+55 (19) 3377 5412 - COMEX@COMPRACO.COM.BR




+55 (19) 3377 5412

We bend steel profiles to specified radii, our core competencies include bending complete systems. State-of-the-art bending technology requires extensive knowledge of bending products such as steel profiles .

FOLDED SHEET PROFILES OF 1/4", 5/16", 3/8" and 1/2". length of 6 meters

Bent steel profiles come in a wide variety. Using modern and extensive machines to bend standard construction profiles and customer specific sections. We use methods of bending to bend a wide variety of types and sizes into virtually any desired profile , taking into account specific requirements (tolerance).

How sheet metal works

During the bending process , the upper tool, also called punch, is pressed against the lower tool (die) in a controlled manner. The steel sheet is placed between the two tools and is bent into the required shape, lowering the punch.

The advantage of professional brakes is that the angles and radii can be bent . This is done by simply changing the punch of the folded material. The punch has the precise shape needed for the steel sheet . The sheet can be bent by different amounts, depending on the lowering depth. The material to be folded is positioned against a stop (back gauge) to make the bending process as efficient as possible.

The configuration of all our machines is done by CNC (computer numerical control). This also allows simulation of the planned bending operation. In this way, the insertion depth (stroke depth) can be optimally planned without the need to carry out an experimental bend .

Depending on the profile properties and product application, the profile is bent as per customer request

Radius and radius of curvature

We have two pressure brakes with dimensions 3,500 mm and 6,000 mm. In these press brakes, we can use radius dies to bend high precision inner radii. Radius seals must be used if extremely strong steels , e.g. Hardox, are to be bent . These materials are very hard, but tend to tear if the inner radii are too small.

With our dies and radius seals, we ensure that materials are optimally bent according to their specific properties without losing their stability.

Before a radius can be bent into sheets , the minimum radius of curvature must be known. The minimum bending radii depend on the types of material and sheet thickness. Preset radii are required for many applications. Regardless of whether they are needed for visual or design reasons.

With our radius tools (punches and dies) we can produce inner radii with an accuracy of 0.5 mm. We achieve larger radii through multiple bends or segment bends .

Folded Sheet Profile

What bending methods are there?

air bending

The sheet must be inserted into the machine so that the material is only on the two upper edges of the die. The pre-programmed insertion depth (stroke depth) of the punch is controlled by the CNC; the top tool (hole punch) presses the sheet into the die and, in doing so, bends the required angle. However, the lowering operation ends before the sheet touches the mold. The main advantage of air bending is the flexibility to bend different angles without having to change the tool (die). This is also a reason why airbending is used so often.


The basic principle of coining is the same as that of air bending. The only difference is in the large pressing force, which acts on the workpiece. Angles bent in this way are more accurate as the part is pressed completely into the die. The disadvantage of this method is its low flexibility.
Each die allows a defined profile angle to be bent . In the case of parts with different angular specifications, the press brake must be readjusted. This has a disadvantageous effect on the unit price.

three point bend

As with air bending , the sheet to be bent is placed in the die so that the material just touches the lower tool on the two upper edges of the die.

The lowering process is also similar to air bending; only the punch is lowered until the plate touches the die in the middle (at the third point). If the lower tool is equipped with an adjustable pressure pad or clamp (adjustable height matrix), it is possible to bend different angles without changing the tool.

These tools are very expensive to buy and are only used by a few manufacturers.

double step

We have a large number of radius dies and punches for bending sheets with specific internal radii. However, there are orders that require larger radii than the tools we keep in stock. In this case, we bend all the necessary radii by "step bending ".

In this computer-controlled bending process, the steel sheet is bent step by step with different size bends until the required inner radius is produced.

The CNC control sets the insertion depth of the punch and back gauge with millimeter precision. However, the dimensional accuracy of the radius depends on several factors. In principle, the radius of curvature or radius of curvature is defined by the number of bends required and the thickness of the material.

Why is a folded film necessary?

The use of bending film (also called bending tape) prevents the risk of marks on sensitive sheet , bent steel parts, ground surface stainless steel, aluminum or mirror-polished V2A/V4A steel .

The folded film is placed between the workpiece and the die and protects the steel sheet from direct tool contact. It is made of polyester or polyamide, is extremely mechanically resistant and can be used for various folding operations.

The bending film is easy to handle. It can be changed quickly and easily. As the film prevents direct contact between the tool and the material to be bent , there is no dirt or contamination of the bent parts. Therefore, there is no need to rework or finish the steel sheets . This naturally increases the quality of the product.

What is the minimum radius of curvature?

Bending is a method of forming sheets , in our case for the manufacture of profiles , in which sheets are formed by the effect of mechanical force.

Forming is carried out using four modern CNC presses with dimensions of 4 and 6, however dimensions of 8 and 16 m are possible. These presses are CNC controlled and greatly facilitate the bending operation. Our ability to simulate bending processes helps us avoid experimental bending and therefore save time and material. However, machines cannot do all our work for us. In principle, bending is done by inserting the punch into the mold.

The steel sheet is inserted between the two tools, and when the punch is lowered, the sheet is pressed into the die and thus the required angle is bent . However, this folding process hides several details, which always need to be taken into account for an optimal fold . All metals do not behave in the same way when exposed to large forces.

Minimum bend radius

The minimum bending radius is the smallest possible radius with which a sheet steel profile can be bent without damaging the material. This value depends on the material and sheet thickness. There is a rule of thumb for sheet steel , which says that the minimum radius of curvature must be at least equal to the sheet thickness value. For aluminum, the minimum radius of curvature is equal to the value of twice the sheet thickness. If the radius of curvature is less than this value, the sheet may tear at the edges or the material may split from the surface.

work back

If a workpiece is to be bent at a specific angle, it must be bent beyond that angle, because the workpiece comes back a little after the bend . The return spring can be compensated very well with modern CNC press brakes.

It only becomes critical if a sheet of steel is to be accurately bent to its minimum bending radius, as the rear spring means that the bending radius must be less than the minimum bending radius. For this reason, the actual minimum radius of curvature must always be greater than the theoretical possible radius.

What are large parts needed for?

Steel sheet formats from 8 to 16 meters in size. Larger sizes - The search for progress, moving one's limits and overcoming technical limits are deeply anchored in human nature. And so, every year, new records are broken. 

In sheet metal machining, the trend is towards ever-larger workpieces. There are several advantages to bending sheets for profiles longer than 8 m. A few years ago, it was not possible to machine large parts. For example, if a 16 m long folded part was needed; these pieces had to be welded together from several smaller pieces.

Despite modern soldering procedures, solders are still a weak point. The effect of heat during soldering does not just melt the material. It also slightly alters its crystalline structure, which weakens the carrying capacity and increases the susceptibility to rust of the large part produced. Fabricating welds is also time-consuming and material-intensive, for example because welded bridge profiles need to be welded using a gas shield and then verified using X-ray tests.

Larger and larger parts are produced to reduce this expense. Machines capable of machining these parts grow with the ever larger sheet metal parts. There hasn't been a strong demand for large parts in recent years. Transporting sheets or sheets with long lengths is more expensive, so imports are only worthwhile for small parts.

Some Profiles we manufacture

  • Bent Steel Profile and L-Beam
  • Profile and U-Beam of Bent Steel
  • Bent Steel Profile and C-Beam
  • Bent Steel Profile and Z-Beam

Fields of application of Folded Profiles