Executive summary A steel strap under tension springs back the moment it is cut, making manual cutting of coil straps one of the highest-risk operations along a steel coil processing or packaging line. Our automatic de-strapping head physically clamps the strap against the coil surface, executes the shear cut under rigid containment, and mechanically draws the cut strap clear of the coil body. This sequence prevents uncontrolled strap release and keeps operators entirely outside the hazard zone. The de-strapping head configuration, tooling metallurgy, and scrap extraction paths are engineered per specific project coil dimensions and strapping types.
Table of Contents
- What the machine does
- Why automate strap removal
- The de-strapping sequence
- Strap scrap per coil
- Controls and safety
- Selection checklist for a de-strapping machine
- Engineering FAQ
- Next step
- Related reading
- Sources
What the machine does
The automatic de-strapping station secures the coiled load, neutralizes residual strap tension, and disposes of spent strap without manual handling:
- Surface clamping: The de-strapping head travels down to contact the strap directly, exerting clamping force to lock the steel strap flat against the coil perimeter or test mandrel.
- Constrained cutting: With tension restrained on both sides of the contact zone, the integrated shear mechanism cuts through the strap section.
- Mechanical withdrawal: A motorized feed-out and extraction gripper pulls the severed strap clear to the lateral scrap handling zone, while the coil remains stationary.
- Head retraction: The vertical slide retracts the de-strapping head to its upper datum position, clearing the envelope for subsequent indexing or coil discharge.
Why automate strap removal
| Hazard by hand | How the head deals with it |
|---|---|
| Strap springs back when cut | The head holds the strap before it cuts |
| Sharp strap ends | The cut strap is pulled clear by the machine |
| Operator at the coil | Nobody needs to stand at the strap |
| Strap left on the floor | The strap is taken away from the coil |
Eliminating operator exposure at the shear point is the primary safety rationale. Heavy-gauge packaging straps store significant strain energy when tensioned around a large outer diameter. By pressing the strap firmly against the work surface prior to shearing, the head physically confines both cut ends, preventing explosive whip-back (snapback). Line personnel remain isolated behind interlocked perimeter guarding throughout the removal cycle.
The de-strapping sequence
- Position. The coil (or test block representing the coil perimeter) is positioned directly beneath the head assembly, aligning the target strap with the center of the clamping pad.
- Press. The vertical drive drives the head down, mechanically locking the strap against the surface under controlled clamping force.
- Cut. Integrated shear tooling cuts the strap cleanly beneath the clamping pad while tension remains locked.
- Pull clear. The extraction pinch mechanism engages the strap body and draws it continuously away from the coil circumference into the disposal line.
- Return. The head assembly elevates to home position, re-arming the shear tooling for the next strapping band.
Coils banded with multiple radial or circumferential straps are rotated via powered coil-turning rolls or indexed axially between cutting cycles to present each strap line sequentially beneath the de-strapping head.
Strap scrap per coil
Illustrative example for a coil secured with three heavy-duty high-tensile steel straps, each 4.5 m long, 32 mm wide, and 0.8 mm thick:
| Item | Value |
|---|---|
| Strap section, 32 × 0.8 mm | 25.6 mm² |
| Mass per metre, at 7.85 g/cm³ | about 0.20 kg/m |
| Strap per coil, 3 × 4.5 m | 13.5 m |
| Scrap per coil | about 2.7 kg |
| Scrap per 100 coils | about 270 kg |
At high processing line throughputs, strap accumulation poses significant housekeeping and tripping hazards. Integrating a dedicated mobile scrap bin or an automatic mechanical strap winder/chopper directly adjacent to the extraction head ensures that cut bands leave the active handling envelope continuously.
Controls and safety
The de-strapping head combines high-force clamping and a mechanical shear blade; all personnel must remain clear of the operational envelope during automatic cycling. Safety perimeter fences, optical light curtains, and safety interlock gates are engineered to match each plant’s layout and material flow logistics.
Applicable machinery safety standards depend on regional target markets. For CE compliance, ISO 12100:2010 defines the core risk-assessment methodology and risk-reduction principles, while EN 415-10:2014 specifies safety requirements for integrated packaging lines, strapping, and de-strapping machinery.
Selection checklist for a de-strapping machine
- Coil dimensions: Outer diameter (OD), inner diameter (ID), and face width range.
- Strap material specification: High-tensile steel strap or polyester (PET) strapping.
- Strap cross-section and layout: Strap width, nominal thickness, and number of bands per coil.
- Engineering benchmark (steel strapping line reference): Heavy cold-rolled coils are standardly secured with strap widths of 31.75 mm ± 0.13 mm and thicknesses of 0.8–1.0 mm, tensioned up to ≤20,000 N [manufacturer rating for upstream strapping equipment]. Cutter hardness and clamping geometry must be matched to these yield strengths.
- Engineering benchmark (PET strapping line reference): High-performance PET bands typically span widths around 12 mm × 0.8–1.2 mm [manufacturer rating for upstream strapping equipment], requiring dedicated blade geometry and pinch-wheel profiles.
- Strap orientation: Circumferential (eye-horizontal/parallel to roll face) or radial (through-the-eye) bands.
- Line throughput: Required processing speed in coils per hour.
- Scrap management: Scrap bin discharge, continuous strap winder, or integrated inline scrap chopper.
Engineering FAQ
Q: Why remove coil straps automatically instead of using manual pneumatic cutters? A: Tensioned steel strapping stores substantial strain energy. Manual cutting exposes workers to direct lacerations, severe facial injuries, and snapback hazards. The automatic de-strapping head clamps the band firmly before shearing, fully containing the release of strain energy while keeping line workers outside the safety enclosure.
Q: Does the system accommodate coils bound with multiple straps? A: Yes. For coils with multiple circumferential straps, an axial traversing carriage steps the head across the coil face, or the coil saddle indexes the load. For radial straps through the eye, a motorized turn-roll station indexes the coil about its core axis to align each strap with the cutter.
Q: How much scrap weight does a single processing line generate? A: In our worked illustrative example (three 4.5 m steel straps, 32 × 0.8 mm), scrap volume totals approximately 2.7 kg per coil, or about 270 kg per 100 coils. Upstream scrap handling must be sized for this cumulative mass.
Q: What is the mechanism for collecting the severed strap? A: An automated pinch-roller or mechanical gripper grips the free end directly after the cut and pulls it clear of the coil face into an adjacent collection chute, automated scrap winder, or rotary scrap chopper.
Q: Can the same head cut both heavy steel strap and PET plastic strapping? A: Steel and PET possess vastly different mechanical elongation and shear properties. Heavy steel strap requires high-shear hardened tool-steel blades, whereas PET requires high-speed slicing geometries to prevent band fraying or incomplete severance. Tooling modules and drive profiles are customized for the primary strap material specified for each project (such as 12 mm × 0.8–1.2 mm PET or 31.75 mm high-tensile steel).
Next step
We plan your custom de-strapping machine in three steps:
- Submit your layout drawing along with coil dimensions (OD, ID, width), strap material/sizes, and output requirements to info@fhopepack.com.
- Receive a formal technical proposal within 48 hours, including de-strapping head arrangement, cycle-time calculations, and scrap handling layout.
- Book a site survey to verify coil handling conveyors, floor space clearances, and upstream line integration.
Related reading
- Steel coil strapping machines
- Steel coil PET strapping machine
- Video: trolley car for steel coil with track
Sources
- Automated Radial Strip Coil Strapping Machine By PET product technical specification (FHOPE)
- Cold Rolled Steel Coil Strapping Machine product technical specification (FHOPE)
- Scrap calculation: Worked example, illustrative values; carbon steel density 7.85 g/cm³
- International safety standards: ISO 12100:2010 (Safety of machinery — General principles for design — Risk assessment and risk reduction), EN 415-10:2014 (Safety of packaging machines — General requirements)
Last reviewed: 2026-10-29
