Semi-auto rotary arm stretch wrapper

Executive summary The R200 semi-automatic rotary arm stretch wrapper secures pallet loads while the pallet remains completely stationary on the floor or dock. A heavy-duty gantry supports the rotating arm, eliminating load tipping risks associated with rotary turntables on unstable, tall, or ultra-heavy products. Its dual-roller powered pre-stretch carriage achieves elongation ratios up to 250% prior to load application, substantially lowering film consumption per unit. Industrial safety fencing, pneumatic load stabilizers, and automated film clamping and cutting modules are available as configurable options.

Table of Contents

• Where a semi-auto rotary arm fits
• What powered pre-stretch does to film use
• Gantry, ring bearing and carriage
• R200 features and options
• Worked example: film for one carton pallet
• Selection checklist: what to send us
• Safety and EN 415-6
• Engineering FAQ
• Next step
• Related reading
• Sources

Where a semi-auto rotary arm fits

A semi-automatic rotary arm stretch wrapper is engineered for manufacturing environments and logistics distribution hubs running moderate production cycles. A forklift or hand pallet truck places the palletized goods directly on the designated floor station. The operator secures the film tail to the load, initiates the automatic wrap cycle via the main panel or pendant control, and severs the film at cycle completion.

Because the load remains static on the floor while the overhead cantilever arm rotates around its vertical axis, the R200 resolves the kinematic limitations of traditional turntable wrappers:

• Unstable and lightweight loads: Empty PET bottles, lightweight corrugated cartons, and tall beverage stacks that would shift, twist, or collapse under centrifugal acceleration remain fully stable.
• Ultra-heavy or irregular pallets: Pre-cast concrete, metal castings, drums, and heavy machinery parts have no operational weight limits, as the floor bears the entire payload rather than a motorized turntable bearing.
• Off-center stacking: Pallets with product overhang or non-uniform weight distribution wrap without inducing dynamic wobble or drive-system stress.

Common deployment sectors include chemical processing, electronics assembly, building materials, home appliances, paper mills, and food and beverage lines.

What powered pre-stretch does to film use

The R200 incorporates an independent motorized film carriage utilizing dual pre-stretch rollers connected by a fixed gear ratio. The secondary downstream roller operates at a higher circumferential surface speed than the primary roller. This speed differential forces the linear low-density polyethylene (LLDPE) film to yield and elongate mechanically within the carriage before contact with the load.

At a 250% pre-stretch setting, 1.0 m of unworked film off the supply roll elongates to 3.5 m applied to the pallet perimeter.

Yielded Film Length = Unstretched Film Length × (1 + Pre-stretch Ratio)
3.5 m = 1.0 m × (1 + 2.50)

Pre-stretching re-aligns the polymer chains within the film, transitioning the material past its initial yield threshold. This delivers measurable engineering advantages:

1. Enhanced Restoring Force: Work-hardened film possesses significantly higher tensile memory, minimizing package relaxation during transit.
2. Puncture Resistance: Oriented film resists edge punctures from corrugated corners and pallet nails better than slack film.
3. Corner Tension Decoupling: A spring-loaded dancer arm coupled to an analog position potentiometer modulates the independent DC film-feed motor. When the rotating arm traverses the long corners of a rectangular pallet, the dancer system dynamically accelerates film delivery, maintaining constant web tension and preventing box corner crushing.

Gantry, ring bearing and carriage

The R200 structural assembly is engineered for structural rigidity and fatigue endurance under continuous operational loading:

• Structural Steel Gantry: Four heavy-gauge hollow structural section (HSS) columns support an overhead structural cross-beam, minimizing dynamic deflection when the cantilever arm accelerates.
• Slewing Ring Drive: The rotary arm is mounted to a large-diameter internal-tooth slewing ring bearing with induction-hardened raceways. Driven by an AC gearmotor via a variable frequency drive (VFD), the system executes smooth S-curve acceleration and deceleration ramps to prevent shock loading on the drive train.
• Dual-Chain Hoist: Carriage vertical displacement is driven by a heavy-duty industrial double roller chain, engineered with high safety margins to prevent carriage drop in the event of drive engagement failure.
• Hinged Carriage Access: The film carriage features an ergonomic latching swing-door, permitting rapid film roll changes and unobstructed web threading.
• Automation Control Architecture: An OMRON programmable logic controller (PLC) governs cycle execution. Top and bottom reinforcement wraps, pitch overlap, and carriage travel speed are configured independently through the operator interface. A diffuse-reflection photo-eye automatically registers load height variations.

R200 features and options

Note: Arm rotational speed (RPM) and wrap cycle times are finalized based on specific pallet dimensions and required hourly throughput.

Worked example: film for one carton pallet

The following engineering calculation illustrates film consumption for a standard industrial unit load wrapped on the R200:

• Pallet Dimensions: 1,200 mm (Length) × 1,000 mm (Width)
• Stack Height: 1,050 mm
• Film Specification: 500 mm width, 23 µm (0.023 mm) thickness, standard LLDPE density of 920 kg/m³
• Overlap & Cycle Settings: 50% overlap (250 mm carriage vertical advance per arm rotation); 2 bottom wraps, 2 top wraps

1. Total Rotational Turns:

• Vertical traverse stroke: 1,050 mm
• Carriage vertical displacement per wrap: 250 mm
• Upward traverse turns: 1,050 ÷ 250 = 4.2 turns
• Downward traverse turns: 1,050 ÷ 250 = 4.2 turns
• Reinforcement wraps: 2 (bottom) + 2 (top) = 4.0 turns
• Total revolutions required: 4.2 + 4.2 + 4.0 = 12.4 turns

2. Applied Film Length on Load:

• Pallet perimeter: 2 × (1,200 mm + 1,000 mm) = 4,400 mm (4.4 m)
• Stretched film applied: 12.4 turns × 4.4 m = 54.56 m

3. Unstretched Film Consumed from Roll:

• At 250% Pre-stretch (3.5× yield factor): 54.56 m ÷ 3.5 = 15.59 m
• At 100% Pre-stretch (2.0× yield factor): 54.56 m ÷ 2.0 = 27.28 m

4. Weight and Cost Basis:

• Volume of 1 linear meter of 23 µm film: 1.0 m × 0.5 m × 0.000023 m = 0.0000115 m³
• Mass per linear meter: 0.0000115 m³ × 920 kg/m³ = 0.01058 kg (10.58 g/m)
• Film consumption per pallet at 250% pre-stretch: 15.59 m × 10.58 g/m = 164.94 g (approx. 0.165 kg)
• Film consumption per pallet at 100% pre-stretch: 27.28 m × 10.58 g/m = 288.62 g (approx. 0.289 kg)

Summary: Upgrading from 100% to 250% powered pre-stretch reduces film consumption by 123.68 g per pallet—a 42.8% reduction in raw material demand, saving 12.37 kg of plastic per 100 pallets wrapped.

Selection checklist: what to send us

To configure the correct structural footprint and carriage gearing for your facility, provide our engineering department with the following parameters:

1. Load Envelope: Minimum and maximum pallet dimensions (Length × Width × Height including pallet base).
2. Gross Pallet Weight: Minimum and maximum weight, stack consistency, and cargo fragility.
3. Packaging Film Parameters: Current roll width, film thickness (µm or gauge), roll outer diameter, and core size.
4. Target Throughput: Required pallets per hour or per shift.
5. Ancillary Requirements: Perimeter safety fencing, pneumatic top stabilizing platen, automatic film clamping/cutting, or wireless remote cycle start.
6. Electrical Service: Supply voltage, phase, and frequency available at the installation bay (e.g., 380V/480V, 3-Phase, 50/60 Hz).

Safety and EN 415-6

The R200 rotary arm stretch wrapper is engineered in strict compliance with EN 415-6 (Safety of Packaging Machines – Pallet Wrapping Machines) and the risk reduction frameworks of ISO 12100:2010:

• Rotational Hazard Zone: The sweeping path of the cantilever arm represents a mechanical shear and impact hazard. The carriage lower edge incorporates an obstacle bumper switch that immediately commands an emergency stop if physical interference is encountered.
• Physical Guarding: Standard installations include heavy-gauge yellow wire-mesh perimeter fencing compliant with EN ISO 13857 safety reach distances.
• Interlocked Access: Enclosure access gates feature positive-break safety limit switches conforming to EN ISO 14119. Opening any access gate while the machine is armed executes a Category 0 / Category 1 stop via safety-rated control circuits.
• Emergency Stop Integration: Latching E-stop pushbuttons are placed on the main operator station, safety enclosure gates, and remote pendant boxes.

Engineering FAQ

Q: Does high pre-stretch weaken film performance on sharp edges? A: No. High-performance machine-grade LLDPE film increases tensile modulus when pre-stretched. The dancer-controlled feed system prevents over-tensioning across pallet corners, preserving tear resistance while delivering maximum load containment force.

Q: Can the pneumatic film clamp and cut module be retrofitted in the field? A: While retrofitting is mechanically possible, pneumatic lines, solenoid valves, and PLC I/O mapping must be pre-configured. We recommend specifying the pneumatic grab-and-cut option during initial order placement to avoid field modification costs.

Q: What is the maximum load height accommodation on the R200 frame? A: The standard gantry accommodates finished pallet loads up to 2,000 mm. An extended structural column and chain package can be configured to wrap payloads up to 2,500 mm.

Q: What machinery safety standards apply for European installations? A: European market directives require CE compliance under EN 415-6 for pallet packaging machines, ISO 12100 for risk assessment, and EN ISO 13849-1 for the functional safety of related control systems.

Next step

1. Submit your parameters: Email your pallet dimensions, load profiles, film specs, and target cycle rates to info@fhopepack.com.
2. Receive engineering proposal: Our application engineering team delivers an equipment proposal within 24 hours, specifying optimal pre-stretch ratios, cycle calculations, and unit pricing.
3. Layout drawing validation: We supply detailed 2D/3D CAD layout drawings confirming gantry clearance, guard door locations, and loading access.

Related reading

• Semi-auto rotary arm stretch wrapper R200
• Stretch film and packing material technical specifications
• R100 rotary arm pallet wrapping machine
• Rotate arm stretch wrapping machine, pallet wrapping machine
• FHOPE-R100 rotary arm pallet wrapper with film cutter
• High pallet packing machine with top press device

Sources

• Equipment Specifications: FHOPE semi-automatic rotary arm stretch wrapper R200 engineering datasheet
• Technical Reference: Semi-auto rotary arm stretch wrapper on YouTube
• Consumable Calculations: Engineering calculation model for stretch film yield and mass density
• Safety Directives: EN 415-6 (Pallet wrapping machines); ISO 12100:2010 (Safety of machinery); EN ISO 13857 (Safety distances); EN ISO 14119 (Interlocking devices)

Last reviewed: 2026-10-17