Is It Worth 3D Printing Without Infill?

Infill is considered essential to FDM 3D printing with filaments. Every popular slicer offers more than a dozen standard infill patterns to choose from, and you can customize key parameters for your 3D models. But what if you don’t want to use any infill? Is it worth 3D printing without infill?

3D printing without infill isn’t worthwhile if the increased base, top, and wall thickness or the larger shell end up using the same quantity of filament and similar print time. Also, a design can’t have a flat top without infill or support. Zero infills may lead to failed prints.

That said, there are some instances when you can get away with 0% infill, especially if you have a rounded top. You may also 3D print without infill using the spiralize or vase mode in a slicer for suitable designs or models. Read on to know why it is and isn’t worth 3D printing without infill.

3D Printing Without Infill: The Good and the Bad

You are probably familiar with the different infill patterns and densities you can use for your 3D prints. Let me keep aside the potential customizations you can consider to focus solely on the viability of 3D printing without any infill at all. 

3D printing without infill is plausible, but whether or not it will work depends on the design and all the critical parameters for a specific model. There is no thumb rule here, so one can’t say that 3D printing without infill is generally or universally feasible. But it’s worthwhile at times.

The Advantages of 3D Printing Without Infill

Here are the probable advantages of 3D printing without infill:

• 3D printing times may be shorter.
• A 3D print may use less filament.
• A hollow object will likely be lighter.
• Better pliability of flexible filaments.

These advantages aren’t assured because of the pertinent variables. You may not experience these benefits of 3D printing without infill if the compensatory measures that you have to take will neutralize the filament usage, which naturally dismisses the possibility of a lighter model.

Likewise, if you use the same quantum of filament, the print time may not be significantly shorter than printing with infill. Here are the reasons why the advantages are not universally applicable:

• You have to increase the base, top, and wall thickness to make the shell of a print self-sustainable so that the object doesn’t cave in or collapse due to no infill. Your modified shell may use as much filament as a typical infill pattern with medium density.
• You will need sufficient support inside the object if the 3D model has a flat top or any other shape that requires a foundation. Some 3D printers have a bridging mode that can deposit filament in the air without support, but only for very short distances.
• If a model has a thicker shell on all sides and adequate supports inside the object, the 3D print is unlikely to be any lighter than one with a little infill. Of course, the 3D print will still have some hollow space inside, but the object may be structurally weaker.

Having mentioned the caveats, let me highlight the instances when 3D printing without infill is worthwhile: 

• You have a 3D design that is suitable for the spiralize or vase mode that doesn’t require any infill. You don’t have to 3D print a vase to use this feature. Hollow models with walls and layers gradually tapering inward or outward are likely to be viable.
• You have a large 3D design that saves a lot of filament even after increasing the wall thickness. Such a model may be horizontally large or vertically tall, or both. The increased base and top thickness are unlikely to use as much filament as infills.
• You have a 3D model with mostly external overhangs requiring a few supports. These parts of the object will have adequate support externally, so those walls won’t require the typical infill to serve as the foundation or to provide any structural base.
• You are printing with TPU or another flexible filament that won’t be as elastic or pliable if you have too much infill. However, you may not be able to 3D print without any infill if the flexible filament doesn’t have layers to build on for a hollow model.

The Disadvantages of 3D Printing Without Infill

Here are the usual disadvantages of 3D printing without infill:

• Angular and flat tops aren’t possible.
• Inward overhangs need internal support.
• Printed parts may be vulnerable to warping.
• Walls may cave in or collapse in large models.
• Weaker prints with little to no structural integrity.
• Wastage of filament if new prints continue to fail.

Even 3D printers with a bridging feature encounter issues if designs have large flat tops and overhangs or sharp angular layer addition. A nominal infill density is recommended by the likes of Prusa and others, regardless of the pattern and whether or not you use the bridging mode.

3D prints are vulnerable to layer separation and warping with infill. Imagine the lack of infill for the external walls of a 3D object, and you will be able to visualize how easily they may deform as the print progresses. Besides, the ambient condition and cooling fan can affect the print.

Any 3D print will be structurally weaker without infill. The normal functioning of the extruder fan may be sufficient to deform or warp parts of your 3D prints. Also, every new layer will contract as it cools. Zero infills may allow layers to excessively contract inward, and your print might fail.

Is It Worth 3D Printing Without Infill for Resin Printers?

SLA and other types of 3D printers using resin don’t have the typical infill features of FDM. So, you don’t really get to toggle infill patterns and densities like you can with filaments. Support structures are different. Any hollow space inside will be filled with resin unless it flows out.

If you want to have hollow parts or pockets inside a resin print, you must have drainage holes so that the liquid photopolymer can flow out during the print process. Otherwise, any trapped resin in the pockets will eventually cure during post-processing, leading to some or a lot of infills.    

Whenever you print a hollow design or one with a convex shape using a resin 3D printer, you’ll anyway need drainage holes to prevent blowouts due to cupping. The same holes will also let you have less or no infill in the hollow pockets of the object. The rest of the print will be solid.

Conclusion

It is worth 3D printing without infill only if a design saves you filament and print time. However, a print has a much greater likelihood of failing without infills. I recommend nominal infill densities for the patterns you like, which will require the least filament and the shortest time for a design.