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A Gem of a Printer

2020 Two Trees Sapphire Pro Review: 10-Hour Testing

Picture of Emmett Grames
by Emmett Grames
Jan 3, 2020

The Sapphire Pro is an interesting FDM printer with a CoreXY-style setup. Read our review to see what we found after 10 hours of testing.

Two Trees, the Chinese printer manufacturer, has released a new budget-friendly machine in the form of the Sapphire Pro, an upgraded version of their previous Sapphire S.

With a print area and machine size similar to an Ender 3, the Sapphire Pro has a cube shape and makes its mark with a CoreXY belt setup. It’s advertised as fast, accurate, and reliable, with some high-tech features to boot. Selling for a price point right around $300, the Sapphire Pro is marketed to hobbyists and beginners on a midrange budget.

Some of the advertised features include linear rails on the X and Y axes, as well as a dual gear BMG Bowden extruder and a filament monitor for increased reliability. With this in mind, the Sapphire Pro seems to be quite a bargain, with features typically seen only in printers at least twice its asking price.

Let’s take a closer look to see what Two Trees is offering with their Sapphire Pro.

The Sapphire Pro review unit was kindly provided by Gearbest.

Two Trees Sapphire Pro
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Two Trees Sapphire Pro: Review the Specs

Feature Check

Image of Two Trees Sapphire Pro: Review the Specs: Feature Check
This cube of a machine is full of high-tech components (Source: All3DP)

The Sapphire Pro seems to be a very promising platform, with an impressive set of features that you wouldn’t expect to see on a printer in this price range. Let’s break down the most prominent specifications to see what this printer really offers.

CoreXY Motion System

The belt system on the Sapphire Pro is based on CoreXY kinematics (Source: Two Trees)

The Two Trees Sapphire pro features CoreXY kinematics, which theoretically allows it to print much faster than other types of printers. The reason for this is that the motors are fixed, so the “flying mass” of the print head and gantry are greatly reduced. In turn, this results in less vibrations during a print, reducing artifacts like ringing and ghosting during a print, and increasing accuracy even at higher speeds.

From our tests and observances, this system works well, even though the belts are not properly aligned (a common problem with budget CoreXY builds). Another design flaw with the kinematics is that the X-axis limit switch doesn’t have enough clearance, meaning that the ends of the belts get in the way and prevent it from triggering. This has caused us to perform multiple emergency-stops to avoid breaking the motors.

Linear Rails

The linear rails on the Sapphire Pro ensure smooth movement of the gantry and toolhead. (Source: All3DP)

The perfect pair for a CoreXY system, linear guide rails on the horizontal X and Y axes ensure smooth motion and reduced wear over time. Typically only seen on professional-grade printers, these are a welcome sight in the hobby 3D printing arena, signaling a move to higher quality builds at lower price points.

The inclusion of these high quality parts means that despite some problems with the belt path design, the printer should remain dimensionally accurate.

Robin 32-Bit Control Board with Trinamic (TMC) drivers

Under the hood of the Sapphire Pro is a Makerbase MKS 32-bit Robin Nano control board, featuring TCM2208 stepper motor drivers. The 32-bit processor on the Robin allows the Sapphire Pro to quickly and effectively run calculations and coordinate movement without missing a beat. The TMC2208 stepper motor drivers allow the printer to run quietly and smoothly, thanks to efficient and quiet power cycling and “StealthChop” functionality (a noise-reducing feature built into the TMC driver chips).

Something we noted while building the machine is that only the X and Y motors have TMC stepper drivers, while both the Z-axis and the extruder use other, presumably cheaper, stepper drivers that do not include the silent running capabilities.

Auto Levelling

The Sapphire Pro includes the ability to auto-level with a small removable sensor. A pressure-based system, the printer will probe the bed by tapping at multiple points to create a data grid, allowing the software to correct for inconsistencies. Similarly to some Delta printers where toolhead space and weight are at a premium, the sensor must be removed before printing.

BMG Dual Gear Extruder with Filament Sensor

The dual gear extruder helps increase reliability and precision during printing (Source: All3DP)

One of the other features that are new to see on hobby printers, a BMG dual gear extruder is mounted to the side of the Sapphire Pro. This system is based on popular BondTech extruders, with two gears gripping the filament, rather than a single gear and a bearing. Compared to other extruders, the BMG setup can better push filament through the Bowden tube, with much lower chances of jamming or stripping the filament thanks to the extra gripping power.

Also included is a mechanical filament sensor, which can detect if the filament runs out or breaks, pausing the print. This means that you don’t need to keep as close an eye on your filament reels, especially for long prints.

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Two Trees Sapphire Pro: Review the Specs


To get started with our Two Trees Sapphire Pro review, we printed the two torture tests on a new, freshly unboxed and unaltered machine, using PLA filament and averaged slicer settings for the ranges specified for the material.

Benchmarking Object 1: Benchy

A relatively clean print, the most apparent problem is the sagging in the tops of the doors and windows (Source: All3DP)

We used white eSun PLA+ filament. For preparing the needed G-code, we used the slicing software Cura included on the provided SD card. We set the hot-end temperature to 215 °C and the bed to 60 °C.

It took us one attempt to 3D print a Benchy.

While the details are quite well-defined, some slight z-axis inconsistencies can be spotted between layers (Source: All3DP)

We measured the physical dimensions of the print. The Sapphire Pro achieved an excellent 13 out of 15 points. The visual inspection was also good, with few issues.

  • Surfaces: The surfaces for the most part turned out very well, with little in the ways of issues.
  • Details: The details in the 3DBenchy were generally decent. Some sagging layers were present under the boat’s doors, which is a  common issue, but no loops were dropped. The letters on the base were nicely printed, evidence of the good bed adhesion.
  • Overall consistency: The overall consistency was fairly good. The only issues were some rather thick strings, and a very slight amount of wobble in the Z-axis.

Benchmarking Object 2: Kickstarter Autodesk Test

Not the worst we’ve ever seen, despite the messy stringing the dimensions are nearly spot-on (Source: All3DP)

The Autodesk Kickstarter test model looks at an FDM printer’s precision. We used the same white eSun PLA+ filament and the same temperature settings (215 / 60 °C).

The excellent fine negatives were offset by some thick stringing and bad bridges in the flow control portion of the test (Source: All3DP)

With a score of 20.5 of 30 points, the Two Trees Sapphire Pro performed well. Measuring aside, while inspecting the printer test visually, we found several problems:

  • Surfaces: Similarly to the Benchy, surfaces were not an issue for this printer.
  • Details: In vanilla-state, the Sapphire Pro did a fairly good job on the details, but could have done better. 5 out of 5 fine negative pins were removable, however the bridging was less than optimal in places. The fine flow control was lacking, as all of the spikes had thick, heavy stringing.
  • Consistency: The consistency of the Kickstarter test was very good. Overall, this printer held up to our expectations based on our first look at the hardware.

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Two Trees Sapphire Pro: Review the Specs

Benchmarking Verdict

Image of Two Trees Sapphire Pro: Review the Specs: Benchmarking Verdict
This engine block, printed in transparent orange PLA, exhibits excellent precision and detail (Source: All3DP)

While the physical dimensions of our benchmarking test prints are good, upon visual inspection of the prints we were able to find some issues, most of which we believe are related to retraction.

An additional print of an engine block (see above) turned out excellent: Even with the stock slicer settings, the supports came off easily, and details were exceptionally well defined. All things considered, we would say that the stock Two Trees Sapphire Pro seems to function well enough for even a beginner to start 3D printing, but to achieve absolute perfection you will definitely need to fiddle with the slicer settings.

Two Trees Sapphire Pro
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If you want to know in detail how we benchmark, please continue here.

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Two Trees Sapphire Pro: Review the Specs

Technical Specification

Image of Two Trees Sapphire Pro: Review the Specs: Technical Specification
The Sapphire Pro features dual turbo part cooling fans (Source: All3DP)


  • Technology: FFF
  • Year: 2019
  • Assembly: Partially assembled
  • Mechanical arrangement: CoreXY
  • Manufacturer: Two Trees


  • Build volume: 235 x 235 x 235 mm
  • Layer height: 0.1 mm
  • XYZ resolution: 0.01 mm, 0.01 mm, 0.0025 mm
  • Feeder system: Bowden
  • Extruder type: Dual Gear BMG
  • Nozzle type: J-Head
  • Nozzle size: 0.4 mm
  • Max. extruder temperature: 260 °C
  • Max. heated bed temperature: 100 °C
  • Frame: Aluminum
  • Bed leveling: Manual, Automatic (removable sensor)
  • Max. Print Speed: 300 mm/s
  • Max. Travel Speed: 1000 mm/s
  • Connectivity: USB, TF-Card
  • Build-in camera for monitoring: No
  • Average operating noise: < 60dB
  • Print recovery: No
  • Display: Touchscreen control


  • Filament diameter: 1.75 mm
  • Third-party filament: Yes
  • Filament materials: PLA, ABS, TPU, Flexible, Wood, PVA, HIPS


  • Operating system: Windows, Mac
  • Recommended Slicer: Cura


  • Assembled dimensions: 405 x 360 x 480 mm
  • Weight: 11.5 kg
  • Shipping weight: 14.0 kg

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Two Trees Sapphire Pro: Review the Specs

Where to Buy

You can order the Two Trees Sapphire Pro from the following retailers:

Two Trees Sapphire Pro
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Two Trees Sapphire Pro: Review the Specs

Benchmarking Results

Image of Two Trees Sapphire Pro: Review the Specs: Benchmarking Results
All in all, the benchmarking turned out well, but could be improved (Source: All3DP)

Here you find the detailed results for the Two Trees Sapphire Pro test prints. For our benchmarking procedure, please click here.


  1. Overall length (60 mm ±1 % tolerance): 59.82 mm, 1 point given
  2. Overall width (31 mm ±1 % tolerance): 30.7 mm, 1 point given
  3. Bridge Roof length (23 mm ±1 % tolerance): 22.9 mm, 1 point given
  4. Chimney roundness inner diameter (3 mm ±10 %): 2.7 mm, 0 points given
  5. Chimney roundness outer diameter (7 mm ± 5 % tolerance): 6.9 mm, 1 point given
  6. Vertical overall-height (48 mm ±1 % tolerance): 48.11 mm, 1 point given
  7. Box depth (9 mm ± 5 % tolerance): 9.8 mm, 0 points given
  8. Box inner length (7 mm ± 5 % tolerance): 6.99 mm, 1 point given
  9. Box outer length (10.81 ± 5 % tolerance): 10.99 mm, 1 point given
  10. Box outer width (12 mm ± 5 % tolerance): 11.95 mm, 1 point given
  11. Box inner width: (8 mm ± 5 % tolerance): 7.97 mm, 1 point given
  12. Hawsepipe inner diameter left (4 mm ±10 % tolerance): 3.97 mm, 1 point given
  13. Hawsepipe inner diameter right (4 mm ±10 % tolerance): 4 mm, 1 point given
  14. Bridge front window width (10.5 mm ±5 % tolerance): 10.39 mm, 1 point given
  15. Rear window inner diameter (9 mm ±5 % tolerance): 8.84 mm, 1 point given

Kickstarter Autodesk Test

  1. Dimensional Accuracy: 5 of 5 points (24.96, 24.91 / 19.99, 19.91 / 15.06, 14.93 / 10.1, 10.0 / 5.11, 4.9)
  2. Fine Flow Control: 2.5 points (all spires were printed, but there was a lot of stringing)
  3. Fine Negative Features: 5 points (all five pins were removable)
  4. Overhangs: 2 points (dropped loops began at the 30-degree overhang)
  5. Bridging: 1 point (all but 1 bridge contacted the surface beneath)
  6. XY Resonance: 2.5 points (no ringing detectable)
  7. Z-axis alignment: 2.5 points (layer registration effect was not visible)

Overall, the Two Trees Sapphire Pro scored 33.5 out of 45 points.

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Two Trees Sapphire Pro: Review the Specs

How We Benchmark

For the benchmarking element of our review, we use the following guidelines:

Unbox the printer: We unbox the printer and assemble it according to the manufacturer’s instructions. Deficiencies and errors are noted and build around according to the consensus online for the printer.

Filament: We use white eSun PLA+ filament. Temperature settings are 215 °C for the nozzle and 60 °C for the bed.

Printing: We print two test models — Benchy and the Kickstarter x Autodesk FDM 3D Printer Assessment — using the manufacturer-provided/recommended slicer and settings. If the printer ships without a dedicated slicer and profile, we generate a generic Cura profile using the essential information of the printer.

After the first print, we inspect the object for easily fixable problems (i.e., a loose belt or a poorly leveled print bed) and then print again. If the printer can’t provide a decent result after three attempts, we stop. Printers that fail to produce a test object receive zero points for the respective test object.

1. Benchy

The Benchy 3D printer torture test is one of the world’s most popular prints. It helps to measure the dimensional accuracy capabilities of your printer and helps highlight other visible print nastiness.

We measure our best Benchy print using digital calipers, scoring 15 criteria against their target value. A total of 15 points are available.

  1. Overall length: 60 mm
  2. Overall width: 31 mm
  3. Bridge Roof length: 23 mm
  4. Chimney roundness inner diameter: 3 mm
  5. Chimney roundness outer diameter: 7 mm
  6. Vertical overall-height: 48 mm
  7. Box depth: 9 mm
  8. Box inner length: 7 mm
  9. Box outer length: 10.81
  10. Box outer width: 12 mm
  11. Box inner width: 9 mm
  12. Hawsepipe inner diameter left: 4 mm
  13. Hawsepipe inner diameter right: 4 mm
  14. Bridge front window width: 10.5 mm
  15. Rear window inner diameter: 9 mm

To accommodate the difficulty and inaccuracies when measuring small features, we have implemented a sliding scale of tolerance in our scoring. The smaller the feature, the greater our allowance for deviation:

  • 60 mm to 23 mm: 1 percent tolerance allowed
  • 23 mm to 7 mm: 5 percent tolerance allowed
  • 7 mm to 0 mm: 10 percent tolerance allowed

Finally, we do a visual inspection.

2. Kickstarter x Autodesk FDM 3D Printer Assessment

The Kickstarter x Autodesk print exposes an FDM printer’s precision via six distinct tests in one object.

By pushing a printer’s hardware and software the system to the point of failure, the print reliably visible imperfections that can be used to assess the performance of the slicer, the extruder, and the motion system together.

The Kickstarter Autodesk test 3D printer test (image: Kickstarter)

Here’s what’s getting measured.

  • Dimensional Accuracy
  • Fine Flow Control
  • Fine Negative Features
  • Overhangs
  • Bridging
  • XY Resonance
  • Z-axis alignment

The tolerances and measurements are very detailed. You can find the exact measuring procedure on Github. The highest possible score is 30, indicating a very well-calibrated system.

It’s worth noting that these benchmarking tests are not a definitive measure of a printer’s worth. More an indication of a printer’s state out of the box with no-tinkering, it’s only after a full evaluation and in-depth review that we fully judge a 3D printer.

(Lead image source: Two Trees)

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License: The text of "2020 Two Trees Sapphire Pro Review: 10-Hour Testing" by All3DP is licensed under a Creative Commons Attribution 4.0 International License.

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