Making laminated bamboo as a substitution of aluminium in electric scooter frames

Electric scooters are one of the attractive alternative vehicles to provide clean and sustainable mobility solutions for densely populated cities. Aluminum has several advantages, such as strong, light and corrosion resistance, making it an ideal material for scooter manufacturing. However, the use of aluminum is not without environmental concerns. Laminated bamboo canes are made by combining multiple layers of bamboo with a strong adhesive or glue to create a block with excellent mechanical properties. However, the use of laminated bamboo straws in electric scooters needs further research.


Introduction
One of the main causes of air pollution and greenhouse gases in the world is urban transportation.With increasing awareness of the negative effects of fossil fuels and the challenges of climate change, the demand for environmentally friendly vehicles is increasing.Several types of these emissions include Carbon Monoxide (CO), Hydrocarbon (HC), Carbon Dioxide (CO2) which have an adverse impact on human health and erode the ozone layer in the atmosphere [1].Electric scooters, offering clean and sustainable mobility in congested cities, have emerged as an attractive option.
The frame of an electric scooter is very important for the performance, safety, and efficiency of the vehicle.Until now, aluminum is the most common material used as a frame.Aluminum is used because it is light, strong and corrosion resistant, making it an excellent material for electric scooters.However, aluminum can cause environmental problems.Aluminum is obtained from bauxite mines, the emergence of critical land is due to bauxite mining which is carried out by open pit mining and stripping of overburden, so that it has an impact on the destruction of all plants in the soil layer.On critical land there is damage to the soil structure so that the soil conditions become dense.This causes a system of water management and aeration (air circulation) which can directly have a negative impact on root function and development [2].Bamboo is an abundant material in Indonesia but is still not optimally and massively used.Bamboo is only used for scaffolding in building projects for now in Indonesia.Bamboo is strong, elastic, and light, bamboo can also grow much faster than wood.Laminated Bamboo Gombong is made by combining multiple layers of bamboo with a strong adhesive, resulting in a composite material that has exceptional mechanical strength.Because bamboo grows faster and has a smaller carbon footprint, the production process is more environmentally friendly than mining aluminum.Bamboo laminate has many advantages and is widely felt in the field of construction, reduction in building weight is achieved by using composites made of bamboo and steel or bamboo and concrete, glubam panels with mineral wool increase fire resistance, and use of bamboo structures reduces energy consumption by up to 65% [3].But the use of Gombong laminated bamboo in electric scooters requires more research.Important research was conducted on the benefits of replacing aluminum framing materials with Gombong laminated bamboo to evaluate potential weight reduction and positive effects on the environment.

Experimental Work
This research was carried out with the very first being the manufacture of an aluminum prototype to form the basis of the scooter design that we will work on.After getting the prototype, we moved on to choosing a material where the material is bamboo.The bamboo we chose is gombong bamboo, however, the gombong bamboo must be free from pest attacks and is dry and has appropriate humidity.The bamboo is selected according to the diameter, density and strength of the fiber.
After selecting the bamboo, it is made into laminated bamboo, where the layers of bamboo are stacked and then put into a press.In this press, layers of bamboo that have been cut according to size and shape are given polyurethane glue so that they can stick together properly.The bamboo is left in a pressurized condition for approximately 3 hours.After being left alone, the bamboo is sanded and cleaned of residual glue.Assembling the bamboo frame involves rounding off laminated beams to become a substitute for aluminum.After rounding, make joints for connection.

Result and Discussion
This study aims to replace aluminium materials into bamboo materials.The bamboo we chose is gombong bamboo because the fibre of the bamboo is straight so it's easy to cut.To meet the size and width of the laminated beams, gombong bamboo has an adequate diameter.Laminated bamboo that has been made must be dried or dried vertically so that the water content drops, or in a standing position as long as the sun is present so that the water content is maintained.The laminated beams are dried in a vertical position or standing with clamps pressed to suppress the glue which can crack when it is moist.The laminated beams are dried as shown in Figure 1.The laminated beams are dry and have a humidity below 15% but still above 11%, the clamps can be removed and the drying process is complete.The next stage is entering the refinement stage.This refinement stage is an important stage in the process of rounding the laminated beams.To round the laminate using a lathe the beam must be smooth and also not have sharp corners.Sharp angles can cause the layers of the laminated beam to break and destroy the beam.Smoothing of laminated beams using a seated grinder.The refinement is done slowly for the durability and maintenance of the seated grinding machine.
After the refining stage has been completed, we enter the rounding stage where we use a lathe with a slow rate to round the beam.We use large lathes, these large lathes can be found at a turner's business.The rounding of the laminated beams must be at a rate that is not too fast so that the layers of the laminated beams do not break and the knife must be sharp to minimize friction which can cause the beams to break.Rounding of laminated beams using a lathe can be seen in Figure 2.
The bamboo laminated beams were already in elliptical shape but it was found that some of the beams were broken, which caused a reduction in the available raw materials.After going through the turning stage, the frame which is initially made of aluminum we plan to replace the material with bamboo.Bamboo laminated materials may be able to provide a reduction in weight, and are also more friendly to the environment because there is no mining when the material is taken and bamboo can be recycled and it grows quickly.Bamboo can grow 3-5 years compared to wood which grows 10-15 years.The next stage is the cutting stage of the aluminum frame or the initial frame, which can be seen in Figure 3 and Figure 4.If some of the aluminum material is to be replaced with bamboo, then there needs to draw the structure so that there is an image of how the scooter frame is looked like.The aluminum frame is drawn then replace with bamboo material.Not all the frames are replaced, only a selected frame are being chosen due to the strength of the bamboo laminate.These designs were created using Autodesk Inventor as shown in Figure 5 and Figure 6.With this design, we started cutting the aluminum frame then replaced the parts with bamboo.Starting with cutting the middle frame, then replacing the rear swing arm and making a joint to connect the bamboo frame with the bamboo.The rear dynamo bracket must also be regenerated to calibrate with the dynamo.The results of replacing these materials can be seen in Figure 7 and Figure 8. From the design, it can conduct a stress analysis test because it has a relationship with the strength of the material in the laminated bamboo frame.The results of the stress analysis can be seen in Table 1.

Conclusion
This research focuses on making vehicles that do not produce emissions but have sustainable and environmentally friendly materials.With the initial target of having a size that can be included in public transportation, but due to constraints on limited tools and also the skill of the tool, the scooter has a longer length.The laminated bamboo can be a substitute for aluminum to become the material for the electric scooter, but it still needs improvement.The laminated bamboo is sometimes still too damp which causes the glue contained in the beam to crack, expand and then break.The drawback for bamboo laminates is where the material wants to bend.Aluminum is easier to bend by heating, but bamboo and bamboo laminates must be more careful when bending, which must be heated slowly, then pressed and bent slowly so it doesn't break.Replacing the bamboo material makes the frame lighter, but because the joints and brackets that are used or made are iron, the frame becomes heavier when the aluminum frame weighs 4.5 kg, while the bamboo laminate weighs 5 kg.This research can be developed and produced to become an electric scooter that has a bamboo frame as a whole, using a peg system and using bamboo straps for fastening.Researchers can continue their research by studying and mastering techniques in bamboo lamination so that it can be optimal and consistent for making bamboo scooter frames as a whole.Researchers can learn and master the bending technique for laminated bamboo to have varied shapes and eliminate joints made of iron.Researchers can make the scooter durable and can be recycled if it becomes waste.Researchers can make these scooters have more proportions or sizes that are in accordance with public transportation regulations so that they can be relied upon by someone who really depends on public transportation.

Figure 1 .
Figure 1.Drying of Beams Figure 2. The process of turning bamboo laminates

Figure 3 .
Figure 3.The initial cutting process Figure 4.The part of top frame is cut off

Figure 5 .
Figure 5. Overview of the scooter frame Figure 6.Illustration of an aluminum frame

Figure 7 .
Figure 7. Joint over the frame Figure 8.The final result of the frame

Table 1 .
Stress Test Results [1] Ahmad Marabdi Siregar, CA 2019 Motorcycle Exhaust Gas Line Engineering.Motorcycle Exhaust Gas Line Engineering [2] Ricka Aprillia, WM 2021 CHARACTERISTICS OF EX-BAUXITE MINING SOIL AND TAILINGS IN [3] Assima Dauletbek, HL 2021 A review of mechanical behavior of structural laminated bamboo lumber