Pneumatic Screen Press
This project was a LEAN effort to improve manufacturing within the production line and automate securing a clear screen to a plastic part. The two parts are joined by an adhesive that cures within minutes. The requirements were to create a safe, compact, and part-variable press.
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Pneumatic cylinder rods were chosen as the main actuator due to their low costs and high life cycle. Since our production lines are already equipped with airlines, this seemed straightforward to integrate. A center-open, three-way pneumatic solenoid was chosen to control each of the cylinders (a solenoid that could release both incoming and outgoing airlines to stop the press from acting in case of an emergency stop ). A safety button was also introduced between the +24v line and the respective cylinder buttons. This safety button along with the cylinder-specific button needs to be pressed simultaneously to actuate the cylinder and to ensure a worker's hand isn't in the way of the cylinder rod.
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The timing mechanism was conducted through a TRM-10-D-24AD multi-mode relay timer with an off delay.
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Design Process:
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Safety was my top priority. Since this machine will sit on a production line member's table, I needed to ensure there were no pinch points and included redundant safety measures mechanically and electrically. This meant introducing a safety cover, finger blockers alongside the pressing blocks, redundant safety switch, e-stop, and circuit breaker.
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Though I don't have any CAD screenshots during the design process, I'll write out the flow of my design process for this press.
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- Defined desirable outcomes and constraints: volume constraint, # of parts to press, calculated force required to adhere glue (through previous press PSI, adhesive datasheet, and screen dimensions), and safety concerns
- Began with a design file of the front case, created resting block for the part, measured general hand widths to decide on the space between front covers to design the bottom base, chose pneumatic cylinders based on stroke length (height constrain mattered here) and force requirements, next the solid screen blocks to transfer pneumatic force evenly across the screens (material: MJF printed nylon) were designed, then additional spacing changes were made to include 2" aluminum extrusion in between the pressing blocks to ensure the press was fully enclosed through its range of motion (reduce pinch points), the top plate holding the pneumatic cylinder and height of the side extrusions were also decided around this time, a front cover was laser cut from .25" acrylic and the front switches were also attached here, and finally the safety switch and e-stop were added to the side from a small bent piece of aluminum sheet.
Up close shot with transparent front acrylic cover
Rear view of press with mesh back cover
Screen press with transparent front cover
Drawing for bottom plate
Drilling socket head cap screw holes into aluminum extrusion
Internals of the press
Wiring up the small enclosure box to easily store underneath the production table (unfortunately too small for DIN rails)
Press up and running! (Before relay timer was adjusted to production timing)