Compared to its competitors, the Original Prusa Mini has many features that are otherwise not included in 3D printers of a similar price point. The Prusa Mini+ includes a removable magnetic build plate, automated bed levelling, 3-to-1 geared extruder, all-metal hotend, trinamic 2209 silent stepper drivers on a custom 32-bit buddy electronics board, and a color LCD screen. There is also an optional filament runout sensor for $20 USD. Though we did not purchase the sensor for this review, it is a useful feature as it pauses the print to add new filament instead of cutting off the print process, which requires a complete restart.
On their website, Prusa Research has mentioned software updates, including remote 3D printing via the internet and power loss recovery. These features have not been implemented as of the writing of this article but will likely be included in future upgrades.
Customizable Build Plate
The Original Prusa Mini+ offers three kinds of build plates at the time of this review. The choices include smooth PEI, textured PEI, and satin PEI. All of them are mounted on flexible spring steel sheets, which makes it easy to remove prints once they are completed. In general, PEI is a great material as it provides effective adhesion to filament when heated.
Smooth PEI is designed for PLA and ABS and gives the bottom of the print a smooth glossy finish. With that said, it is not recommended for PETG and TPU because those two materials stick to the smooth PEI too much, which may lead to ripping when the print is removed from the smooth PEI spring steel sheet.
Textured PEI is suitable for PETG and TPU filament and gives the bottom of the spring a slightly rough texture. In contrast to the smooth PEI, textured PEI is not recommended for PLA since the surface does not have adequate adhesion for heated PLA. The worst case is that a PLA print can detach from the build plate, which would ruin the entire print.
For those who wish to print using a wide variety of materials, the new satin PEI steel sheet is a perfect middle ground for most filament types. It provides effective adhesion to all filaments and a very fine texture on the bottom surface of the print.
On a personal note, the team at 3DGearZone prefers having specialized PEI spring steel sheets suited for different types of filament instead of one that is adequate for general use. However, this option may be more expensive as each build plate costs around $40 USD. For those on a tight budget, we recommend getting the satin PEI since it performs well with most materials.
Automatic Bed Leveling
Manual adjustment of the bed level often leads to unreliable coordinates since it completely depends on the user’s accuracy. The Pusa Mini+ has an automatic levelling feature which avoids running into this issue. The bed leveling process is operated by a probe that records the measurement at various points of the bed to ensure the accuracy of a flat surface and its accuracy. This allows the 3D printer to provide reliable adhesion to the print since it has even contact with the bed surface.
Compared to the original Prusa Mini, the Mini+ upgraded the probe into a superPINDA probe. The original PINDA probe was reviewed for inaccuracies caused by the bed’s temperature. The newly improved superPINDA probe includes a temperature sensor that adjusts for the bed’s temperature, making levelling more accurate.
Extruder and Hotend
Having a 3-to-1 drive gear ratio extruder means there is three times the pushing force (torque) feeding filament into the hotend, compared to a single gear extruder. This allows for a quicker 3D printing process, especially with TPU, which can be printed up to 40mm per second.
Compared to the Mini+ with an all-metal hotend, most inexpensive 3D printers only have hotends lined with PTFE (polytetrafluoroethylene). PTFE hotends limit the printing temperature to around 245-250°C since the plastic rapidly degrades and releases toxic fumes if heated to a higher temperature. Due to the incapability to print at higher temperatures, printers with a PTFE hotend limit them from working with more exotic materials such as polycarbonate and nylon.
With the Mini+’s all metal hotend, it would not be an issue to print at high temperatures surpassing 250 degrees celsius, as the metal lining can be heated up to 280°C.
Online Features
The Mini+ has built-in ethernet connections that let users view its print status online by searching the IP address of the 3D printer on any web browser. The information displayed includes the ongoing print file, time remaining, and 3D printer temperature. Prusa has announced they will add a new feature that allows users to start and stop 3D printing on the site; however, this has not been implemented yet.
Software Upgrades
The first thing to note about software upgrades is that the control board features a tab that must be broken if users want to install a custom firmware update. Breaking this tab would void its warranty, so we do not recommend doing so unless you are sure the warranty won’t be used.
Physical upgrades for the Mini+ are unnecessary since the 3D printer base is already well built and includes many useful features. Prusa itself is also not very upgrade-friendly as it lacks first-party mods due to warranty issues. But for those interested, the industry offers many third-party replacement parts. Benefitting from its popularity, several companies offer parts compatible with the Original Prusa Mini+, including Matterhackers, Bondtech, Spool3D, and Digitmakers (add hyperlink). For example, the extruder can be upgraded to ones produced by Bondtech, which reduces under-extrusion reported on the original Mini+ extruder.