Automatic Steel Tube Bundle Strapping Machine: Strap Count and Head Data

Executive summary Our automatic steel strapping machine bands a formed tube bundle with 5 to 7 straps, placed along the bundle according to its length. It uses blued, waxed steel strap 0.8 or 1.0 mm thick with 25 or 32 mm seals, joined by a double seal notch. We plan strap positions and strap use from your bundle length and cross-section.

Table of Contents

How the automatic tube bundle strapping station works

The formed bundle travels on the conveyor into the strapping station. The strapping machine is situated at a fixed point [manufacturer rating], and the bundle moves to perform each strapping. The machine feeds steel strap around the bundle, tensions it, seals it with a double seal notch and cuts it, then moves to the next position along the bundle. It performs every strap at the positions set for that bundle length, automatically or with manual operation.

The bundle centre must line up with the conveyor centre while it moves. The strapping machine itself does not position the bundle, so we plan the strap positions with the line controls.

Round tubes nest into a hexagonal bundle in the bundling frame before the bundle is banded with steel straps.

Steel tube bundle with steel straps on a green roller conveyor after the strapping station
Steel-strapped tube bundle. Straps are placed along the bundle according to its length.

Strap count and spacing along the bundle

Illustrative example: we keep 500 mm from each end to the first strap and spread the rest evenly across the tube bundle span.

Bundle length Straps End distance (illustrative) Spacing
6,000 mm 5 500 mm (6,000 − 1,000) ÷ 4 = 1,250 mm
6,000 mm 7 500 mm (6,000 − 1,000) ÷ 6 = about 833 mm

Tension for thin-walled tubes and heavy pipe

Too much tension can dent thin-walled outer tubes, while too few straps let the bundle loosen when it is lifted. For thin walls we use more straps at lower tension; heavy pipe takes fewer straps at higher tension.

Strap length for hexagonal and rectangular bundles

For a nested hexagonal bundle of round tubes, the perimeter band length is calculated using the derived formula 6 × (n − 1) × d + π × d, where n is the number of tubes along one outer facet and d is the individual tube outer diameter (OD). In automated processing lines, bundle cross-sections typically accommodate hexagon widths from Min 450 mm to Max 1100 mm [manufacturer rating].

Example bundle n d Band length 7 straps
37 tubes, hexagonal 4 60 mm 6 × 3 × 60 + π × 60 = about 1,270 mm about 8.9 m

For a square or rectangular bundle, the band length is 2 × (bundle width + bundle height). Add the overlap at the seal to each band when you order strap.

Steel strap, seals and joint

Item Specification
Strap material Cold-rolled low-carbon steel
Finish Blued and waxed
Strap thickness 0.8 or 1.0 mm (±10%)
Width tolerance ±0.127 mm
Camber Under 8 mm per 2,000 mm of strap
Seal Cold-rolled low-carbon steel, magazine fed, about 180 seals per load
Seal width 25 or 32 mm
Joint Double seal notch

The joint formed by this head is also classified as Notching [manufacturer rating].

Strapping head data: tension, speed and pressure

Item Auto steel strapping machine
Strap tension 7,000–18,000 N
Strap feed and take-up 2–3 m/s
Tension speed 6 m/min
Hydraulic pressure 100 bar
Working pressure 80–90 bar
Oil cooling Water

Our banding data also give up to 13.7 kN at 0.54 MPa air pressure [manufacturer rating], so we confirm the tension your tubes need on trial.

Utilities and safety

The head runs on hydraulic oil at 80–90 bar working pressure with water cooling for the oil, and it needs compressed air. The standards that apply depend on the destination market. For CE markets, ISO 12100 sets the risk-assessment method and EN 415-10 sets general requirements for packaging machines.

Selection checklist for tube bundle strapping

  • Tube OD, wall thickness and length.
  • Bundle shape and tube count.
  • Straps per bundle and positions.
  • Strap thickness and seal width.
  • Bundles per shift needed.
  • Hydraulic, air and cooling water supply.

Engineering FAQ

Q: How many straps go on one bundle? A: 5 to 7, placed according to bundle length.

Q: What strap does it use? A: Blued, waxed cold-rolled steel strap, 0.8 or 1.0 mm thick, with 25 or 32 mm seals.

Q: How much strap does one band use? A: For a 37-tube hexagonal bundle of 60 mm tubes, about 1,270 mm plus the seal overlap.

Q: How tight is the strap? A: The head is rated 7,000–18,000 N, and our banding data give up to 13.7 kN at 0.54 MPa air. We set it on trial.

Q: Does the machine place the straps along the bundle? A: The strapping machine is stationary at a fixed point [manufacturer rating]; the bundle moves on the conveyor to each set position, planned with the line controls.

Q: How does tube wall thickness change the strapping? A: Too much tension can dent thin-walled outer tubes, and too few straps let the bundle loosen when it is lifted. Thin walls take more straps at lower tension; heavy pipe takes fewer straps at higher tension.

Q: What seals and joint does the head use? A: Magazine-fed cold-rolled low-carbon steel seals, 25 or 32 mm wide, about 180 seals per load, joined by a double seal notch (also classified as Notching).

Q: What utilities does the strapping head need? A: Hydraulic oil at 80–90 bar working pressure (100 bar hydraulic pressure) with water cooling for the oil, plus compressed air.

Next step

We plan your tube strapping in three steps:

  1. Submit your layout drawing with tube sizes, bundle shapes and lengths to info@fhopepack.com.
  2. Receive a proposal within 48 hours, with strap count and positions.
  3. Book a site survey to fit the station into your line.

Sources

Last reviewed: 2026-10-04

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