Team:UESTC-China/Hardware1
Hardware design requirements
The equipment needs to complete the automatic process of deinking the paper with enzyme solution. It needs to solve several tasks including the paper driving in the equipment, the application of enzyme solution, the removal of impurities on paper surface,
the paper drying, and the operator's control of the whole equipment.
Based on this, we designed and manufactured the corresponding hardware. After several iterations of optimization, the current hardware equipment that can accomplish this purpose is obtained.
First generation deinker
Figure1. Schematic diagram of the first generation deinking machine.
The initial equipment design as shown in the figure. Because the paper needs water to deink, whitch can cause electrical leakage in the circuit, the equipment is composed of two parts: paper drying and enzyme smearing. The paper is fastened to the board,
which is carried on the track by a DC motor. In the first part, the paper will be coated with enzyme solution, and the surface fiber of the paper will be detached. In the second part the paper will be dried.
The heating part can be made smaller, so that the heating module can heat the whole space faster.
Figure2. Heating part of the first generation deinking machine.
The outer shell of the hardware is composed of acrylic plate and the basic frame is made by 3D printing technology.
Figure3. First generation framework design drawing.
The aluminum slide rail is used in the transmission track. By DC motor, the board on the track is driven to move in the equipment.
Figure4. The aluminum slide rail.
Figure5. Board design drawing.
Four pieces of high temperature ceramic heating sheet are used to heat and dry the paper. Heat sinks are attached to each side to enhance heat transfer rate.
Figure6. High temperature ceramic heating sheet.
Steam generated during heating is discharged from the device through a cooling fan.
Figure7. Cooling fan.
But there are many problems：large volume, low drying efficiency and low transmission efficiency
Second generation deinker
Figure8. The second generation deinking machine.
In the second generation of hardware design, we combined the original two parts together to reduce the device's size. The entire workflow of the second generation hardware is as follows. A lead screw drive guide drives the movement of the board. When
the paper moves under the water pipe, the pump starts to spray the enzyme solution onto the paper. The paper passes under the brush, and the brush scrapes the fibers from the surface of the paper. Finally, the paper is dried by the
heating pad under the board.
Figure9. Schematic diagram of the second generation deinking machine.
The driving system of the whole equipment is changed to stepping motor screw.
The motor is driven by a driver, which is connected to the controller.The controller is an MCU, which based on G language programming control and could communicate with the upper computer through serial port.
Figure10. Motor and control system.
We use plastic wrapped heating pads instead of ceramic heating sheets, so circuit leakage could be avoided. The heating pad is arranged under the paper loading board. In this way, most of the heat can be transferred directly to the paper for drying with
higher effeciency than the previous generation.
Figure11. plastic wrapped heating pads.
We line up several toothbrush heads to form a brush, which is used to scrape away separated fibers from the surface of the paper.
Figure12. Brush plate design drawing.
Figure13. Brush.
A small water pump is located above the hardware, which can pump the enzyme solution and spray it on the paper.
Figure14. Small water pump.
The second generation of equipment can operate stably to complete the entire deinking process. However, there are still problems in the experiment.The brush is so destructive to the paper for wet paper is easily damaged by the brush force.
Figure15. Problem happened when second generation device runs.
Third generation deinker
Figure16. The third generation deinking machine.
In order to solve the problem of the second generation hardware, we designed the third generation deinking machine. The whole workflow of the third generation is similar to that of the second generation.
Figure17. Schematic diagram of the third generation deinking machine.
The overall electronic system design is shown in the figure
Figure18. Third generation hardware system design's drawing.
Firstly, we use the shell mode of the second generation and replace it's materials to Acrylic plate and 3D printed skeleton, while slot structure is used to replace the original adhesive structure for convenient disassembly and assembly of the equipment.
Figure19. Third generation shell design drawing.
Next, in order to reduce the damage to the paper, we use sticky cylinders instead of brushes. Two secondary tracks are added besides the main track to enhance the stability of the board. It will make the board more flat and stable, so the force acting
on the paper would be smoother.
Figure20. Third generation hardware's rail system.
At the same time, a small step motor is set on both sides of the lead screw to control the rise and fall of the sticky cylinder. It uses a control system to lower the intensity of sticky cylinder so as to further reduce the damage to the paper.
Figure21. Third generation hardware's fiber separation system.
The heating module is also changed from a heating pad to a heating lamp. This prevents the original heating pad wire from winding into the lead screw.
Figure22. Third generation hardware's heating system.
The enzyme coating mechanism is also changed to sprayer in the third generation, which reduces the amount of wasted enzyme solution. The coverage of enzyme solution on the paper is also more uniform.
Figure23. Third generation hardware's enzyme spray system.
The third generation deinking machine can completely realize the process of deinking a piece of used paper in situ.
In order to offer our users a better experience, we have designed a manual interaction module.The program logic of hardware controling is shown in figure.
Figure24. Third generation hardware's programming block diagram
GUI of the hardware is shown in the figure.
Figure25. GUI
Figure26. Third generation hardware's control system.
Future
The third generation of hardware is already a complete machine for in-situ deinking. So we moved the it out of the lab for public display and participated in competitions. During this, our projects attracted interest from many makers, judges, and teachers.
But they also offered some suggestions to us about equipment improvement. Obviously, we still need to iterate again and agian to commercialize our Deinker.
Due to limited time, our fourth generation hardware is still on the way. In our plan, it should have smaller size, lower power consumption, higher deinking efficiency and more deinking options. It will be closer to an inverse printer.
Figure27. Fourth generation hardware concept diagram.
We design the ink spot recognition model based on artificial intelligence. This technique can be used in equipment to provide feedback about the effect of deinking to the control system. To be specific, It can control various deinking parameters instead
of naked eyes to achieve the best deinking effect and give users a better experience. Moreover, it can recognize a single ink spot, and cooperate with the control system to complete the targeted deinking. Click
here for more details.
We are still working hard to improve Deinker. We believe that when the fourth generation is completed, Deinker would become much more closer to people's real life.