For this week's assignment we are supposed to design and print a 3D object that cannot be made using subtractive technique for example milling. Also we need to scan a 3D object using a 3D scanner.
3D printing is an additive fabrication technique. The idea behind it is to heat a material like PLA and extrude it through a nozzle while moving along the 3 axes according to the G-code of the job adding layers of material one on top of the other until the object is formed.
3D Designing and Printing
First step was to design the 3D object. I used Solidworks to fulfill this task
My Idea is to design a chain that forms a closed loop. The reason why this can not be done suptratively is because of the undercuts and hidden spots that the milling machine wont be able to mill.
-I started by choosing to design a part and then created a new sketch.
-I started by drawing 2 elipses using the elipse tool and setting the 2 radii of each elipse.
-I constrained the 2 elipses to be concentric by selecting them and then right clicking and choosing concentric constraint.
-Next thing I did was to extrude this drawing into an object.
-I filleted the edges of my object using the fillet tool.
-This is the first part of my model at this point it was done. The second part is almost exactly the same except that the 2 radii of the elipse are the same in other words the base of the sketch is a circle this time not an elipse.
-I went on with creating the third part. I used pretty much the same sequence. Firstly I created a new part and started a sketch. Then I used circle command, then extrude and finally fillet.
-For the fourth part I wanted to add an extruded text. I used the text tool to add the text .
-I extruded the text using the extrude tool. This was the final step now I have the fourth part ready.
-For the final part I used the FabLab logo DXF file I already made before as part of Week three assignment. I created a new part and imported the file.
-I extruded the drawing into an object using extrude command.
-Next thing I did was to scale it down by going to Insert >Features >Scale ,then I entered the appropriate scaling factor and pressed Ok.
-At this point all the parts were ready to be assembled. I created a new assembly by clicking on Make Assembly from Part from file drop menu.
-I inserted all the other components to the assembly by clicking on browse and choosing the components.
-After inserting all the components I started assembling them by placing them correctly. Here are the commands I used: First: I selected the first component, right clicked and chose Move with triad
Second: I Copied part one and part two couple of times as I will need them, I did this by selecting them and pressing CTRL+C then CTRL+V. Third: I used the move commmand. I chose to move by Detla XYZ.
I kept using those commands until I reached what I wanted
I used Cura to slice my model for Ultimake 2+ printer with nozzle diameter of 0.8mm.
-Here are the settings that I used: Layer height: 0.07mm --> The thinner the layer height the better the quality, I wanted good quality Wall Thickness: 0.7 mm--> Because some parts of the chain were really small I chose to go with a thickness less than 1mm Top/Bottom Thickness: 0.6mm--> Same as with wall thickness Infill denisty: 25%--> Because it's a small piece and it's not going to sustain any forces or stresses Print speed: 50mm/s--> It's a moderate speed to get good printing quality Travel Speed: 120mm/s--> Also affects the quality of the print if the head moves too fast after printing it may cause some damage Enable support: Yes--> As some parts are not touching the builplate of the machine Support placement: Touching Build Plate Support Pattern: Grid Support Denisty: 25%--> I tried with less but I saw that not all the parts are properly supported Support Z Distance: 0.4 mm--> Distance between support and actual object in Z direction, The less the distance the better the quality of the surface but also the harder to remove support later on. Support X/Y Distance: 1mm--> Horizontal distance between the object and support, I wanted to be able to remove support easily without breaking the small pieces Build plate Adhesion Type: Brim--> Makes a brim around the object to fix it to the buildplate Brim Width: 3--> Because the object is really small so no need for more than this
I used Ultimake 2+ printer with nozzle diameter of 0.8mm along with PLA of diameter 2.85 mm.
-Here is how it looked after printing and before removing supports
-Here is how it looked after removing supports
Problems and Commments:
-During my first printing trial I was using 8% infill for support I thought that it would be okay but I noticed that it was not good enough to hold the details of the model so I increased it to 25%.
-One other problem was that not all of the text part was not printed succesfully some pieces are missing.
-Also the surface of the model facing the supports came out a bit rough I would say that this is because of the Z Distance but I believe it would have been very hard to remove the supports if I decreased the distance because of the small size of the object.