Writing down all the ideas and concepts that come to mind on a piece of paper or a board is the first stage in both group and individual projects. This aids in my comprehension and helps me see the project clearly
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Me and my team wrote all the important thoughts that came to our minds on the whiteboard and transformed our thoughts into ideas.
Mind Mapping using Miro
Miro is a digital whiteboard platform that allows teams to collaborate visually. It can be used to create mind maps, user story maps, wireframes, roadmaps, and more.
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Follow the link below to open the Miro digital whiteboard.
After brainstorming, our team utilized Miro, a digital whiteboard platform, to create a mind map. This step allowed us to visually organize information and ideas, facilitating better understanding and collaboration among team members.
Gantt Char
A Gantt chart is a type of bar chart that illustrates a project schedule. It shows the start and finish dates of the various elements of a project.
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Each task in the project is represented by a bar. The length of the bar corresponds to the duration of the task.
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The horizontal axis represents time, typically broken down into days, weeks, or months.
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The chart can display dependencies between tasks, indicating which tasks must be completed before others can begin.
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Important points or events in the project, such as project start or finish dates, key deliverables, or reviews, are often marked with milestone symbols.
Google Meet
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Unfortunately, I had a bike accident during machine week and had to return home, but my mind let me down. For our team's group discussion, I used Google Meet.
Research 🔍
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Research is something I enjoy doing. My first task was to design the gears for the turn table, so I started to research the turn table, gears, resolution, and so on.
Gears
Gears used to transmit motion and power between rotating shafts. Gears are essential components in various machines, mechanisms, and systems. They work by meshing teeth or cogs to transfer rotational energy from one shaft to another, changing the speed, torque, or direction of the motion in the process.
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Check out the YouTube video to learn more about gears.
There are several types of gears, including spur gears, helical gears, bevel gears, worm gears, and planetary gears. Each type has its own specific design and application.
Function
Gears work by meshing together, with the teeth of one gear fitting into the gaps between the teeth of another gear. As one gear rotates, it transfers motion and power to the other gear.
Mechanical Advantage
Gears can also provide mechanical advantage, increasing or decreasing the rotational speed or torque of a system. For example, a gear reduction system can increase torque output while decreasing rotational speed.
Gear Terminology
Understanding gear terminology is essential for effectively communicating about gears and their applications.
Pitch Diameter
The theoretical diameter of the gear where the tooth size is measured. It is the diameter of the pitch circle.
Pitch Circle
An imaginary circle that passes through the point where the teeth of mating gears mesh. The pitch circle diameter is directly related to the gear's size and tooth spacing.
Module
A measurement used in metric gear systems that represents the size of the gear teeth. It is the ratio of the pitch diameter to the number of teeth.
Diametral Pitch (DP)
A measurement used in imperial gear systems that represents the size of the gear teeth. It is the number of teeth per inch of the pitch diameter.
Pressure Angle
The angle formed between the line of action (the imaginary line along which the force between the meshing teeth acts) and the tangent to the pitch circle. Common pressure angles include 14.5°, 20°, and 25°.
Addendum
The radial distance from the pitch circle to the top of the gear tooth.
Dedendum
The radial distance from the pitch circle to the bottom of the gear tooth.
Clearance
The radial distance between the top of one gear tooth and the bottom of the mating gear tooth. It prevents interference between mating gears.
Backlash
The amount of clearance or play between mating gear teeth when they are not engaged. It is necessary to prevent binding and ensure smooth operation.
Helix Angle
The angle formed by the tooth helix and an element of the pitch cylinder or pitch cone. It is important in helical gears and affects tooth contact and load distribution.
Face Width
The width of the gear tooth measured parallel to the axis of rotation.
Center Distance
The distance between the centers of two mating gears, measured along the line of action.
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Follow the link below to learn more about gear terminology.
Gear ratio is a term used in mechanics to describe the ratio of the number of teeth on one gear to the number of teeth on another gear in a mechanical system. Gears are toothed wheels that mesh with each other to transmit rotation and torque. By changing the sizes of the gears (i.e., the number of teeth), you can change the speed and torque of the system.
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The gear ratio is calculated by dividing the number of teeth on the driven gear (the gear being turned by the driving gear) by the number of teeth on the driving gear.
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For example, if you have a driving gear with 20 teeth and a driven gear with 40 teeth, the gear ratio would be 40/20, or 2:1. This means that for every one revolution of the driving gear, the driven gear will rotate half a revolution.
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Check out the link below to learn more about different ways to determine gear ratio.
Spur gears are a cylindrical shaped toothed component used in industrial equipment to transfer mechanical motion as well as control speed, power, and torque. These simple gears are cost-effective, durable, reliable and provide a positive, constant speed drive to facilitate daily industrial operations.
Internal Spur Gear
An internal spur gear is a type of gear with teeth cut into the inner surface of a cylindrical or conical shape. Unlike external spur gears, which have teeth on the outer circumference, internal spur gears have teeth cut on the inside diameter.
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Internal spur gears are often used in applications where space constraints or specific design requirements necessitate the gears to be positioned inside a cylindrical or conical cavity.
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They are commonly found in gearboxes, planetary gear systems, and other machinery where compactness and efficient power transmission are required.
Torque
Torque measure of the rotational force applied to an object around an axis or pivot point. In simpler terms, torque is the tendency of a force to rotate an object about an axis.
Torque, denoted by the symbol τ (the Greek letter tau), is defined as the product of the force applied and the distance from the axis of rotation to the point where the force is applied. Mathematically, torque (τ) is given by τ = r × F, where r is the distance from the axis of rotation to the point of application of the force, and F is the magnitude of the force applied.
In a gear system, torque is inversely proportional to the gear ratio. This means that as the gear ratio increases (i.e., the output gear has more teeth than the input gear), the torque at the output decreases, and vice versa. The relationship between input torque
the torque at the output decreases, and vice versa. The relationship between input torque (Ti) and output torque (To) in a gear system is given by the formula:
To=Ti×G
Where:
Ti is the torque at the input shaft (driving gear).
To is the torque at the output shaft (driven gear).
The relationship between power (P), torque (T), and angular velocity (ω) is given by the formula:
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P=T×ω
Where:
P is power (in watts or horsepower)
T is torque (in Newton-meters or foot-pounds)
ω is angular velocity (in radians per second)
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This formula tells us that power is directly proportional to torque and angular velocity. In other words, to increase power, you can either increase torque, angular velocity, or both.
Basic Design Sketch
Why Internal Spur Gear ❓
The choice between internal and external spur gears depends on the specific requirements and constraints of the application, with factors such as space, protection, alignment, power transmission, aesthetics, and specialized needs influencing the decision-making process.
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In our instance, we want to install a stepper motor and PCB inside the turntable. So the machine would be compact and look professional. I chose to utilise internal spur gears because, after performing the calculations, I found that I had to create an 8:1 gear ratio. Creating external gears with an 8:1 gear ratio would take up more area than creating internal gears.
Calculations
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Final gear ratio obtained from the calculation is mentioned below.
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Gear Ratio =(1.8 degree)/(0.23 degree) = 8:1
Gear Generator
To calculate a spur gear, simply decide and input your tooth count, gear module, and pressure angle and the online spur gear DXF generator will do the rest. A spur gear calculator uses these parameters to generate the involute tooth form that's the right size and shape to take into your CAD software, or straight to a CNC router or laser cutter.
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For generating the gears, I have utilized the spur gear generator online tool.
This tool helps me create gears by inputting the required parameters, which I mentioned below.
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To create internal gears, I set n1 to -80 instead of 80. n1 set to 10, so the gear ratio would be 80/10, which is 8:1.
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Once the gears are generated I downloaded the DXF file and uploaded it to the Fusion 360.
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The image below illustrates the internal spur gear with an 8:1 gear ratio.
Collaborative Design in Fusion 360
Collaborative design in Fusion 360 is a cloud-based solution that allows users to collaborate with internal and external teams on product design and manufacturing projects. Users can share, review, and manage design projects on any device, and centralize all design changes, comments, and markups made from various teams.
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The Entire Design Lead was assigned to me, so I created a new project and named as “Machine Week”. From the web I added rest of the team members to my project.
Turn Table Design
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The turntable consists of four different parts. The top turn plate consists of driven gears, which appear pale green in color. The main part appeared blue. The main part also houses a proximity sensor holder and a driver spur gear.
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The photo below illustrates the complete design of the turn table.
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The image below depicts the multiview of the turn table.
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The image below depicts the bottom view of the top plate. It consists of space to place the bearing; a shaft connects to the bearing.
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To place the metal sheet and enable the proximity switch to detect the point, I cut a small circular portion from the top plate.
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The image below depicts the bottom view of the top plate, along with the driver spur gear, proximity switch holder, and three bearings. The bearings are attached to the main part, not to the top plate.
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The image below shows the top plate's bottom view from where the stepper motor attaches to the spur gear.
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The image below depicts the Multiview of the turn table without the top plate.
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The image below illustrates the bottom view of the turn table.
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The Nema 17 stepper motor needs to be placed from the bottom and mounted using screws from the top of the main part.
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Initially, holes are provided to mount the stepper motor, but later the holes are converted into slots so that the motor can be adjusted for the mesh between the gears.
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The turn table is designed to be placed on top of the 20 20 aluminium extrusion, and holes for the M3 T nut are provided.
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The image below illustrates the cake placed on top of the turn table.
Test Print
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Before printing the final part, I decided to do a test print of all the critical parts to make sure everything would be perfect.
Bearing fit test
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While analyzing, I found that the fit of the main shaft is the most vital to check, so I cut the main shaft part for test printing using the Fusion 360 split body feature, sliced it in a slicer, and printed that individual part.
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The Image below depicts the 3D printed parts of the main shaft bearing test.
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The Image below depicts the 3D printed parts of the main shaft bearing test with the bearing.
3D Printing
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The image below depicts the “Top Plate” after slicing in the prusa slicer.
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Estimated Printing Time: 5h 58m (normal mode).
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The image below depicts the “Base Part” after slicing in the prusa slicer.
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Estimated Printing Time: 19h 1m (normal mode).
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The image below depicts the “drive spur gear”, and “proximity switch holder” after slicing in the prusa slicer.
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Estimated Printing Time: 37m (normal mode).
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The image below depicts the main shaft with the components placed in it.
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The main base part is represented in the image below.
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The image below depicts the top part's representation.
Testing
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The testing of the turn table is shown in the video below.
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The photo below depicts the base part along with the PCB and wires placed within. This is one of the reasons that I chose the internal spur gear.
Final Result
Challenges
Shaft Bearing Fit
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After printing the test part, I found the test was a complete success. My center bearing was not fitting on the top plate of the turn table. When probing further, I forgot to add clearance to the bearing's outer diameter. I added a 0.1mm clearance to the outer dimension, and a 0.2 mm clearance to the inner dimension.
Seam Position
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While slicing the parts in "PrusaSlicer,” I forgot to change the seam position from “Aligned” to "Random". I discovered this after printing the base part of the turn table. “Aligned” puts it on the sharpest corner, and works best for most models. However, this option is vital to change when printing cylindrical shapes without any sharp edges. When the seam position is set to ”Aligned" (the default setting) then the start position and the end position will be the same, which creates a sharp straight line on the shaft and needs to be filed while post-processing. When the seam position is set to “Random”, the start and end positions won’t be the same, which eliminates this problem.
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I set the Seam position to “random” for the rest of the design.
https://www.youtube.com/watch?v=4ROtKKuSaBI
https://www.automotioncomponents.co.uk/en/pageid/automotion-spur-gears
https://www.wikihow.com/Determine-Gear-Ratio
https://akotorque.com/resources/torque-101/
https://mae3.eng.ucsd.edu/machine-design/gear-ratios
https://evolventdesign.com/pages/spur-gear-generator
