When you hear the term “3D printing,” the first thing that often comes to mind is a thread being pulled out of a small nozzle and building an entire structure, similar to what you might have seen in the show Westworld. This is the most widely used 3D printing process and is called the Fused Deposit Method (FDM). It involves printing a layer of material on the XY plane and sequentially moving up on the Z axis to create a 3D object. It does so by adding layers over layers. Printers that use this method are called FDM printers.
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Image Credits: Westworld (HBO)
FDM, or Fused Deposition Modeling, works on sequential layering of material. FDM printing materials melts a thermoplastic material which is typically a filament and deposits it layer by layer to make a 3D object. Before we even start printing, we have to start with a 3D model that needs to be sliced before it is given to the printer, which is done on a slicing software. Once this is done, a filament is heated in the extruder and liquid filament is applied on the build plate. This FDM printing process goes on until we get a 3D object. If the object has a complex geometry, chances are the slicing software would have placed support structures to enable printing in overhanding areas. These supports need to be removed and post-processed before it is used. It is the versatility and ease of use that makes FDM printers so popular in multiple industries.
What is FDM 3d Printing
FDM 3D Printing is a revolutionary technology that took the world of manufacturing by storm and has now been adopted by nearly every industry. Achieving high-quality prints, though, isn’t child’s play. This is achieved through carefully tweaking each and every setting based on the 3D model and the material being used. This FDM Printing Explained article discusses exactly what FDM printing parameters to tweak and how the interplay for these settings paves the way for a successful print. A careful optimization’s of these settings can unlock the true potential of your FDM printer.
1. Layer Height
Remember when we told you how the printer deposits the material layer by layer and then jumps on the Z axis to deposit the next layer? That jump is layer height. Layer height is a critical parameter and needs to be carefully considered to achieve the right kind of finish. This, in turn, also impacts other parameters like print speed and overall performance of the printed object.
It all depends on what it is you are trying to achieve with your print. We have to be cognizant about the print quality and print time as they are inversely proportional. If you draw parallels with a human craftsman, wouldn’t you prefer someone who takes less time and gives you quality work. Sometimes, a certain layer height might not even be compatible with your printer and the filament.
It is quite an experimental task to tweak layer height and arrive at a certain result for an optimal setting for your specific application. Layer height is the bridge between speed and quality in your FDM print, so its impact is vital in the success of your print’s application.
2. Print speed
Print speed is another crucial factor for your print. It refers to the rate at which the extruder moves, deposits filament and prints each layer of your 3D model. Print speed is directly proportional to the overall print time, quality and mechanical strength of the print.
For larger prints, we can consider higher printing speeds in order to reduce print time, making it a more efficient print. However, the tradeoff here is with print quality. Naturally, if you ask a craftsman to hasten the process, chances are the quality of their work will be lower than expected. If there’s a small or complex 3D model and you need a more detailed finish, the print speed needs to be low. This however, will increase print time so a balance is required.
For example, intricate models can have print speeds as low as 40mm/s and larger prints can handle speeds up to 80mm/s. These numbers may vary based on the material used, filament type, layer height and printer’s capabilities.
FDM Printers melt solid material and deposit it on the build plate, so playing around and finding the right temperatures sits at the core of a successful print. Different filament materials have different printing temperatures. It is also important to note that usually the build plates are also heated for better adhesion of the print.
Higher nozzle temperatures will improve layer bonding but may lead to warping of the print at the base layer if the temperature is higher than necessary. Lower temperatures will plague you with a different problem of stringing or uneven layers.
Apart from the nozzle and the build plate temperatures, ambient conditions, especially temperature, need to be consistent. Any fluctuation can cause the print to fail. In order to reduce this chance of rapid fluctuation, cooling fans are employed to keep the layer cooling at a constant rate. Materials like ABS, however, require slower cooling and have a slower fan speed.
Here’s a table comparing different filament materials and their printing temperatures and corresponding build plate temperatures.
|Material||Printing Temperature||Bed Temperature|
|PLA (Polylactic Acid)||180-220°C||20-60°C (optional)|
|ABS (Acrylonitrile Butadiene Styrene)||220-250°C||80-110°C|
|PETG (Polyethylene Terephthalate Glycol)||220-250°C||60-80°C|
|TPU (Thermoplastic Polyurethane||210-230°C||20-60°C (optional)|
|ASA (Acrylonitrile Styrene Acrylate)||230-250°C||80-110°C|
|PVA (Polyvinyl Alcohol)||180-220°C||0-60°C (optional)|
|HIPS (High Impact Polystyrene)||220-250°C||80-110°C|
|Wood-based Filaments||180-220°C||20-60°C (optional)|
An important note here is that these ranges may vary based on the filament brand, how it was manufactured and the printer itself. So reading the manufacturer’s guidelines should be a best practice before you feed the filament to the printer.
4. Infill density
Ever wondered what’s inside a 3D print? Is it hollow, is it completely filled with material? This answer lies in a property called Infill Density. Infill refers to the internal structure of your print. Infill density allows you to keep a balance between strength, weight, and material used. A higher infill density will increase strength but will take more time, material and will weigh higher. Let’s discuss how different Infill densities affect your print.
A sliced version of a 3D print with different Infill Densities
High Infill Density
- Strength If you want something to be strong, you would want more substance in it. Similarly, a higher infill density affords the print strength and resistance to mechanical stress that might lead to deformation. This is especially important where structural integrity under stress is paramount. Higher densities range from 65-90%.
- Weight It is given that more material would mean more weight. If the print needs to be lightweight, a lower infill will be the way to go.
- Print Time Print time then becomes a function of the required strength and weight of the final output. Tweaking these parameters will give you an optimal print time.
Low Infill Density
- Cost and Material Savings Lower infill density will reduce the material consumption leading to reduced costs. This is especially important when the material is expensive.
- Weight Lower infill densities result in lighter parts as less material is used internally. This can be advantageous for objects where weight reduction is important, such as drone components or lightweight prototypes.
Variable Infill Density
- This use case is pretty important. A careful analysis of structurally load bearing parts can be given a higher infill and the remaining parts can be given a lower infill. This kind of optimisation will reduce weight, print time and material consumed.
To summarise, functional parts will require higher density for durability and strength while decorative or parts in the prototype stage may use a lower infill to optimise for cost and material.
5. Support Structures
Not every print will have clean and simple geometry. Sometimes geometries can be as complex as shown below.
Supports are extraneous structures that are not part of the model but are essential to the success of a print. They have to be removed later and the part post processed for a good finish. Support is important because no matter how good an FDM printer is, it cannot print mid air without the material holding on to something. Supports provide stability, prevent sagging or even a complete collapse while the model is being printed. Here are a few pointers while optimising for support.
Identifying the Need for Support
Does the print even need support? Sometimes a print wouldn’t need support structures but the slicing software would put supports based on default parameters. As someone who is here to master FDM printing, identifying whether a support is required is an important skill. You can always add support blockers on the model while slicing it so that you save on some material.
Optimising Support Settings
Once you’ve identified parts that need support, internal support settings can also be tweaked. Parameters like support density, type of support and contact area can be adjusted. The latest in the support type is the tree structure that mimics a tree bark and uses much less material. However, there may be parts that can benefit from grid or zigzag patterns.
Minimising Support Material
Here are two parameters to look out for in your slicing software: “Support only where necessary” and “Support angle threshold”. This will reduce unnecessary supports and reduce material consumption.
A very basic but very effective tweak that you can do is ensure that the model is oriented such that it minimises or even eliminates the need for support. Remember that print quality is also affected when there are supports, so you may want to reduce supports as much as possible.
As discussed earlier in the Temperature module, cooling the deposited layers is as important as melting them to the right temperature. You wouldn’t want your print to fail because the previous layer didn’t solidify.
Cooling maintains structural integrity while printing. When the nozzle deposits a layer of molten material, it undergoes a phase transition from liquid to solid. A rapid transition will solidify it faster ensuring that it bonds effectively with the layer below and maintains the right shape. Excessive heat may deform the layer leading to warping, curling or dimensional inaccuracies.
Another important reason to cool the layer fast is to prevent drooping or sagging of overhanging or bridging sections. These areas may lack underlying support of the previously printed layer making them susceptible to deformation as it is being pulled down by gravity and the heat from the extruder.
Cooling fans are essential for this process and helps in faster solidification of the layers being printed. This controlled cooling ensures that the print is dimensionally accurate and devoid of any defects.
After going through this article we’re sure that FDM printing might seem like child’s play to you. Carefully selecting the correct settings and experimentation will help you achieve the desired results you may be looking for. By understanding how parameters like layer height, print speed, temperature, infill density, supports and cooling affect your print, you can optimise them for quality, efficiency and marry them to functionality. Keep iterating and experimenting with these settings and master FDM printing to unlock new possibilities with your printer.
With Fracktal Works, you can find the right settings and a touch of creativity to bring your ideas to life with unparalleled precision and craftsmanship. Visit our website and contact us to start your 3D printing journey.
Download the “Mastering FDM Printing: Choosing the Perfect Settings for Optimal Results” Cheatsheet here