Background
Porticos worked with Bell and Howell to develop the state-of-the-art Solix™ Mail Tray Loader.
Challenges
The project started when Porticos was requested to transfer the Solix™ design from another group, convert 750 unique parts from SolidWorks into Unigraphics, integrate Durham Bell and Howell’s drafting standards, and import all data into the TeamCenter PDM tool.
One major advantage of the Solix™ Mail Tray Loader is that it works on almost any inserter base system and can handle a wide variety of paper. This made the design and prototyping phase after the design transfer very challenging as it required many design changes to the drive belts, conveyor motor layout, paper path belts and sensors, offset mechanism and stack lean algorithms, and multiple configurations of subassemblies and adjustable mechanisms. But the Porticos design team gladly accepted the challenge and, by working closely with Bell and Howell team, was able to deliver 3 different Solix™ Mail Tray Loaders with various options, such as Tray Tag Printer and Divert, which can support 5 different inserter base systems.
Innovative Sheet Metal Design with Manufacturing in Mind
When the Porticos team was challenged to design and release Right Hand Solix™ Mail Tray Loader in less than 3 months, the team performed a complete bottoms-up review of the existing Left Hand design and, with feedback from Manufacturing, created a sleeker sheet metal version to reduce the part count by 8% and manufacturing cost by 4%. Major welded frames and sheet metal components were replaced with bent sheet metal frames manufactured out of a single stock sheet. Porticos performed structural FEA and compared the new sheet metal design to the original design before finalizing the sheet metal thickness. Critical components to evaluate were roller shafts and motor pulleys and their attachment to the sheet metal frame; Porticos had to ensure that the new design could withstand tension forces from the paper path belts.
Paper Handling Challenges and Electromechanical Mechanisms
Anyone who has ever tried to collect a dropped stack of paper can relate to the fact that paper is notoriously difficult to control. Some of the characteristics that make paper challenging to work with are its flexible structure, sensitivity to moisture, high piece-to-piece friction, and relatively imprecise dimensional stability and tolerances.
The Solix™ product’s high operating speeds, on-edge paper stacking, and one-size-fits-all design requirements added a challenging level of complexity. Solix™ Mail Tray Loader can support envelope sizes ranging from 3.75” x 7.5” to 6.4” x 11.5” and thicknesses of 0.5 mm to 6.35 mm. In addition, each customer runs their own paper that can vary in size, weight, and gloss. Envelopes may also differ in size and design with various window and flap locations.
The Porticos team worked side by side with Bell and Howell engineers to redesign a paper path belt system and offset mechanism to support such an array of working materials. The offset mechanism in the conveyor stacker section contains actuators that come into action by pushing away the stack when a new envelope comes in to prevent material damage. It also contains upper and lower pressure sensors that take pressure measurements in the stack and based on readings, with the help of the thickness detector mechanism, move the conveyor belt to adjust the stack, and keep it from leaning. Many mechanical prototypes and electrical and software configurations were tested to fine-tune the high-speed on-edge stacking of the Solix™ Mail Tray Loader.
Custom Divert Module without Footprint Impact
Porticos was asked to design a custom optional “Divert” module for Solix™ Mail Tray Loader but without a major impact on the system’s footprint. The Porticos design team conceptualized a few ideas and with Bell and Howell’s approval designed a Divert module that consists of less than 30 parts and only adds 100 mm to the conveyor’s overall length.
The Divert module has a gate that is attached to a small, but very powerful, servo motor via a 4-bar linkage mechanism. In order to minimize footprint impact, the Porticos design team decided to mount the divert bin under the existing twist module and extend the paper path belts to pull the envelopes into the bin when they are diverted.
Outcomes
The final Solix™ Mail Tray Loader handles up to 30,000 envelopes per hour. This equates to an impressive 150 inches of paper per second! On-edge paper stacking of Solix™ Mail Tray Loader increases efficiency by providing conveyor capacity of up to 5 USPS® 2-foot mail trays and reduces the number of trips the operator must make to the output section of the system. The offsetting feature of Solix™ Mail Tray Loader allows the operator to easily see mail tray breaks; each tray can be loaded in as little as five seconds.
