5. 3D Scanning and printing¶
This week’s assignment is to create a 3D printed object that could not be created by using a subtractive process such as a laser cutter or mill. I plan on creating a grocery bag holder to intertwine into my school course of bioengineering. We also are supposed to create a 3D scan of an object. I am fascinated by this and hope to try out many techniques. I would like to scan a non geometric shape such as a shoe or a car using the water method where I take photos as levels are hidden by the water. Below you will find my documentation for this weeks projects.
This weeks group assignment was to use our lab and personal 3D printers and print a series of test files on our printers to detirmine thhe effects of overhang, bridges, clearnece, finish, and infill. As this was my last week of quarintine I could not be in the lab to aid my group. Instead I created a document and defined all the terms that they would be testing. These terms will be put onto the group website to help better explain what is going on in the tests my classmates ran within the lab. Group site found here.
Following this week’s lecture I learned alot about the different file types, print constraints, and print materials. For print materials I had no idea about the safety concerns with the petroleum based plastics and how they need to be ventilated. My career in the engineering lab I have only ever used PLA which is a plant based plastic that is not harmful to the lungs. I also learned about PETG, another type of plastic. In our lab we have two different types of 3D printers, resin and plastic. There is also another type of printer which is a fiber printer and a powder printer which both aid in getting many different colors in print but at a greater price tag. Neil displayed a series of test prints to define the terms of our printer including overhang and shelled out tests. I saw what failed prints of each kind looked like which are errors regarding extrusion settings, and adhesion. Finally I learned about file types when sending to the printer and 3D scanning. For our lab we slice files into Gcode to send to our Prusa minis. There are many different types of slicers and file types. Finally 3D scanning is a robust way to generate objects. Scanners can range from hundreds of thousands of dollars to a simple web based software that analyzes pictures. The process fascinated me, especially the reflective sunglasses. I hope to try this out by scanning an object.
For the 3D print for this week my task was to create something specific to a 3D printer that could not be completed by using a subtractive process. I used this opportunity to combine my bioengineering course with Fab Academy to create an object that helps people with arthritis carry multiple grocery bags. I used fusion to create the file by measuring the width of my knuckles and creating a box. Then I offsetted the box to create the grip itself. To make the grip more ergonomic I used a circle, then used the pattern to make 4 and created indentations for a grip in the handle. I then added the hooks that will grasp the grocery bags. In this particular design I used 3 hooks to not put too much weight on the users hands. I then extruded the entire apparatus to create it. Once I had the final 3D design I finished up some final touches such as adding fillets to each 90º joint to make it more pleasing to the eye.
Above is an Image of the 2D design where I have everything ready to be extruded including the indentations in the grip as well as the sketch fillets on the hooks to prevent the grocery bags from sliding around on the handle.
Above is the finished prototype of my grocery bag holder. I finished by extruding the entire handle by 15mm. I then added a small fillet to the corners of the handle itself so that when pressure is applied via the grocery bags, sharp edges won’t dig into your hands. I finished the design off by adding a nice orange appearance to the body of my holder.
I also created another design to go along with the theme of creating a object that could not be created by a subtractive process. For this I decided to create a traffic cone as the inside will be hollowed out which meets the requirment for the assignment. I used the loft command to get the cone shape and then added a shell to the inside like a real cone.
Above is an image showing me slicing the cone. The slicer converst the .stl file into Gcode where my printer will print the design from there. I used a Prusa mini to print this file and used the Prusa slicer as well.
To initially set up my printer I first had to level the bed. In order to do this I slid a piece of paper underneath the bed and raised the bed using the leveling dials to the point where the extruder would touch the paper when I slid it underneth. Once I had accomplished leveling the bed I then had to extrude some of the PLA to make sure I was heating up to the correct tempreture. Once these settings where correct, I imported the sliced file for the print test onto my printer. I went though the menu and selected a print off of the SD card. Then I watched as the bed and extruder heated to the given tempretures.
Above is the process of leveling the bed of my Ender 3 printer
Above is an image of the bed and extruder heating to the given tempretures. On the top is the desired tempreture and the bottom is the current tempreture.
Above is an image of the print test I used to test my printer. I downloaded this file form Thingverse and will have the .stl file linked in the file downlaod folder above. I sliced this file to a Gcode file compatible with my printer and then saved it to my SD card to print. While this boat test file, benchy, may looks simple, it demands alot from my 3D printer with the many overhangs and bridges within the boat design. This was a good test to demonstrate that my printer will be fully compatible with all my futre prints.
Before printing my design for the assignemnt this week I tested my printer by printing the demanding boat file which included many bridges overhangs and other difficult features After I printed the boat, I printed my personal file, the chain
Above is an image of the first layer of the test boat being layed down. I made sure to heat the bed and clean before hand. I watched the first layer to ensure nothing occured such as an extruder clog or other problems that would waste material and time.
The image above is the test print boat halfway done. I checked up on the boat to make sure there were no errors discovered. The printer had completed the hull of the boat and is now progressing twords the center console. The boat was being printed nicely and Once it is completed I will move forward with my print for week 6.
Above is the completed boat. My printer completed this print with zero problems showing the capabilites of the printer. While the boat looks quite simple, it actually very demanding and combines bridges with overhangs as well as different surface texturs for testing. I printed this boat to ensure that my printer was capable of complex prints. The boat is a quite demanding file and is used by many different 3D printers to test printers. I wanted to make sure that I would encounter no errors on the behalf of my printer while printing my traffic cone.I printed this boat to ensure that my printer was capable of complex prints. The boat is a quite demanding file and is used by many different 3D printers to test printers. I wanted to make sure that I would encounter no errors on the behalf of my printer while printing my traffic cone. Now I will print my fianl print.
Above is an image of my completed print that I designed. I created a traffic cone that was hollowed out on the inside as seen in the photo above. For times sake it is a very small print but when scaled up will work as well. I used the loft feature to create the cone then shelled it out and added a filleted base. The reason this cone could not be created in a subtractive process is due to the unsupported inside of the traffic cone. It would have to be able to access the inside of the traffic cone which it is unable to do. This was a small scale file to not clog up printer usage in the lab.
I was quite interested with the idea of 3D scanning especially how it pertained to the idea of designing the shell of the car for my final project ideas. Originally for my final project I wanted to create an actual replica of my car for the RC car and this allowed me to understand how I would do it. In terms of completing this week’s assignment I took a different approach then many of my classmates. Following the lecture I learned a lot about different scanning techniques such as machines, hiding layers with water, and taking hundreds of photos to render a design using softwares, which was most common among my peers. I recalled in the lecture the mentioning of lidar in generating 3d scans of objects and remembered that the newest Iphone 12 had this technology. As I myself do not possess this technology, my friend who I pitched my idea too allowed me to use his phone to attempt rendering a 3D object using Lidar scanning. After numerous attempts at setting the various range and detail I was able to generate a rough render of a rain boot using the Iphone’s lidar technology. I encountered a few different problems where I was not getting complete scans or the background was coming through but overall I believe I had great success. Once I had settled upon a scan that was the most completed I exported the file as an .stl. I then imported the file into fusion where I was left with an editable version of the scan from the iphone. In order to repair the scan to become printable and a solid I began by scaling the density of faces way down to make the object smoother. I then used the create solid tool to fill in all the holes and was left with a printable 3D scan of the boot. These two tools transformed my rough scan into a smooth printable object. This process aided my learning of how to create 3D scans and I now know how I will create the shell of my car, something I struggled with thinking of before this week’s assignment.
Above is the original object I started with to begin my 3D scan. I positioned it on a box with a flat, dark background so that it would remain unoticed. I then walked around the object using the scanner and scanning each face of the object as well as setting the distance adn quality to get the best possible scan.
Above is the process of scanning the boot using the Lidar technology within the new Iphone 12. I was able to generate a 3D rendering just by walking around the object and scanning all of the faces of the boot itself. I will put the rough render and attempt to clean it up within fusion.
Above is the me switching between the different render modes within the iphone’s scanning app. The only drawback to this is that the scan did in fact render some excess around the boot causing it to not be a clean scan but I will fix this in fusion.
Above is the .stl file generated from the phone as it has been imported into Fusion from this point I will patch up the holes and make the design flow and look smoother.
Above is the final filled in rendering of the boot I originally scanned using Lidar. Once I had exported the original file as a .stl it had many problems including holes, excess amterials and a density of faces nearing a quarter million. In order to transform my file into a smooth printable object I first selected the object and reduced the density down to .05. This reduced the number if faces greatly and made the boot look much smoother. Then I used the make solid tool whihc filled in all my gaps. These two tools transformed my rough scan into a smooth printable object and provided me with lots of insight on how I will atempt parts of my final project.
Over the course of this assignment I encountered my fair share of failed prints. Many resulted in the printer speed being too high which caused the print to not stick to the bed and it to move around far to much during the print. This cuased many different prints to fail. I fixed this by cleaning the bed beforhand which allowed the PLA to stick better. This print below was a failed overhang test for my printer.