WIST has new capability to produce two-layer paper on the UW-Stevens Point pilot paper machine, thanks to a successful senior design project of the university's paper science and chemical engineering class.
Seniors are required to complete a capstone engineering design project and a four-person team of Farrah Scears, Justin Okruszynski, Luke Mason and Joe Kinscher designed a second headbox for the pilot machine and rerouted feed lines so that pulp can be added to the wire in a second location, creating that second layer.
Paul Fowler, WIST executive director, said the institute typically presents several ideas each year to the senior class instructors for projects that have capacity to broaden WIST services and fill new customer needs. WIST contributes to funding the senior projects and the students get to work on real-world design challenges.
"We've had several inquiries in the past couple of years for development projects where two-layer production of rolls and sheets is required," Fowler said. "I'm excited about the success the students had with this and look forward to putting it to the test with a commercial application."
Last year, a senior design team built a second headbox but the design had problems. This year's team took up that project with the intention to improve performance but, after examining the prior design, realized they had to start from scratch on the headbox.
"We rebuilt everything," Scears said.
"That was a bit of a decision, itself, that we were reluctant to do," Okruszynski said. "Our original job was to try to optimize last year's headbox."
But after attempting to work with the first design, the team realized that several elements amounted to fatal flaws, including a rod meant to stabilize the box that warped the baffles and base. Also, the headbox was suspended above the wire, which decreased stability and meant its location couldn't be adjusted.
During a trial run, Kinscher said, the team found that by adjusting the location of the headbox, "It helped our drainage and helped improve the formation of the sheet."
The team overcame several other challenges in finalizing the design, leading to a great feeling of accomplishment with success, the students said.
"We have two separate stock tanks and each stock tank can feed the separate headboxes so we do have that capability to have two completely different types of furnish to the different layers," Scears said. "We can also control the basis weight for each."
A two-layer sheet can provide advantages in specialty papers where different properties are needed on one side compared to the other. Fowler said the new capability has applications in specialty paper and packaging. "It's about adding value, being able to provide a wider range of services," Fowler said. "We see potential uses in proof-of-concept, niche production or R&D."