The Kingroon KP3S Pro S1…the little 3D printer that couldn’t.

Update 7/21/2023 : Kingroon has refunded me for the defective printer. I will give Kingroon kudos for their support once you get their attention. I went ahead and put the $200 refund toward their newly updated KLP1 CoreXY printer. I realize it’s newer and less tested, but I figured since I’m already down the Kingroon rabbit hole why not explore deeper. Keep watch for a review in the near future.

As you can probably tell from my profile, I’m a little bit of a 3D printing enthusiast. My wife would probably call it an obsession. Nine printers later and she might be on to something. Though, after the latest addition to the printer family, I may have found the first machine that, if I had happened to buy it as my first printer, I would have written off the entire 3D printing industry as a whole.

Meet the Kingroon KP3S Pro S1. The bane of my 3D printing existence. Every time I touch it I notice something else not quite right. At the time of this writing I’ve had it a grand total of two weeks.

Looks pretty snazzy right?

If you know anything about 3D printers a couple things jump right out. For starters, every axis has linear rails. Linear rails are supposed to be an upgrade which in some cases they are over the standard POM wheels that come with most of the sub $300 category printers. They’re more stable at higher speeds, and dang it they just look cool. In the case of this printer, they are terrible. The linear rails are supposed to be lubricated with grease. Preferably a Teflon based grease. Mine came bone dry and sounded like they were dipped in sand when moved.

The next thing that stands out in the picture is the hotend/extruder assembly. It’s direct drive and based on the E3D V6 hotend. Kingroon calls it the “Titan”. Looks and sounds like something that will blast through even the most challenging of filaments right? In reality, there is nothing “Titan” like about this direct drive assembly. It FEELS cheap. Every time I loaded filament it felt like the spring release lever for the extruder would snap in my fingers as I squeezed.

From just LOOKING at the picture this seems like it would be an awesome 3D printer for less than $300. I thought the same, and after reading reviews, and watching videos about this printer I would have gladly recommended this to any one considering it….until I actually laid my hands on it.

Assembly

Upon assembling this printer I noticed some issues right off the bat not including the lack of grease on the linear rails.

1. The Z-Axis assembly does not sit flush on the bottom of the printer, but there are 4 screws to make sure it does..sort of. It took a little finesse and a small square to make sure the z axis assembly stood perfectly perpendicular to the base. Not that it helped. More on that later. Also the screw holes were not machined properly and needed to be filed a bit for the screw head to actually fit.

2. The X-Axis was not mounted properly. After all the squaring of the z-axis assembly, when I looked at the printer straight on, the x-axis was tilted. Lower on the left and a 5mm rise to the right. Annoying, but still fixable. I had to remove the entire x-axis arm and adjust the mounting block.

3. The z-axis rod would not fit into the coupling with the stepper motor without some force. If you’ve dealt with most other printers, the coupling is big enough to just slide the z-axis rod into the coupler. The coupler on the KP3S requires you to screw in z-axis rod. Still no issue…unless you can’t screw it in all the way…like mine. The coupler was machined terribly and had burrs that would not allow you to screw it in completely. I had to dig out the burrs with a pick.

4. The z limit switch screw is to short. Since it’s to short you can never actually level the bed. I printed a small modification to put a taller cap on the screw head.

5. Even after modifying the z limit switch screw, I still had add a few washers to the bed springs to get enough height to tram the bed properly.

6. The build plate is severely warped. A flexible bed sheet is out of the question.

7. The extruder/hotend assembly was not perpendicular to the x-axis.

8. X-Axis belts were to long and not trimmed properly. Even after getting it to print at all I watched these bump into the prints when they traveled over the print. The belt was also to long making it impossible to tighten the x axis belt properly.

9. I keep getting a thermal overload producing an err1. It will be in the middle of a print and for some weird reason go into a run away pre-heating mode.

At this point in my trial and tribulations I started to wonder why in the world I was putting myself through this for a $199 printer. (Also, I know, it’s a $199 printer.) So I contacted Kingroon. In typical fashion, one email to the company a day after I received the printer detailing these issues, produced no response. So I sent another email the next day. Still no response. Fed up, and a little angry I decided to go ahead and raise a claim with PayPal. The same day I received an email to leave a review on Kingroon’s website.

That produced a response.

Their solution was to completely disregard the previous emails I sent and have me re-send them again. So, I sent the emails again.

The response from “Frank” was odd. Frank even aknowledges the issues with the printer are pretty bad. Then proceeds to offer to send a new x-axis assembly, new belts, and refund me a whopping $40 for my troubles. You would think, with all of the aforementioned issues, this would be grounds for either a complete replacement or a total refund. From Franks emails neither of those seemed to be on the table.

Needless to say, I declined and here’s why. I didn’t buy this as a “project” printer, and even a project printer shouldn’t have these types of manufacturing and QC issues. I didn’t pay $200 for the unwanted privilege of fixing their problems. For example, 5 of the printers I run for my business are under $200, minimal cost of mods included. The other 3 were roughly in the $500 range. Half of them had some quirks I needed to work out, but nothing someone who knows their way around a 3D printer would have an issue with. Loose belts, screws, bad bearings on POM wheel, etc, etc. You get the drift and kind of expect it from cheaper printers.

The KP3S Pro S1 build quality and QC on the other hand was on another level of bad (This is coming from a guy with quite a few Enders ;-) ). I did eventually get it to print, but it’s all over the place. No print is of the same quality from one to the next. I haven’t tackled the thermal runaway issue just yet so that happens randomly. Their support seems responsive, but you have to really push them. I would recommend buying via Amazon or using Paypal to protect yourself if you decide to buy one of these printers.

As of 7/20/2023 I’m waiting for a response back from “Frank”. I’ll make an update if I hear back.