Automatic Square Tube Bundle Making and Strapping Line: Engineering Guide and Specs

Executive summary

An automatic square tube bundle making and strapping machine stacks square or rectangular tubes into a tight block and straps it with steel strap. It counts the tubes, squares the bundle and places each strap at the set position. This page covers the line, the strapping specs and how to work out bundle size and strap count.

Square and rectangular tubes are stacked layer by layer between the side posts on the roller stands, squared into a block of about ten tubes wide by ten high, and then run along the line to the strapping station.

Table of Contents

Why square bundles

Square and rectangular tubes stack flat against each other, so a square bundle has no gaps and does not roll. Square bundles stack safely in the yard and fill trucks and containers well. Stacking and strapping by hand at the end of a tube mill is heavy, slow work, and the bundles come out uneven.

Automatic squaring and strapping creates tight, uniform packages that prevent transit shifting, protect surface finishes, and optimize storage volume in industrial logistics.

How the line works

The automated bundling and strapping process follows five discrete mechanical steps:

  1. Collect: Cut tubes arrive directly from the tube mill run-out table and are verified by an optical counting system.
  2. Stack: Tubes are systematically laid layer by layer between adjustable vertical containment posts on the roller bed.
  3. Square: Side alignment posts and bottom rollers exert controlled mechanical clamping to press the entire bundle into a compact, squared block.
  4. Strap: The strapping machine head remains fixed (stationary) while the squared bundle is indexed forward along the roller conveyor to each pre-programmed strap position [manufacturer rating].
  5. Discharge: The fully strapped bundle advances downstream to automated weighing, labeling, or storage transfer systems.

The operator touchscreen interface (HMI) displays the tube count per bundle, external cross-sectional dimensions, and the exact quantity and spacing intervals of the strap cycles. An integrated PLC database logs every completed bundle for production traceability and quality records.

Strapping specs

The high-tension strapping station utilizes heavy-duty steel strapping with seal-less notched joints to resist settling and handling impacts.

Item FHOPE steel tube strapping machine
Strap material Steel strap
Strap width 25, 32 mm [manufacturer rating]
Strap thickness 0.8 / 1.0 mm [manufacturer rating]
Strap tension 7,000–18,000 N [manufacturer rating]
Seal Notching (sealless crimp)
Strap feed and take-up 2–3 m/second [manufacturer rating]
Tension speed 6 m/min [manufacturer rating]
Hydraulic system max (relief) pressure 100 bar [manufacturer rating]
Work pressure 80–90 bar [manufacturer rating]
Oil cooling Water heat exchanger

Note: The machine design incorporates stationary strapping head kinematics where all straps are applied across different longitudinal positions as the bundle traverses the station.

Bundle size

Tube pack cross-sections are determined by row and column layout:

Tubes per bundle = tubes per row × rows

(Illustrative example: A 10 × 10 bundle holds 100 tubes. With 40 mm square tube, the nominal bundle cross-section measures approximately 10 × 40 = 400 mm square. Actual finished dimensions and package weights are calculated from tube wall thickness, length, and nominal weight per metre, confirmed at formal quote stage.)

Strap count

The quantity of radial straps required depends on the overall mill product length, target center-to-center spacing, and the necessary end margin:

Straps per bundle = (bundle length − 2 × end margin) ÷ strap spacing + 1

The end margin prevents the outermost straps from slipping off raw, deburred tube ends during crane rigging, fork handling, or marine transit. Both the end margin and the required intermediate strap pitch for specific tube gauges are configured on the HMI and confirmed during project quotation.

Selection checklist

When specifying an automated bundling and strapping line, prepare the following operational parameters:

  1. Tube sizes (outer dimensions) and wall thickness range?
  2. Tube cut length range (minimum and maximum in mm)?
  3. Target bundle shape (matrix configuration) and tubes per bundle?
  4. Mill exit speed and cycle output (tubes per minute)?
  5. Preferred steel strap width (25 mm or 32 mm) and thickness (0.8 mm or 1.0 mm)?
  6. Downstream requirements (in-line load cell weighing, marking, or automatic labeling)?

Safety

The machinery conforms to internationally recognized industrial equipment safety directives:

  • EN ISO 12100:2010: Safety of machinery — General principles for design, risk assessment, and risk reduction.
  • EN 415-10: Safety of packaging machines — General requirements.
  • EN 60204-1: Safety of machinery — Electrical equipment of machines.

Primary mechanical hazard zones include high-speed transfer arms, electro-mechanical/hydraulic bundle squaring compactors, and the high-tension strapping head. The line requires physical perimeter safety fencing, Category 4 interlocked access gates with guard locking, and prominent, mushroom-head emergency stop buttons distributed along both sides of the conveyor.

Engineering FAQ

Q: Can the line stack rectangular tubes? A: Yes. The alignment guides handle both square and rectangular structural hollow sections. Exact aspect ratios and orientation requirements are confirmed during project engineering.

Q: What is the adjustable strap tension range? A: The hydraulic tensioning module provides an adjustable clamping range of 7,000–18,000 N [manufacturer rating], preventing bundle looseness while preventing structural crushing on thinner tube walls.

Q: Can the system be configured to make hexagonal bundles for round pipe? A: Yes. For round tubing, the line can be adapted with a hexagonal bundle forming cradle. Depending on the line configuration, hexagonal bundle widths typically span 450 mm to 1,100 mm [manufacturer rating], with recipe management stored directly in the HMI.

Q: Is individual bundle production data recorded? A: Yes. The onboard PLC and industrial PC interface record tube counts, applied tension levels and completed strap quantities for integration with plant MES/ERP systems.

Next step

  1. Send your production parameters: Forward your tube dimensions, length variations, target bundling configurations, and mill line speeds to info@fhopepack.com.
  2. Technical sizing: Our engineering team designs the stacker geometry, squaring clamping tonnage, and strapping head kinematics.
  3. Formal proposal: We reply within 24 hours with a comprehensive engineering layout, cycle time simulation, and quotation.

Sources

Last reviewed: 2026-10-20

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