Upright Rack Beam Automatic Welding Machine

Six CO2 welding heads close the longitudinal seam on P beams and box beams in one automatic pass. The beam is clamped on the bed, a ball screw carriage runs the full length, and a three side tracing system keeps every torch on the real joint instead of a fixed line.

This is the welding station of a pallet racking line. It sits after the roll former and cut off, before the stacker, and it is the step that turns two roll formed pressings into one closed hollow section that carries the load the rack design assumes.

Specifications at a glance

Machine type	Automatic longitudinal seam welder
Beam types	P beam, box beam
Beam width	50 to 220 mm
Beam height	40 to 70 mm
Sheet thickness	0.8 to 5 mm
Seam gap	0.5 to 1.8 mm
Welding heads	6 x NBC300 CO2
Welding speed	up to 15 mm/s (0.9 m/min)
Beam length	3.5 m standard, custom on request
Control	Delta PLC + touch screen

What an upright rack beam automatic welding machine does

A roll formed box beam starts life as two open sections. Until the longitudinal seam is closed, they behave as two separate pressings. Under a point load the halves slide against each other, the section twists, and the beam carries far less than the load table for that section promises.

Welding changes the mechanics. Once the seam is closed, the two pressings act as a single hollow section with a much higher torsional stiffness, which is what the beam load table assumes in the first place.

A P beam is the same argument in a simpler shape. The formed seam is the only thing holding the section together. An open seam lets the flange unwind at the ends, exactly where the beam hooks into the connector and where the bending moment is highest.

Manual welding versus the automatic station

Hand welding a rack beam is not difficult. Doing it 300 times a shift at the same weld size is the hard part.

Item	Hand welding	Automatic station
Arc time, 3.5 m seam	12 to 18 min	3.9 min
Weld size	Varies by shift	Same recipe every cycle
Distortion	Heat input follows the operator	Steady travel speed
Skill needed	Coded welder	Line operator
Fume and spatter	At the face	Extracted at the torch
Section changeover	Re-set by eye	Recall the recipe by section

The 3.9 minute figure is arithmetic, not a claim. At 15 mm/s the torch covers 0.9 m per minute, so a 3.5 m seam takes 3 min 53 s of arc time. A hand welder laying a continuous 3 to 4 mm fillet runs at roughly 3 to 5 mm/s, which puts the same seam at 12 to 18 minutes.

How the six head station works

• Frame and clamping. A fabricated steel base carries the beam platform. The beam is located and clamped so the seam sits in the torch window along its whole length.
• Travel. A stepper motor drives a ball screw, and the carriage runs on a linear guide rail. That combination gives a steady travel speed, which is what keeps weld size constant from one end of the beam to the other.
• Tracing on three sides. Copying rollers follow the actual flange and web on three sides of the beam. If the formed profile is uneven, or the beam came out slightly parallelogram, the head follows the real joint rather than a straight line and still finds the seam.
• Six torches. Six NBC300 CO2 units weld at the same time, so both seams of a box beam close in one pass. Each torch angle can be micro adjusted for the section in production.
• Control. A Delta PLC and touch screen hold the sequence and output digitally. The operator picks the program for the beam size, and the station repeats it.
• Cooling and gas. A closed circulation system cools the torches and cables on long runs. Shielding gas is CO2, or a 80/20 argon CO2 mix for a smoother bead and less spatter.

Technical parameters

Beam types	P beam, box beam
Beam width	50 to 220 mm
Beam height	40 to 70 mm
Beam material thickness	0.8 to 5 mm
Seam gap	0.5 to 1.8 mm
Welding wire	0.8 to 1.0 mm
Shielding gas	CO2 or 80/20 argon CO2 mix
Welding speed	up to 15 mm/s
Welding heads	6 x NBC300
Beam length	3.5 m standard, longer on request
Travel drive	Stepper motor, ball screw, linear guide
Control	Delta PLC and touch screen
Cooling	Circulation system
Power requirement	380 V, 3 phase, 50 Hz, other voltages on request

Cycle time and shift output

Arc time is only part of the cycle. Load, clamp, weld and unload are what the operator feels. The table below adds two minutes of handling to the arc time and assumes both seams of a box beam close in the same pass.

Beam length	Arc time	Cycle	Beams / 8 h
1.0 m	1.1 min	3.1 min	about 120
2.0 m	2.2 min	4.2 min	about 90
3.5 m	3.9 min	5.9 min	about 65

The right hand column is 80 percent utilisation on an eight hour shift. Real output drops on short runs, on frequent section changes, and whenever the beam arrives at the station with a seam gap outside 0.5 to 1.8 mm and has to be reworked.

Matching the welder to your roll forming line

The welder is rarely the machine a buyer researches first, and it is often the one that sets the ceiling on the whole line. These are the four points worth settling before the order.

• Cut off length. The standard bed takes 3.5 m beams, which covers most pallet racking. If your mill cuts 6 m, spec a longer machine at the order stage. Retrofitting a bed is expensive.
• Throughput balance. A step beam line at 25 to 30 m/min can outrun a welder that needs 5.9 minutes per 3.5 m beam. Decouple the two with a buffer table, run a second welder, or weld on a separate shift. Plan the balance, not just the machine.
• Services. Confirm 380 V three phase, a CO2 manifold sized for six torches, fume extraction at the station, and cooling water if the site runs long shifts in a hot climate.
• Seam gap discipline upstream. The 0.5 to 1.8 mm window is set by the roll former, the punch and the cut off, not by the welder. A gap of 3 mm burns through and a gap of 0.2 mm lacks penetration, and both come back as rework.

What we check before the machine ships

• Seam gap measured on sample beams from each section in the order
• Weld leg and penetration on a destructive test beam
• Straightness and twist after welding, measured against the beam tolerance your racking standard requires
• Spatter level and clean up time recorded, because it sets the labour content after welding
• Welding procedure and consumables documented for projects that need EN 1090 or ISO 3834 paperwork

Believe Industry has built roll forming equipment since 2005, with 500+ machines in 50+ countries and an ISO 9001 quality system behind the CE marking on the machines we export.

Where this machine fits in the racking line

Beam welding is one station in a sequence. If you are specifying the whole line, start from the pallet racking roll forming machine overview, then look at the sections that feed this welder: the box beam roll forming machine and the P beam roll forming machine. Uprights come from the upright rack roll forming machine, and the horizontal members from the step beam roll forming machine.

Two related reads on the same production problem: the step beam production process from coil to finished beam, and the comparison of step beam versus box beam roll forming machines. Beam to connector welding is a different station, covered on our box beam welding machine page.

Frequently asked questions

Q: What is an upright rack beam automatic welding machine?
A: It is a fixed station that welds the longitudinal seam of roll formed rack beams. Six CO2 torches run along the beam on a ball screw carriage while a tracing system follows the profile, closing the seam on P beams and box beams without a hand welder.

Q: Can one machine weld both P beams and box beams?
A: Yes. Both sections fall inside the same 50 to 220 mm width and 40 to 70 mm height window, so one machine covers a mixed racking catalogue. The program changes with the section, and the torch angle is micro adjusted between runs.

Q: How fast is it compared with manual welding?
A: A 3.5 m seam takes 3.9 minutes of arc time at 15 mm/s, against 12 to 18 minutes by hand. The gap widens on long beams and on thin sheet, where a hand welder has to slow down to avoid burn through.

Q: What beam length can it handle?
A: 3.5 m is standard and covers most pallet racking beams. Longer beds are built to order, so specify the maximum cut off length of your mill when you ask for a quote rather than after the machine arrives.

Q: Does it weld the beam to the connector as well?
A: No. This machine closes the beam seam along its length. Welding the beam ends into the connector or frame is done on a separate four head station, the box beam welding machine, at 15 to 25 seconds per piece.

Q: What gas and wire does it use?
A: 0.8 to 1.0 mm copper coated wire with CO2, or an 80/20 argon CO2 mix if you want a smoother bead and less spatter. The mix costs more per hour but usually pays back on clean up time.

Q: What power and floor space does it need?
A: 380 V three phase is the standard build, with other voltages on request. The bed is about 3.5 m of beam plus the carriage travel, and the footprint depends on the beam length, so we confirm it on the layout drawing before shipment.

Q: Can it run inline with a roll forming line?
A: Yes, it normally runs after the cut off and before the stacker. If the mill is faster than the welder, put a buffer table between them so the mill does not stop every cycle.

Send us your beam section

Send a section drawing with width, height, sheet thickness and seam position, plus the beam length you cut and the output you need per shift. We will come back with the head count, the cycle time and a layout that fits your line. Email darren@believeindustry.com or message us on WhatsApp.

If your project is specified to RMI, the Rack Manufacturers Institute publishes the tolerance tables we measure against. European projects usually cite EN 15512 instead.

Last updated: 2026-11-06

Page changelog

2026-11-06: Rebuilt the page from 188 words, added the specification, comparison and cycle time tables, eight FAQs with FAQPage schema, and Rank Math title and description.

Next review dates

New beam section outside the 50 to 220 mm width or 40 to 70 mm height range

Change in head count, PLC platform or wire diameter

A customer project that requires a racking standard not yet covered on this page