3D scanning and printing

  • 3D scanning
  • 3D printing
  • Group Assignment


    • 3D scanning

    In this week I learned how to scan object.What is significance of scanning and 3D printing too.How to get real diamensions using scanning and how to develop reverse engineering without using original dimensions of any object.And 3D printing is also great tool for complicated geometry designs where manufacturing limitations occures there 3D printing is important tool for prototyping.It will save cost and realizes actual geometry shape function.

    I used Sense scanner for my 3d scanning task.I was scanning my water bottle because of bottle has curves which is goes inside surface to outside surface like spline curve.

    Before scanning you have to install 'sense software' in your computer.Then enter pin number in sense software.After that adjust distance between scanner and object you have to scan. Then rotate scanner around the object with minimum speed. Otherwise it gives error like signal not found. Don't shake scanner during scanning.

    After starting the scanner, select which type of object you have to scan! like small, medium or large. In that case I was selecting medium object for my bottle.

    Now, remove unwanted parts which is scanned during scanning of object such as support of the object etc.

    Then call that object into the 'Autodesk Meshmixer' software. If your object has some missing parts like support then you can recover it through filling that object inside the meshmixer.Then save your .obj file.

    Now, call file into the 'kislicer software' and save G-code file.

    Before slicing you have to check size of your object. If you want large object in a small size then scale down that object by using 'cura software'

    Then as I explained 3D printing assignment ,set bed temperature 80 degree and print file through SD card.

    This is the scale down size of my original bottle.


    3D printing

    Firstly I understand the printer,i.e. Accucraft i220+.Then we are discussing limitations of printer.At very first the input of printer file should be in stl format.Temperature is another important task.You should enter bed temperature and filament temperature too.In this assignment we use ABS material.And I was printing my project aeriator wheel for this assignment but due to simple design and errors in file I changed my design. I was printing motor pin socket which has number of curves and internal holes for traditional method of machining. So , when we considering substractive machining process it might be a complicated one.

    For this assignment I use Fusion 360 for the 3D modelling.Also I get information about mesh..according to google mesh is material made of a network of wire or thread and Watertight is a term used to describe a 3D mesh suitable for 3D printing. In short, it means that there are no holes, cracks or missing features on the mesh. The easiest way to describe a good mesh for 3D printing is to think of it as a skin, and filling the inside with water. It is important to create watertight meshes, so that it is clear to the 3D printer what is the inside (which needs to be made up of 3D print material) and what is the outside.

    After finishing my drawing I went to kisslicer software which is a fast, easy-to-use, cross-platform program that takes 3D files (STL) and generates path information (G-code) for a 3D Printer.

    I was loading stl file for the g-code

    Then I remove support and set the filament fineness.After that I save that file.

    After that I went to repitier host software which is a simple to use host software, which is be compatible with most firmwares around. You can add and position your STL files on the simulated printbed and slice them all together.

    .

    This is our Accucraft i220+. 3D printing is a way to create physical objects directly from digital files.
    ■Temperature for bed=60

    ■Temperature for exdruder=225

    .

    Technical specifications
    Maximum Printable Area 300mm*250mm*200mm
    Filament Diameter 1.75 mm
    Extruder Diameter 0.4 mm
    Extruder Temperature Upto 270 C
    Print Accuracy 80 - 150 microns
    Layer Precision 0.1 - 0.30 mm

    When I remove the support, the print damaged like this...

    This is the part of aerator which is not finished properly due to extruder problem. When print rurring upto 20% the extruder gets stops to extrude material. I have tried to print my aerator file but due to printer problem it does not completed. My instructor suggested me that I will design non substractive machining part. After repairing the printer I followed same steps which I explained before.

    I was designing pin socket using solidwork software.There is curves inside the socket and holes too. Its difficult and time consumming to create by traditional machining processes.

    This is my final 3D printed object.

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    • Group Assignment

    Wall thickness test

    We have an Accucraft 3d printer at Vigyan Ashram, it uses Repeteier host as a machine software and Kisslicer as a slicer software. It can be seen in the image that the printer failed to print wall thickness from 0.25mm -0.75mm thick, some layer shift can also be seen in 1 mm thick wall. Wall thicknness of 2mm was clearly printed.

    Wall thickness varying from 0.25mm to 2 mm

    Bridge test

    In this test we wanted to see the amount of sagging of the object when it is supported on its two ends. The infill is set to hollow and the supports are set to OFF settings. We tested the object by varying the unsupportd lenght.

    The bridge could support its weight upto 60mm unsupported lenght, the bridge starts to sag.

    Infill and time test

    In this test we wanted to try out the strenght of various infills of 20mm*20mm cube. Slicer software lets us change the infills of the material.Skin thickness was also changes during the course.

    The time of printing was to the longest for 100% infill, it took 17 mins to print 20mm*20mm*20mm cube, while it was 14 mins for 10% infill. The accuracy was set to 29 and skin thickness to 1mm in Slicer software.

    Hole diameter test

    In this test we tested our 3d printer for its minium dimension that it can print. We made a cube having holes of various dimensions from 0.25mm to 3mm and printed it to set a limit to the minimum diameter of hole it can clearly print. The infill here was set to 0 and skin thickness to 1 mm.

    Overhang and supports test

    In this test I made a parametric design and changed the angle of the overhang. We wanted to test at which angle the 3d printer can print overhang without supports.

    The printer could print without the support upto an angle of 25 degree, after 25 degree it starts creating supports, this is an important observation as we have set a limit for the permisible overhang.

    Orientation test

    There we tested a simple object by changing its orientation of printing. We checked the strength,the supports and the fininsh of the object.

    This orientation resulted in a best surface finish as smaller area was touching the bed although there is some distortion observed at the top surface, this might be because the narrow section bent under its own weight.

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