$320 Linear Rail 3D Printer – Sapphire Pro REVIEW (Two Trees)

The Sapphire Pro from Two Trees is a Core-XY
3D printer with real linear rails for X and Y that you can currently get for around $320
dollars delivered. I tested this machine and in this video we’ll
find out how good or bad it performs at this price tag. Let’s find out more. Guten Tag everybody, I’m Stefan and welcome
to CNC Kitchen! A couple of months ago, Two Trees a Shenzhen
3D printer manufacturer reached out to me and asked me if I want to try out their new
flagship 3D printer. I usually do not tend to do a lot of 3D printer
reviews but this machine stood out due to a couple of reasons.

A coreXY is nothing new, but other similarly
prized competitors like the Ender 5 use the commonly known rollers for the axis, whereas
the Sapphire Pro uses linear rails which should give the axes more rigidity. This allows faster print moves at higher quality
and since I usually want my parts fast, this was totally what I was looking for. It also advertised silent stepper drivers
for the X and Y axis which is always a bonus. Extruder and Z-Axis unfortunately only use
good old Allegro A4988 drivers, probably to save cost. They are mounted on a Makerbase Robin Nano
32bit board and the whole system runs on 24V. The build area is advertised as 235mm in all
dimensions but as it turns out, only around 220mm are usable due to clearances. Together with a sturdy frame, a Bondtech BMG
style knock-off extruder and a 3.5” color touchscreen, this machine seemed to be a very
competitive combo for around $320 with stock also available in the EU and US to avoid trouble
and costs with customs.

So, I decided to give it a try! If you have experience with this printer then
please leave a comment down below and tell us what you think about it because my experience
may differ, since I got one of the earlier machines. Assembly was actually planned on a live stream
but that didn’t work out, fortunately. Fortunately, because this was quite a frustrating
process for me. It first started with a really bare-bones
manual that I just was able to follow, but especially the wiring is nothing for a newbie. There is an assembly video around but that
also doesn’t help that much more. The printer comes as a kit and requires roughly
around 1 to 2h to put together if everything goes well.

This includes assembling the top plate with
the linear rails and the belt system that unfortunately lacks a proper tightening mechanism. Here, I unfortunately already hit two dead
ends. At first, I noticed that the linear rails
were loose and it turned out that on further inspections the screws they used were too
long. They delivered M3x8mm screws that bottomed
out whereas M3x6mm would have been necessary. Since I couldn’t get such short screws on
short notice, I used my handy crimping tool, which is probably more designed for softer
screws to cut the bolts to length so I could continue with the assembly process. The next problem directly occured when I wanted
to screw everything down because the top plate was all bent and dented. Tightening everything down this way just resulted
in the carriages binding up, so I tried my best and used vice clamps to bent everything
back straight.

This is something that should not happen and
didn’t come from shipping because there everything was really well packed. So Two Trees, I hope you sort out this kind
of quality control problems. Also, things like a way too long Bowden tube
just complicate things for beginners. When fastening the linear rails, make sure
they are parallel because otherwise your carriages will not run smoothly.

So, I finished that, at which point I noticed
that the upper mounts for the z-axis were missing as well. Designed my own, printed them out and a couple
of hours later I was able to continue with the build. The rest of the build went smooth besides
figuring out where every plug needs to go on the mainboard. Usually I despise these corrugated plastic
hoses in which you put your wire harness, because they make your fingertips bleed when
inserting the wires. This time though I printed myself a nice,
handy tool that made the insertion process quite easily and honestly, in the end, the
printer did look very clean.

One thing that did bother me was that there
is no strain relief for the heatbed, which is kind of dangerous and I do have to print
me something as soon as possible! All right, we have come that far, so how does
it print? Well, not at all in the beginning. The reason for this is that the PID control
values for the used 50W heater cartridge were so off, that the printer overshoot the desired
temperatures by 40°C or more in the beginning and was not able to reach an equilibrium so
that the machine never started printing.

At first, I seriously waited more than 30
minutes, noting happened, only the temperatures oscillated. A connoisseur of 3D printers and a couple
of G-code commands would now advice to do auto-PID tuning with M303. Well, that didn’t work because Marlin spits
out an overtemperature warning due to the severe over-shoots. In the end I managed to reduce the first over-shoot
in the process with blowing air on the heaterblock so that the process was able to finish. After that the temperatures were still not
perfectly stable, but at least printing started at some point …. Until the machine lost
steps on the x and y axis.

Great. Well, turned out that the reference voltage
of the TMC2208 was set way too high to around 2V instead of a reasonable 0.9V. Changed that
and I was finally able start printing! I hope this is sorted out for current machines
but you never know. In order to make this review as realistic
as possible and not mod the whole thing spending again as much as the printer cost in the first
place, I tried to test it as out-of-the-box as possible. The only things I did besides reference voltage
and PID values were that I printed two new fan shrouds from PETG because the part cooling
fans are horribly underpowered in the first place and the stock shrouds spread the air
too widely.

Then there is the homing switch that just
touches the housing of the bearing and makes it really unreliable. Here I also printed a small clamp so that
I get an even surface for the switch. Last but not least I added the new PID value
in the firmware configuration file and also adjusted the stock print area parameters and
maximum speeds, accelerations and jerk because they were more than conservative and slowed
everything down. I linked the firmware files down below for
everyone who wants to install them as well.

The topic firmware is also a bit controversial,
because Two Trees only provides the precompiled binary with the configuration file. Makerbase does provide a version of Marlin
for their Robin Nano but considering the date probably not the latest release. So if you currently want to mod the firmware
of your Sapphire pro you need some tinkering, but I linked a very useful guide down below. If you by the way enjoy reviews like this,
then don’t forget to subscribe and remember to click the notification bell to not miss
any upcoming videos.

Now, when it prints, it kind of does that
very nicely. Look at those parts! I made myself a profile in PrusaSlicer that
you can also download form my website that is linked below. Due to the rigidity of the linear rails you
can go quite fast and accelerations also don’t need to be horribly low. To dampen the rattling frame, I usually have
my printer on a big slab of concrete with some foam below it. You can’t imagine how much that isolates
noise and vibrations! The parts show almost no ringing marks on
the surface, which is pretty nice.

You should only tighten the screw on the extruder
slightly because otherwise it squeezes the material to the side and together but after
a proper setup, I have to say that it does work quite well. The retraction torture test with the chainmail
did work perfectly. I didn’t have a jam or something like that
so far. The only thing is that the extruder is noisy
due to the allegro driver that it uses. Also, the spoolholder on the side does it’s
job well even though I thought it was too small in the beginning.

Unfortunately, even with the new fan shrouds,
the printer has a cooling issue what can especially be seen in some overhanging areas. This is definitely something I need to work
on in the future if I want to print fast. And now to the elephant in the room that you
might have already noticed on the previous shots. The printer unfortunately suffers from visible
z-banding or wobbles. I checked the lead screw if it was straight
and it was. I replaced the coupler for a test, didn’t
change anything. I even printed a new lead screw nut out of
IGUS polymer bearing material, which also didn’t change anything.

So that’s kind of unfortunate and might
require major upgrades either with the bearings and linear rods, or with a stepper motor that
has an integrated leadscrew. The thing is that a slight wobble is visible
on especially flat surfaces. Still, on most parts you have to look for
it to notice it. So even though it’s not very pretty, I think
this still might be okay for many because other than that, I really can’t complain
about the print quality, if anything it’s really great! The fake-tak build surface holds the parts
very well, actually even too much up to the point that you sometimes break them while
removing. This does allow it though that you can print
PLA at 30°C on it and save energy that way. I’d probably ditch the print surface and
use glass or some aftermarket flexible print plate system on it. In terms of noise level, it could be way better
that it currently is, because the printing noise itself is very low due to the TMC drivers
besides the extruder. The thing that makes it quite a bit unpleasant
is the fan of the powersupply that is clearly hearable even at minimal load and also the
30mm hotend fan is not the most pleasant.

It’s not that bad and still better than
a CR-10 for example. Still it bothers me a little when I’m working
next to it and eliminates a bit the advantage of the stepper drivers. So let’s get to the verdict. In my opinion the Two Trees Sapphire Pro is
a project and not a tool. What I mean with that is that if you’re
looking to a new printer that just works out of the box I think it’s not the right machine
for you. If it is your first printer seriously think
twice if you’re really into debugging a. Though, if you’re looking for a project
to work on and tinker with that machine then the $320 that you currently get it for is
not wasted.

The Sapphire Pro delivers a nice frame especially
with the linear rails but does require some upgrades to make it work really well. I want to mod this one that I can print really
fast but you can also get acrylic panels for the Sapphire Pro and with a proper hotend,
this might become a machine for some really technical material printing! You can always argue that you can get something
better for cheaper but I think that this package has some potential, even though it’s not
perfect. But what do you think? Leave your ideas and maybe even experience
with this printer down in the comments to help out everyone else! Full disclosure, this printer was sent to
me for free as a review unit.

No money has exchanged hands and all the opinions
are my own! Thanks for watching everyone. If you liked this review then please leave
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out the rest of my videos and my website. Thanks for watching, auf wiedersehen and good

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