THE CLIENT’S NEED
NOVO engineers, while working at the client company, were asked to design a new type of cost-effective, large-format UV printer using belt loading to allow continuous printing on rigid substrates in addition to printing to rolls on flexible substrates. Product development needed to include collapsible loading tables to save print shop floor space. The company assigned the project to one team of four mechanical engineers and two designers; a job of this scope normally requires several such teams.
THE TECHNICAL AND DESIGN CHALLENGES
Primary challenges of this project were media feed accuracy for both rigid and flexible substrates, with issues of vacuum belt rigidity and roller design, respectively, and ink delivery system reliability. Classic failure mode analysis pointed to a number of contributors to the ink delivery system reliability concerns. Part count reduction, precision seal design, functional consolidation of filters and fittings, and improved control of the servicing and delivery functions played major roles in the overall improvement in reliability. Cost and schedule constraints also imposed further challenges on the project.
THE ENGINEERING BEHIND GREAT PRODUCTS
Media advance accuracy challenges were resolved by breaking down the system components into contributing factors. Conscious of costs, the team quantified an accuracy budget and allocated funds to change the advance system. By increasing system rigidity and encoder accuracy, they doubled the media feed accuracy. Flexible media feeding issues, including media tracking problems and poor take-up quality, were eliminated with system drag refinement and an improved gear train design.
To address issues of the ink delivery system, a number of solutions were implemented, first through simplification. The team removed components and reduced the number of fittings by an order of magnitude, resulting in fewer opportunities for failure. They also switched from complex to simple components while increasing the dimensional control of the remaining simpler components. Second, unique reservoir designs to eliminate ink frothing and its associated failure modes were successfully instituted, increasing the reliability of the ink delivery system even further. Additionally, the impact of printer operation and environment on ink temperature variation was minimized to add significant margin for ink pumping control.
Because they were accustomed to designing printers for early adopters, these engineers had extensive experience with new systems, which allowed them to give consideration to time to market, value proposition, and innovation during design. Additionally, they leveraged expertise gleaned by working on internationally marketed products to anticipate and address safety, supply chain, and testing obstacles, ensuring reliability in the global market. Both large-format UV printers in this series have enjoyed higher-than-expected sales performance with continual growth since their release in 2010.