Week 5

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Subtractive and Additive manufacturing

Additive Manufacturing

Definition: Building objects layer by layer from digital models

Process: Adding material where needed using 3D printing technology.

Waste:Produces less waste as it uses only necessary material.

Advantages:Allows for greater design complexity and customization.

Subtractive Manufacturing

Definition: Removing material from a solid block to create a desired shape.

Process: Cutting away material using tools like lathes or mills.

Waste:Generates significant waste

Advantages: Limited complexity and design intricacy.

3-D Printer

This is the 3-D Printer we have at our lab.

It is the Original Prusa i3 MK3S+

Detailed Information and Printer Maintenance

Visit the above for more information on the Printer

This is a labelled diagram of it.

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Group Assignment

Group Assignment: test the design rules for your 3D printer(s)

Document your work on the group work page and reflect on your individual page what you learned about characteristics of your printer(s)

For more information, please visit our Group Assignment page

For the design rules test, we use the All in one design rules checker

Here is me and my team with the design rule model

There were four tests we learned on this all in one design rule test.

1.Hole and Diameter Test:

Hole test: Text visibility affected by gaps, circles turned out well.

Diameter test: Circles printed nicely without shakiness.

Conclusion: Machine works well for diameters, gaps affect text clarity.

2.Bridging Test:

Hole test: Text visibility affected by gaps, circles turned out well.

Diameter test: Circles printed nicely without shakiness.

Conclusion: Machine works well for diameters, gaps affect text clarity.

3.Overhang Test:

Printer struggled beyond 60-degree overhangs, sagging observed.

Conclusion: Printer performed well up to certain angles, optimization needed.

4.Vertical Pillar Test:

Filament deposition became shaky as pillar height increased.

Conclusion: Issues with consistency and smoothness, calibration adjustments necessary.

Individual Assignment

Design and 3-D print an object that could not be made subtractively

Idea

I looked into many other previous assignments and I found that many people made keychains, jewelry and minidecorative items, So I chose a Gyroscope keychain

Designing process

The body is created using only two commands. Set up user parameters to drive thickness and clearance, followed by sketching the side profile. Set up user parameters to drive thickness and clearance, followed by sketching the side profile.

I will be using the revolve tool to create the 3d bodies.

Add parameters from the modify drop down menu.We'll type out ring thickness for the name, Keep in mind we can change this parameter value at any time.

We'll start by sketching a line from the origin point running vertically.

We'll need to sketch out a curved using the threepoint arc command. Place the three points of the arc without adding dimensions.

We'll start with a midpoint constraint, followed by the center point of the arc.And the midpoint of the construction line.This will constrain the arc so it's always centered

We can then apply a horizontal constraint to the end of the arc and the end of the construction line, making sure this is done to both sides. You'll find that our sketch is not yet fully defined. We can still drag the arc left and right

We can now use the offset sketch command to offset the existing curvature.However, you'll find the offset geometry does not extend to the top and bottom, As we'll select the offset icon and delete it.We can instead use a sketch dimension to apply a dimension between these two arcs using our ring thickness parameter for the value because we deleted the offset relationship, we can apply horizontal constraints to each endpoint.

Note that we'll need to turn off the chain selection option in the dialog as we only want the individual arc segment to offset, not the entire profile. Once again, we'll delete the offset relationship, so we'll simply drag the arc to.

We can now activate the revolve command.

Lastly, sketch a rectangle and extrusion to make the keychain portion.

Fillet

End design

The 3D model

Generating G-code

I used Prusa Slicer

PrusaSlicer offers a user-friendly interface for 3D printing tasks. The main screen is dominated by a 3D view, allowing users to manipulate models easily. The top toolbar facilitates adding and removing objects, while the left toolbar provides tools for model manipulation, such as scaling and rotation. On the right panel, users can select print, filament, and printer profiles, as well as options for generating supports or brims.

The "Slice now" button generates G-code for printing, which can be exported or sent directly to a printer. Advanced functions are initially hidden but can be enabled by switching to Advanced or Expert mode. This allows users to access additional settings for fine-tuning their prints, such as layer height, infill density, and printing temperature. PrusaSlicer's intuitive interface and comprehensive features make it a popular choice among 3D printing enthusiasts for preparing models and optimizing printing parameters.

I refered to this website for the User Interface of Prusa slier. UI overview

Slicing and Generating G-code. Set the :

• 1. Quality / Speed: Balance between print quality and printing speed. Higher quality prints take longer to complete.
• 2. Setting of a print: Configure parameters like layer height, shell thickness, and print temperature for optimal results.
• 3. Material selection: Choose the appropriate filament type (e.g., PLA, ABS) based on the project's requirements and printer compatibility.
• 4. Printer selection: Ensure the correct printer model is selected to match the slicing settings with the printer's capabilities.
• 5. Infill: Determine the density and pattern of the internal structure of the print, affecting strength and material usage.

Fill Density

Most models can be printed with 10-15% infill. If the top of the model closes gradually, it can be printed hollow (0% infill), though we generally do not recommend it. If you need the model to be heavier, want more compression resistance or higher stiffness, you can increase the infill. You'll rarely need infill higher than 30%. Finally, you can print the model with 100% infill and the infill pattern will be forced to rectilinear. Keep in mind that 100% infill can have a negative impact on the look of the printed object.

The above information is derived from the Prusa's Official page The page has information on the other features of the Prusa Slicer

Why the Default Infill in PrusaSlicer is 15%

PrusaSlicer has a default infill setting of 15%.Infill refers to the internal structure of a 3D printed object.This specific infill percentage is chosen for several key reasons:

• Balance of Strength and Material Usage: A 15% infill provides a good compromise between structural integrity and material conservation. It ensures that the printed object is strong enough for most practical uses without excessive material consumption.
• Print Time Efficiency: Lower infill percentages reduce the amount of filament used and the overall print time. A 15% infill is efficient for many prints, keeping the print times reasonable while still maintaining sufficient strength.
• Default Starting Point: The 15% infill serves as a good starting point for most users. It allows beginners to achieve successful prints without needing to tweak settings extensively, while experienced users can adjust the infill based on specific requirements.

For my project, I kept the infill at 15% (default) because it provided the right balance of strength and efficiency, ensuring the parts were durable without unnecessary material use or extended print times.

While the 15% infill is a default setting, users can easily modify this value in PrusaSlicer to better suit the specific needs of their projects. Adjustments can be made depending on the desired strength, weight, and material efficiency for different print jobs.

Then export

Printing!

Making adjustments during a print

I adjusted the speed to 20, and started slow.

Printing Speed Explanation:

The printing speed was initially set to 20% of the maximum speed to ensure optimal print quality for the round structure of the model. As the printing progressed and the stability of the print was confirmed, the speed was gradually increased to 30%. This incremental adjustment allowed for a balance between print quality and printing time, resulting in a smooth and accurate finish for the printed object.

Started the print

Result!

Why the 3D printed Gyroscope keychain cant be easily made subtractively?

A 3D-printed gyroscope keychain can't be easily made subtractively because of its complex geometry and intricate moving parts. Subtractive manufacturing involves removing material from a solid block, which is challenging for creating internal structures and detailed components without causing damage or requiring complex assembly. 3D printing allows for the creation of these detailed and interconnected parts in a single build process, which is not feasible with subtractive methods.

3-D Scanning

For 3D Scanning I used PolyCam. I used the software on my phone by installing the software from playstore.

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I downloaded Polycam from the app store. It's really user-friendly and great for creating 3D models. To use it, I scanned my object from different angles using my phone's camera. PolyCam offers the users to either record videos and take photos automatically or take photos manually. The app then processed these images into a detailed 3D model. I could determine the final product by deleting images that didnt capture the model good and kept the pictures that captured the model well right in the app. Once done, I exported the model to share it. Polycam did a good job capturing the details, and the digital model looked very close to the actual object.

What I scanned

This is a bhutanese sculpture, sculpted from a mold by one of the students at my academy. It is a sculpture of Moley(princess).The Dance of the Princes and Princesses, known as Pholey Moley in which Molay is the sculpture i scanned, is a beloved Bhutanese dance. It tells the story of jealousy among queens and reconciliation between King Norzang and his favorite queen, Yidrogma. In a popular version, two princes return from war to find their wives engaged in playful activities with atsaras. The princes punish their wives by cutting off their noses, but eventually regret their actions and seek a doctor to sew them back on, leading to reconciliation and a happy ending. This dance is performed during tshechu which is a celebration in Bhutan.

Scanning process

To scan my model using Polycam, I took approximately 200 pictures in total. For the first set of 100 images, I kept the device still and moved the model slowly to ensure thorough coverage. Then, for the remaining 100 images, I kept the model still while moving the device around it. This method provided Polycam with a comprehensive range of angles and details, resulting in a highly accurate 3D model of the object.

I used PolyCam to do the 3D scanning

To export, there are many options for the type of file you want to export to but since I didnt have the premium version I could only export in the GLTF format.

Result

When comparing the actual model with the digital model created using Polycam, I found that the digital representation was quite impressive. The overall accuracy and detail were remarkable, capturing the essence of the original object effectively. However, upon closer examination, I noticed that the backside of the digital model wasn't as well-defined as the front. Despite this, I prefer PolyCam and recommend for other users since I tried other softwares before in my school years and the outcome was not even half as good as PolyCam.

Files

Gyroscope keychain