TPT July 2021

T E CHNOLOG Y

Forever Machinery re-designed the fin pass section and the sizing section of the direct forming mill and incorporated motorised roll adjustment system into the mill. Tooling (rolls) became an integrated part of the tube mill and changeover could be completed by adjusting the gap between the rolls via electric motors. Not a single roll of the entire tube mill needs to be replaced for changeover. Several patents have been granted to the exclusive design of the upgraded direct forming mill. In 2017, a servo motor was implemented for the first time to the roll adjustment system for the direct forming mill. Combining a PLC-based control system; the level of automation for the production process of structural SHS and RHS has again leapt forward. While not compromising the quality of the forming process, the PLC- based servo motor roll adjustment system seamlessly integrates with the mechanical structure of the tube mill to further improve the changeover time. Controls are either via HMI on site or SCADA from the central control room.

The control system incorporates Siemens PLC and uses RS485 communication cable to achieve digital control of the tooling. Implementing more than 100 servo motors across the direct forming mill, the PLC is able to accurately position each roll using feedback loop in the case of the changeover. Data stored in the control system can be imported every time a certain size product needs to be produced again. On average, a complete changeover can be completed within 35 minutes. Components of the direct forming mill such as forming section, welding section, sizing section, straightening section (Turks Heads) are interconnected by Profibus and Profinet, ensuring a synchronised stable operation of the whole production process. Siemens servo motor control system provides real-time monitoring and display of the status for each servo motor and raises alarm should any of the motors gives a fault signal. Siemens S7-1500 PLC is incorporated to process all the control signals including input

from HMI, which also displays the operation status and production data including speed, KW output and cutting- to-size length. Fine adjustment for each individual roll is also attainable from the onsite HMI or SCADA. By exhibiting information of motor load, real-time roll position and fault alarms, not only do operators and supervisors gain more knowledge of the production data, they are also more likely to identify fault or detrimental factors that reduce efficiency and plan for subsequent trouble-shooting or rectifying procedure in a timelier manner. In general, high level of automation and tooling compatibility help workers escape the risky and intense workload of heavy roll changes, significantly boost productivity and improve work health and safety conditions at a structural tube and pipe production line and make the production process more cost-effective.

Forever Machinery Company www.frv.cn www.pipemill.cn

Precision straightening of stainless steel tubes BÜLTMANN 10-roll straightening machines have been successfully used by leading manufacturers of seamless stainless steel tubes in addition to standard steel tube applications. Specially developed for high-precision straightening of precision tubes in various fields of application, the Bültmann machines can also be used effectively in the production of demanding stainless steel tubes. For example, three straightening machines of the RRM series have been invested in at a leading German stainless steel tube manufacturer in recent years. The types RRM 10/025, RRM 10/032 and RRM 10/050 cover tube dimensions of Ø4-50mm, wall thicknesses from 0.3-5mm and lengths of 4-18m. The machines are combined with appropriate charging and discharging systems and in some cases with non-destructive testing equipment, thus offering ideal conditions for the highest precision, maximum throughput and high process reliability.

The Bültmann machines are developed for high- precision straightening of precision tubes

Bültmann www.bueltmann.com

23

www.read-tpt.com

JULY 2021