Believe it or not, 3D printing may sound like a quite modern manufacturing process, but it's actually way older than you think. Modern 3d printing started with a publication by Hideo Kodima of Nagoya Municipal Industrial Research Institute in 1981.

Four Years later in 1986, Charles Hull patented Stereolithoraphy, and in the following year made SLA-1, the first ever 3D printer.

The first step for 3D printing is creating a 3D design file. It can be done by a 3D CAD tool or it can be generated using 3D scanning where the latter can become a tricky and complicated process.
After the 3D design is made, it has to exported to a file type that is supported by the slicing software we will use. In most cases, the set standard in this regard is a Stereolithography file (.stl). It describes the entire 3D object as polygons(triangles).

The second step is to create a g-code from the 3D model we just designed that the 3D printer can understand. Usually this is done by a slicing software like Cura, Meshmixer, FlashPrint, etc.

Once the g-code is generated, we start the printing process. The printing part of 3d printing is a tedious job. It usually takes a long time and requires somewhat constant attention, depending on various factors.

Depending on the print technique and finishing wanted on the end product, 3D printed parts require a post-processing step. This step may include removal of support material, UV curing, High temperature compression, sanding, alcohol baths.

As the name suggest, Infil is the pattern how material is filled inside the surface of a 3D printed object.

There are two settings to infil which need to be remembered.

• Infil Style or pattern:

The Infil Style is how Materials is layed out in the infil. Most common patterns are line, hexagon and cubic.



• Infil Density

The Infil Density refers to how much material will be put inside. This setting can significantly increase or decrease the print time.

Wall thickness, also known as shell thickness, is the thickness of the outer walls of your design. In manufacturing, you always want to use as little material as possible, or just as much as you need.This goes for 3D printing, as well. The added luxury is that you can decide the material thickness of your project’s walls, top, and bottom when you prepare the 3D print file for your 3D printer.

The wall thickness parameter can siginificantly increase or decrease print time.

Like all CNC machines, 3D printers work in layers which is governed by the z-axis and this greatly affects the finishing of the design file.
All 3D printing processes build parts layer by layer. Due to the additive nature of 3D printing, the thickness of a layer determines the resolution of a print in a similar way that the number of pixels determines the resolution of a television or a computer monitor. The downside is that the lower the layer height the longer it takes to print.

With FDM printing, each layer is printed as a set of heated filament threads which adhere to the threads below and around it. Each thread is printed slightly offset from its previous layer. This allows a model to be built up to angles of 45°, allowing prints to expand beyond its previous layer’s width. When a feature is printed with an overhang beyond 45°, it can sag and requires support material beneath it to hold it up

For the 3D printing week Assignment, I wanted to make a small scale version of the LED arm of my final project. So I went back to my work for week 1 work.

I knew that I was working with Addressable LEDs, so I have been searching the local market for WS182/SK6812 or anything equivalent. Apparently it's not very popular yet in Ahmedabad, and I couldn't individual 5050 LEDs. But what I did manage to find was this LED strip with ws182b LEDs. It had 12mm spacing between each LED, a bit too much for my liking but it was okay for the first spiral.

I also checked the price for shipping in individual ws182b LEDs with SMD 5050 packaging and it would cost me 40 rupees per piece where I get got 60 LEDs for 19 rupees each on the LED strip.

I started by analyzing my initial Sketch and came up with this in rough sketch in Fusion360 for the arm.
I wanted the arc length to be parametric, so first I created the inner, mid and outer arcs with a concentric constraint.

Then I extended the arcs with lines and made a tangent constraint with the lines. I made the lines parallel and equal to eachother. This ensured the lines were always constrained together.
After that, I closed the area in between and added an 'arm thickness' parameter for the distance between the arcs.

Parameters Used:

• armCurvature
• armHeight
• BaseDiameter
• armThickness

I played around with the parameters a bit to see if I could make any of them dependant on eachother, and made

armCurvature = baseDiameter * 0.9

Then I extruded the the sketch to make the initial 3D object. I used a parameter an 'armWidth' parameter for the extrusion. Since I extruded from both sides, I used the distance as (armWidth/2)

Parameters Used:

• armWidth

I started by creating a sketch on the x-y plane, right at the center. I found that it's convinient in using the center to align my design.

I made two circles, the outer one for the arm, the inner one for a connector hole.

Parameters Used:

• armWidth
• topConnectorHoleDiameter

I extruded the the area between the outer circle and the inner circle. The extrusion type was join.

Parameters Used:

• topConnectorThickness

I extruded using the inner circle area, the extrusion type was cut. This cleared away the hole for a connector on top. The

I created a small rectangle on the x-y plane. I used the space where the LED arm touches the ground. It made constraining my LED slot much easier.

Parameters Used:

• armWidthSlot
• slotInside
• slotOutside

I used a Sweep function to create the slot inside the arm. The profile was the sketch, path was the mid line in our initial arm sketch and the operation was 'cut'. This created a hollow arm with the profile of the slot sketch on the inside.

I measured the LED's again just to be sure, the size is 5mm since the package is 5050. I used constraints to keep the LED hole aligned with the sides of the arm. The first LED has a clearance of 5mm is there for the first LED.

Parameters Used

• ledSize

I used extrude to cut out the LED holes from the top surgace of the arm. The cut distance was from top surface to the inner surface.

I used Pattern along path to recreate 8 LEDs on the arm. I then adjusted the height of the total arm to leave no empty space on top.
The distance between each LED was ledSize+ ledSpacing.

Parameters Used

• ledSpacing

First I imported my .stl file into flashprint. This is the default slicing software for the FlashForge printers.

Since my design is long on the vertical axis, it's always a good idea to lay it flat on the bed. All FDM printers have much stronger bonding on the horizontal axis and the vertical axis usually has the layer patterns.

The design then needs to be oriented for optimum printing. Right now the print is hovering on air, and has to be put on the bed surface.
** Some surface on the printbed might have less adhesion randomly due to various reasons.**
For my case I had to move my print area to the corner for perfect adhesion.

Clicking on the print Icon on the top will bring up the print settings. I put in my parameters which where:

Since FlashForge needs to stay connected to the device if you print directly from the computer, I opted to send the file to the printer using a memory card.

I saved the print output as a .gx file from FlashPrint and plugged in the memory card on the machine.

Using the Touch Panel, I navigated to my file and printed it.

The first problem I had was design related. I used the wrong distance spacing between LEDs and as you can see, on the output the LED holes didn't match the LED strip.

So I went back to measurements, the 'Pattern Along path' function in Fusion360 takes one distance paramter, and the spacing was from center to center. My initial Setting was just the spacing I measured from the LED strip.

I simply put the correct distance in the parameter and it worked like a charm.

Distance = (1/2 * radius of 1st LED + spacing + 1/2 * radius of second led)
= (led Size + spacing)

Since My print was long but thin, one end of it wasn't adhering to the bed properly. After multiple failed attempts, and trying out rafts and brims, I found that it was a problem with our print bed. The Center Area had bad adhesion. Another reason for it was that long prints tend to bend if there's no proper adhesion.
The print worked out great once I placed it on an edge of the print bed.

I haven't yet found a solution for this problem yet where the print dimensions are not accurate as the design dimension. I haven't found a way 'yet' to put in the printing offset into a parametric design.

As illustrated on the image, projects a laser beam on a surface and measures the deformation of the laser ray.

Structured light 3D scanning measures the deformation of a light pattern on a surface to 3D scan the shape of the surface.

Photogrammetry, also called 3D scan from photographies, reconstructs in 3D a subject from 2D captures with computer vision and computational geometry algorithms.

Contact-based 3D scanning technology relies on the sampling of several points on a surface, measured by the deformation of a probe

Laser pulse (also called time of flight) 3D scanning technology is based on the time of flight of a laser beam. The laser beam is projected on a surface and collected on a sensor. The time of travel of the laser between its emission and reception gives the surface’s geometrical information.

3D Printed Output:

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