Two Jobs, One Machine: How Hydraulic Pre-Curling Flanging Machines Simplify Steel Drum Production

I remember visiting a steel drum factory where the flanging and curling stations were located at opposite ends of the 

workshop. Drums had to be transported between them on carts, and the handling was causing scratches, delays, and a lot 

of frustration. The manager asked me, "Isn't there a machine that can do both jobs in one go?" That's when I told him about 

hydraulic pre-curling flanging machines.

Here's the thing about steel drum production. After the drum body is welded, it needs two edge treatments before it's ready 

for seaming. The first is flanging, which curls the edge outward to create the flange that the lid will grip onto during seaming. 

The second is pre-curling, which rolls the edge of the lid or drum body to prepare it for the double-seaming process. 

Historically, these were separate operations on separate machines. But a hydraulic pre-curling flanging machine combines 

both jobs in one setup, saving floor space, reducing handling, and improving consistency.

A hydraulic pre-curling flanging machine is a forming machine that integrates flanging and pre-curling into a single 

operation. The machine holds the drum body or lid in position, and hydraulic cylinders drive forming heads that 

simultaneously create both the flange and the pre-curl. The process is controlled by a PLC, with adjustable parameters for 

different material thicknesses and drum sizes. Some modern machines can handle diameters from 200mm to 600mm and 

material thicknesses up to 4mm. The hydraulic drive provides stable pressure, which is essential for consistent forming 

quality on thin steel sheets.

Why hydraulic? Unlike mechanical systems that have fixed motion profiles, hydraulic systems let you adjust pressure and 

speed precisely. That's important because steel drum edges are sensitive to forming force. If you apply too much pressure, 

you can crack the metal or create wrinkles. If you apply too little, you won't get a proper edge profile. Hydraulic pre-curling 

flanging machines let you dial in the right pressure for your specific material thickness.

When you're choosing a machine, pay attention to a few key specifications. First, the diameter range. For standard 200L 

drums, you'll need a machine that can handle diameters around 560mm to 571.5mm. Some machines also handle smaller 

drums down to 200mm, which is useful if you're running a mixed production line. Second, the material thickness. Most 

machines handle steel up to 1.5mm. For heavier-duty applications, you might need a machine that handles up to 2.5mm or 

even 4mm. Third, the cycle time. In a modern steel drum line, you'll want a machine that can process at least 8 to 12 drums 

per minute.

One practical tip: look for a machine with quick-change tooling. If you're running different drum sizes, you'll be swapping 

forming heads frequently. A machine where the tooling can be changed in minutes—rather than hours—will save you a lot 

of downtime. The Grotnes 940V Combination Flanger/Curler-Beader, for example, has tooling that can be swapped in 

minutes, and recipe adjustments take less than 2 minutes.

Another thing to consider is the control system. A good machine will have a PLC control with a touchscreen interface that 

lets you store multiple recipes for different drum sizes and material thicknesses. That way, when you switch from a 200L 

drum to a 210L drum, you just recall the recipe and the machine adjusts itself. Some advanced machines even have 

automatic loading and unloading for seamless integration with conveyors.

Your hydraulic pre-curling flanging machine is one of those investments that pays for itself in reduced handling, improved 

consistency, and higher throughput. It eliminates the manual transfer between separate flanging and curling stations, 

which reduces scratches and handling damage. And because both operations happen in one pass, you get better alignment 

between the flange and the pre-curl, which means better seaming quality down the line.