For precise speed control in rolling mills the main drives of the roll stands and the coilers need to be equipped with an encoder. In addition, it is often necessary to provide increased protection for personnel during special operating modes, such as: For this application Johannes Hübner Giessen has been working with Motor OEMs for many decades to provide complete solution ie. Electrical and mechanical components.
Hot Rolling Mill / Screw downs: Replacing of old resolver technology
Pilger mill in tube rolling mills - hot and cold pipe detection
- Assembly of hollow shaft absolute encoder ASSH 60 K-16 / 50P (SSI interface)
- Improved final quality of the rolled material due to increased thickness accuracy
- Direct assembly to the screw down spindle
Before: The old resolver transducer
Challenges
The customer needed to replace the old resolver technology to improve the thickness control precision and thereby, the material quality. For this purpose they attempted a solution using a linear transducer, which did not give satisfactory results due to its mechanical weakness.
Finally, they came to the conclusion to use a high resolution absolute encoder suitable for heavy duty applications.
Solution
- Due to the required robustness, a hollow shaft absolute encoder model ASSH 60 K-16 / 50P with corresponding torque bracket was chosen.
- The SSI interface with a resolution of 16 bit provides highly accurate signals for the thickness control.
- At the customer‘s request, the Hübner Giessen engineering department helped in the design of the mounting materials, which were produced by themself.
After: Hollow shaft absolute encoder type ASSH 60 K-16 / 50Pwith torque bracket (directly mounted)
Products and Accessories
Case Study Number
- TP3
Challenge
- The increasing flexibility of production lines requires a high adaptability of sensors. Continually changing object geometries, different temperatures and very high radiation or surrounding temperatures are no rarity.
- In a pilger mill those rough conditions can be found, among others in the production of seemless steel pipes. The raw steel blocks, each weighing a few tons are heated up first in a round oven at a temperature of 1300 °C.
- After descaling of the surface, the steel block is prepunched in a hole press with a strength from a converted 2000 t. In the next sloping rolling mill the growing pipe rotates between two rollers that are positioned at an angle to each other. The punching is widened to the size of the mandrel diameter.
Previous solution / Competitor product
- N/A
Solution
- The sensor that was installed at this application is the HMD OKA 2038.38 G with tube OL 19.
- The signal of the infrared sensors controls the movement of centering device and abutment. The point of view is restricted by the tube and prevents disturbances by steam in the cooling phase.
- An optimum adaptation to the operating conditions is given due to the adjustable response temperature. The HMD with self-learning response temperature (Auto-Teach function) is suited to continually changing conditions.
- The compact sensor with a stainless steel housing can withstand surrounding temperatures of up to 75° C. The use of a cooling jacket raises this up to 200° C.
- Alternatively sensors with fibre optic cables are available which permit an application at ambient temperatures up to 600° C without cooling.
Customer Benefits
- Maintenance-free
- High temperature stability
- Recognition of hot objects at big distances
- Self adjustment with Auto-Teach or step switch for the response temperature
Product Part number
- OKA 2038.38 G
Brand
- Proxitron
Accessories
- Piros swivel stand HM2
- Tube OL 19
- Pilot light unit (for alignment) DAK 308 + OL 26
- Different cable lengths (e.g. 15 m)
Customer Testimonial
compared to previous solution or competition
