Cambridge Engineered Solutions, Maryland, USA, has introduced a new woven T314 stainless steel conveyor belt used in the final sintering stage in Powder Metallurgy production lines. The company’s Knuckleback™ Platinum belt is stated to last 25% longer and could save up to $20,000 annually per sintering line.
The Knuckleback™ Platinum’s belt life is significantly extended through a pre-oxidation process that provides surface protection to prevent carbon build up in the furnace and along the edges of the belt. The belt was developed in collaboration with Abbott Furnace Company, a leading manufacturer of continuous belt furnaces in North America.
Field tests performed by the two companies have shown that the pre-treating process not only increases belt life but also reduces operational down time for belt replacement by more than 18%.
Dr Stephen Feldbauer, Director of Engineering and Technology at Abbott and Cory Bloodsworth, Director of Business and Market Development at Cambridge are co-authors of a white paper reporting on the belt field test results titled ‘Increasing Belt Life Performance and Maximizing Production Time in Powder Metal Sintering Operations.’ The paper will be presented at the POWDERMET2015, May 17-20, in San Diego, USA.
Metal belts are an ongoing cost associated with the operation of a continuous Powder Metallurgy sintering furnace. Typically, their service life is measured in months depending on workload, stated Feldbauer. “To perform optimally, they should be subjected to a break-in period of one to three days that soaks the belt as it slowly moves into the furnace,” Feldbauer added. “Most manufacturers, however, can’t afford the extended production downtime for a new belt to be pre-oxidized and installed. This results in a reduced service life.”
Closely associated are issues with excess lubrication on powdered metal products. Often, manufacturers facing production deadlines are not able to give products sufficient time in the de-lube heat zone prior to the sintering stage. As a result, a portion of the soot (carbon) from the lubricants naturally develops and collects inside the sintering furnace. It is carried out of the unit due to the motion of the belt.
Carbon then forms on the edges of the belt causing embrittlement and eventually results in broken welds and frayed edges. “With these issues in mind, Abbott came to Cambridge for a remedy,” stated Bloodsworth. “We have a long relationship working together to optimise products for the marketplace.”
Tom Perdue, Cambridge Product Development Engineer, added that the company’s engineering team worked on and tested a solution for more than a year. “What we developed is a controlled pre-treatment process where the belts undergo a series of heat ‘soaks’ to build a protective layer of natural oxidation on the surface of the wires. Field tests show this process can extend the average belt service life from 60 days to more than 75 days.”
The process effectively replaces the desired break-in period that is not practical for most companies operating a PM sintering furnace.
“The additional 15 days of average belt life means one to two less replacements per year for powdered metal manufacturers,” said Bloodsworth, “which results in $15,000 to $20,000 in production uptime for a single sintering line.