Week 5. 3D Printing & Scanning
Image Courtesy: Photo by Gavin Allanwood on Unsplash
By the end of this assignment, we will have a better understanding of the exciting possibilities for innovation and creativity that 3D printing and scanning offer.
Assignment Tasks:
- Group Assignment: Test the design rules for the 3D printer.
- Individual Assignment: Design and 3D print an object that could not be made using subtractive or formative manufacturing. 3D scan an object (and optionally print it).
Learning Process
What is 3D Printing?
Let us explore the world of 3D printing.
3D printing is an additive manufacturing process. It is “additive” in the sense that it stacks and fuses layers of material rather than using a block of material or a mould to make physical objects. It can produce more complicated geometries than “conventional” technologies, is typically rapid, has cheap fixed setup costs, and a growing list of materials. The production of lightweight geometries and prototyping are two common uses for it in the engineering sector.
Let’s look on to the different manufacturing methods:
Additive
Subtractive
Formative
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Additive manufacturing: This technique, involves building a part or product by adding material layer by layer. The material is usually a plastic, metal or composite material that is deposited in precise patterns to create the final object. Additive manufacturing is useful for creating complex geometries that are difficult or impossible to achieve using traditional manufacturing methods.
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Subtractive manufacturing: This technique involves removing material from a block or sheet of material to create the final product. CNC milling machines and lathes are examples of subtractive manufacturing technologies. Subtractive manufacturing is useful for creating complex shapes that cannot be produced using additive manufacturing methods.
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Formative manufacturing: This technique involves shaping or forming a material into a specific shape or form through processes such as forging, casting, or stamping. Formative manufacturing is commonly used in the production of metal parts and components.
Additive manufacturing has only been around since the 1980s, so the manufacturing methods developed before it are often referred to as traditional manufacturing, which are subractive & formative types.
3D printing is a method of creating three-dimensional objects from a digital model by layering material. This technology has grown in popularity over the years due to its ability to create complex geometries and customised parts that traditional manufacturing techniques cannot achieve.
The 3D printing process begins with the creation of a 3D model of the object to be printed using computer-aided design (CAD) software. The software slices the model into thin layers and creates a file with 3D printer instructions. The file is then read by the 3D printer, which prints the object layer by layer, adding material as it goes.
There are several types of 3D printing technologies available, including Fused Deposition Modeling (FDM), Stereolithography (SLA), Selective Laser Sintering (SLS), and Digital Light Processing (DLP). Each of these technologies uses a different material and process to create the final object.
The materials used in 3D printing include plastics, metals, composites, and even biological materials such as cells and tissues. The choice of material depends on the requirements of the object being printed, such as strength, durability, flexibility, and temperature resistance.
Group Assignment
Understanding the Printer
Detailed report on our Group Assignment Page.
Individual Assignment
Let’s start the process
Design
3D printers only understand G-code, which can be translated using the printer software. So choosing the software to design is the first step. Since not all formats are supported by the printer software. The most popular format is STL, although other important ones include STEP, OBJ, and 3MF. So, it’s important to choose CAD software that offers STL formats.
We have a Prusa i3 MK3S machine. These are the supporting formats for our printer.
Most commonly used softwares for 3D Printing are:
Blender
Rhino/Grasshopper
Fusion 360
Solidworks
OpenSCAD
Designing the Idea
I choose Rhino & Grasshopper for designing my idea. I found some interesting tutorials in youtube and I choose to go with a voronoi design. There are various design options available when it comes to 3D printing, but for my project, I decided on the Voronoi design because of its complex structure, which makes it challenging to produce using other traditional means. The Voronoi-designed Beijing Olympic Stadium has long captivated me. When I discovered the world of Rhino and Grasshopper, I made a voronoi design and had it printed for my weekly assignment.
However after completing my design, I discovered that the structure creates serious printing challenges. The design itself was the first issue. I created the design in accordance with the video tutorial, however the wall doesn’t have any thickness, so I tried several alternative approaches without luck. I then understood that the design shown in the lesson was not suitable for 3D printing.
At first, I placed a box on top of a plain surface. Then I randomly add points to a 2D surface using Populate 2D Node. My next step was to apply planar voronoi to that surface, then separate component parts using Deconstruct Brep Node. I built nurb curves on top of that. Area node was added, and using it, the centre points were marked and scaled. The surface was then divided using a number of curves. This was eventually extruded and merged to bake for a final outcome.
My first attempt yielded this result. This resembles the tutorial’s shape in appearance.
But when i tried to slice this file in Prusa Slicer software, the result was not pleasing and a warning pop-up.
I tested various dimensions and tried to make the structure thicker because the design was parametric. But the result was the same.
Being new to Rhino and grasshopper, I had no idea what was going on. So I decided to try another tutorial that I came across while looking for a solution to my problem. This was also a voronoi design but made using multipipe.
This is another voronoi design, but this one is made of continuous pipes.
Step 1: Here, what I did was first create a box. by adding a Domain Box node and parametrically adding dimensions for length, breadth, and height in the X, Y, and Z directions.
Step 2: Then I poulated points on the outer surface by adding Populate Geometry
Step 3: Then I added Voronoi 3D and was connected from both the box and population.
Step 4: Now cells from Voronoi is connected to the Brep from Deconstruct Brep, which creates boundary.
Step 5: Volume geometry is connected from both Voronoi cells as well as Brep faces. This creates cem\ntre points on the Breped faces and inside cells of the cube.
Step 6: Now we connect Lines with these points.
Step 7: Finally we make these lines to pipe using Multi Pipe and making the factors parametric, so that we can change dimensions lately if needed.
Step 8: Now we will hide the rest of the nodes to view the final result. For this, select every other node execpt the multi pipe node and switch off the preview by right clicking the mouse.
Step 9: BOOM…!!! Our final structure.
Step 10: Now we will Bake it get the 3d Model from this structure. For this Right click on the Pipe -> Bake
Step 11: Our Final Result.
Complete Grasshopper Nodes for this Design.
Finally, there were no warning pop-ups after I uploaded this new design to the Prusa Slicer software. At this point, however, my tutor Jogin gave me a suggestion for combining my previous design with the multipipe method. So I decided to give it a shot as well.
I started from scratch again.
Step 1: Created a Box in Rhino and in Grasshopper, created a Brep and selected the box.
Step 2: Connected the Brep to Populate 3D.
Step 3: Connecting the population to Voronoi 3D.
Step 4: Connecting the cells to Deconstruct Brep.
Step 5: Until this stage it was same as the above design. Here we connect the faces to edges on Boundary Surface Node.
Step 6: Now we connect surfaces to Multi Pipe
Step 7: Now we Bake
Step 8: Our Final Result
Complete Grasshopper Nodes for our Final Design.
Final 3D Model Embed using Sketchfab
Now is the time to print.
It’s not just like a 2D print when it comes to 3D printing. Before we instruct the machine, there are a few steps to take. First among these is the format. As previously stated, the printer only understands G-Code. And therefore, we must export our model in STL format. Since we are using a Prusa machine, this file needs to be opened in the Prusa Slicer software.
To create the G-code, each machine has its own software.
Step 1: Export the file from Rhino and save as STL format.
Step 2: Install Prusa Slicer software.
Step 3: Import STL file into Prusa Slicer or by simply drag and drop the STL file to Prusa slicer window.
Step 4: Now is the time to understand the Prusa Slicer software. On the Left it has some basic tools such as Move, Rotae, Place on face etc. On the Top Add, Delete, Arrange etc. On the Right it has printer settings, filamet type etc to select.
Step 5: When everything is finalised, we must slice it. One very important thing to remember is to provide supports before slicing. As we characterised the printer, we realised the need of supports. But due to the complexity of the structure in this design, I chose to forego support. If I provide supports because of this complexity, it will be challenging to remove those supports. And the material I chose was PLA (ESUN Brand).
Different types of Supports:
An example of support: This is what it looks like when given with full support on a model.
Step 6: This is what the outcome will look like after Slicing. We can Export the G-Code to a memory card if everything is in order. There is only a Memory Card reader on the printer.
The software provides us with the option to preview the printing before it is executed. The video down below demonstrates how to do that. A scroller is on the right and bottom side.
The right side scroller displays up and down slicing.
The bottom scroller displays the printer head’s path.
Knowing more about Prusa i3 MK3S
Prusa i3 MK3S offers a range of advanced features and capabilities. It is a 3D printer that uses FDM (Fused Deposition Modeling). Its high level of precision is one of its key attributes. It can print with layers as thin as 0.05 mm in height. The build volume of the printer is 250 x 210 x 210 mm. With the help of the printer’s sophisticated auto bed levelling system, which makes sure that the print bed is level and the nozzle is at the right height for each print, more accurate and consistent prints are produced. The printer has a filament sensor that recognises when the filament runs out and stops the print automatically so the user can replace the filament and continue the print without losing any time. The printer is designed to work with open-source software, Prusa Slicer which allows for greater customization and flexibility in the printing process. The printer can print with multiple materials, including PLA, ABS, PETG, and TPU.
Material Used
PLA (Polylactic Acid) is what i choose for printing. It is a thermoplastic polymer that is commonly used as a 3D printing material. It’s a biodegradable, sustainable material made from renewable resources like cornflour, sugarcane, and cassava. PLA is simple to print with and doesn’t need a heated print bed. However, it is advised to pre-heat the bed to 60 to 80℃. Print temperature for PLA is 205-225℃. Due to PLA’s low warping and shrinkage during printing, printed parts have less distortion and are more accurate. PLA is available in a variety of colours and can be easily painted or finished to achieve the desired look or finish.
Settings can be adjusted in the printer using the knob given next to the screen. File can be uploaded to the printer through memory card.
Start with Pre-heat by making sure the bed is clean and in place. Once selected, it will display a predefined material list from which we can choose our PLA, which has a pre heat temperature of 215/60°C. This is 215°C for the printer head and 60°C for the printer bed. Then, add filament by selecting the Auto-filament option.
Once this is completed, we can insert the memory card, at which point the machine will automatically read the file and choose our file from a list of files. DONE. Printing starts.
At first machine will auto level the print head and bed.
And that was a failure 😔
Because I did not add support to the model, it slid away from the print bed during printing. I believe the reason for the failure was that the model’s weight and the forces produced by the printing process were too much for the printer to handle, which is why the print failed.
After consulting with my tutor, he suggested that I add a brim to the model. It might be a great solution to my problem because it will give the model more stability and support while it is being printed. I was able to create a modified version of the model with the required support structures by adding the brim using the Prusa slicer software. The brim will attach the model to the print bed, helping to prevent it from sliding or shifting during the printing process.
I can now re-slice the model and try printing it again after making these adjustments. With the additional support structures in place, I anticipate having a successful print with fewer issues than before.
I used to feel down whenever I encountered problems that were unexpected to me. Before starting, I always check the odds, but this time, I wasn’t foreseeing anything of the sort. However, it was more exciting this time than usual. The setbacks were more difficult, and the helpers who came my way made it more enjoyable to solve problems.
The new Slice with Brim.
Finally my first 3D Printing is taking a shape.
Final Result
Post Printing Procedures
After printing, I discovered small threads on my 3D printed model, which can detract from the overall appearance of the finished product.
I then went back to my tutor to figure out what was wrong. He explained the theory behind this problem, which is frequently related to the moisture content of the printing filament. The development of these threads or “hairs” on the surface of the model during printing may be caused by the filament absorbing moisture from the air.
To remove these threads and restore the appearance of the model, he recommended using a hot air gun to gently heat and melt the surface of the model. By doing this, the threads can be melted and smoothed out, leaving a clean and polished finish. I used the hot air gun to remove the threads, and the results were successful. The model now looks much better without the distracting threads.
Final result comes out like this.
3D Scanning
3D scanning is the process of capturing a physical object’s shape and geometry in three dimensions using specialized equipment. There are several technologies and techniques available for 3D scanning, including structured light scanning, laser scanning, and photogrammetry. Each of these techniques uses a different approach to capture the object’s shape and geometry.
Here in our lab, we have an Artec Leo 3D. It is a handheld, portable scanner designed for fast and accurate scanning of a wide range of objects, including people, animals, and mechanical parts. The Artec Leo 3D scanner features an integrated touchscreen and an onboard computer, which allows for real-time scanning and 3D model processing without the need for an external computer. It uses structured light scanning technology to capture high-resolution 3D scans with accuracy up to 0.1mm.
Structured light scanning involves projecting a pattern of light onto the object and using cameras to capture the distortions in the pattern caused by the object’s shape.
Here is what I did to scan Mr. Sibin, a friend of mine, at Kochi’s Superfab Lab. I made an effort to fully scan him with Artec Leo. It was entertaining to fully scan a person using this new tool, which I had previously seen only in Tom Cruise movies. I used to think it was some kind of technology that some filmmakers made up. I never imagined that technology would advance to the point where even someone like me could operate like Tom Cruise team member 😂.
Fun apart, the process for scanning start with understanding the machine. The machine’s front has a camera with LED flash lights surrounding it, and the LIDAR is right next to the camera. It has a Power button and a Touch screen on the back that shows the functions and scanning data.
The process starts by adding a new project. After adding the new project, focus the camera on the thing you want to scan. Once the object is visible on the screen, pressing the record button will begin the scanning process. Now move all around the object to thoroughly scan it. A parabola-like action with an upward and downward wiggle can produce positive results.
The Scanning Process
Processing the Data
Once the scanning is finished, it must be processed before the final result is presented. Artec Studio 15 Professional software is used for that. The process is as follows.
Step 1: Import The file from the scanner. Connect the scanner to the PC and import directly from the scanner using Artec Studio.
Step 2: Once connected, it shows the list of files saved in the machine. Select our model from list and import it to PC.
Step 3: Once imported, the file shows different layers. This is because of the different scans made for same object.
Step 4: Use Auto Pilot feature to merge all these into a single model. This can be done manually also.
Step 5: Now we can edit using Editor to fix the missing features and unwanted things.
Step 6: Use Eraser to erase unwanted objects that was captured. Use Lasso tool to select the objects and erase it.
Step 7: Use Registration & Fusion for smoothening the object.
Step 8: Once this is done, Use Postprocessing for filling holes & simplify mesh. We can fill holes manually also.
The Result obtained after this.
Step 9: We can do the Hole Filling manually also for getting better results.
Final Result
The Scanned 3D Model Embed using Sketchfab
Downloads
Download Grasshopper File here
Help Taken & References
Chat GPT used for doubt clearing and content helps.
Youtube Tutorials for Rhino 01
Youtube Tutorials for Rhino 02