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Industrial Packaging (工業包装)

Industrial Manufacturing - Machinery and Electronics · 製造分野 · Written by Tokutei Pass based on the official study texts; not copied verbatim.

1. Role in Specified Skilled Worker (i) and Fundamentals of Industrial Packaging

In the Specified Skilled Worker (i) Industrial Product Manufacturing field, there is no standalone exam division called "Industrial Packaging"; candidates take the exam under one of three divisions: "Machine and Metal Processing", "Electrical and Electronic Equipment Assembling", or "Furniture Manufacturing". This chapter serves as a specialized supplementary track covering the packaging and logistics quality topics tested in those three divisions while preparing workers for the National Trade Skill Test in Industrial Packaging (Grades 3 & 2) and transition to Specified Skilled Worker (ii).

Under JIS Z 0108, "industrial packaging" (工業包装) is defined as packaging whose primary purposes are protecting the quality of products and parts and improving cargo handling and logistics efficiency during transport and storage. This differs fundamentally from "commercial packaging" (商業包装), which prioritizes attractive visual design to stimulate consumer purchasing desire at retail stores.

Packaging structure is classified from the inside out into three levels: "Unit packaging" (個装) wrapping individual items; "Inner packaging" (内装) protecting against moisture, rust, and shock; and "Outer packaging" (外装) placing items into the outermost container (such as a wooden box or corrugated box) and applying shipping marks. For metal parts, work begins with "pre-treatment" (前処理: cleaning, drying, and rust prevention) followed in order by "Unit → Inner → Outer packaging".

In cargo mass markings, the mass of the product alone is "Net Weight" (純質量: N/W), the mass of packaging materials such as wooden boxes and cushioning is "Tare Weight" (風袋質量), and the combined total mass of the cargo is "Gross Weight" (総質量: G/W = N/W + Tare Weight). Consolidating multiple packages onto a pallet for mechanical handling as a single unit by forklift is called "palletizing" (パレタイズ) or "unit load formation" (ユニットロード化).

Logistics quality is classified into three pillars—"delivery date quality, product quality, and shipping/delivery quality"—and is managed using "PPM" (defects per 1 million cases). Workers must strictly follow all dimensions and material rules specified in the packaging specification sheet (包装仕様書).

Key points


  • In Specified Skilled Worker (i), candidates take the exam under Machine & Metal Processing, Electrical & Electronic Equipment Assembling, or Furniture Manufacturing

  • Industrial packaging (JIS Z 0108) protects product quality and cargo-handling efficiency, proceeding in order: Pre-treatment → Unit → Inner → Outer packaging

  • Gross Weight (G/W) = Net Weight (N/W) + Tare Weight; logistics quality is managed using PPM (defects per 1 million cases)
WordMeaning
Industrial packaging vs. Commercial packaging
Pre-treatment / Unit / Inner / Outer packaging
Net Weight (N/W) / Gross Weight (G/W) / Tare Weight
Palletizing (Unit load formation)
Logistics quality (PPM management)

2. Properties of Lumber & Plywood and Phytosanitary Standards (ISPM No.15)

Softwoods (such as cedar, pine, and spruce) and lauan lumber are widely used for industrial wooden boxes. Lumber with high moisture content shrinks as it dries, causing splitting and warping, losing nail-holding power, and promoting rust on enclosed machinery; therefore, properly seasoned lumber (moisture content around 15–20%, and 20–25% or less under JIS standards) must be used.

Wood shrinkage during drying is anisotropic: it is largest in the direction tangential to the annual rings (接線方向 / flat grain: 板目), followed by the radial direction (半径方向 / edge grain: 柾目), and smallest in the longitudinal fiber direction (繊維方向). Regarding wood defects, "dead knots" (死に節 / loose knots: 抜け節) are not intergrown with surrounding fibers and easily fall out, reducing bending strength far more severely than "live knots" (生き節).

Plywood (合板) is made by gluing an odd number (3, 5, 7, etc.) of thin wood veneers (単板) together with their fiber directions perpendicular (90°) to each other, resulting in minimal warping or splitting and uniform strength across directions. For reinforcing lumber of equal cross-sectional area, a cross-section close to a square resists multi-directional bending loads much better than a thin flat board.

Solid wood used in export wooden boxes and pallets must undergo phytosanitary treatment and be stamped with an IPPC mark under the International Standards for Phytosanitary Measures (ISPM No.15) to prevent the spread of forest pests. Standard Heat Treatment (symbol: HT) requires heating the wood so that the "wood core temperature reaches 56°C or higher for at least 30 minutes". Packaging made solely of engineered wood processed under high heat and pressure—such as plywood, particle board, or OSB—is exempt.

2. Properties of Lumber & Plywood and Phytosanitary Standards (ISPM No.15)

Key points


  • Lumber for wooden boxes must be seasoned to about 15–20% moisture content (JIS ≤ 20–25%) to prevent shrinkage splitting, nail loosening, and internal rust

  • Wood shrinkage follows Tangential (flat grain) > Radial (edge grain) > Longitudinal fiber direction; dead knots severely reduce bending strength

  • ISPM No.15 heat treatment (HT) for export solid wood requires a core temperature of ≥ 56°C for ≥ 30 minutes; all-plywood packaging is exempt
WordMeaning
Wood moisture content and Drying shrinkage
Live knots vs. Dead knots (loose knots)
Plywood (odd number of cross-laminated veneers)
International phytosanitary standard (ISPM No.15)
Heat treatment (HT: core temperature ≥ 56°C for ≥ 30 min)

3. Structure of Nailed Wooden Boxes (JIS Z 1402) and Framed Wooden Boxes (JIS Z 1403)

A "nailed wooden box" (普通木箱: JIS Z 1402) is used mainly for cargo with a content mass of 1,500 kg or less and an internal length of 4 m or less. It includes "close-boarded boxes" (密閉木箱) with boards fitted tightly together and "slatted/crated boxes" (すかし木箱) with gaps between boards. The shorter ends consist of "end boards" (つま板) and "end cleats" (つま桟); the longer sides consist of "side boards" (側板) and "side cleats" (胴桟); the bottom is the "bottom board" (底板); and the top is the "top board" (天井板).

A "framed wooden box" (枠組箱: JIS Z 1403) assembles truss-framed "side panels", "end panels", and a "top panel" onto a heavy-duty "base" (腰下), and is used for heavy machinery and large cargo. In the base, the bottom-most longitudinal timbers contacting the floor are "skids" (滑材), the end cross-members joining the skids are "headers" (ヘッダー), and the crosswise timbers resting on top of the skids to directly support the product weight are "load-bearing floor members" (負荷床材).

The side panel framework of a framed wooden box consists of horizontal "top frame members" (上かまち) and "bottom frame members" (下かまち), vertical "side struts" (側支柱), and diagonal "braces" (すじかい) that prevent lateral racking deformation. Diagonal braces are installed at a "standard angle of 45° (within 35° to 55°)" relative to the horizontal plane of the bottom frame member.

In addition, "auxiliary posts / scabs" (そえ柱) nailed to the inside of the vertical side struts to support the ceiling "joist bearers" (はり受け) must have a length at least two-thirds (2/3) of the length of the side struts (側支柱).

3. Structure of Nailed Wooden Boxes (JIS Z 1402) and Framed Wooden Boxes (JIS Z 1403)

Key points


  • Nailed wooden boxes (JIS Z 1402) apply to cargo ≤ 1,500 kg and internal length ≤ 4 m, consisting of end boards, side boards, bottom boards, and top boards

  • A framed wooden box base (JIS Z 1403) is stacked from the floor up as Skids (滑材) → Load-bearing floor members (負荷床材), with skid ends joined by headers

  • Side diagonal braces (すじかい) are set at a standard 45° (35°–55°), and auxiliary posts (そえ柱) supporting joist bearers must be ≥ 2/3 of the side strut length
WordMeaning
Nailed wooden box (≤ 1,500 kg, internal length ≤ 4 m)
End board / End cleat / Side board / Side cleat
Framed box base (Skids / Headers / Load-bearing floor members)
Top/Bottom frame members / Side struts / Diagonal braces (45°)
Joist bearer and Auxiliary post (≥ 2/3 of side strut length)

4. Rules for Nailing, Bolting, and Wooden Box Fabrication Practice

In "flat nailing / clinch nailing" (平打ち) where nails penetrate through overlapping plywood/sheathing and cleats, a wooden backing plate (木製敷板) is placed on the workbench during nailing, and the protruding nail tips on the back are bent (打ち曲げ: clinched) parallel to the "wood fiber direction" (繊維方向) and driven flush. This maximizes holding power and prevents protruding nail points from injuring workers or damaging cargo.

In "assembly nailing" (組立て打ち) where boards are nailed into the edges or ends of frame members/cleats to assemble a box, the standard nail length is 2.5 to 3 times the thickness of the board being penetrated. When driving multiple nails near the end of a board (木口), to prevent wood splitting (木割れ), leave proper distance from the board end and arrange nails in a "staggered pattern" (千鳥状: zig-zag) rather than along the same wood grain line.

When assembling a nailed wooden box, to prevent the bottom from dropping out (底抜け) when lifted, never drive nails upward from the bottom board into the bottom edge of the side board. Instead, extend the side board down past the edge of the bottom board and nail horizontally into the bottom board or end cleats so the nails carry shear load.

When bolting skids (滑材) to headers or load-bearing floor members in the base of a framed wooden box, machine recessed "counterbore holes" (座ぐり) into the bottom surface of the skids so that bolt heads or nuts sit recessed and never protrude below the underside of the skids.

Key points


  • In flat/clinch nailing (平打ち), protruding nail tips on the back face must be bent parallel to the wood fiber direction (繊維方向) and driven flush

  • Assembly nails (組立て打ち) should be 2.5–3 times the penetrated board thickness and driven in a staggered pattern (千鳥状) near board ends to prevent splitting

  • Never nail upward from the bottom board into the side board to prevent bottom drop-out; recess bolt heads on skid undersides using counterbore holes (座ぐり)
WordMeaning
Flat nailing and Clinching nail tips (along fiber direction)
Assembly nailing length (2.5–3 times board thickness)
Staggered nailing pattern to prevent wood splitting
Bottom drop-out prevention (no upward nailing from bottom board)
Counterboring on the bottom surface of skids

5. Corrugated Fiberboard Packaging, Pallets, and Film Wrapping

A corrugated fiberboard sheet (段ボールシート: JIS Z 1516) consists of wave-shaped fluted paper called "corrugating medium" (中しん) bonded to flat paperboard sheets called "liners" (ライナ). Major types include "single-faced corrugated board" (片面段ボール: 1 medium + 1 liner, used for cushioning wrap), "single-wall / double-faced board" (両面段ボール: 1 medium + 2 liners), and heavy-duty "double-wall board" (複両面段ボール: 2 mediums + 3 liners).

Among flute (段) profiles, "A-flute" (flute height ~4.5–4.8 mm, ~34 flutes per 30 cm) excels in cushioning performance and vertical compressive strength, whereas "B-flute" (flute height ~2.5–2.8 mm, ~50 flutes per 30 cm) has superior flat crush resistance. In outer corrugated boxes (0201 type), flutes must always run in the "vertical direction" (垂直方向) to withstand stacking loads (上積み荷重). Because paper absorbs moisture, high relative humidity causes a sharp drop in box compressive strength.

When assembling a 0201-type corrugated box, fold the shorter "inner flaps" (内フラップ) first, then close the longer "outer flaps" (外フラップ) and seal the seam with adhesive tape extending about 50–70 mm down the end panels. When applying PP bands or steel strapping, tension properly and use "corner protectors" (当て板) so box edges do not crush or tear.

Japan's standard flat pallet for through-transit under JIS Z 0161 is the "T11-type pallet" with plan dimensions of "1,100 mm × 1,100 mm". When palletizing boxes, stack them flush within the pallet edges without overhang, and unitize the load with elastic "stretch film" or heat-contracting "shrink film" to prevent load collapse (荷崩れ).

Key points


  • Corrugated fiberboard consists of liners and fluted medium; A-flute excels in cushioning and vertical compression, while B-flute resists flat crush

  • Flutes in 0201 boxes must run vertically (垂直方向), folding inner flaps first then outer flaps; high humidity sharply reduces box compressive strength

  • Standard JIS T11 flat pallets measure 1,100 mm × 1,100 mm; stack boxes without overhang and unitize with stretch film or heat-shrink film
WordMeaning
Liner and Corrugating medium (Single-wall / Double-wall board)
A-flute vs. B-flute / Vertical flute orientation
Inner flaps / Outer flaps and Box sealing
T11-type standard flat pallet (1,100 mm × 1,100 mm)
Stretch film and Shrink film

6. Rust-Preventive Packaging (JIS Z 0303) and Moisture-Proof Packaging (JIS Z 0301)

When moisture (humidity) and oxygen act simultaneously on steel parts, oxidation causes rust (corrosion). Closed dry marine containers experience severe day-night temperature swings during ocean transport that cause heavy condensation (container sweat), making thorough rust-preventive and moisture-proof packaging essential.

In rust-preventive packaging, metal parts are first cleaned of machining chips and oil, thoroughly dried, and treated with rust preventives. Workers must wear gloves and never touch cleaned parts with bare hands, as salt and moisture in human sweat cause fingerprint rust. When using volatile corrosion inhibitor paper (VCI paper: 気化性さび止め紙), face the chemical-coated side toward the metal surface at close range and seal the package to block outside air so the VCI vapor forms a protective film over all details.

In moisture-proof packaging, the product and "desiccant" (乾燥剤: silica gel) are enclosed inside an "aluminum-foil laminated moisture-proof barrier bag" (アルミ防湿バリヤ袋) with an extremely low water vapor transmission rate, and the bag opening is hermetically sealed by "heat sealing" (ヒートシール) without any wrinkles or gaps.

Because silica gel absorbs moisture immediately upon exposure to outside air, reseal its storage container right away and seal the barrier bag quickly. If blue indicator silica gel (青ゲル) has absorbed moisture and turned "pink (light red)", its dehumidifying capacity is exhausted and it must be replaced with fresh desiccant before resealing.

6. Rust-Preventive Packaging (JIS Z 0303) and Moisture-Proof Packaging (JIS Z 0301)

Key points


  • In rust-preventive packaging, never touch cleaned metal parts with bare hands; face the chemical-coated side of VCI paper toward the product and seal

  • In moisture-proof packaging, enclose the item and silica gel desiccant inside an aluminum-foil laminated barrier bag and hermetically heat-seal it

  • When blue indicator silica gel turns pink (light red), its moisture-absorbing capacity is exhausted and it must be replaced with fresh desiccant
WordMeaning
Cleaning, drying, and Prohibition of bare-hand contact
Volatile Corrosion Inhibitor (VCI) / VCI paper
Aluminum moisture-proof barrier bag (low WVTR)
Heat sealing (thermal welding)
Silica gel desiccant (Blue when dry → Pink when saturated)

7. Cushioning Packaging, Product Blocking/Bracing, and Waterproofing

Cushioning packaging absorbs drop shocks and transport vibrations through deformation of cushioning materials to keep peak acceleration (G) transmitted to the product at or below its allowable fragility limit. The three primary methods are "Full-surface cushioning" (全面緩衝包装: covering all faces), "Partial cushioning" (部分緩衝包装: corner/edge pads), and "Suspension packaging" (サスペンション包装: suspending the item with springs or straps).

Air bubble sheets (bubble wrap) and expanded polyethylene (EPE) foam offer high flexibility and elastic recovery against repeated shocks. By contrast, expanded polystyrene (EPS / Styrofoam) is a rigid foam whose cells crush plastically under heavy or repeated drop impacts and do not recover 100% of their original thickness. Furthermore, making the load-bearing area too small causes "bottoming out" (底づき: complete compression of the cushion), transmitting high shock directly to the product.

To secure machinery inside a wooden box, heavy machines are firmly bolted to the base with anti-loosening hardware, supplemented by "base blocking cleats" (根止め材) against lateral sliding and "hold-down braces" (押さえ材) against vertical lifting. Hold-down braces must press against rigid structural frame sections (never thin sheet-metal covers) with protective pads (当て材 such as felt or rubber sheets) interposed to prevent paint scratches.

For internal waterproofing of outer wooden boxes, waterproof paper or plastic sheeting is draped like a roof/umbrella over the top and upper sides of the machine to shed rainwater and condensation drips—a method called the "Shed method" (シェッド張り / 傘掛け防水法). The bottom board is never sealed watertight so any water can drain out.

Key points


  • Expanded polyethylene (EPE) has high elastic recovery, whereas rigid expanded polystyrene (EPS) crushes permanently under heavy repeated impacts

  • Secure machinery inside wooden boxes using anchor bolts, base blocking cleats, and hold-down braces pressing against rigid frames via protective pads

  • Draping waterproof sheeting like a roof over machinery inside a crate is called the Shed method (シェッド張り), leaving the bottom open for drainage
WordMeaning
Full-surface / Partial / Suspension cushioning
Expanded polyethylene (EPE) vs. Expanded polystyrene (EPS)
Load-bearing area and Bottoming out
Base blocking cleats / Hold-down braces / Protective pads
Shed lining method (umbrella/canopy waterproofing)

8. Cargo Handling Attention Marks (JIS Z 0150) and Shipping Marks

Graphical symbols specified in JIS Z 0150 (aligned with ISO 780), called "cargo handling attention marks / care marks" (取扱注意マーク), are stenciled on outer packages so cargo handlers worldwide can intuitively understand proper handling regardless of language.

Key symbols include: two upward arrows for "This way up" (天地無用); an umbrella for "Keep dry" (水ぬれ防止); a wine glass for "Fragile, handle with care" (壊れもの注意); a crosshair circle for "Center of gravity" (重心位置); a chain for "Sling here" (つり位置); and a crossed-out hook for "Use no hooks" (手鉤使用禁止). For asymmetrical machinery, mark the actual center of gravity rather than the geometric center of the box; never use hand hooks on any package bearing the "Use no hooks" mark.

Export "shipping marks" (荷印) stenciled on the side of crates include the consignee abbreviation (Main mark), destination port (Port mark / 仕向地), Case Number (e.g., C/NO. 3/10 = Box 3 of 10), Gross Weight (G/W), Net Weight (N/W), crate dimensions (L×W×H), and Country of Origin (e.g., MADE IN JAPAN).

8. Cargo Handling Attention Marks (JIS Z 0150) and Shipping Marks

Key points


  • JIS Z 0150 marks: Two upward arrows = This way up; Umbrella = Keep dry; Wine glass = Fragile; Crossed-out hook = Use no hooks

  • Crosshair circle = Center of gravity (marked at actual center of gravity); Chain symbol = Sling here (where crane wire ropes are placed)

  • Export shipping marks include Main mark, Port mark, Case No. (C/NO. 3/10 = Box 3 of 10), G/W, N/W, Dimensions, and Country of Origin
WordMeaning
Cargo handling attention marks (JIS Z 0150)
This way up / Keep dry / Fragile
Center of gravity / Sling here / Use no hooks
Shipping mark (Main mark, Port mark, Case number)

9. Tool Handling, Occupational Safety, and Package Testing

When operating rotating cutting machinery such as circular saws (丸のこ盤) or drill presses (ボール盤), "wearing knitted cotton gloves (軍手) is strictly prohibited" to prevent entanglement, and the blade safety guard (接触予防装置) and riving knife / anti-kickback splitter (割刃 / 反発予防装置) must never be removed. Precision measuring tools such as carpenter's squares (曲尺) and convex tape rules must never be dropped, stepped on, or used as hammers.

When using a pneumatic nailer (エアネイラ), wear safety glasses, keep your finger off the trigger until nailing, never tie back the contact arm safety device, keep your supporting hand well away from the nailing point in case a nail deflects off a knot, and always disconnect the air hose before loading nails or clearing jams. Wear safety glasses and gloves when cutting tensioned steel strapping (帯鉄) while holding down the band, and immediately collect pulled nails and strap offcuts to prevent foot puncture injuries (踏み抜き).

When lifting heavy loads manually, stand close to the load, bend your knees, lower your hips, and lift with your leg muscles to prevent lower back pain. Operating a forklift (maximum load ≥ 1 t) or crane slinging (玉掛け: lifting capacity ≥ 1 t) requires an official Skill Training qualification; during slinging, hook wire ropes at the "Sling here marks" and lift slightly off the ground first (地切り) to check balance.

Completed packages undergo final inspection for dimensions, nailing/bolting, strap tension, and marking accuracy. Packaging designs are evaluated under JIS Z 0200 / JIS Z 0202 using vibration tests and drop tests in three orientations: "Flat drop" (面落下: landing flat on a face), "Edge drop" (稜落下: landing on an edge line), and "Corner drop" (角落下: landing on a single corner vertex).

Key points


  • Never wear knitted cotton gloves (軍手) when operating rotating machinery like circular saws or drill presses, and never remove blade guards or riving knives

  • Never disable a pneumatic nailer's contact arm safety, and always disconnect the air hose before loading nails or clearing jammed nails

  • Forklift operation and crane slinging ≥ 1 t require Skill Training certificates; drop tests (JIS Z 0202) cover flat drop, edge drop, and corner drop
WordMeaning
No cotton gloves on rotating saws / Blade guard & Riving knife
Pneumatic nailer safety (Contact arm & Disconnect air hose)
Forklift & Crane slinging qualification (≥ 1 t) and Ground-clearance check
Drop test orientations (Flat drop / Edge drop / Corner drop)

10. Exam Preparation Essentials (Key Numbers & Common Traps)

【Essential JIS Numbers】 ① Nailed wooden box (JIS Z 1402): content mass ≤ 1,500 kg, internal length ≤ 4 m. ② Framed wooden box (JIS Z 1403): diagonal brace (すじかい) angle = standard 45° (35°–55°); auxiliary post (そえ柱) length ≥ 2/3 of side strut; base order from floor up = "Skids (滑材) → Load-bearing floor members (負荷床材)". ③ Assembly nail length: 2.5–3× board thickness (flat nailing 平打ち clinches protruding nail tips along the wood grain).

【Quarantine, Pallets & Corrugated Board】 ① ISPM No.15 heat treatment (HT): wood core temperature ≥ 56°C for ≥ 30 min (plywood is exempt). ② Standard T11 flat pallet: 1,100 mm × 1,100 mm. ③ Corrugated board: A-flute has superior cushioning and vertical compression; flutes in 0201 boxes must run vertically (垂直); fold "inner flaps first → outer flaps second".

【Rust/Moisture, Waterproofing & Safety】 ① Rust prevention: Never touch cleaned metal with bare hands; face VCI paper's coated side toward the product. ② Moisture protection: blue silica gel turning pink means it is saturated and must be replaced. ③ Roof-like internal waterproofing over machinery is called the "Shed method" (シェッド張り). ④ Safety: Never wear cotton gloves (軍手) on circular saws; disconnect the air hose before clearing a pneumatic nailer jam.

Key points


  • Wooden box figures: Nailed box ≤ 1,500 kg & ≤ 4 m / Framed box diagonal brace = 45° (35°–55°), auxiliary post ≥ 2/3 of side strut / Assembly nail = 2.5–3× board thickness

  • Quarantine, Corrugated & Pallet: ISPM No.15 HT = core ≥ 56°C for ≥ 30 min / T11 pallet = 1,100×1,100 mm / 0201 box = vertical flutes, fold inner flaps first

  • Rust/Moisture & Safety: No bare hands, VCI coated side toward item / Replace blue silica gel when pink / Shed lining = roof-like waterproofing / No cotton gloves on saws, disconnect nailer air hose
WordMeaning
Nailed box (1,500 kg / 4 m) & Framed box (45° diagonal brace)
ISPM No.15 (HT: 56°C / 30 min) & T11 pallet (1,100×1,100 mm)
Blue silica gel (dry) → Pink (saturated, replace immediately)

Industrial packaging (wooden crates, cartons, rust and moisture proofing, cushioning, marks)

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