6. 3D Scanning and printing¶

Highlights of the Week:¶

Group Assignment:¶

To test the design rules for the 3D printer at Vigyan Ashram.
Test 1: For this test we used a Thingiverse file suggested by our instrcutor. The design file looks like-

A. Converted .stl file to GCode-Used Fracktral software, changed setting fill density to 20% and bed temperature to 60 degree Celcius saved the file in GCode. B. Printing: Printed the file on Julia in Normal and Fast print to compare them.

Comparison: we compared the following parameters in the following tests:
a. Z Height
b. Warp Check
c. Spike
d. Hole in wall
e. Raft Test
f. Overhang test
The conclusion was that there was no major differnce between print quality except for Overhand test. Normal print had better overhang results compared to normal print. It is visble in the picture below:

Test 2-In fill Test In this test we made 4 cubes in fast, normal, high and ultra print to study and compare there appearance and sizes.

a. Design: We designed cubes of size 20mm in OpenSCAD. b. Print: Converted file to GCode and printed it on Julia. The shapes were small so it didn’t take very long to print them. c. Results: The differnce is explicitly visible from fast to ultra print. The ultra print has squares small, precise and closer compared to high, normal and fast print. d. Comparison: The length of ultra print was 19.90mm and fast print was 20.05mm. I thnk depending on the application the choice of print should be made.

Test 3:Hole Test Made holes from 0.5mm to 5mm diameter and printed them in a cuboid.

Test 4: Resolution Test Lines of 0.5mm to 5mm thickness were printed. Clearly, the thinnest line wasn’t printed well.

Conclusion: For our 3D printer Julia at Vigyan Ashram, I concluded to keep a minimum thickness of 1mm. And depending on the design and application I will choose between fast,normal,high and ultra print. Because although Ultra print may aesthetically look the best but it takes longer time to print. At the same hand, if my design involves overhang, I will not prefer fast print.

Individual Assignment:¶

1.I designed and 3D printed a “perforated sphere with another sphere inside and a heart at core” that cannot not be made subtractively.
2.I 3D scanned a Dell dekstop using 3D Systems scanner.

Inidividual Assignment 1: Design & 3D Printing-¶

1.Design: I used fusion 360 to design.
A. Display settings and Axis: I selected the Front axis, viewport to single view and the display settings comfortable to me. B.Sketch: Sketch> Arc> Centre Point Arc.Made arcs of thickness 5mm with radius 50 mm and 45 mm. Closed these arcs with line connecting the end points. C.Revolve: Create>Revolve. Selected the profile the arcs and an axis around which it rotated to make a sphere. D.Circle: Sketch>Circle. Made a circle of diameter 17 mm at the origin. Hiding the body only shows the circle sketch. E.Extrude:Create>Extrude. Cut the extruded circle from the sphere in a single direction. F.Pattern:Create>Pattern>Circular Pattern. Selected the feature “Extrude”, the axis and enetered quantity 2 at various angles till 90 degrees got 5 perforated holes on the sphere. G. Circular Pattern Axis: Changed the axis and extruded holes with the above 5 holes on axis. Selected the quantities carefully that the holes should have optimum gap inbetween. H.Mirror:Create>Mirror This extruded holes on the surfacce of the entire sphere. Pattern types id features and selected the objects to be mirrored. The extruded holes replicated on the other side of sphere along an axis. I.Replica:RIght clicked the body and “copy”,”past” the selected body.This gave me 2 spheres of excatly equal dimensions. J.Scale:Modify>Scale. Under unifrom scale parameter decreased the size of the other sphere to 0.6 factor. K.Spline & Mirror:Using the tools made a sketch of a heart. Spline gave the freedom to freely make curves and the mirror made the hal image complete. L.Extrude:Create>Extrude.Converted sketch from 2D to 3D giving it thickness of 10 mm using the tool extrude. K.Alignment:I alligned the centre of the 3 bodies at origin and checked the final design from various axis.Finally, the file was ready for printing.

2.Software: I used the software Fracktory to adjust settings and make the file format legible to the machine.
A. Print Quality: I used “Fast print” which predited the least time for printing.
B. Support:the sphere and the heart inside are not attached to any surface. Also, out of 3 the two bodies being spherical I added print support structure.
C. File Format:The “.stl” file is saved in “GCode” format which is legible to the 3D printing machine Fracktal Works-Julia 2018.
D. Time Required: The file showed 5 hours for printing.

3.Machine:
A.Calibration:I calibarted the machine adjusting the bed level and the distance between nozle and bed.
B.Printing: The nozzle moved with PLA flowing out and slowly making the design on the hot bed.

C.Removing Support: The printer had given support to the object from outside and inside too. I used twisers to remove the support.

D. Final Look: After removing the external support the object looked perfect.

It is quite evident from the object that it cannot be made by subtractive manufacturing. Being Additive manufacturing successive layers of Polylactic Acid(PLA) material have made inner heart, inside sphere and outside sphere simultaneously.

Rather than adding layers, subtractive manufacturing involves removing sections of a material by machining or cutting it away. This object isn’t possible to manufacture subtractively.

4.Trobuleshooting: The first time I 3D printed the ball was heavy because the thickness of outer ball was 1 cm. The inner ball and heart werenot visible. I made mistake thinking 10mm was the correct thickness which turned out be a bad decision.

Improvement: I redesigned the object with better sense of design. The final object sphere is just 2 mm thick and I increased the size of the holes for the inner sphere and heart to be vsible.

Design and GCode files available here

Inidividual Assignment 2: 3D Scanning-¶

I used 3D system sense scanner to scan a “Dell Dekstop” and edited the scan in 3D System scan software.
1.Scan an Object: In the sense software I selected to scan “Object”.
2. Size of object: For the dekstop to be scanned chose “Medium Object.” 3. Operations: To scan the Dekstop from a constant distance, I made a circle and rotated on it keeping the object fixed. 4. Movement: I moved the scanner fixed on laptop 360 degree. I covered scannning from various levels to add details. 5. Editing: The tools in Sense software give us the freedom to give a final touch up before printing.
A.Crop: During scanning a few details in the background were also scanned. This were easliy deleted using the tool.
B.Erase: I erased the large unnecessary details.
C. Solidify: After applying this tool, it made the surface flat.
D. Colour: This gave the option to adjust the brightness and the contast.
E. Trim:The minute details not required were deleted.
F. Touch Up: The rough parts were flattened using this tool.
6.Save: I saved the file in the local system in .obj format. It has other options to upload or directly print the file. Scanning file available here

Machine Learning:¶

1. Fracktal: Julia 2018¶

Specifications:-
a. Bed size of Julia:(210mm)(250mm)(260mm)
b. Filament diameter:1.75mm
c. Printing Material - ABS, PLA, carbonfill(ABS), Copperfill(PLA), Creoflex, Woodfill(PLA),etc.
d. Printer Software Supports .stl and .obj files via USB or SD card.
e. Nozzle Diameter- 0.4mm
f. Nozzle Temperature for PLA material: 210°C.
g. Bed temperature for PLA Material: 60°C.

2.3D systems Scanner:¶

Specifications:-
a. Supporting Operating Systems: Windows 8 and 10, 64bit.
b. Operating range: Min.0.4m, Max. 1.6m
c. Maximal Image Throughput: 30fps
d. Scan Volume:
Miimum: 0.2mx0.2mx0.2m
Maximum:2mx2mx2m
e. Colour Image Size:1920(w)*1080(h)
f. Depth Resolution @0.5m:1 mm

Documentry: Print the Legend:
¶

I watched the documentry and loved it. It takes us back in the journey of 3D printing companies especially MakerBot and FormsLab.I wish to write a review and publish it.

Concepts & Terminologies:
¶

1.FDM:Fused Deposition Modelling,3D printers that run on FDM Technology build parts layer-by-layer from the bottom up by heating and extruding thermoplastic filaments.
2.PLA:Ploylactic Acid, PLA is a biodegradable thermoplastic which is derived from renewable resources, such as cornstarch, sugar cane, tapioca roots or even potato starch. This makes of PLA the most environmentally friendly solution in the domain of 3D printing.
3.ABS:Acrylonitrile Butadiene Styrene (ABS) is part of the thermoplastic polymers family. As its name implies, ABS is created from Acrylonitrile, Butadiene and Styrene polymers. It is a material commonly used in personal or household 3D printing, which is done using primarily FDM or FFF 3D printers.
4.Stereolithography: Stereolithography (SLA or SL or resin printing) is a form of 3D printing technologybased on Production parts in a layer by layer fashion using photopolymerization, a process by which light causes chains of molecules to link, forming polymers.
5.Selective Laser Sintering:SLS is a printing technique that uses a laser as the power source to sinter powdered material (typically nylon/polyamide, aiming the laser automatically at points in space defined by a 3D model, binding the material together to create a solid structure.
6.Design sketching: A simply or hastily executed drawing or painting, especially a preliminary one, giving the essential features without the details.
7.Drawing in perspective: Perspective drawing is a system of representing the way that objects appear to get smaller and closer together, the further away they are.
8.Sketch based shapes: 3-dimensional shapes based on the 2-dimensional sketches we make. For example, you can get a cylinder by drawing a circle and then extruding it.
9. 3-point perspective: Linear perspective in which parallel lines along the width of an object meet at two separate points on the horizon and vertical lines on the object meet at a point on the perpendicular bisector of the horizon line.
10.Workplane: An imaginary 2-dimensional horizontal plane, usually shown as a grid , formed by squares of a specified dimension. One workplane is kept as the active building surface at a time.
11.Translation: In 3D modeling, there are many ways to move an object.The first type of moving is “translation.” Translation is changing an object’s position without rotating the object or changing its size.
12.Boolean Operations: There are several boolean operations from math(AND, OR, NOT, XOR..), and we can use these on polygons as well. The Boolen Addition (A AND B ) operation will combine two polygons and the subtraction operation(A NOT B ), will remove from the first polygon the part that intersects(overlaps) with the second polygon.
13.Uniform scaling: A linear transformation that enlarges (increases) or shrinks (diminishes) objects by a scale factor that is the same in all directions. The result of uniform scaling is the same form with different size to the original.
14. Primitive shapes: Pre-defined 3-dimensional shapes, like the box and cylinder creating tools in Fusion 360.
15. Sketch based shapes: 3-dimensional shapes based on the 2-dimensional sketches we make. For example, we can get a cylinder by drawing a circle and then extruding it.
16. Orthographic view: Orthographic views are two-dimensional views of three-dimensional objects. Orthographic views represent the exact shape of an object as seen from one side at a time as you are looking perpendicularly to it. Depth is not shown.
17.Parametric solid modeling: Parametric solid modeling is a key technology to define and manipulate solid models through high-level, parameterized steps. These steps can be modified by users and to specific parameter values and constraint configurations.

Learnings and Conclusions:¶

1. I will prefer Fusion 360 software for 3D design over solidworks because it is easily accessible and free to download.
2. I was disappoinnted to undestand once a file saved in 3D System Scan Software cannot be opened again in the software to edit it.Also, the software doesn’t function unless the device is connected to the laptop.
3. Fracktory doesn’t have the feature to show print support structure to the design. A preview could have proven helpful in alligning object such that it requires the least support.
4. The time anticipated by the 3D printing machine Julia 2018 is unreliable. Initially, it is way too much than the exact time taken by the machine.

Refernces:
¶

1.Fab Academy Tutorial
2. 3D Systems

Future Scope¶

I want to use SLS and SLA printer. Moreover compare their print quality.
Make 3D printed tie. I want to wear one.

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