Summary
- Customer type: A South China regional distribution center handling ambient beverages and chilled/frozen prepared foods.
- Pain points: Wooden pallets absorbed moisture, warped, and shook during stacking; frequent temperature-zone switches drove condensation and hygiene risks.
- Approach: Introduced washable 3-runner plastic pallets with color zoning, temperature buffers, washing cadence, SOPs, and batch labels.
- Result: Breakage/scrap ranges narrowed downward, stacks stabilized, washing wait time shortened, and odor/contamination complaints in cold areas dropped near zero; label discipline and training remain in continuous improvement.
Background
The site sits in an inland South China city, serving supermarkets, convenience chains, and community fulfillment hubs within roughly a three-hour drive. Daily outbound runs span the teens to low twenties. SKUs include ambient beverages, large bottled water, chilled dairy/egg products, and frozen prepared foods. Pallets cycle among ambient pick zones, 0–4°C chill rooms, and -18°C freezers. The warehouse manager remarked, “When it’s humid, wooden pallets keep drinking water and wobbling higher and higher—forklift drivers get nervous.”
Challenges
- Temperature swings: Pallets moving between cold rooms and ambient picking caused condensation; cartons softened and stacks became unstable.
- Breakage and debris risk: Old wooden pallets cracked in frozen areas, shedding splinters that raised food-safety concerns and forced detours.
- Heavy sanitation workload: In rainy weeks, wooden pallets dried slowly, occupying wash space and delaying circulation.
- Mixed specifications, unstable throughput: Different pallet sizes led to inconsistent stack heights, so truck loading windows had to shift.
- Weak traceability and labeling: Prior temperature zones were unknown, blurring washing priorities and causing misrouted pallets.
Goals
- Bring pallet breakage/scrap proportions down to about 40%–60% of the previous level to avoid sudden shortages.
- Narrow single-truck loading-height swings to roughly half of prior variance for steadier linehaul windows.
- Shorten washing/drying waits enough to keep a “workable rhythm” even in high humidity.
- Build a traceable temperature/batch label system so return priority and wash cadence have evidence.
Solution Design
Packaging unit and load
- 1200×1000 mm 3-runner plastic pallets with low-temperature impact resistance and four-way entry.
- Reinforced ribs aligned to a 600–900 kg distributed load range for beverage full pallets and frozen mixed loads.
- Anti-slip grains and pads on the deck to cut carton sliding when condensation appears.
Carrier and circulation
- Two colors: blue for frozen/chilled only, gray for ambient-compatible; sorting gates at entry.
- Standard stack heights: 1.2–1.3 m for ambient beverages; 1.0–1.1 m for cold-chain mixed loads. Drivers mainly confirm wrap integrity.
- A 5–8 minute tempering buffer before crossing temperature zones to reduce sudden condensation.
In-warehouse flow
- Short buffers at freezer/chiller exits before picking conveyors to keep condensate off belts.
- Color-separated lanes: blue pallets avoid ambient loose-pick lanes to cut cross-traffic.
- Forklift routes planned by pallet color to reduce empty returns and waiting.
Washing and disinfection
- Washing cadence by zone and turns: frozen/chilled pallets cleaned in batches every 7–10 days; ambient pallets sampled by return lot.
- Tilted drainage racks after washing to shorten drying; mobile fans added in rainy seasons.
- Weekly paper/low-temp adhesive labels on pallet sides to show wash batch and last zone.
Cold-room compatibility
- Chamfered runners to reduce snagging on frost.
- Rack-beam spacing checked and recorded as a “pallet–cargo–slot” pairing list to avoid overhanging stacks.
- Side buffer lanes reserved in freezers; no double stacking to keep airflow clear.
Traceability and labeling
- Low-temperature QR labels on side beams store purchase batch, last temperature zone, and last wash week.
- Scanned on return to build coarse turn counts, guiding wash or retirement priority.
- Gate staff verify “color + label” quickly to reduce misrouting.
People and SOP
- Forklift drivers trained to avoid single-corner impacts in the cold; no wood-pallet “ram pushing.”
- Pickers stage by color; frozen-only pallets should not sit long in ambient zones.
- Sanitation teams schedule by scan sheet; during humid weeks they log extra drying time. Storekeepers spot-check stack height and wrap quality weekly.
Implementation Timeline
- Small-batch proof (Weeks 1–2): Placed a small batch at two chiller docks to watch low-temp toughness and stack balance. Goal: low-risk validation. Risk: small sample may miss edge SKUs.
- Color zoning go-live (Weeks 3–5): Rolled out blue/gray zoning and entry sorting with labels. Goal: create minimum viable color discipline first. Risk: legacy pallets not fully recovered and mixing back in.
- Flow and buffer tuning (Weeks 6–8): Added tempering buffers and adjusted forklift routes by congestion data. Goal: reduce condensation and cross-traffic. Risk: buffers take space and may extend queues at peaks.
- Wash cadence and drainage upgrade (Weeks 9–11): Added tilted racks and mobile fans; scheduled by scan logs. Goal: shorten rainy-season drying. Risk: fan noise/power coordination with other equipment.
- Stage review and expansion (Week 12): Compared breakage, loading variance, and wash wait times; decided to expand the pallet model to main ambient lines while keeping a small wooden reserve for emergencies. Risk: execution gaps across sites, requiring periodic audits.
Results and Improvement Tracks
- Breakage and scrap: Frozen/chilled pallets saw roughly 40%–60% lower breakage/scrap ranges than old wood, cutting sudden shortages.
- Stack stability and loading rhythm: Standard heights narrowed single-truck loading variance to about half of prior swings; drivers said loading “feels steadier without improvising shims.”
- Hygiene and temperature control: Condensation-related carton collapse dropped noticeably; wash queues shortened; cross-odor complaints in frozen areas fell near zero, with ongoing monitoring of drying time in humid weeks.
- Traceability and execution: Scan logs give a coarse view of turns and help set wash priority; some night shifts missed scans, so weekly spot checks are planned.
Takeaways for Peers
- Color zoning with entry sorting is step one: Separate temperature-zone pallets before chasing fine-grained labels, or management overhead stays high.
- Use buffer time to soften condensation shocks: A 5–8 minute tempering slot at cold entries materially improves carton condition and is inexpensive to replicate.
- “Turns + zone” beats fixed wash cycles: Combining usage frequency and temperature zone aligns cleaning with contamination risk and avoids over-washing.
- Standardized stack heights steady loading windows: Pre-set heights by SKU so drivers and loaders work in a consistent rhythm.
- Training and spot checks keep discipline: Color rules and scanning need recurring reminders; weekly reviews of missed scans or mixed-use incidents help.
- Keep an emergency pallet pool: Retain a small reserve of legacy pallets for shortages, clearly marked “non-rack/non-freezer” to avoid misuse.
