3D printing

3D printing

3D printing as the name suggest is a method of creating a three dimensional object layer by layer from a CAD model. 3D printing is an additive process where materials are added to build the desired geometry, as opposite to machining (subtractive manufacturing) process in which material is cut off or removed from larger block of material. Therefore it is also known as additive manufacturing process. There are varieties of materials that can be utilized in 3D printing ranging from polymers like PLA (Polylactic acid), ABS (Acrylonitrile butadiene styrene), CPE (Chlorinated polyethylene), Nylon etc. to metals and alloys like Aluminium, Stainless Steel, Titanium etc.

3D printing is widely used for creating models, prototypes and highly complex geometry which are hard to create using subtractive manufacturing process. But, cost of printer and printing and the build size which confines to around 400mm * 400mm *400mm generally, limits the application of 3D printing.

Steps for 3D printing-

Step 1 : Designing the geometry in CAD software

Every 3D printing process begins with making the geometry in any Computer Aided Design (CAD) software and saving or exporting the geometry in format .stl (generally preferred), .wrl, .amf or .obj etc. One can also use 3D scanner to scan an object and generates it’s geometry.

Step 2 : Selection of material and printer

Once the design is generated, based on the requirement and feasibility material is selected. The major constraints in the selection of the material is the type of material your printer supports. Generally, polymers are widely used because of two major reasons – cost and feasibility. Polymers are cheaper and so is their printers, one can easily get a low cost printer in around ₹15,000. The metals printers are generally in the high end side and can cost in crores for a good resolution one.

Step 3 : Slicing the geometry and defining print parameters

Before every print ,slicing is to be done and the print parameters need to be specified like layer width, wall thickness, print speed, in fill density and support density etc. which can be done with various slicing software like Cura, IdeaMaker, Sli3r, Simplify 3D etc. Some geometry which are complex in shape need support structure which can be provided by the slicing software itself, these supports can be water soluble or made from same material. All these parameters determine the fineness of the structure and the print time which can vary from few hours to several days, for example if print speed is low then fineness can be higher but print time will also be higher and vice-versa.

Sliced geometry

Support structures are shown in blue and the actual object is shown in red in the above figure.

Step 4 : Printing the geometry

Based on the material and printer type, printers needs to be configured like raising the base (bed) temperature and removing clogs from nozzle.

Step 5 : Post processing

Once the object is printed, the final step is to remove the supports and smoothen the surface which can be done with the help of sand papers or file.

Final object post processing

If you are a researcher from any institution or any industry professional, then you have two options to print 3D objects –

  • Research labs and institution – One needs to register in the I-STEM portal to access the 3D printers available at very nominal price in various institutions and research labs. There are 70+ 3D printers available across India in which two are metal printers situated at IIT-Palakkad and CSIR-CSIO, Chandigarh.
  • Private industries and companies – One can easily find companies that provides 3D printing service, but cost of print can be higher.

If you are from IIT-Roorkee then you can use the printers available at Tinkering Lab and step 2 to step 4 gets eliminated; one needs to just design the geometry, register in I-STEM portal, collect the print from Tinkering Lab and do the post processing.

Categories: Miscellaneous

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