Rotary Arm Pallet Wrapper with Top Film Dispenser: Five-Sided Protective Stretch Wrapping

Executive summary

A rotary arm pallet wrapper with an integrated top sheet dispenser (TS) secures pallet loads that are tall, light, or dynamically unstable. Unlike conventional turntables that rotate the load, the pallet remains stationary on the conveyor while an overhead mechanical arm orbits stretch film around it. An overhead dispenser simultaneously cuts and lays a polyethylene (PE) top sheet over the load crown. Subsequent top wrap cycles lock the draped skirt firmly against the load sides, delivering a full five-sided barrier against moisture, yard dust, and transit spray. The FHOPE RAS200 with TS dispenser handles loads up to 1,200 × 1,200 × 2,000 mm at variable speeds of 3–12 r/min, achieving 40–50 pallets per hour.

Table of Contents

Why a rotary arm for tall carton pallets

High-cube corrugated pallet loads (approaching 2,000 mm) present severe centrifugal stability challenges. On a rotary turntable, every acceleration and deceleration cycle applies lateral shear forces to the carton columns, risking layer shifting, creasing, or total pallet collapse.

A rotary arm wrapper eliminates load movement entirely:

  • Zero Centrifugal Disruption: The pallet remains static on the powered roller or chain conveyor throughout the wrapping and sheeting cycle.
  • Direct Overhead Dispensing Integration: Because the pallet does not rotate, the automated PE top sheet dispenser is mounted directly within the upper gantry frame, eliminating secondary repositioning stations.
  • Continuous Line Flow: In-feed, positioning, five-sided wrapping, film clamping/cutting, and out-feed occur inline along a single conveying axis.

Rotary arm and top sheet data

The RAS200 platform combined with the overhead TS top sheet dispenser is configured as a standalone cell or integrated into automated packaging lines.

Technical Parameter Specification (RAS200 + TS Dispenser)
Automation level Fully automatic, PLC controlled with color HMI
Maximum load dimensions L 1,200 × W 1,200 × H 2,000 mm
Minimum load dimensions L 800 × W 800 × H 600 mm
Arm rotation speed 3–12 r/min (inverter controlled acceleration/deceleration)
Throughput capacity 40–50 pallets/hour (load height and wrap pattern dependent)
Stretch film carriage Powered pre-stretch 200%–300% (fixed or variable gear ratio)
Film specifications Standard LLDPE stretch film, width 500 mm, core 76 mm
Top sheet material Flat or center-folded PE sheet roll, automated pull-and-cut
Height detection Optical diffuse reflection photo-sensor
Pneumatic requirement 0.4–0.6 MPa (4–6 kgf/cm²), dry filtered plant air
Power supply 220 V / 380 V, 50/60 Hz, 3-Phase; 3.0–4.5 kW total power
Machine weight Approximately 1,500 kg (excluding auxiliary conveyors)

Inline Integration Architecture

In automated end-of-line configurations, the RAS200 cell operates with upstream and downstream powered roller conveyors (driven by 1.5 kW SEW or equivalent gearmotors). The PLC manages variable parameter profiles: bottom wrap counts (0–99), top lock winds (0–99), film tension profiles, carriage elevator speeds, and top sheet pull-lengths for diverse SKU profiles.

Sizing the top sheet

The PE top sheet must drape evenly over the load crown, providing an overhang (skirt) on all four vertical walls so the circumferential film wraps capture and seal it securely.

The sheet sizing formula is:

  • Top sheet length = Load length + (2 × Skirt drop)
  • Top sheet width = Load width + (2 × Skirt drop)
Load Top Face (L × W) Target Skirt Drop Calculated Sheet Length Target Sheet Roll Width
1,200 × 1,000 mm 200 mm 1,200 + 400 = 1,600 mm 1,000 + 400 = 1,400 mm
1,200 × 1,200 mm 200 mm 1,200 + 400 = 1,600 mm 1,200 + 400 = 1,600 mm

Engineering Considerations for Skirt Sizing

  1. Overlap Margin: A skirt drop of 150–250 mm is ideal. With standard 500 mm wide stretch film, this ensures at least two consecutive horizontal film bands overlap the skirt by 100%, securing the PE sheet without secondary heat sealing.
  2. Roll Sizing: The PE sheet roll width must match the calculated Load width + (2 × Skirt drop). The machine’s motorized pull-clamps cut the running length dynamically based on the active recipe, preventing material waste when running mixed load lengths.

Sheet first, then the top winds

To achieve water runoff, the film wrapping and sheeting sequence must follow the roofing shingle principle, where upper layers lap over lower skirts:

  1. In-feed and Auto-Centering: The pallet conveys into the wrap zone. Optical sensors verify positioning and determine total load height.
  2. Base Reinforcement: The rotary arm accelerates, applying programmed base winds around the pallet deck and bottom carton tier to unite the load with the pallet base.
  3. Upward Spiral and Sheet Staging: The carriage spirals up to the top tier. The arm pauses or rotates at low indexing speed while the overhead dispenser pulls the exact PE sheet length, cuts it via a rodless pneumatic knife, and drapes it centered over the crown.
  4. Down-Spiral Lock Wind: The rotary arm resumes full rotation, applying reinforcing top winds over the draped skirt. As the carriage descends, the continuous stretch film overlaps the skirt downward, creating an outward-shedding water seal.
  5. Clamp, Cut, and Wipe: At the base, a pneumatic clamp catches the film, a hot-wire or mechanical blade cuts it, and a pneumatic wiping brush seals the tail to the pallet. The finished load exits the cell.
Wrap Cycle Chronology:
In-Feed ──> Base Wraps ──> Spiral Ascent ──> Drape Top Sheet ──> Overlap Top Lock Winds ──> Spiral Descent ──> Cut/Wipe ──> Exit

Setting top winds before the sheet lands causes the sheet to lie loose on the crown, where transport drafts blow it off. The lock-down step is mandatory for true 5-sided integrity.

What sets the hourly rate

A rated throughput of 40–50 pallets/hour equates to a gross cycle window of 72 to 90 seconds per pallet. This total cycle is divided among discrete sub-routines:

  • Pallet indexing in/out: 12–15 seconds
  • Top sheet dispensing and positioning: 8–10 seconds
  • Arm rotation (base winds, spiral ascent, overlap winds, spiral descent): 45–60 seconds (dependent on load height and RPM)
  • Pneumatic film clamping, cutting, and tail wipe: 5–7 seconds
Total Cycle (72–90 s) = In/Out Conveying (15 s) + Top Sheeting (10 s) + Arm Orbit Wrapping (55 s) + Cut & Wipe (5 s)

Variables that lower throughput:

  • Raising load height to 2,000 mm (adds elevator transit time).
  • Unstable cartons requiring reduced arm rotation (e.g., dropping from 12 r/min down to 6–8 r/min).
  • Increasing reinforcement winds from 2 to 4 layers at the base or top.

What five-sided cover protects against

Circumferential stretch wrapping leaves the pallet core completely open at the top. This results in:

  • Airborne warehouse dust settling directly onto exposed goods.
  • Water accumulation during outdoor yard storage, rain exposure during intermodal dock transfers, or roof condensation drips inside shipping containers.

With the PE top sheet trapped under the vertical film band, moisture rolls down the exterior walls without entering the carton stack.

Note: For complete six-sided sealing (hermetic/vapor-proof), an automated bottom sheet applicator or pre-laid pallet slip sheet must be placed on the wooden pallet deck prior to carton loading.

Top sheet or full stretch hood?

Functional Metric Rotary Arm + Top Sheet Dispenser Stretch Hooder System
Five-sided water resistance Yes (rain-shedding overlap; splash/dust tight) Yes (hermetic, continuous barrier hood)
Pallet stabilization method Adjustable horizontal film tension and reinforcement winds High elastic retention force of single gusseted hood
SKU size variation handling High flexibility; adjusts cut length via HMI recipe Moderate; limited by roll gusset stretch elasticity
Capital investment (CAPEX) Medium-low (accessible automation) High (2.5× to 4× investment of rotary arm line)
Consumables cost Lower (standard LLDPE stretch film + standard PE roll) Higher (specialized co-extruded high-elasticity hood film)
Maintenance complexity Low; standard electromechanical and pneumatic parts High; complex hydraulic/servo finger expanding mechanisms

Selection checklist

To configure and quote a rotary arm wrapping cell with a top sheet dispenser, verify the following plant parameters:

  1. Load Dimensions: Minimum and maximum Length × Width × Height (including pallet deck thickness).
  2. Load Mass & Dynamic Stability: Gross weight per pallet, stacking pattern (column vs. interlocked), and carton rigidity.
  3. Target Production Throughput: Continuous pallets per hour (instantaneous peak vs. daily average).
  4. Logistics & Storage Conditions: Indoor dry warehouse, covered transfer, or open flatbed truck / outdoor yard exposure.
  5. Conveyor Integration Data: Conveyor top-of-roller (TOR) height, direction of pallet entry (short side vs. long side leading).
  6. Utility Availability: Plant supply voltage, frequency, and compressed air CFM / line pressure at the installation point.

Safety

The RAS200 with TS dispenser is engineered to comply with EN 415-6 (Safety of packaging machines: pallet wrapping machines), EN ISO 12100:2010 (Risk assessment and risk reduction), and EN 60204-1 (Electrical equipment of industrial machines).

  • Zone Perimeter Protection: The orbiting arm radius is fully enclosed by 2.0 m interlocked wire mesh guards. Opening any maintenance access door initiates a Category 0 safety stop.
  • Optical Muting Light Curtains: Pallet in-feed and out-feed portals are guarded by Type 4 optical light grids with pallet-pattern muting logic to distinguish pallets from human intrusion.
  • Safety Circuits: Dual-channel safety relays control the drive contactors. Following an E-stop or curtain breach, a manual reset on the main control panel is required to restore system power.
  • Mechanical Safety: The vertical carriage elevator incorporates anti-drop safety pawls or dual counter-weighted chain mechanisms to arrest carriage fall in the event of primary drive failure.

Engineering FAQ

Q: Does the pallet rotate at any point in the cycle? A: No. The pallet remains stationary on the conveyor throughout the sequence. The stretch film carriage orbits the load on a balanced rotating arm.

Q: Can the overhead dispenser handle varying load heights automatically? A: Yes. An optical photo-sensor on the film carriage detects the load’s top edge and signals the PLC to trigger the sheet placement sequence at the correct elevation.

Q: Can we change top sheet dimensions without physically swapping the film roll? A: The sheet width is fixed by the loaded PE film roll width, but the sheet length is fully adjustable via the HMI recipe, allowing optimization for long and short pallets.

Q: Will this configuration protect against water accumulation from bottom pooling? A: No. The top sheet provides five-sided crown and side protection. If bottom moisture rising from wet wooden decks is a concern, an under-load bottom PE liner must be applied before loading cartons onto the pallet.

Q: What utilities must be routed to the machine cell? A: Standard 220 V / 380 V 3-phase electrical power (3.0–4.5 kW) and a dry, filtered compressed air drop supplying 0.4–0.6 MPa (4–6 kgf/cm²).

Next step

  1. Submit pallet specs: Send minimum/maximum pallet dimensions, stacking heights, pallet weights, and line throughput (pallets/hour) to info@fhopepack.com.
  2. Engineering Review: Our mechanical engineering team will calculate the top sheet drop, confirm the powered pre-stretch ratio, and establish the arm rotation speed profile.
  3. Formal Proposal: Receive a complete dimensional layout drawing, functional sequence description, and system quotation within 24 hours.

Sources

  • FHOPE Technical Specification: Rotary Arm Stretch Wrapping Platform RAS200 with Overhead Dispenser TS
  • EN 415-6: Safety of Packaging Machines – Pallet Wrapping Machines
  • EN ISO 12100:2010: Safety of Machinery – General Principles for Design – Risk Assessment and Risk Reduction
  • EN 60204-1: Safety of Machinery – Electrical Equipment of Machines – Part 1: General Requirements

Last reviewed: 2026-10-19

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