Copper sheet and bronze bar wrapping machine

Executive summary

An industrial copper sheet and bronze bar wrapping machine transfers elongated, non-ferrous profiles along a precision roller conveyor through a high-speed horizontal orbital ring, applying a continuous spiral helical wrap from tip to tail. This protective packaging process preserves critical mirror/mill surface finishes, shields against atmospheric oxidation, and eliminates mechanical abrasion caused by metal-to-metal rubbing within storage or transit bundles. Engineered for versatility, the semi-automatic S200 system processes non-ferrous profiles longer than 300 mm, with cross-sectional envelope dimensions up to 200 mm and payload weights spanning 10–100 kg, supported by an inverter-controlled ring speed of 20–120 r/min.

This specialized horizontal orbital packaging system is engineered specifically for narrow copper strips, busbars, and drawn bronze bars. A blue heavy-duty powered roller conveyor transports each profile directly through a compact rotary ring housed within an OSHA/CE-compliant yellow perimeter safety cage. Overhead pneumatic vertical hold-down assemblies with non-marking polyurethane rollers clamp the elongated workpieces continuously, suppressing vertical vibration, transverse shifting, and edge flutter during high-tension spiral wrapping cycles.

Table of Contents

Why copper sheet and bronze bar are wrapped

High-purity copper and architectural bronze profiles command premium pricing based entirely on pristine surface finish, exact geometric flatness, and metallurgical integrity. Even microscopic surface defects can cause commercial rejections:

  • Atmospheric & galvanic oxidation: Residual moisture, airborne sulfates, and acidic fingerprint oils initiate rapid chemical tarnishing, discolouration, and copper patina, rendering bare stock unacceptable for electrical switchgear or architectural installations.
  • Fretting abrasion & micro-scratching: Copper is a relatively ductile non-ferrous metal (Mohs hardness ~3). Unwrapped bars packed into bundles vibrate dynamically during road or ocean transport, causing aggressive inter-pass friction, gouging, and surface scuffing.
  • Burr snagging & edge deformation: Sheared strip edges often possess micro-burrs that hook into adjacent components unless sealed under stable tension.

Encapsulating each workpiece or consolidated mini-bundle in an unbroken spiral envelope of LLDPE stretch film, paper, or multi-layer VCI (Volatile Corrosion Inhibitor) material preserves factory-fresh mill surfaces completely from final cut-off to end-user unboxing.

How the orbital wrapper works

The semi-automatic orbital packaging process coordinates two synchronized kinematic axes:

  1. Longitudinal feed axis: The profile rests on a motor-driven infeed roller conveyor lined with non-marking synthetic sleeves. Photoelectric sensors detect the leading edge of the workpiece, triggering the automatic conveyor drive and sequence interlocks.
  2. Rotary wrapping axis: The profile advances through the rotating orbital ring. An integrated roll carriage spins orbitally around the moving profile, dispensing tensioned wrapping material in a uniform spiral helix along its entire length.

Ring rotation speed is modulated through an AC variable frequency drive (VFD), while web tension is maintained mechanically via a micro-adjustable friction core brake. Both infeed and outfeed conveyors utilize programmable soft-start/soft-stop acceleration ramps to prevent workpiece slippage.

Overlap Kinematics

Film overlap percentage is strictly governed by the ratio between conveyor linear speed and ring rotational velocity:

Advance per ring revolution (mm) = Conveyor speed (m/min) × 1,000 ÷ Ring rotational speed (r/min)

Effective overlap width (mm) = Film web width (mm) - Advance per ring revolution (mm)

Overlap percentage (%) = [1 - (Advance per ring revolution ÷ Film web width)] × 100%

Increasing conveyor linear advance or decreasing ring rotational speed lowers overlap density, whereas elevating ring speed creates a tighter, multi-layered protective barrier.

Flat strip vs round bar

Non-ferrous profiles exhibit distinct mechanical dynamics inside an orbital wrapper:

Comparative Engineering Parameter Flat Copper Strip / Sheet Bar Round Bronze Bar / Rod
Ring Envelope Clearance Rule Profile cross-section diagonal √(W² + T²) must not exceed 200 mm External diameter OD must not exceed 200 mm
Dynamic Workpiece Restraint Pneumatic vertical hold-down rollers prevent upward lift, edge flutter, and torsional twisting V-groove guide rollers maintain axial centering; minimal vertical downforce required
Film Dispensing Length per Turn Theoretical perimeter: 2 × (Width + Thickness) Theoretical perimeter: π × External Diameter
Primary Process Vulnerabilities Knife-edge film shearing; transverse profile bowing under excessive web tension Rotational rolling drift; impact damage to precision bar ends
Contact Surface Protection Polyurethane (PU) coated rollers prevent indentation marks on broad copper faces High-density polyethylene (HDPE) rollers eliminate metallic transfer marks

S200 technical specifications

The S200 model represents an optimal footprint for standalone packaging cells or extrusion line discharge tables:

Engineering Parameter S200 Standard Machine Rating
Workpiece Length Range Minimum 300 mm to unrestricted maximum
Cross-Sectional Envelope (OD / Diagonal) 10 mm minimum to 200 mm maximum
Payload Weight Range 10 kg to 100 kg (balanced line load)
Infeed / Outfeed Roller Conveyors 2,000 mm length each, motor-driven with PU sleeve protection
Conveyor Linear Speed Range 4.0–12.0 m/min (inverter variable speed control)
Orbital Ring Rotational Speed 20–120 r/min (inverter variable speed control)
Installed Power Supply Approx. 2.1 kW, AC 380 V, 3-Phase, 50/60 Hz (customizable)
Wrapping Consumable Specs LLDPE stretch film (25–50 µm), roll width 120–200 mm, roll OD 150–200 mm, core ID 50 mm
Alternative Consumable Compatibility Crepe kraft paper, woven PE strip, VCI corrosion-inhibiting film

Note: Heavy-gauge sheared copper with aggressive burrs requires 35–50 µm film to prevent puncture failures. Profile-matched pneumatic hold-down assemblies and automated pneumatic clamp/cut systems are customized and confirmed at quote.

Worked engineering example: copper busbar

Evaluate the wrapping parameters for an extruded pure copper busbar measuring 100 mm (width) × 10 mm (thickness) with a total cut length of 3,000 mm, wrapped using 120 mm wide film targeted at a 50% overlap. Pure copper density is taken as 8,960 kg/m³.

Calculation Step Engineering Formula & Input Data Validated Output
1. Total Profile Volume V = 0.100 m × 0.010 m × 3.000 m 0.003 m³
2. Total Workpiece Mass M = 0.003 m³ × 8,960 kg/m³ 26.88 kg (about 27 kg)
3. Sectional Diagonal D = √(100² + 10²) = √(10,000 + 100) = √10,100 100.5 mm
4. S200 Dimensional Envelope Check Length ≥ 300 mm (actual 3,000 mm); D ≤ 200 mm (actual 100.5 mm); Mass 10–100 kg (actual 26.9 kg) Fully compliant (Pass)
5. Advance per Ring Revolution Advance = Film Width × (1 - Overlap Ratio) = 120 mm × (1 - 0.50) 60.0 mm
6. Total Helical Ring Turns Turns = Profile Length ÷ Advance = 3,000 mm ÷ 60 mm 50 revolutions
7. Operating Speed Kinematics Ring set at 80 r/min; Conveyor Speed = 80 r/min × 0.060 m = 4.8 m/min 4.8 m/min (within 4–12 m/min range)
8. Cycle Wrap Time T = 3.0 m ÷ 4.8 m/min = 0.625 min 37.5 seconds
9. Theoretical Film Consumption 50 turns × 2 × (0.10 m + 0.01 m) = 50 × 0.22 m (excluding prestretch & tail wraps) 11.0 linear meters

Engineering Validation: The 100.5 mm diagonal leaves approximately 49.7 mm of radial working clearance inside the 200 mm ring cavity, ensuring no web snagging. Operating the ring at 80 r/min matches a conveyor speed of 4.8 m/min, operating smoothly within the S200 mechanical thresholds (4.0–12.0 m/min). If the ring were run at only 60 r/min, a 60 mm advance would demand 3.6 m/min conveyor speed—falling below the motor VFD minimum continuous cooling threshold (4.0 m/min).

Engineering selection checklist

To configure an optimal packaging machine specification, confirm the following application parameters:

  1. Alloy Grade & Finish: Electrolytic copper (ETP/OFHC), architectural bronze, brass, or mirror-buffed profiles.
  2. Cross-Sectional Bounds: Minimum and maximum section dimensions (Width × Thickness for flats; OD for rounds).
  3. Length & Mass Bounds: Minimum cut length (must exceed 300 mm for continuous conveyor transfer) and maximum bundle weight.
  4. Bundle Consolidation: Single-profile packaging versus nested multi-piece master bundles.
  5. Consumable Selection: Cast LLDPE film, VCI anti-corrosion barrier film, or neutral-pH kraft paper.
  6. Automation Level: Manual film tail tethering/severing versus pneumatic automatic clamp-and-cut integration with downstream sorting.

Machine safety standards: EN 415-10 and ISO 12100

The S200 horizontal wrapping machine is engineered in strict compliance with harmonized European packaging machinery standards:

  • EN 415-10 Compliance: Governs safety requirements for horizontal orbital wrappers, ensuring physical interlocking perimeter guarding around rotating parts, nip-point shielding on infeed/outfeed rollers, and captive key safety interlocks.
  • ISO 12100 Risk Assessment: Comprehensive risk mitigation protocols reduce residual mechanical risks (pinching, trapping, cutting) to tolerable industry limits.
  • Operator Safeguards: Features an ergonomic industrial control panel with prominent emergency-stop (E-stop) pushbuttons, low-voltage control circuits (24 V DC), and comprehensive operational fault annunciation.

Engineering FAQ

Q: Can the S200 wrap brass profiles and aluminum extrusions without mechanical modification? A: Yes. The orbital ring wrapping principle relies strictly on workpiece exterior geometric dimensions and total mass, completely independent of the non-ferrous alloy composition.

Q: How is exact wrapping overlap adjusted during production changeovers? A: Overlap is controlled digitally by modifying the ratio between the conveyor VFD linear speed and the orbital ring VFD rotational speed. A higher ring speed relative to conveyor advance increases the overlap percentage.

Q: Can multiple flat copper strips be wrapped together as a consolidated bundle? A: Yes. Multiple pieces can be strapped or direct-wrapped as a unified bundle, provided the outer bounding diagonal of the bundle cross-section does not exceed 200 mm and total bundle mass remains within the 100 kg system capacity.

Q: What electrical utility connection is required for the S200? A: The baseline system requires approximately 2.1 kW connected load on a 3-phase AC 380 V 50/60 Hz supply. Custom drive packages for 220 V, 415 V, or 480 V industrial grids are available upon request.

Next step: engineering review & quotation

  1. Submit Product Data: Send your cross-section drawings (W × T or OD), profile lengths, and target production rates to info@fhopepack.com.
  2. Engineering Layout Review: Our packaging engineers will model your profile envelope, calculate ring clearances, and determine the optimal roller PU compound and hold-down geometry.
  3. Comprehensive Proposal: Receive a detailed technical specification sheet, formal quotation, and cycle time analysis within 24 business hours.

Reference standards & sources

  • FHOPEPACK Engineering Documentation: S200 Semi-Automatic Horizontal Orbital Wrapping Systems
  • EN 415-10: Safety of Packaging Machines – Part 10: General Requirements
  • ISO 12100:2010: Safety of Machinery – General Principles for Design – Risk Assessment and Risk Reduction
  • Copper Development Association (CDA): Surface Preservation and Packaging of Wrought Non-Ferrous Alloys

Last reviewed: 2026-10-19

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