American University of Beirut

​​​​​​ About the 3D Printers:

ArD TechLab includes the following 3D printing technologies:

Preparing your file for 3D Printing, considerations and guidelines:

• There are several main elements one should consider when drawing files for 3D printing; these elements are not only related to the actual design drawn but also the 3D printing material or filament to be used, the 3D printer's abilities, resolution and level of details needed etc. Getting to know these elements will help you save time and once understood will provide you with the best 3D printed result.
  
• The most important thing to remember while drawing your file is that your digital design will become a physical object. 
  
• Anything can be drawn using 3D modeling software, but not everything can be 3D printed. Each 3D printing process has its own limitations. 
  
• Below are the most important design considerations that apply to the fused deposition modeling (FDM) 3D printers available in ArD TechLab.
  

Overhangs and Supports: 

• All 3D printing processes work under the concept of additive manufacturing building parts layer-by-layer. Material cannot be dropped into the air, so every layer must be printed over the below layer. 
  
• Overhangs or extensions are areas in the model that are either somewhat supported by the layer below or not supported at all. Every printer has its own angle limits to print without using additional supports generally in FDM printing it is 45⁰ degrees. 
  
• Using additional supports usually creates rougher surface finishing when removing with extra time to 3D print the file. It is recommended to limit the overhangs in the model as much as you can for a better result. 

Wall thickness:

• Another thing to keep in mind when drawing your file is the wall thicknesses. The 3D printers can produce a very accurate thin shapes but to a certain point. The 3D Printers in ArD TechLab have a layer resolution range between 200 - 20 micron (0.2 mm – 0.02 mm) using the 0.4 and 0.6 mm nozzle.  3D printed layers are measured using micron, the thinner the layers the higher detailed print we will have (Extra fine 0.02 mm) and for fast prototypes we use thicker layers to save time (Fast 0.2 mm). 
• To have a good result from the first attempt always add thickness to your models. Walls with thickness not less than 0.8 mm can be printed successfully.
  

Warping:

• The material we use for 3D printing undertakes physical change melting at a temperature of 200⁰ C. This process of heating and cooling the plastic filaments causes the 3D printed parts to warp while printing.
• Large and flat surfaces are usually disposed to warping. To avoid warping strong surface adhesion should be used between the model and the printing bed. 
• To have a good result, avoid having large flat surfaces and try to have rounded corners in your 3D shape. 
  

Bridging:

• Bridging a gap happens when the printer prints between two entities, this occurs in FDM 3D printers when the initial layer has no support to hold it the printer bridges the gap leading to material sagging. This usually happens in the horizontal axis where there are openings in the walls or top layers. Horizontal bridging is recommended to be a maximum of 10 mm without the use of supports, for an excellent result 5 mm.
  

Vertical Pins and Holes:

• When we have 3D shapes to be assembled or aligned we usually use vertical pins, but most important is to know how accurate can the printer do vertical pins. Usually vertical thin pins will not print as accurate as we may think since the nozzle at a temperature of 200⁰ C moving in a small area melts the shape resulting in less detailed circles. Using FDM printers the minimum diameter is 3 mm to have an accurate rounded shape pin. Larger pins greater than 5 mm is printed with a shell and infill having a stronger shape. 
• Same concept applies for holes preferably not to have diameters less than 2 mm in FDM printing.  
• Design consideration that may help: add a small fillet in the end of the pin if it is less than 5 mm diameter. You can also consider adding a hole in your design where the pin is set to sit and insert an off-the-shelf pin.
  

Supported & Unsupported walls:

• For supported walls that are connected from at least two sides of the whole shape it can have a minimum of 0.8 mm for a good result. 
• For unsupported walls meaning walls that are connected from less than two sides can also have a minimum thickness of 0.8 mm for a good result. 
  

Splitting or dividing your model:

• For complex projects or models it is recommended to divide the file to reduce printing time. Overhangs requiring a large amount of support can be printed separately then glued. 

Hole orientation:

• Removing the support in the horizontal axis can often be difficult and creates surface roughness. Having the correct orientation 90⁰ degrees support is no more needed. 

Final Step:

• As a final step export your file as an STL format and import into Ultimaker Cura the 3d printing slicing application in which the recommended settings according to each 3d printer is put and saved into a Gcode ready to be printed. 

 

3D Printing Filament Guide:

As mentioned before the 3D printers available at ArD TechLab are FDM technology using plastic filaments of different types. In this list we will get to know the most known types of 3D printing filaments available and the way they are used, tips and guides. 

Polylactic Acid known as PLA: environment friendly and biodegradable filament made from cornstarch or sugar cane. It melts at a temperature between 190⁰ C and 210⁰ C and does not smell bad when printing.

PLA can be used in printing detailed objects and sharp corners because it flows easily outside the printing nozzle. PLA prints have a relatively glossy surface compared to other types of filaments.

When to use PLA:

• If you want to easily achieve high resolution prints when fine details are needed.
  
• A heated bed 3D printer isn't necessary for PLA prints, it works with glue and blue tape just as well.
  
  

Special Effects PLA
PLA is offered in many different colors some having special effects.

• Glow-in-the-Dark PLA: switch of the lights and your print lights up at night.
• Photo chromatic PLA: when exposed to sunlight changes color.
• Sparky PLA: Contains glitters.
• PLA + Wood, PLA + Copper, PLA + Brick and many others.
  

Acrylonitrile Butadiene Styrene knows as ABS:  It melts consistently at around 225⁰ C, it is relatively strong and little bit flexible. ABS is very suitable to 3D Print functional parts, like spare parts for machines or objects that exposed to high temperatures like sunlight or hot water.

When to use ABS:

• ABS is used when excellent interlayer adhesion is needed.
• For printing manufacturing parts that are exposed to strength.
  

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Special Effects ABS:

• ABS is generally available in fewer colors than PLA, an interesting ABS to be used is the temperature sensitive ABS, Smart ABS and Bendable ABS.
• Flexible filaments Thermoplastic Elastomers known as TPE: has many useful properties including elasticity, transparency, and resistance to oil, grease and abrasion. 
• Melts consistently at 225⁰ C - 245⁰ C.
• Breakaway: a support material used in dual-extrusion 3D printers. Supports can be quickly removed and give a smooth finish to your 3D print. Melts at 220⁰ C.​
  

Dissolvable Filament:

• Dissolvable filaments generally used to print support structures with dual extruder printers.
• Polyvinyl acetate known as PVA: is a component of a widely used glue type, like glue sticks or wood glue. It is dissolvable in water, which makes it very safe to experiment with. It's typically used as support material for PLA 3D Prints. 
• Dissolving PVA is as easy as putting your print in a glass of water for a while. It melts at a temperature of 215⁰ C - 225⁰ C and a build plate temperature of 60⁰ C.