In this article, we review the Prusa Pro HT90 from Czech FDM 3D printer manufacturer Prusa Research. This delta-kinematics 3D printer was the first addition to the company’s engineer-focused Prusa Pro lineup, which now includes the Prusa Pro SLX and Prusa Pro AFS.
Unveiled last year at Prusa’s Prague HQ, the HT90’s delta architecture is advertised as unlocking “ultra fast” 600 mm/s travel speeds, 250 mm/s 3D printing speeds, and 20,000 mm/s² acceleration. The system features lightweight, quick-swap printheads with a direct-drive extruder to enhance production efficiency. Its High-Temp printhead can reach temperatures up to 500°C for challenging materials. A High-Flow head is also included. This performs best at 300°C, allowing the 3D printer to deposit 1 kg of PETG or ABS in 8 hours.
According to Prusa, the HT90 is the “only 3D printer an engineer needs,” and is designed for professional users targeting applications like rapid prototyping. The 3D printer’s build chamber can heat up to 90°C, enabling compatibility with advanced filaments including PEEK, PCCF, PA11CF, PEI (ultem), PEKK-CF, PACF, PC, TPU, and TPE. A high-pressure turbine ensures rapid cooling of the build chamber following each print job, enhancing surface quality and minimizing 3D printing defects.
Although designed for professionals, the HT90’s intuitive workflow and full-color touchscreen interface ensure accessibility for anyone requiring high-performance FDM 3D printing. Its impressive precision, material compatibility, and complex design capabilities make it a strong contender in the engineering 3D printer market.
Prices for the Prusa Pro HT90 start at €11,490. Prospective customers can access more information and request a quote on the official Prusa Research website.
The PrusaPro HT90. Photos by 3D Printing Industry.
Why choose the Prusa Pro HT90?
With a Ø 300 mm (X, Y) × 400 mm (Z) build volume (28 liters), the HT90 surpasses most FDM 3D printers on the market, which typically offer less than 20 liters. This generous build volume makes the 3D printer well-suited to most use-cases, allowing users to fabricate full-sized prototypes, proof of concepts, and functional components.
Another standout feature of the HT90 is its fully enclosed build chamber, which heats up to 90°C. This creates the perfect internal environment for processing high-temperature filaments to a high standard.
Prusa’s 3D printer comes with a High-Temperature printhead, equipped with an abrasive-resistant quick-swap 0.6mm Revo nozzle capable of reaching 500°C. When paired with the system’s heated build chamber, it enables the fabrication of small-to-mid-sized parts using high-performance thermoplastics like PEEK, PEKK, PPS, PSU, PES, and Ultem. This makes the FDM 3D printer ideal for the demanding aerospace, space, and automotive industries that require high-strength and temperature resistance. The HT90’s integrated HEPA filter helps to minimize the release of harmful plastic particles created during high-temperature 3D printing, making the HT90 suitable for most indoor working environments.
A High-Flow printhead is also included. This features a quick-swap 0.4mm Revo nozzle and heats up to 300°C to deliver an impressive maximum filament flow rate of 40 mm³/s. This extruder is compatible with most common 3D printing filaments, including PLA, PETG, ASA, ABS, PA, PC, PVA, and TPU. Both printheads are lightweight, enhancing print speed and helping to maintain print quality
The Prusa Pro HT90 also stands out thanks to its delta kinematics. Unlike conventional Cartesian or CoreXY systems, which move the printhead along fixed linear axes, the delta 3D printer features three arms above the print bed that control its movement. The part remains static during 3D printing, making the HT90 particularly valuable when fabricating large components at high speeds.
Delta 3D printers typically deliver faster kinematics and travel speeds than Cartesian or CoreXY systems. They also offer superior accuracy, precision, and surface finish. Additional benefits include reduced Z-axis wobble and smoother motion for complex geometries. These advantages allow the HT90 to reach a 600 mm/s travel speed, 20,000 mm/s² acceleration, and a maximum 3D printing speed of 250 mm/s. In our extensive testing, the HT90 maintained impressive repeatability, accuracy, and precision even when operating at top speeds.
The PrusaPro HT90’s High-Temp (first image) and High-Flow printheads. Photos by 3D Printing Industry.
Accessible 3D printing for engineering applications
Setting up the HT90 is quick and straightforward, even for 3D printing beginners. Each unit arrives fully pre-assembled, requiring only the power cable and spool holder to be attached. Our unboxing and setup took just 20 minutes, with no issues encountered.
The HT90’s intuitive 7-inch full-color LCD touchscreen enhances accessibility, serving as the central hub for 3D printer operation. It allows for quick setup and effortless navigation through essential functions. With clear, step-by-step guidance, users can start printing within minutes right out of the box.
Prusa HT90 unboxing and user interface. Photos by 3D Printing Industry.
Getting the first layer of a part to adhere properly can be frustrating and expensive. This challenge is even greater for engineers using costly high-performance filaments like PEEK and Ultem, where consistency is crucial. The Prusa Pro HT90 addresses these issues with its PEI aluminum magnetic build plate and heatbed. The latter’s single aluminum tile is securely bolted to the printer’s frame, ensuring rapid heating and efficient heat dissipation.
A precise Loadcell sensor further enhances reliability by automatically calibrating the first layer. At the start of each print, the nozzle measures the distance to the build plate, calculates the offset, and applies the necessary adjustments. This automation is designed to ensure a smooth, consistent first layer every time without user intervention. Prusa HT90 also uses thermal model calibration, including PID tuning at common printing temperatures. The process takes about 12 minutes and ensures consistent temperature control.
Prusa HT90 Heated bed and buildplate. Photos by 3D Printing Industry.
Most high-performance filaments, including PEEK, PVA, PA (Nylon), and TPU, are hygroscopic, meaning they absorb moisture. Printing with damp filament degrades surface finish, weakens mechanical properties, and increases the risk of print failures.
To help mitigate these risks, our HT90 was delivered with the Prusa Pro Filament Drybox. Available for €239, Prusa’s bright orange DryBox features a fully sealed, airtight environment. Designed to hold a single 1kg spool, the device uses silica gel to continuously absorb moisture, reducing humidity inside the enclosure and keeping filaments dry for high-quality printing. Filament can be 3D printed directly from the DryBox, minimizing the risk of reabsorption before fabrication.
Our team also used a Memmert UF30 oven to dry the material. This device features a 32-liter chamber capacity and offers adjustable temperatures ranging from +20 to +300°C, making it ideal for drying hygroscopic materials. The UF30 can also be used to anneal 3D printed parts, enhancing their mechanical strength and thermal resistance for improved performance.
The Prusa DryBox and Memmert UF30 dryer. Photos by 3D Printing Industry.
PrusaPro HT90 software compatibility
Aligning with Prusa’s open-source philosophy, the HT90 is compatible with most third-party software. However, Prusa recommends using its proprietary PrusaSlicer, which includes verified material profiles for Prusament filament.
PrusaSlicer offers an intuitive, user-friendly interface. A simplified beginner mode guides newcomers through the workflow, while warning messages alert users when printing parameters need adjustment.
Users can also access remote monitoring through Prusa Connect. Remote connectivity grants access to a live camera feed, 3D printer status information, device parameters, and other settings, allowing 3D print jobs to be controlled and monitored from anywhere.
Benchmarking the Prusa Pro HT90
We conducted several benchmarking tests. These assessed how the Prusa Pro HT90 compares to other FDM 3D printers and evaluated the claims made by Prusa Research.
First, we 3D printed a clamp test file that came preloaded with the HT90. All three parts were fabricated in just 2 hours, an impressively low print time. Once assembled, the device demonstrated excellent functionality, with optimal surface quality and accuracy, representing a strong start for Prusa’s HT90.
3D printed Prusa clamp test file. Photos by 3D Printing Industry.
Repeatability is essential for engineers and industrial users fabricating batches of identical parts. To assess the HT90’s repeatability, our team 3D printed square, hexagon, and tube models 12 times each. These parts were then measured and compared against the intended dimensions. Proficient 3D printers should achieve an average deviation under 0.1 mm and a standard deviation below 0.05 mm.
Square, hexagon, and tube repeatability test prints. Photos by 3D Printing Industry.
All three shapes were within the benchmark results, highlighting the HT90’s impressive precision. The square test achieved an average deviation of 0.0983 mm and a standard deviation of 0.0155 mm. While within the desired limits, there is room for improvement, especially for the squares’ height. In fact, the average deviation for the height was found to be +0.14 mm from the reference value, negatively impacting overall results.
Our hexagon results were much stronger, with an impressive 0.017 mm average deviation and a 0.01 mm standard deviation. 3D print quality was especially noteworthy. Unlike most FDM 3D printers, the HT90 did not produce corner bulging, indicating a well-calibrated pressure advance value and extrusion multiplier.
The tubes also met our expectations, with a 0.054 mm average deviation and a 0.012 mm standard deviation. However, we observed some discrepancies. While the cylinder’s external diameter showed excellent accuracy, its height exceeded the reference value. In fact, all three geometries displayed slight over-extrusion in the Z-height. Adding a dedicated Z-height compensation tool could help address this issue.
Normal distribution results for the 3D printed tubes. Images by 3D Printing Industry.
3D printing circles often pose challenges for FDM systems, especially those with Cartesian architectures. However, thanks to delta kinematics, we did not expect the HT90 to share these shortcomings.
3D printed circular trajectory test parts. Photos by 3D Printing Industry.
To assess the HT90’s ability to print circles, we tested several models with circular sections measuring 100 mm, 65 mm, and 20 mm in diameter. The printer achieved a standard deviation mean of 0.049 mm (below the 0.05 mm benchmark) and a mean difference of 0.098 mm (under the 0.1 mm limit). While the margins were narrow, these results demonstrate the HT90’s ability to produce circles with a high level of repeatability, placing it above the FDM market average.
Prusa Pro HT90 circular trajectory results. Images by 3D Printing Industry.
Engineers wanting to 3D print complex geometries for prototypes or functional parts will likely include overhang sections in their designs. To assess the HT90’s value for these applications, we produced test parts with 6 overhangs each, increasing by five degrees from 40° to 65°.
The Prusa Pro 3D printer excelled here, achieving consistently strong results across all 5° increment changes in the X and Y axes. Defects only became prominent at the 65° overhang level, likely caused by the heat of the build chamber, which inhibited the toolhead’s cooling efficiency. However, virtually all FDM systems struggle with the 65° angle.
Our testing confirmed the system’s ability to 3D print high-quality overhangs exceeding 60° while maintaining seamless layer quality. 3D printing at 65° is possible but comes with a slight quality sacrifice. The standard overhang limit for most FDM printers is around 55°, meaning the HT90 stands out as one of the best in the industry for overhang performance.
Overhang tests 3D printed in the X (yellow) and Y axes. Photos by 3D Printing Industry.
To further validate whether the HT90 can 3D print parts without supports, we conducted a bridging test. The small bridge lengths range from 5mm to 25mm, while the larger bridges increase from 20mm to 60mm.
The HT90’s closed build chamber retains heat, which is not ideal for bridging sections that require rapid cooling to solidify and prevent drooping. As such, the 3D printer’s bridging results were below average. At 30 mm, sagging became more pronounced, with visible layer detachment. This effect worsened as the length increased. Therefore, the HT90’s effective bridging capability is limited to 25 mm.
HT90 3D printed bridging tests. Photos by 3D Printing Industry.
Prusa’s HT90 also stands out in the FDM market thanks to its substantial 400 mm Z-axis height. We conducted a tower test to determine whether the 3D printer can meet its advertised height limit.
The HT90 performed excellently here, and the 400 mm target was achieved effortlessly. Its delta configuration was particularly well suited to this test because the 3D print bed is static, meaning vibrations are minimal. Our tower model exhibited a consistently smooth surface finish and impressive layer consistency. Ringing defects, common among tall vibration-sensitive parts, were also absent.
Next, we conducted a perimeter test to validate the HT90’s Ø 300 mm diameter claims. The 3D printer again passed with flying colors. The entire Ø 300 mm diameter was achieved without any issues, with our parts showing no signs of stringing or layer shift defects. Both first and last layers were smooth, confirming the system’s optimal extrusion rate and filament flow.
We also conducted our in-house 3DPI test. This unique benchmark provides a comprehensive view of the HT90’s ability to handle intricate geometries and common 3D printer challenges.
Prusa’s HT90 offers six selectable print presets: Balanced, Precision, Speed, Super Speed, Strength, and Super Strength. For our 3DPI test, we used Precision mode and Balanced mode. The first uses a 0.1 mm layer height and is optimized for higher resolution and finer detail. Ultimately, the Precision mode model achieved an impressive score of 88.22/100, demonstrating strengths in accuracy, repeatability, ringing suppression, and flow rate.
Some limitations were found in 3D printing retraction, as evidenced by substantial stringing in the spikes section of the model. This could have been aggravated by the 0.1 mm layer height, which tends to hamper retraction. If stringing is eliminated from our calculations, the HT90 achieved a remarkable score of 96.55/100, our best 3DPI score yet.
HT90 3DPI test and results using Precision mode. Photos and images by 3D Printing Industry.
When using the 3D printer’s Balanced mode, the 3DPI test achieved a lower score of 80.89/100, which was still respectable for an FDM system. Poor retractability was again a notable issue for the HT90, with stringing evident throughout the model. Oozing was also present at the tips of the spikes, suggesting that the 3D printer’s default retraction settings are suboptimal.
Despite this, we were again impressed by the overhang sections, which maintained impressive layer consistency from 10° to 60°. Additionally, the overall surface finish was not reduced compared to the Precision mode, making this mode well-suited to those requiring a balance between faster 3D printing time and quality.
HT90 3DPI test and results using Balanced mode. Photos and images by 3D Printing Industry.
Testing 3D printer applications on the Prusa Pro HT90
The Prusa Pro HT90 is advertised as ideal for engineers and industrial users wanting to produce functional prototypes for product development and reverse engineering applications. To assess its value for prototyping, we 3D printed a swing arm designed by Surron. Although produced at an 80% scale, the part was 430 mm at its longest point, making it relatively large.
Despite its size, the HT90 completed the 3D print in under 12 hours, a fast time compared to competing devices. To accommodate the model’s size, we generated organic tree supports, which allowed us to 3D print the prototype at an angle. We were impressed by this print speed and the overall quality of the part, which featured minimal defects. The swing arm possessed impressive geometric accuracy. Additionally, support removal was seamless, thanks to the 0.2 mm interface gap between the supports and the component’s surface.
3D printed Suron swing arms prototype. Photos by 3D Printing Industry.
Next, we tasked the HT90 with fabricating a 3D printed vehicle intake manifold at 100% scale. Produced using PETG filament, this test sought to assess the HT90’s performance for rapid prototyping.
Ultimately, the part was successfully produced at the first attempt, extruding 550 grams of PETG over 17 hours. It possessed exceptionally high quality. All features were precisely defined, and no defects were visible on the main body. Organic support structures were again generated to stabilize overhanging features. This reduced the contact points on the part, accelerating support removal and minimizing surface marks.
3D printed engine intake results. Photos by 3D Printing Industry.
Users may also wish to 3D print functional prototypes using more advanced materials. Therefore, we fabricated a functional motorcycle belt cover using ABS filament. We successfully produced this part in under 12 hours. 270g of Filamentum ABS Ultrafill filament was used, while organic tree supports again minimized contact with the part’s main body. After post-processing, the final part was defect-free, confirming the HT90’s value for functional prototyping applications.
3D printed motorcycle belt cover. Photos by 3D Printing Industry.
Polyetherimide (PEI) is an advanced engineering material often used in demanding sectors like aerospace, space, defense, and automotive. An extrusion temperature above 400°C is needed to process this material, making it incompatible with many competing FDM 3D printers.
To demonstrate the HT90’s ability to fabricate parts with PEI, we produced a geared pinion model. It was fabricated with a 420°C nozzle temperature on the HT90’s High-Temp printhead. After following the dying guidelines on Prusa’s website, we achieved an exceptional result with minimal stringing and a clean surface finish.
However, Prusa does not provide specific annealing times and temperatures for use with the Memmert oven. Therefore, we conducted additional external research to determine the appropriate annealing parameters. This lack of information may pose challenges for those with minimal annealing experience.
3D printed PEI gear. Photos by 3D Printing Industry.
Finally, we assessed the HT90’s ability to 3D print parts using CarbonX PEEK+CF10, a high-performance thermoplastic reinforced with 10% high-modulus chopped carbon fiber. This combination unlocks high stiffness, strength, temperature resistance, and dimensional stability, making it ideal for demanding industrial engineering applications.
Firstly, we 3D printed a print-in-place XYZ test cube. This part was completed in just 16 minutes and featured an excellent surface finish with no defects. The internal ball component could move freely, confirming the HT90’s accuracy when processing advanced thermoplastics. Next, we 3D printed a functional starter motor turbine cover. Our first attempt failed due to poor bed adhesion. After applying Magigoo PA, we successfully fabricated the part with impressive layer consistency and no visible gaps or surface defects.
3D printed PEEK+CF10 XYZ test cube and starter motor turbine. Photos by 3D Printing Industry.
Finally, we 3D printed velocity stacks using PEEK+CF10, but the results were disappointing. Poor first-layer adhesion caused defects that prevented the formation of perfect holes, while warping further compromised the part’s integrity. Ultimately, we found that specialized adhesives are necessary to achieve optimal first-layer adhesion when 3D printing this demanding material.
3D printed PEEK+CF10 velocity stacks. Photos by 3D Printing Industry.
The Prusa Pro HT90: a delta 3D printer ideal for engineers
Prusa Research’s Prusa Pro HT90 stands out as an excellent choice within the FDM 3D printer category. Impressive 3D print speeds combine with high-temperature operation to unlock compatibility with high-performance filaments like PEEK, PEI, PEKK, PPSU, PSU, and PPS. This makes the system ideal for engineering applications. Functional prototypes, proofs-of-concept, and end-use parts can be made with ease thanks to the HT90’s automated workflow and user-friendly operation.
Thanks to its lightweight printhead and delta kinematics, the Czech-made 3D printer offers high-speed 3D printing, which allows large-scale parts to be produced quickly and efficiently. Additionally, our testing confirmed the 3D printer’s ability to consistently deliver high-quality parts with excellent dimensional, mechanical, and surface properties.
For repeatability, the mean dimensional difference across all measurements was 0.067 mm, well within the benchmark of 0.1 mm. Equally, the standard deviation for all dimensions was 0.021, comfortably below the 0.05 mm limit. The HT90 also performed well during the 3DPI tests, posting impressive scores of 88.22/100 (Precision mode) and 80.89/100 (Balanced mode). These results place the HT90 as one of the top-performing FDM 3D printers we have tested, positioning it well for the demands of industrial 3D printing.
However, our team noted some weaknesses. For instance, it features an upwards-sliding door to its heated build chamber, which extends the system’s height to 1470 mm when it is open. Although we fit the 3D printer onto a benchtop, this somewhat awkward design could pose problems for those with restricted ceiling clearance.
Additionally, the HT90 lacks sensors to detect print failures, such as filament clogging. Without user intervention, undetected errors can lead to material waste and lost time, limiting effectiveness during lights-out 3D printing. We also found that the UI would often become unresponsive when operating the build chamber to 90°C. This occurred after removing a completed part while the device was still warm, seemingly affecting the internal electronics. Prusa Research could reinforce the electronics bay with a heat-resistant shield to mitigate this.
Despite these limitations, the HT90 is a strong addition to the FDM 3D printing market. It delivers impressive material compatibility, print quality, repeatability, accuracy, and precision. This makes it an excellent choice for engineers looking to efficiently produce high-quality prototypes and functional components. Its €11,490 price tag offers good value for money, while the intuitive workflow and automated calibration make the HT90 an ideal option for 3D printing newcomers.
Technical specifications of the Prusa Pro HT90
| 3D Printing Technology | FDM (Fused Deposition Modeling) |
| 3D Print Volume | Ø 300 mm (X, Y) × 400 mm (Z), 28 liters |
| 3D Printer Dimensions | 530 mm (without the filament holder) x 530 mm x 1050 mm (1470 mm with the door opened) |
| 3D Printer Weight | 43.5 kg |
| Layer Height | 0.05-0.30 mm |
| Filament diameter | 1.75 mm |
| High Flow Hotend Max Temp | 300°C |
| High Temp Hotend Max Temp | 500°C |
| Max Print Speed | 250 mm/s |
| Max Speed | 600 mm/s |
| Acceleration | 20000 mm/s² |
| Maximum Filament Flow | 40 mm³/s (ABS and 0.8mm nozzle) |
| Operating Temperature Range | 20°C – 32°C |
| Maximal Air Humidity | 85%, non-condensing |
| Maximum Bed Temperature | 155°C |
| Maximum Chamber Temperature | Up to 90°C |
| Maximum Nozzle Temperature | 300°C/500°C |
| High Temp Print Head Materials | PEI (Ultem), PEEK, PEKK, PPSU, PSU, PPS, PES and more. |
| High Flow Print Head Materials | PLA, ASA, PETG, FLEX (TPU, TPE), ABS, PA, PC, PCCF, and more |
| Power Supply | 110V 15A/230V 10A 50/60Hz |
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Featured image shows the PrusaPro HT90. Photos by 3D Printing Industry.
