveyors.
Pharma/Healthcare — STE face for codes; tamper seals, braille, DataMatrix zones.
Electronics/Components — CLB base + insert tabs to immobilize; anti-scuff.
E-commerce — fast erecting for kitting; label zones and return-friendly tops.
Sustainability
- Fiber choices: FSC options; recycled content in CRB/FBB variants.
- Chemistry: water-based inks, AQ/UV over heavy films when possible.
- Windows: RPET or cellulose for plastic-reduced messaging.
- On-pack guidance: clear disposal notes (“Carton: recycle curbside; remove film if present”).
- Right-sizing: optimize board gsm and dimensions to cut fiber and freight.
Cost, MOQ & Lead Time (Ranges)
- Cost drivers: size (L×W×H), board gsm/grade, print coverage/colors, finishes, window patching, run length.
- Typical MOQs: CLB cartons 1,000–3,000 (offset); digital pilots lower.
- Lead time after approvals: 12–25 days (finishes/windows add +2–7).
- Save more: shared knife lines, limit full-coverage film, standardize top style, group SKUs.
Production Process (From Brief to Delivery)
Inquiry → Spec lock → White mockup → Printed drawdown → Pilot run → Mass production → QA → Delivery
- Lock board & gsm, base/top style, window, finishes.
- Approve drawdowns on live stock; provide barcodes/code specs.
- Align packing method (bundle, strap, pallet pattern) to your magazine.
Customization Menu (Pick-to-Order)
- Base: Auto-Bottom (CLB)
- Top: RTE / STE + dust flaps / tamper features
- Board: SBS / FBB / CRB (250–500 gsm)
- Print & Color: Offset / Digital / UV + Pantone targets
- Finish: AQ / UV / matte-gloss-soft-touch; foil/emboss/spot UV
- Window: PET/RPET / cellulose; size/position
- Inserts/Add-ons: tabs, dividers, tear strips, hang holes
- Size: L×W×H with opening orientation
- Sustainability: FSC, recycled %, on-pack guidance
RFQ Checklist
- Carton size (L×W×H, opening orientation): ___ × ___ × ___
- Board & gsm: SBS/FBB/CRB, ___ gsm
- Top closure: RTE / STE (+ dust flaps? Y/N)
- Print & finishes: colors ___ ; AQ/UV ; matte/gloss/soft-touch ; foil/emboss/spot UV
- Window: none / PET / RPET / cellulose ; size/position
- Add-ons: inserts/tabs/tear strip/security seal
- Line info: cartoner type, magazine feed, target CPM, bundle prefs
- Qty & delivery: ___ units by ___ ; FSC / recycled % (if required)
Case Studies
Personal Care (FMCG) — Switched to CLB + RTE; +22% packing speed, –18% labor hours; anti-scuff reduced returns.
Pharma Cartoning — STE front code area; tamper seal; zero mis-reads after code zone redesign.
Electronics — CLB base + insert tabs; –30% product shift incidents in vibration tests.
FAQ
What’s the difference between auto-bottom and snap-lock?
Auto-bottom (crash-lock) is pre-glued and locks on squaring; snap-lock needs manual panel interlocks and is slower at scale.
Which top—RTE or STE—should I choose?
RTE for fast hand-close and versatility; STE for the cleanest front face and code windows.
What gsm should I pick?
Light SKUs: 300–350 gsm; medium: 350–420 gsm; heavy/susceptible: 420–500 gsm—always validate with a pilot.
Can you run on automated cartoners?
Yes—specified for magazine feed on vertical/horizontal machines; we tune tolerances and bundle packs for hopper reliability.
Can I avoid plastic windows?
Use cellulose film or omit the window and add a die-cut reveal paired with internal retention.
What are typical MOQs and lead times?
1,000–3,000 units; 12–25 days after proof and drawdown approvals (finishes/windows may add time).
Conclusion
Auto-bottom (crash-lock) cartons convert speed and consistency into lower total cost. Specify the right board, top style, and tolerances, validate on a short pilot, and scale with confidence.
Ready for line-ready specs and samples?
Send your L×W×H, board & gsm, RTE/STE, finishes/window, cartoner type, and target CPM—we’ll return KDF samples, drawings, and a quote aligned to your production goals.
