Gräbener Maschinentechnik GmbH & Co. KG

Am Heller 1, 57250 Netphen
Germany
Telephone +49 2737 989-0
Fax +49 2737 989-110
info@graebener.com

Location

  •   Hall 7a / B15

Our range of products

Product categories

  • 01  Manufacturing machinery for metallic tubes and pipes
  • 01.03  Lines for the production of welded tubes and pipes
  • 01.03.02  Lines for finished products
  • 01.03.02.01  Machines for welding preparation
  • 01.03.02.01.01  Edge milling machines

Edge milling machines

  • 01  Manufacturing machinery for metallic tubes and pipes
  • 01.03  Lines for the production of welded tubes and pipes
  • 01.03.02  Lines for finished products
  • 01.03.02.01  Machines for welding preparation
  • 01.03.02.01.04  Three-roll bending machines

Three-roll bending machines

  • 01  Manufacturing machinery for metallic tubes and pipes
  • 01.03  Lines for the production of welded tubes and pipes
  • 01.03.03  Machines for downstream cold forming
  • 01.03.03.06  Other forming lines

Other forming lines

  • 02  Processing machinery for metallic tubes and pipes
  • 02.01  Machinery for mechanical processing
  • 02.01.01  Tube straightening machines

Tube straightening machines

  • 02  Processing machinery for metallic tubes and pipes
  • 02.01  Machinery for mechanical processing
  • 02.01.14  Tube chamfering / bevelling machines

Tube chamfering / bevelling machines

  • 02  Processing machinery for metallic tubes and pipes
  • 02.01  Machinery for mechanical processing
  • 02.01.20  Other machines for tube processing

Other machines for tube processing

  • 02  Processing machinery for metallic tubes and pipes
  • 02.02  Tube forming lines
  • 02.02.01  Tube bending machines

Tube bending machines

  • 02  Processing machinery for metallic tubes and pipes
  • 02.02  Tube forming lines
  • 02.02.03  Hydroforming lines

Hydroforming lines

  • 02  Processing machinery for metallic tubes and pipes
  • 02.02  Tube forming lines
  • 02.02.04  Other tube forming lines

Other tube forming lines

  • 02  Processing machinery for metallic tubes and pipes
  • 02.09  Second-hand machines for the tube industry

Second-hand machines for the tube industry

  • 02  Processing machinery for metallic tubes and pipes
  • 02.12  Repair and rehabilitation measures
  • 02.12.03  Special machines and fittings

Special machines and fittings

  • 02  Processing machinery for metallic tubes and pipes
  • 02.13  Profile Machinery
  • 02.13.05  Profile end forming machines

Profile end forming machines

  • 05  Testing technology, sensor technology and quality assurance for the tube and pipe industry
  • 05.02  Process testing and sensor technology
  • 05.02.06  Sensor evaluation systems (see also 7.1)

Sensor evaluation systems (see also 7.1)

  • 07  Software for the tube and pipe industry
  • 07.07  Tube Bending software

Tube Bending software

  • 07  Software for the tube and pipe industry
  • 07.08  Other software

Other software

  • 11  Services for the tube and pipe industry
  • 11.03  Industry 4.0: Consulting and solutions

Industry 4.0: Consulting and solutions

Company news

Date

Topic

Download

Jul 21, 2020

RadiiPro®: Electronic radius measurement system for pipe bending presses in real time. Innovative cooperation between the companies fabforce® and Graebener®.

To this day in large pipe manufacturing, the production large-diameter pipes in a step-by-step process is set up and monitored manually using templates. This is time-consuming and requires well-trained machine operators. fabforce®, in cooperation with Graebener®, has now developed a radius measurement system that allows the radius to be checked conveniently, safely and precisely via a monitor. In addition to this, the system offers insights into the material behavior of the pipe. An important milestone on the way to a fully automated bending process.

Since the beginning of large-diameter pipe production, it has been common practice to check the individual steps in the bending process using a template. In other words, the operator interrupts the bending process at regular intervals and measures the result using an analog template which he places on the partially bent pipe. For this purpose, the machine must be switched to safe mode and the operator has to leave his operator desk. During all this time, the machine is not working productively. Therefore, the time exposure and the costs of manual measuring are quite significant. The industry has long been striving for an uncomplicated and cost-effective solution. fabforce®, a company specializing in Industry 4.0 applications, has taken up the issue and, in cooperation with Graebener®, a special machine manufacturer with a 100-year tradition, has developed a digital template that paves the way to a fully automated pipe bending process in the medium term.

The RadiiPro® radius measurement system uses a laser system that transfers the contour in the bending process to the operator's screen in real time. The trick: the measurement system is located in the lower tool and can therefore measure live during the entire bending process, even under load. At the same time, the software compares the bending of the contour with the desired target radius and calculates the contour deviations. This way, the forming differences without load and under load can be seen. The result is displayed precisely and objectively within milliseconds on a screen in the operating panel. For this reason, non-productive times of manual measuring as well as possible misinterpretations when placing the template are avoided. In addition to this, the information obtained can be saved for each pipe, enabling transparent quality management right up to the final product.

But the RadiiPro® application has even more to offer: the calculation of the local curvature of the contour. A characteristic value with considerable potential. This value offers the advantage that the degree of current deformation can be displayed with high precision even on very small measuring sections. This way it can be seen in minute detail which areas are actually formed and in what way. The operator gains information about the optimum bending step width, the correct tolerance values and the evenness of the pipe.
Incidentally, the data of the curvature also allow a multitude of further conclusions, e. g: Does the steel mill supply the correct quality? How can the workpiece properties be ideally reacted to in subsequent processes? Does the quality vary within the component or batch and, if so, within which tolerances?

Fabian Kapp, Managing Partner at fabforce®, sums up the advantages in a nutshell: "No matter how qualified an individual operator may be, a human being cannot in fact keep up with the precision and speed of our measurement system. Added to this is the safety advantage and the immense additional gain in information. Our application offers our customers the opportunity to clearly set themselves apart from the competition and to lay an important foundation for the digitalization of their pipe mills".
In the medium term, fabforce® and Graebener® are even aiming at full automation of the entire pipe bending process. "This would then allow the forming of any common material quickly and in highest quality - without any operator training, without corrections and without non-productive time," says Hubertus Valpertz, Authorized Officer and Technical Sales Manager at Graebener®.

fabforce® has also specialized in the backup and evaluation of machine data. In connection with the RadiiPro® data, there is huge potential for process optimization: from tracking the pipe quality through the entire production process up to the monitoring and maintaining of the machine quality over the entire life cycle.

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Feb 13, 2020

Two-side pre-bending in a step-by-step process without plate waviness in the pre-bent edges – Graebener® innovation for the production of large pipes

The company Eisenbau Krämer GmbH (EBK), an internationally renowned specialist for the production of large steel pipes once more banks on an innovation by the special machine builder Graebener®. At the end of 2019, Graebener® delivered a 2-Side Pre-Bending Press for the production of thick-walled pipes which raised the pre-bending technology to a new level.

Up until now, the company EBK, internationally renowned for high quality pipes, has been using conventional roller pre-bending machines for the pre-bending process. During the roller pre-bending process, top and bottom rollers move along the plate in parallel which creates the corresponding radius at the longitudinal plate edge. This standard procedure has proven and established itself over decades and is the most widespread pre-bending method worldwide. In the meantime, however, this process is being looked at more and more critically. The problem of the process is the creation of thinning in the material which in turn requires extensive reworking efforts to achieve a high pipe quality. Ever increasing requirements for pipe tolerances and weld seams are becoming more and more challenging for pipe manufacturers – especially when it comes to high quality special pipes for the gas and oil industry. For this reason, EBK was looking for a solution and turned to the German company Graebener®.

The Graebener® 2-Side Pre-Bending Press, in contrast to the roller pre-bending machine, is suitable for the simultaneous pre-bending of both longitudinal plate edges in a step-by-step process. While the plate is moved through the machine step-by-step, the longitudinal plate edges are pre-bent to the respective radius by means of the upper and lower pre-bending tools. This way, crushed edges and thinning out of the plate ends can be avoided.
This process is not an entirely new one on the market, but up until now has been causing a plate waviness throughout the entire length of the pre-bent edges. As the goal is to produce a perfect open seam pipe, a faultless weld seam and thus achieving a zero gap without edge offset are very important. Otherwise, excessive reworking efforts such as multiple calibration steps are necessary to compensate and remedy the waviness. Thus, avoiding a plate waviness during the economic production of open seam pipes with proper zero gap is indispensable.

Graebener® has taken up this issue and developed the machine in such a way that today various international customers rely on the Graebener® 2-Side Pre-Bending Presses. Together with EBK, the process has been further perfected during the last year. The key to success: perfectly designed tools.
The tool contour was optimized so that now plate waviness in the pre-bent edges is a thing of the past. Today, the Graebener® 2-Side Pre-Bending Press can achieve a result which is unrivaled worldwide: 100% forming of the pipe, i.e. an open seam pipe with zero gap, no edge offset and with a perfect weld seam preparation. "Our Graebener® pre-bending press is operating with such precision that we can significantly reduce  additional process time on the Graebener® calibration press," says Dr. Scott McCann, Managing Director at EBK.

The Graebener® 2-Side Pre-Bending Press can be used independent of the material (suitable for all kinds of common steels in pipe production, especially Clad material) and can process plates with increased wall thickness and of high steel qualities and special grades.
The forming tools necessary for the pre-bending are designed for cost efficiency. To reduce the number of tools necessary, they are designed in a way that they can be used for wide diameter range with a variety of plate thicknesses.
Hubertus Valpertz, Authorized Officer and Technical Manager Sales at Graebener®, lists yet another cost advantage: "Our process creates a constant pre-bending over the entire plate length, i.e. even at the beginning and at the end of the pipe to be produced. Due to this constant form, in contrast to the conventional roller pre-bending method, the entire plate length can be processed further which eliminates the previously required cutting of the two pipe ends. This, in turn, leads to a significant cost reduction."

EBK has been trusting in Graebener® and the company's know-how in the sector of material forming for decades. Dieter Kapp, Managing Partner at Graebener®, has high hopes for the sophisticated technology: "The pre-bending results with our press for wall thicknesses larger than 50 mm are unparalleled. No matter how accurately the works were carried out in the past, with the technologies available to date it simply was not feasible physically to eliminate waviness over the entire pipe length for this wall thickness range. This chapter is closed now. I am absolutely sure that our solution with conquer the market very soon."

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About us

Company details

Graebener® is a medium-sized, family owned machine building company with locations in Netphen (Germany), Houston (USA) and Shanghai (China) as well as a variety of international representatives. Based on almost 100 years of experience in the metal processing business we develop and realize customized solutions for the core markets of automotive industries, hydroforming, manufacturing of large pipes, shipbuilding, wind tower production, vessel construction and renewable energies. Our product range includes hydraulic forming lines, milling and bending machines, calibration and straightening presses as well panel production lines. Graebener® stands for a holistic approach. As technology and system partner we accompany our customers along the entire process chain – from the initial idea, comprehensive engineering (including hydraulics, automation and control technology as well as intelligent Industry 4.0 applications) up to customized new machines or retrofitted existing lines.

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Company data

Foundation

1921

Area of business
  • Tube industry
  • Automotive supply industry
  • Measuring and control technology
  • Services