Sunlu S8 Pro Review

Full review of the Sunlu S8 Pro 3D printer

Sunlu, filament, but not only...

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All makers know the Sunlu brand for their filaments. But Sunlu has also been offering printers for a few months. There was the S8 and here is the S8 Pro !

We are going to take a tour of the owner during this review and see if Sunlu can hold its own in this market that has become very competitive.


First of all, I can tell you that the cardboard weighs its weight! More than 14 kg on the scale, my postman will remember! …And no, still no lead to ballast the packages ^^

It's just that Sunlu decided to make it heavy, beefy, in a word… robust.

Once the box is opened, we see the beast. It's compact and tidy.

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We already note that everything seems pre-assembled, and that there is a small 200 g PLA reel.
… And that the axis of the spool holder is rikiki in width :-/

Sunlu provides the usual tools, and maybe even a little more. In particular a set of 5 Allen keys and a needle to unclog the nozzles. The Micro SD (8 GB) is from the SanDisk brand , it's rare enough to be reported! There is also a spare tirefit and nozzle (0.4).

The assembly guide in the form of a leaflet is clear and full color.

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Once out of the box this is what it looks like:

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The Z axis rods are pre-greased, delicate attention ^^


The assembly step is very simple. 

  • 6 screws for the printer boby
  • 4 screws for the spool holder

There it is! It's ready !!   

All the connections are already made! Motors, end-stops, filament detector… There is even hot glue on some connectors to secure them.

I invite you to see the video of the assembly on the youtube channel of Nozzle:

Small reminder again here, be sure of the setting concerning the power of the sector: 115 or 220!

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The specifications

Here we are in the presence of a printer with enticing specifications for this price.

  • Volume 310 x 310 x 400
  • Type Bowden
  • MK8 all metal extruder
  • 360W (24v) power supply
  • Double Axe Z
  • Filament detector
  • Recovery in the event of a power outage
  • Magnetic plate (buildtak type but with polycarbonate) 0-100°C

Well, at first glance, nothing transcendent these days. However, everything is made of metal, which gives an impression of reassuring robustness and a final weight of 12 kg ^^ And Sunlu didn't leave any small flaws that complicated our life a little on this type of configuration.

  • The X and Y axes are equipped with belt tensioner
  • The filament guide is compact and smart!
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  • The SD card is not inserted upside down… Well done! 
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  • There is a led that lights up under the nozzle
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The mains socket is hidden under the front tray (the on/off switch is right next to it). At the same time, all the electronics are in front, but fortunately this socket is not on the side, appreciable space saving given the size of the base (600x490x600mm)…

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A small easily correctable defect remained. The tray's power cable rubs quite a bit on the 20×20 bar at the back. I just added a little rubber band to keep it elevated and prevent the sheath from wearing out prematurely. On the other hand, there is indeed a reinforcement piece which secures the connectors of the tray.

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This is the only hardware modification I made, I think it can still be considered “stock” for testing…  

Finally, the screen is tiny and “old-fashioned” with a scroll wheel. But he does the job and the firmware is pretty well done (we'll talk about it later) so it's not a problem. 

And once plugged into a Raspberry, the printer screens become secondary and are almost only used for babysteps…

And the noise in all this?

Well, Sunlu made an effort. The printer is silent, whether at the level of the drivers or the fans.

At rest, the beast measures only 53 decibels.

In operation, the sound rises to 60 decibels, which classifies it in the printers effectively silent. We are far from the fighter planes that some manufacturers still serve us… Bravo Sunlu!

Let's move on to the test prints!

Direct, I print the first file present on the SD card with the supplied PLA spool.

The print comes out clean without any prior modification of the settings. This is often the case with these test files provided by manufacturers. Note that no filament came out of the nozzle at the first heating (also checked with the needle), which means that the machine was probably not tested in printing condition before packaging. Not well… or Sunlu's overconfidence ^^

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I zapped the 2nd file rather ugly and without really technical or aesthetic interest. I'm moving on to more serious things.

Come on, the obligatory Benchy to get a quick idea of ​​the print qualities.

I used a profile of CR10s Pro on my slicer (PrusaSlicer), because the machines seem “physically” very close to me.

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Seems like a good choice, the Benchy comes out well, no flaws, the bridges are decent, the ventilation seems efficient, and the dimensional accuracy is on point.

There is just a little angel wire, maybe too hot (205 deg) or retraction to adjust. I also foresee a slight over-extrusion. We will confirm all this with the following impression.

We pass the torture test!

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So I'm pleasantly surprised. 

I always have a bit of angel wire (200 deg) on ​​the upper part, but it's almost unavoidable on this type of extreme exercise. 

The rest printed perfectly!

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The bridges are clean. First slight burrs at 80 degrees of inclination!

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For the tolerance, the cylinders are removed without forcing up to 0.3, it is quite correct. The 0.2 is achievable with a printer set to small onions while the 0.1 remains a chimera for non-professional machines.

The machine is therefore doing very well on this demanding part.

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Let's test a slightly bigger piece to see how it behaves on the height...

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Well, the 32 cm vase printed without difficulty. The magnetic bed sticks perfectly, it is really good quality (I will come back to this point at the end of the review).

I notice again a slight under-extrusion. I therefore decide to correct the problem, which will allow me to tell you about the firmware of the machine.

The Firmware

The firmware offered by Sunlu is based on Marlin. It is simple and effective. It allows you to make all the settings of the machine without a computer (steps, jerk, acceleration, etc.).

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 The leveling of the plate is carried out in a very simple way on the four corners of the plate (hey, they forgot the center?). Then the babystepping is set during the start of printing and is automatically saved. Little info, do not touch the Z-offset during the first leveling procedure, you have to leave it at 0.00 and act with the wheels on the board because it does not register. In fact it is the babystep which acts as z-offset and is recorded. Not academic but it works ^^.

The only major defect of this firmware is that it cannot be found (!) on the Sunlu site or on the supplied SD card. I hope this point will be corrected soon. 

Power failure resume

Resuming printing in the event of a power outage works very well. 

Scenario: Printing was going well. And there, it is the drama…
“Ha ben naaannnn!!! there's no more juice!… “:'-(
Don't panic, the outage didn't last too long… the printer turns on again:

A print resume screen appears. Phew!

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Except that the plate does not remain at the last temperature before the cut. Shame…

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As long as we have not selected 'resume print' the temperature of the bed goes down again...

When selecting 'Resume print' the heating of the bed and the nozzle restarts.

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…then printing resumes where it was before the power cut.

Filament detector and filament change

To test the “filament break detection” (that sounds more classy in English, huh…?), I cut the wire just before entering the detector.

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As soon as the wire comes out of the detector, the printer signals the problem with a series of beeps, and positions the head at 0,0 …

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…displays a message prompting us to insert filament. Well, you have to think about removing the wire remaining in the PTFE beforehand^^

 Insert the filament fully and press the button. The printer is purging

If the purge is suitable, select 'Continue' and printing resumes where it left off.

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The purge leaves us with a nice little filament pad in the corner of the printer.

It's exactly the same process for a programmed color change during printing, except that we don't lose the length of the bowden...

Note that the length of withdrawal and reinsertion of the filament in this sequence can be configured on the screen, it is very practical. It is 100 mm by default. 

The MK8 extruder

Ha, this good old all-metal MK8… It has already proven itself but also shown its limits. 

Right out of the box, the dimensional accuracy (x,y,z) of the prints was there.

As we saw above, there was just a slight under-extrusion which will disappear with adjustment of steps/mm (firmware) and bitrate (slicer)

     Modification E-steps/mm

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Changing the rate   

This done, I run a longer print (over 9h) to make sure the extruder wheels aren't too tight and eat up the filament.

Conclusive impressions in PETG. This allowed me at the same time to ensure the stability of the temperatures of the plate and the nozzle. I didn't even need to fix the PIDs. 

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PID settings also accessible directly from the screen. Flawless ^^

So everything was going well until I started on a TPU print…

I only had relatively soft TPU in stock, which accentuates the difficulties in bowden and with this type of extruder. And despite my stubbornness (about twenty attempts with different spring settings and retraction parameters) I did not manage to get a complete part out before the extruder damaged the wire or the latter wound up in the MK8…

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All this could be arranged with the printing of an ad hoc part for the extruder,

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 and a replacement of the PTFE by a Capricorn, but here we are testing a “stock” machine and for me it is a failure on the TPU…

What about this magnetic platter then?

I had no problems with adhesion with this magnetic bed, whether with PLA, PETG or TPU. It looks like buildtak but more effective… It is very pleasant to use and sticks well to the magnet of the board. Sunlu indicates a maximum temperature of 100°C, avoid going beyond this at the risk of demagnetizing the magnet. The bed is "PC coated", i.e. it is coated with a polycarbonate film to facilitate adhesion

Another well-thought-out detail, and I didn't notice it right away, is the positioning aid for the magnetic bed. Let me explain: With a "normal" bed, you have to be careful to position it correctly at the bottom of the tray and make sure that when you put it down it doesn't go askew and protrude on one of the sides... otherwise you reposition delicately and we start again...

There, there must be complementary or stronger magnets at the corners because when you get closer to the board the bed is automatically attracted right into the corners, it's very clever and super practical, all you have to do is "let fall” the coating which is then positioned correctly.


In summary, the giant Sunlu, young Padawan of the 3D printer has succeeded in producing a robust and well thought out machine at a contained price despite the volume offered. The firmware is clean and without bugs encountered during my tests. They have thought of the user and include a whole bunch of small details to make their life easier. It is very easy to assemble and use, so it can be intended for beginners as well as experienced makers looking for volume and reliability on a tight budget. 

  • All metal
  • Belt tensioners
  • Filament Guide
  • Management Cable
  • No socket for a USB key
  • No auto-leveling
  • Platter springs too soft
  • the MK8??

The little extra LZP

To really significantly and inexpensively improve this beautiful machine, here is what should be upgraded at a minimum:

  • The MK8 by a BMG type extruder (clone or Bondtech)
  • PTFE by a Capricorn or a Triangle Lab (red) here

I would like to thank and Sunlu who allowed me to test this printer and I hope to see you again very soon for new reviews. Don't hesitate to visit my TikTok channel ( ) and comment on my videos, I'd be happy to chat with you!

Article by Luke Ze Printer for

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