Why Is 3D Printing So Slow?

Nowadays, everyone knows that 3D printers can create 3D objects from Basic materials. You can think of any 3D shape and Design it with CAD software (like FreeCAD), give the design to the printer, and receive it.

But, the problem is that 3D printing is so slow and takes much more time than traditional production methods. For example, An injection molding machine (most plastic objects around you are made by these machines!) makes up to ten parts in a matter of seconds. In contrast, 3D printing a simple phone case can take up to three hours. So:

Why is 3D printing so slow? 3D Printing is slow Because it has to make objects layer by layer. This way, Each object consists of numerous layers. Also, different factors like mechanical limitations and material properties don’t let the machine make the layers faster.

Even though 3D printing is slow, there are several ways to increase its speed. To do that, we need to know its causes and design challenges that should be solved.

Main Factors That Make 3D Printing So Slow:

First of all, when we talk about 3D printing, we should be aware that there are different types of 3D printing methods. Each method has its pros and cons. Some ways are faster but have other limited Applications.

FDM

The most common 3D printing method is called FDM (Fused Deposition Modeling). FDM 3D printer melts a filament plastic string and deposits the molted plastic on a surface to create an object. FDM 3D printers are cheap, though they provide acceptable results. Since this method is highly commercialized, you can easily have one for around 300 USD.

Before going further into details. It’s good to see how the FDM 3D printers work:

The machine has a moving head that fuses filament and squishes it on the previous one. The head consists of a nozzle, extruder gears, stepper motor, and fan. Hence, it’s heavy and has lots of momentum.

As you may guess, moving heavy objects is harder to stop, and when they stop, it’s tough to make them move again. So, it’s the first item that limits FDM printing speed. Reducing weight may be the very first solution that comes to mind.

One of the best ways to reduce speed is to use the Bowden tube feeding mechanism. Bowden tube is a plastic tube that guides filament from feeding gear to the nozzle. Feeding gear moves with a stepper motor. Hence it’s possible to move the stepper from the nozzle, but Bowden tubes also have disadvantages.

3D printing with Bowden tube is tricky because the filament should be compressed into the nozzle. It may jam in the line, especially if the filament is flexible. Therefore, 3D printing flexible materials like TPU will become harder.

It’s good to mention that steppers can perform way faster than what they do in 3D printers. However, increasing their speed results in severe vibrations and heavily affects print quality. So moving them faster isn’t a practical option. However, some tricks can hugely reduce its noise.

Another factor that makes 3D printing so slow is the filament properties. Think of filament as a material like cement. It needs time and desired condition (humid environment) to stick bricks together and create a strong wall. Filament materials (usually plastics) also need proper temperature and time to cool down.

Each hot filament string lays on top of the previous. If speed improves, the layers won’t cool before the new layers come. Such different issues like printing failures and first-layer curling are likely to happen.

Sometimes 3D printing is so slow because we want it to be. Decreasing speed can highly improve print quality. Every 3D printer, no matter how it acts, makes 3D objects by creating too many layers, and it’s the nature of 3Dprinting. So it’s evident that making the whole parts take time unless the layer becomes ready super fast.

There are also a few 3D printers setting that affect speed and quality, which will be discussed in its section.

SLA/DLP

Another interesting method is to use photons to solidify liquid resins and create 3D objects. SLA and DLP 3D printers use this method and special resins to do the work. They have slight differences, but their printing principle is the same.

SLA 3D printers pass a beam of light in specific paths to make a layer, but DLP machines Scan the whole area in one moment.

This video is a good example of SLA 3D printers in practice.

We can conclude from the video that SLA printers have a few moving parts and the layers are created faster. The resin also needs less time to change phase, but it needs some post processes.

In general, SLA/DLP printers are faster and tend to become way more speedy in the future. However, they have limited input materials, and creating a metal object isn’t possible using these methods.

Other Methods

Of course, other 3D printing methods use unique principles to create 3D objects. Powder Bed Fusion (SLS), Material Jetting (DOD), Binder Jetting, and EBM are less common 3D printing methods. The main idea of creating from several layers also applies here, and these methods are relatively slow.

You see an SLS 3D printer in action in the video below.

Ways to increase 3d printing speed:

Infill Pattern/Density

Making infills was one of a few tricks that 3D printer designers used to speed up the process. 3D printing will be slow if the object is solid, even though the hollow part can be printed faster. So, the designer decided to use infill patterns with various densities (from 0 to 100 percent) to reduce printing time.

You see these infill patterns in the time-lapse video below:

Hollow prints have less strength but take less material and time. So, it’s good to have a balance in density.

Slicer softwares suggest different infill patterns that have special features. For example, a line pattern is faster to print, though it doesn’t provide high strength. On the other hand, options like honeycomb and gyroid patterns have strength as their advantage. But, they are highly detailed and need much more extruder movements.

Changing Your Design

When a 3D printer wants to print a sharp corner, it should stop each time and change direction. However, the round corner can be printed without any stop, so it’s faster to print.

Some designs have drafting angles and need a support structure to make them stable. Each layer requires a foundation to be put on. There are a few technics to reduce the support structure and printer faster.

For example, cutting a design into pieces and separately printing them can eliminate supports. Yet, these parts should be glued together. Rotating the model is another option though it’s not always possible.

Change The Nozzle

Using a larger nozzle can Increase printing speed. However, large nozzles can’t provide high-quality prints. You can see it in the form of visible layers or rougher surfaces. Having larger nozzles also results in higher heights.