Following extensive troubleshooting and diagnostic testing, it was determined the Yankee surface condition was contributing to the issue, leading to a full Yankee regrind. While this instantly stabilised the process, vibration gradually returned. Based on further Yankee cylinder testing and analysis, the mill elected to proceed with a full metallization of the Yankee surface and an upgrade to the electronic drives.
As part of this wider improvement project, the mill also took the opportunity to replace the existing Yankee doctors with the Kadant Conformatic™ SL creping blade holder on the creping and cleaning positions.
KADANT worked in close coordination with the Yankee regrind third party to remove the existing doctors to facilitate the regrind and subsequently installed and commissioned the new Conformatic SL creping blade holder and oscillator systems following the completion of the Yankee surface regrind and updated drives.
The project was completed successfully, demonstrating strong collaboration between the leading worldwide tissue manufacturer, Kadant, and third-party suppliers to achieve the mill’s performance objectives. As a direct result of these combined efforts, the tissue manufacturer recently achieved a new production record for tonnes produced in a 24-hour period.
The Conformatic™ SL creping blade holder
The Kadant Conformatic SL creping blade holder incorporates the latest technology, bringing improved blade holder performance to the tissue market. The holder is primarily designed for use in the Yankee creping position.
The Conformatic family of blade holders are the industry standard when it comes to tissue making. The focus of the Conformatic SL creping holder model was on features that would make it easier to use and mitigate risk to the Yankee. The proprietary adjustment mechanism allows for effortless bi-directional adjustment, with enough movement to accommodate even the most extreme Yankee crowns. The modern design uses adjustment screws to maintain the desired positioning and eliminates the need for edge fingers.
As the operating duty is extreme, the load capability of the conforming tube has been increased and a carbon fiber backup blade has been designed to eliminate issues caused when using stainless steel items.
Significant upgrades to the holder’s adjustability have been achieved with a proprietary adjustment mechanism, allowing for precise control of the holder profile across the entire Yankee face. The robust construction is designed for high-performance tissue machines and features a self-conforming liquid tube, a backup blade and a quick removal feature that allows the holder to be removed for cleaning and maintenance. Optional “smart” features can be integrated to provide real time process feedback such as vibration and load.
What makes proper tissue creping so important?
If vibration is not controlled, the Yankee surface can be damaged and will need to be refinished by grinding, which involves downtime of three to five days. As the Yankee ages and is repeatedly ground, the steam pressure rating can be reduced resulting in lower operating steam pressure, reduced speed, and less production. If the process is not stable, the Yankee can wear out in 15 to 20 years. When maintained and managed properly, the Yankee could operate for more than 30 years.
Tissue creping is vitally important when the key characteristics attribute to the final product. Technically, everything can be a factor which affects the tissue creping process. The process is simple in many respects, but to get high quality tissue and meet market expectations, good creping is essential. Doctoring systems are crucial to producing a high-quality product and not damaging the Yankee shell in today’s high-speed process.
Machine and equipment audits
A true understanding of machine and equipment performance is key to a safe, high-quality, and efficient process. Our team performs comprehensive machine and equipment audits including digital machine mapping.
The result is detailed service assessment with feedback, recommendations and project justification. These align to customer corporate strategies including energy efficiency targets, freshwater management reduction and production optimization.
Yankee doctor services
Yankee doctors operating at maximum efficiency is crucial to the success of any tissue operation. The service technician will inspect all mechanical components including mounting brackets, bearings, journals, doctor structure, blade holder, levers, air cylinders, oscillation and other equipment. Also, the blade angle will be adjusted to the specific application and the blade holder profile will be checked and necessary adjustments made to ensure a proper blade-to-surface fit.
A full report including service details, before and after profile diagrams, and recommendations for improved performance will be provided after each service.
