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.
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.
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.
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.
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.
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.
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.
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.
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.
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.
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:
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.
If you want to know in detail how we benchmark, please continue here.
You can order the Two Trees Sapphire Pro from the following retailers:
Here you find the detailed results for the Two Trees Sapphire Pro test prints. For our benchmarking procedure, please click here.
Overall, the Two Trees Sapphire Pro scored 33.5 out of 45 points.
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.
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.
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:
Finally, we do a visual inspection.
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.
Here’s what’s getting measured.
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)
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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