Nevermore Mini - 3D Printer HEPA and Carbon Air Filtration / Scrubber with VOC sensing

NEW: Nevermore Mini - Basic Assembly (5020)

It doesn't need any complicated electronics - just connect a fan you already have (5020, 5015 or 4028) and experience filtration just as good as with all the fancy electronics and sensors! Follow along a basic Nevermore Mini assembly on YouTube! 

NEW: 5015 exhaust option available [40mm]

Upgrade a Nevermore Micro, reuse a single fan and experience 3x the airflow compared to a dual fan smaller sibling.

NEW: Mini PLUS options available [55mm and 70mm]

The difference with Plus size is it hold a lot more carbon - a regular 40mm Nevermore Mini holds about 150g of carbon. A Plus 55mm holds 300g. A Plus 70mm holds 450g, close to half a kilo of carbon while still having air flow! 

Note: These Plus size versions will not fit smaller machines like Bambu X1C, and are extrusion or magnet + metal sticker mount only!

Note 2: Earlier wire path and wire cover bugs fixed [July -24].

Introducing the Nevermore Mini: The Evolution of Compact 3D Printer Filtration

Welcome to the next generation of 3D printer air filtration presented by Nevermore 3D, pioneers in open-source community 3D printer filtration since 2019. We’re proud to announce our latest design, the Nevermore Mini, designed to redefine efficiency and airflow in the realm of compact 3D printer filtering, and that will hopefully fit any machine!

What is the Nevermore Mini?

Engineered for unparalleled performance, the Mini outclasses other filters of similar size in both capturing capacity and airflow. The Nevermore Mini is a cutting-edge filtration system incorporating both HEPA, activated carbon (and later our upcoming photocatalytic technology) to tackle volatile organic compounds (VOCs) and particles. Read more on the bottom of this page on the basis on why adding a recirculation filter to your machine is a good idea!

Build it to your own needs, a simple build with just fan and pwm control from printer/klipper; or as a USB standalone unit to easily hook up anywhere; to a pro version with screen and VOC fume sensors - the choice is yours!

How Does the Nevermore Mini Improve air flow?

Traditional small filters face challenges: noisy fans required for airflow through restrictive activated carbon and HEPA filters lead to inefficient and turbulent air movement as well as very poor air flow. 
The Nevermore Mini changes that, it’s an evolution in compact filter design, simultaneously solving three major issues:

1. HEPA Size: No longer restrictive, the HEPA filter's surface area is now a vast 8,500 mm² - dwarfing the 3,000 mm² of a similar-sized system like a Bentobox or Nevermore Micro (with hepa cartridge option). This translates to almost triple the airflow at the same fan pressure. No more just cleaning the air around the filter itself!
2. Carbon Unrestricted: The carbon filter media now wraps around the HEPA, adopting a circular shape that expands with depth. This design minimizes pressure restrictions, even as the carbon layer thickens. The Nevermore Mini boasts an outer perimeter over 17,000 mm², which is 3-7 larger than its counterparts, ensuring an equally large 3-7 times the potential airflow. A larger outer filter diameter also means slower moving air through the filter - which increase carbon dwell time - which increases filtering efficiency even further!
3. Undisturbed Air Flow: With no front restrictions and a less constrained fan design, air exits the filter at high speeds. This promotes superior chamber air mixing and significantly enhances overall filtration. A pull setup also minimizes efficiency losses common with high-speed air hitting tight restrictions, maintaining a linear and effective airflow through the filter.

In short, these improvements mark a new era in compact printer filtration. Additionally, it looks great (we think).

About the Nevermore Mini

The initial release of the Nevermore Mini represents the most versatile Nevermore version yet. This entry-point filter is compatible with a wide array of 3D printers, including but not limited to Bambu, Voron, Ratrig, Annex, Anycubic, Vzbot, Qidi and Creality printers. It's designed for versatility in installation, capable of:

• Standing or flat mount 
• Mounting on any 1515, 2020, or 3030 extrusion
• Securing to  a panel with back bolt and center 3M 30mm VHB sticker
• Attaching with magnets for metal enclosures
• Fastening with bolts through a panel

For Klipper users, all that's needed is a PWM power source (5-24V depending on the fan). For others, USB power with a manual PWM controller suffices for standalone operation.

Print files on printables, for full model in f3d format, visit Nevermore 3D on GitHub!

Questions about the build? Help figuring out how to install it in your machine, or what the different pieces do and go together? Join our discord community!

Suggested Filament & Print Settings:

• ABS/ASA or other heat-tolerant material that will put up with the repeated heat exposures from a heated bed and chamber without warping. Nevermore Mini was prototyped in ABS+.
• Supports? No. The few places where supports are necessary, theyre part of the STLs/3mfs.
• 0.2mm layer height and 0.2mm bottom layer height (needed for slicer to interpret built in tolerances (wagos, supports, etc) correctly.
• 4 walls, 15-20% infill.

Bill Of Materials:

Assumes 2-wire fan to 2-pin microfit connector, no electronics, mounted to an aluminium extrusion (1515, 2020, or 3030) with t-nuts.

For an install without extrusion mounting, like in a bambu printer, remove m3x8 bolts and t-nuts.

Thoughts on Fan Options [4028 or 5020]: 

5020: Ejects air fast, achieves best air mixing/circulation inside the chamber, but offers lower total air volume per minute (unrestricted 5 CFM).

4028: Highest airflow (>10cfm inside the filter on full), but with wider air exhaust path doesn't eject air as far.

Nevermore Mini - Basic installation [5020 fan, as 4028 just snaps in place]:

Crydteam Mini first look (german):

Crydteam Nevermore Mini Rundown (german):

Cartridge latching and door latching:

Time lapses:

Wiring schematic for advanced version with screen and VOC sensors: 

(courtesy of crydteam!)

I need more information! Why Filter 3D Printer Emissions?

3D printing with plastic filaments releases VOCs and ultrafine particles (UFPs), which can reach harmful levels without proper ventilation. These emissions are more than just unpleasant odors; they pose significant health risks:

• PLA: Generally safer, PLA still emits carcinogens, such as ethylbenzene, and irritants like methyl methacrylate.
• PETG: Known to emit carcinogenic styrene and toluene, which is linked to nervous system damage.
• ABS and ASA: Cause direct toxic/irritant effects (known as "ABS Headache"). They produce carcinogenic styrene and benzene, as well as inflammatory PAHs and butadiene, linked to cardiovascular issues like strokes and myocardial infarctions.
• Polycarbonate (PC): Releases bisphenol A, a substance known for hormonal disruption and banned in children’s products.

Not everyone can vent these pollutants outside. Standard filtered printer exhausts often fall short: Carbon filters quickly saturate due to minimal carbon quantities, and HEPA filters don't efficiently capture the major particles produced in 3D printing — UFPs. These can be 3-100 times smaller than a HEPA mesh can trap. Worse still, UFPs often exist as room-temperature liquids (e.g., styrene oil droplets) and can be absorbed by the body like medication.

Introducing the Nevermore Solution

The Nevermore Mini is a recirculating filter designed for placement inside the print chamber. It effectively traps VOCs with over 150g of activated carbon and captures UFPs electrostatically with an integrated HEPA filter. The system continuously recirculates air, ensuring pollutants missed on the first pass are filtered out subsequently.

Consider the impact: A typical exhaust might only trap 50% of VOCs, leaving the rest for you to breathe. In contrast, the Nevermore Mini, with an assumed 50% capture rate per cycle, would remove 93.7% of VOCs after four cycles, showcasing the efficacy of in-chamber recirculating filtration.

Does my carbon have to be Nevermore branded?

No, of course not. Any carbon in 4mm pellet configuration or 4x6 mesh granular will work. However, be sure to check the specifications for your brand of choice - and if they don't supply the specifications openly, ask for them or avoid the option completely.

Nevermore Carbon is made for 3D printing-specific aromatic hydrocarbon capture, is neutral, steam activated (non-acid, printer-safe) and has stellar specifications (1250m²/g capture area, at 80% CTC efficiency and up to 48% benzene adsorption by weight). We dare say its impossible to find a better 3D printing carbon, but as its custom prepared for our use case there might be cheaper bulk options for those who use larger amounts (carbon should ideally be used within a year or two).

Below is a carbon buyers guide for those who can't get hold of Nevermore, or lacks the means to support our open source community the project (5% of wholesale proceeds benefit Nevermore3D).

Picking the Right Carbon for Your 3D Printer

Choosing the optimal activated carbon for a specific task requires careful consideration of several key factors, including surface area, CTC/benzene efficiency, porosity, and pH. These properties play a crucial role in determining the effectiveness and efficiency of the activated carbon in adsorbing target contaminants!

Surface area is perhaps the most critical factor, as it directly influences the adsorption capacity of the activated carbon. A higher surface area allows for more adsorption sites, enabling the activated carbon to capture and retain a greater amount of contaminants. Activated carbons typically range from 500 to 1250 m²/g, and a carbon of 1200 m²/g would have twice the capture capacity compared to a 600 m²/g carbon. A good carbon usually has at least 1000 m²/g.
Be sure you're not getting scammed by buying 25% cheaper carbon that lasts half as long!

CTC (Carbon Tetrachloride) efficiency - or even better for 3D printing applications, aromatic hydrocarbon efficiency - is another important consideration, as it measures the activated carbon's ability to adsorb volatile organic compounds created from 3D printing. A higher CTC efficiency indicates a greater proportion of micro-pores, which are essential for capturing - and holding on to - small contaminants like airstream VOCs. Choosing an activated carbon with a CTC efficiency that matches the size of the target contaminants ensures optimal adsorption performance. A good carbon usually has at least 60% CTC.
Be sure you're not getting scammed by buying 25% cheaper carbon that captures half as much!

Porosity, which refers to the distribution of pore sizes within the activated carbon, also plays a significant role. Activated carbons, depending on quality and carbon source, will have different ratios of micro-pores (<2 nm), meso-pores (2-50 nm), and macro-pores (>50 nm). For general use, an even mix might be preferred, as they can effectively capture a broad spectrum of contaminants while allowing for efficient mass transfer and regeneration. However, for 3D printing use, a high micro- and mesoporosity is ideal to both capture VOCs (<2 nm) and VOC-agglomerates (ultra-fine particles, <50 nm), whereas macropores will struggle to hold on to VOCs in a hot application like a 3D printer's heated chamber. Good carbon types for our application are usually sourced from coconut or anthracite, as they are highly microporous, whereas other common carbons, such as bamboo or bituminous, usually have a larger percentage of macropores.
Be sure you're not getting scammed by buying 25% cheaper carbon that releases half the VOCs again!

The pH of your activated carbon should be considered, especially when dealing with pH-sensitive applications or contaminants. Activated carbons with a neutral or slightly alkaline pH are suitable for most applications, while acidic or basic activated carbons may be required for specific tasks. In order to capture any VOC type generated from any filament, a neutral carbon (capable of binding to both neutral, acidic, and alkaline VOCs) is preferred. Some users have also experienced severe printer corrosion from using acid-contaminated/treated carbon that, for some reason, got released with the heating cycles.
Be sure to buy a 3D printer-safe carbon that is steam-activated and not acid-treated/coated!

Compare carbons in a jiffy

As a general comparison number for neutral carbons, try multiplying surface area and CTC efficiency (available space * capturing efficiency):

Carbon A: 1250 m²/g * 80% CTC would be 1250 * 0.8 = 1000 (yes, this is Nevermore specs)

Carbon B: 1000 m²/g * 50% CTC would be 1000 * 0.5 = 500

This means that Carbon A can be expected to be 2x the performance, capturing more VOCs for longer.

Be sure to buy Carbon A unless it's twice the price (or if you wish to refill your cartridges twice as often - it gets tedious quickly!).