Anycubic Kobra S1 Combo review: Excellent when it works, frustrating when it doesn't

Anycubic's latest fully enclosed Core XY construction 3D printer is the Kobra S1 Combo, and as soon as it was announced, I just knew I had to get my hands on one. Unfortunately, the rose-tinted glasses soon faded once I started to receive error messages galore from this printer, and several hours and part replacements later, it still isn't working, and I've sadly given up on it.

I expected that the Anycubic Kobra S1 Combo would be one of the best 3D printers on the market, especially at its competitive price point. A lot of creatives are excited by a new entry to the 4+ colour 3D printing market, and the S1 Combo has immense potential to take on more premium rivals from the likes of Bambu Lab, Creality, and Elegoo in this space.

Despite my frustrations with this printer (I really am at my wits' end with it), it's not all doom and gloom, as the first week or two that I spent with the S1 Combo showed me its true power. It was fast, quiet, and produced exceptional quality prints. I plan to dive into both the good and the bad sides of the Kobra S1 Combo during this review, with a focus on its performance overall. I've asked Anycubic if a repair or replacement unit can be delivered, and I'll happily update this review accordingly if/when that happens.

Key Specs

Price

The Anycubic Kobra S1 Combo has a retail price of $749 / £749, although we do occasionally see this printer drop to around $599 / £549 during promotional sales periods. I think this is a very reasonable price to pay for a printer with this kind of spec sheet, and is half the price in comparison with direct competitors like the Bambu Lab X1 Carbon (which retails for $1,449 / £1,439).

The Kobra S1 printer on its own, and not as a combo with the ACE Pro, can be had for £549 / $549, though at the time of writing, the printer is only $399 / £349 for a limited time, which is excellent value and a great choice for those who already own the Anycubic Kobra 3 Combo with an ACE Pro unit.

Keep in mind that if you order the Kobra S1 without the ACE Pro and not as a bundle, then you will need to purchase a separate adapter that allows you to use the printer with an ACE machine that you already own.

Unboxing and setup

The setup process for the Anycubic Kobra S1 Combo was relatively straightforward. You just need to remove the excess packaging, unscrew a few bolts, and you're good to go. The ACE Pro fits nicely inside the S1 printer during transport, so there's only one large box you need to worry about.

Be aware that the combined package is super heavy, even without any filament spools loaded into the ACE Pro. I was a little concerned that the printer with the ACE chamber on top might be too heavy for my chest of drawers to handle, but it seems to hold up just fine.

The Kobra S1 comes with all of the tools, screws, bits, and bobs that you need to set up your machine, including a USB drive and activated carbn filter. I think the setup process took me around 45 minutes in total (but I was taking my time).

Design

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The Anycubic Kobra S1 Combo looks extremely premium, and I love that the lid on top of the printer is see-through and removable so you can watch your printer in action. This obviously depends on where you choose to place your ACE Pro unit, which can sit nicely on top of the printer, or off to the side of the machine since the teflon tubes are long enough to allow reach.

One design aspect that I wasn't too keen on with the S1 is that the "poop shute", effectively a term for the area that discarded filament waste is flung out of the printer, is situated on the very back of the machine, and not off to the side like it is with the Kobra 3 Combo. This might not be an issue for everybody, but the awkward placement does mean that you can't have the printer flush against the back of a wall, and in my case, I had to place boxes behind my printer to prevent waste falling into my radiator. Not ideal.

Performance

Now, onto the performance of the Anycubic Kobra S1 Combo. Everything started off perfectly. After initially setting up my printer, I was able to print a Flexi Rex with no issues, and the result was a great-quality print without any bed levelling or z-offset tweaking needed. I printed mostly with PLA for the first few weeks, but when using ABS, I ran into problems (more on this later).

The ACE Pro is an excellent invention, doubling as an automated material system for the Kobra S1 and a filament dryer all-in-one. The drying system can be a bit loud, but you can easily turn it off when you need and restart it at a later time. It sometimes had some trouble feeding the filament automatically and wouldn't detect that I had placed anything into the slot, but you can get used to this with patience.

When put into Quiet Printing Mode, the Kobra S1 itself is super quiet. You can still hear the occasional mechanical whirring noise, but the fan sounds are virtually muted when the door to the printer is closed, which is great considering that my printer is in the same room as my work-from-home office, and did not interfere with any meetings or video calls.

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The S1 comes with a built-in AI camera, and this can remotely connect to the Anycubic App so you can check on your print no matter where you are. I found this extremely helpful on days where I was away from home and in the office, although I found that on several occasions the print would pause itself and refuse to continue - only to get home and find that the only issue was a strand of filament getting trapped under a spool, something I could have fixed in seconds had I been near the printer.

Not every flaw is detected by the AI camera though, and sometimes spaghetti prints will fly under the radar, like this Flexi Charizard print (designed by IXPatch) that failed thanks to the prime tower getting knocked over. By some miracle, I was able to save the 31-hour print by cutting off the spaghetti mess with scissors and a bit of sanding. I also had a ton of clogging during this print that I luckily noticed in the early stages, and I think this was down to a poorly fitted poop (filament waste) slide that I attached to the back of the printer.

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Speaking of filament waste, I discovered that there is a way to control how much waste is generated with each print by heading into the Ace Pro settings during a print, and dialing the flush volume up or down. This helpped significantly with reducing the amount of printer poop, though be careful that you don't have it set too low or else you'll notice colour bleeding like I did with my Flexi Charmander prints.

Before getting hands-on with the S1 Combo, I had only ever used the Anycubic Kobra 2, which was the first 3D printer that I purchased. I have had very minimal issues with the Kobra 2, and it has been an excellent beginner tool for learning the craft – but the quality difference with the Kobra S1 is astounding.

Not only are the prints near-flawless with no stringing, smooth finishes and minimal overhang, but the multicolour capability is professional-tier. Take a look at some of the sample prints below ( I only got around to printing a handful) to see what I mean.

Sample Prints

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As you can see from the images above, the multicolour print quality and level of detail produced by the Anycubic Kobra S1 Combo is phenomenal.

Errors and troubleshooting

We've arrived at the negative part of this review, where I talk about all of the issues I've had with the Anycubic Kobra S1 Combo since getting my hands on it back in January, and the errors that have eventually led to its death.

The very first problem I experienced with the S1 Combo was a loose tube at the back of the printer that would always pop out of place and prevent the filament from feeding correctly from the ACE Pro unit. I got in touch with Anycubic support, who were fantastic and sent me out a replacement filament hub swiftly. Problem solved.

The next issue, however, was a bit more complicated. I started to print a Deadpool HueForge bookmark, and one of the 4 filaments I was using in the ACE Pro happened to be ABS, and this got clogged in my nozzle. Whenever the printer detects an issue, it will display a QR code on the touch screen with instructions on how to fix the specific problem, which is a super helpful function.

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After taking apart the entire extruder with an allen key, based on Anycubic's instruction, and removing the stuck material from the hotend, something sparked and I saw a brief flash. From this point onward, the Kobra S1 would heat up entirely on its own every time I started the printer, reaching 340-degree temps at an alarmingly fast rate with a little bit of smoke. The printer would then shut itself down. Anyubic sent me a new hotend after I informed them of the issue, but this didn't solve the problem.

In short, I had to put in yet another part request after troubleshooting the problem, and the company sent me a new print head board, which I successfully managed to install (and it wasn't easy). The printer was no longer heating up on its own – problem solved, or so I thought. Now, I was getting retraction abnormal error messages.

When loading the filament from the ACE pro to the printer, the material would get as far as the extruder, and then it would seem like it couldn't go any further, and you could hear it straining on the ACE, almost like a grinding sound. I took the printer apart again and checked that there were no blockages in the extruder path, and that the pendulum and spring of the material break detection board were in the correct position (they weren't). After fixing this, the filament loaded fine but I got yet another error message for 'Unknown feed location for not multi-colour model'.

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You can probably guess what I did next. I took the printer apart (this will be the fifth time), and according to Anycubic, I need another part replacement. This time for a material break detection board. Hopefully, you can feel my frustration through this paragraph, but if it's not coming across, I was pretty ticked off by this point and the thought of spending another almost-hour taking apart the printer or waiting a week for a part replacement filled me with dread. I officially quit.

On another note - I understand that all 3D printers require maintenance and part replacements as time goes on, but this all happened in the space of 3 weeks. A lot of this disassembling was actually quite advanced too (I'm amazed I managed to do it in all honesty), and it strikes me as odd that Anycubic has so much trust in its customers to repair these machines themselves rather than offering a more reliable repair service.

Buy it if

• You want an affordable multicolour 3D printer
• You have the desk space for a larger machine + AMS
• You're looking to make high-quality multicolour prints

Don't buy it if

• You don't have a suitable space to store it safely
• You don't have the patience for longer print jobs
• You aren't comfortable with material wasted from flushing