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Sensor Clamping Technology: Detecting Defective Blanks and Monitoring Production

Optimizing Machining Efficiency through Innovative Clamping Technology

Achieving optimal machining efficiency often revolves around fine-tuning both the machining equipment and the clamping devices used, along with their respective clamping elements. While numerous variables influence this process, the initial stage is heavily influenced by the quality of the workpiece blank being clamped.

However, a significant challenge arises from customers struggling to produce consistent, high-quality blanks while maintaining correct clamping, which necessitates continuous monitoring. To address this challenge, ROEMHELD North America has developed a solution to detect defective blanks early in the process, enabling closer production monitoring. By identifying defective parts early on, the workpieces can be rejected at the initial stage, saving valuable resources and machining costs.

Partnership with Wenzler

Partnered with August Wenzler Maschinenbau GmbH, an innovator and manufacturer of 5-axis machining centers, ROEMHELD North America has introduced an innovative clamping concept utilizing new sensory clamping elements. This concept allows for the measurement of various component states throughout the machining process, ensuring continuous quality monitoring from loading and unloading to machining. This is particularly crucial for lightweight vehicle components, which are increasingly intricate and thin walled.

At the core of this concept are ROEMHELD North America’s clamping elements, equipped with sensors to detect the condition of structural blanks made of cast aluminum, enabling the rejection of defective workpieces before machining. In this collaborative project, intelligent clamping technology checks parts for casting defects and contour variations, detects insertion errors, and provides continuous information about clamping position and force during machining.

Beginning the Project: State Detection

The project began with defining the information necessary for state detection. Through monitoring clamping and support forces at two selected clamping points and stroke measurement, the following determinations can be made:

  • Whether casting defects or contour variations affect the dimensional quality of a blank beyond the tolerance range.
  • Whether the workpiece is correctly inserted, and the clamping position is correct.
  • Whether the applied clamping force reaches the desired value.
  • Whether the contact force of the workpiece is within the specified limits.
  • Whether the clamping pressure on the fixture corresponds to the specifications.

Next: Standard Clamping Technology with Sensor Technology and Stroke Measurement

On the fixture, two modified hydraulic standard swing clamps equipped with sensors, along with a pressure sensor from ROEMHELD North America and two contact sensors, gather essential data. Clamping and support forces are directly recorded at clamping point “1”. At clamping point “2”, a swing clamp with integrated stroke measurement determines the clamping arm's position. Additionally, two sensors measure direct contact force, while an extra pressure sensor positioned near the swing clamp indirectly gauges clamping force.

Lastly: Contactless Energy and Data Transmission

To facilitate communication between the fixture and control, contactless energy and data transmission are employed. Energy for the sensors and their data are inductively transported between the fixture and the machine control. All components are encapsulated, minimizing susceptibility to interference. The actual data are displayed and compared with target values. If they align, the machining process initiates; otherwise, the system refuses to start.

About August Wenzler Maschinenbau GmbH

August Wenzler Maschinenbau GmbH, based in Spaichingen, Baden-Württemberg, specializes in developing and manufacturing 5-axis machining centers primarily for the automotive industry. With a focus on machining chassis and suspension components made of aluminum, the family-owned business has been operating since 1954 and is now part of the Heller Group.

About ROEMHELD North America

ROEMHELD North America has been a key player in various industries for over 60 years, providing cutting-edge technologies and products for aircraft, automobiles, machine tools, and even smartphone cases. Our extensive portfolio includes efficient clamping technology solutions for workpieces and dies in forming technology and plastics processing. Additionally, we offer components and systems for assembly and handling technology, drive technology, automation, and locking mechanisms for rotors on wind energy systems.

With a catalog featuring more than 30,000 items, ROEMHELD North America specializes in both standard and customized solutions, earning a reputation as a market and quality leader globally. Established in 1707, ROEMHELD continues to innovate while maintaining its rich tradition. With a presence in over 50 countries through service and sales organizations, ROEMHELD North America serves customers in the mechanical engineering sector, as well as the automobile, aviation, and agricultural industries, generating an annual turnover exceeding 115 million USD.