How do 3D printers work? – Introduction to 3D printing

How do 3D printers work? – Introduction to 3D printing

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The world of 3D printing gained significant users and fans. It is becoming a household name. In this article, I will introduce you to this world and how it works.

3D printing is a technology called “additive manufacturing” (AM). The construction is built layer by layer by adding material to the object. Unlike “subtractive manufacturing”. Where the construction is built by removing material from raw body to the final shape. Additive manufacturing is efficient in raw material usage and can be used in people’s homes.

I will discuss technology called “fused deposition modeling” (FDM) or “fused filament fabrication” (FFF). Where the plastic filament is heated to melting point and poured on an object.

There is another technology called “Stereolithography” (SLA) and “Selective Laser Sintering” (SLS). This technology basically uses a laser light to solidify liquid plastic. This technology at the time of writing is messy, costly and produces brittle objects. It creates smother object, though. If you want to print in this technology you can approach some vendors that will do it for you.

With the FDM technology, we can have a printer in our homes. It will create plastic objects according to our wishes.

 

Using this printer we can print:

  1. Plastic parts we need. (I needed a connector for PVC pipe so I printed it).
  2. Prototypes. Developing commercial products in our homes.
  3. Actual final products.
  4. Toys/gifts – we can print cool objects and bring them as special gifts to people.

 

The printer components are:

Extruder

This part melts plastic filament and emits it from its nozzle. The smaller the nozzle size the finer the object surface we will be. Using smaller nozzle decrease the print speed. We can choose the filament diameter used to print. Thus controlling the surface roughness VS print speed.

Extruder - edmit melted plastic

The extruder contains a motor that pushes the filament into the nozzle during print. The motor speed changes the amount of material emerges from the nozzle. The motor is coordinated with the printing speed. Making sure that the printer emits an adequate amount of plastic.

The extruder is heated to about 210 degrees Celsius. This temperature melts the filament and allows it to adhere to the object.

Print bed

The print bed is a surface on which the printed object is built. The print bed is moved relative to the extruder during the object printing.

Hited Bed
The bed on which the model is printed

 

Most print beds are heated – allowing printing plastics of high-temperature melting point like ABS. The bed heat allows good adhesion of the object to the bed. It also maintains a stable temperature of the object during the printing process. This reduces object twisting because of rapid temperature changes during print.

The bed is coated with glass or plastic to allow the model to adhere to it. I used plastic blue tape for that and found it to be annoying – the tape is often teared and I need to glue new tape to the bed. I found good solid plastic that allow me to print without any problem.

 

Structure and movement

The printer frame holds the extruder and bed in a proper position to each other. The structure allows accurate movement between the extruder and the bed. Printers contain motors that perform the actual movement. Most printer moves the extruder in the Z (height) axis and the bed in the X-Y axis.

You can see the 3D printer structure.
3D printer frame

In this picture you can see the frame of the printer. The extruder (in the middle) move on a rail in the Y axis. The bed move on two rails in the X-axis and the extruder height is determined by two screws on the sides driver by two motors in the bottom of the frame.

 

Display

Most printers contain a display that shows the printer status and some print information. Such as extruder/bed temperature, estimated time to print finish etc. This is an important component telling you the printer status in a glance.

LCD displays printer status.
Small LCD display showing the printer status.

 

 

Control hardware

The control hardware interprets the print instructions and converts them into electric signals. Those signals drive the printer parts. Most hardware is based on Arduino boards. You can connect to the Arduino board using an USB cable to your computer and control the printer. This is somewhat cumbersome and might prevent the use of the computer for the printing duration.

Adruino control bord

Another hardware that a printer might have is Raspberry pi. It gives the printer a WIFI and ability to print from remote locations. I am using such a device with “Repetier-Server” software installed on it.

 

 

How to get things to print

The best place to search for existing designs is the portal http://thingiverse.com/. Many people contribute their design for the public domain. It contains many cool things to print. Try to do a search on this site. You will find it amazing at what people has invented and created.

If you want to design your own models, you need to use 3D design software. I recommend on using “tinkercad”. Tinkercad is software you can use in your browser without installing software on your computer. It is relatively simple and has anything a beginner might need.

How to compile your design

When you finish ‘tinkering’ with your model, you need to convert it to “gcode”.

You need “slicer” software to compile it into machine instructions. The Slicer gets the object design in “STL” format and converts it to serial instructions in “gcode” format. The gcode format has been invented to control CNC machines. Since 3D printer moves like CNC machines it has been adopted here. I use “Repetier-Host” software on my computer. It contains slicers and printer console. It also sends the sliced code to the printer.  On the other end, I use “Repetier-Server”. It receives the instruction through WIFI and controls the printer.

 

Just select a good printer which suits your needs and start building. If you have any question please write them below in the comment section. I will be happy to hear from you and answer any question you may have.

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