REVIEW: Sunhokey Improved Prusa i3 3D printer

Link to webpage of kit

I purchased this printer kit after the Melzi electronics board that ran my old Mendel 3D printer died. For the price ($255 including shipping), I figured that it was worth a gamble. So, first...

Unpacking: The box that the kit comes in is a work of art in that there are separate compartments for major components (motors, leadscrews and steel rods, electronics, etc) and each compartment has a foam lid that fits in tightly to keep everything where it goes during shipping.

Instructions? Does it come with instructions, you ask? What would YOU do if you were in Hong Kong, shipping printer kits all over the world? That's right! When you open the box, on top of the pieces-parts, there is a DVD, which in a folder labeled 'Videos' has 13 videos that walk you thru the assembly process. For example, the first video starts with 5 or 6 pieces of acrylic sitting on the assembly bench. The guy then pics up each one and shows it to the camera, and then he gets to work. The first video even demonstrates peeling the protective film off of the parts, just in case you didn't know to When screws, nuts, etc, are called for, they are displayed on the screen: 'M3 x 16mm 5, M3 Nut 5' or something to that effect. He physically assembles each piece in front of the camera, and indicates very clearly if there is a specific orientation for a given part. The video assembly sequence is performed using the tools that come in the kit. I did mention that it comes with tools, right?
First assembly, assembled:

Note on the sticky-outy piece: a thumbwheel for adjusting Z-axis zero!

Assembly is pretty straightforward using the videos, the only hiccups are late in the process where mounting the electronic board to the side of the frame is not shown. This is not a difficult process to figure out on your own, so that doesn't really irk me. The acrylic is lasercut and fits together marvelously. Mounting the extruder is a little tricky and would benefit from some captive nuts. I made do with masking tape holding the nuts until the threads caught. The video had a second person helping in that stage, but I was not about to wake the wife over a minor issue The wiring video moves a little quick for my taste, but conveniently on the top-level directory of the DVD is a wiring diagram which was VERY easy to follow and most useful. NO programming is required for the electronics board (which Sunhokey says is 'RAMPS-compatible' altho I have not tested this. It worked well out of the box, though.).
BELOW: The assembled i3. The blue thing on the print bed is a surgical cloth which acts as a blanket for the bed, allowing it to heat faster. You can also see the spool of ABS sitting on the included ball-bearing rack. Very nice touch.


The kit comes with masking tape to put on the printbed (which is heated); this is fine if you are printing in PLA, but not so good for ABS. So I used Kapton tape which has proven itself to me many times over the years.

-continued-

 

Below: The Y-axis belt adjustment mechanism. Left loosey, righty-tighty.

Below: The X-cariage with the hot end visible... The bright red light is the X-axis endstop, lit up to indicate it is at zero.

Below: close-up of one of the vertical leadscrews. No cheapy threaded rod here! Also, a nice long linear bearing to keep everything aligned as it moves up and down. Visible behind the acrylic is the silver box of the power supply. Out of sight in this pic (on the far end of the X-axis) is the thumbwheel for adjusting X-axis belt tension.


Commissioning was simplicity itself relative to the Mendel and the Ormerod 2. Download Repetier-Host to run the thing, and it'll come with Slic3r to do slicing. Repetier-Host has gotten light-years better since I tried it (and dropped it) two years ago. Intuitive and no drama. plug the printer in to your choice of USB ports on the PC, and the drivers load themselves onto the PC. Fire up Repetier-Host, and take the time to enter the appropriate settings (bed size, max height, filament diameter, etc). Also take the time to do the configuration within Slic3r. But this is pretty elementary stuff and easily accomplished.

First prints: Calibration shapes are obviously the order of the day; I had a few messy stringy sculture looking pieces until I got the settings correct (bumped the extrusion multiplier by an extra 10% to put out a little more plastic than it would otherwise), and then printed my old nemesis that I never got right on the Mendel... a calibration pieces that is a square with a circular hole in the middle sized to just barely fit a nickel. And it was most triumphant on the first print! Nickel slides right into place, no wiggling. I did my calibration prints in ABS because the only rolls of PLA that I have are buried in the back room under Christmas presents and the corpse of my Ormerod2, whereas the printer came with two rolls of ABS (you can specify color and type of plastic (PLA or ABS) when you order the kit.
Below (and uncropped ) is the nickel calibration piece. The squiggly lines are a brim to help avoid peeling.


Things I like about this kit:
-Thumbscrews to adjust all belt tensions and axis zero points. Also for bed leveling. Holy crap, this is so awesome compared to hunting for allen wrenches...
-Price! ($255 including shipping from China is a ridiculous bargain)(It got here in a week)
-Ease of assembly (hard to go wrong with lasercut parts and an assembly video)
-All-metal preassembled extruder. It's spring-loaded and sturdy. Love it.
-Heated printbed heats up quickly using the PSU that came with the kit. No idea what the rating on it is, but it's about the same as the one that came with the Mendel and Ormerod2.
-cheap version of the E3D Lite hotend works well, comes with a 0.4mm orifice nozzle, but you can buy several others in different sizes.
-REAL leadscrews. While I got some good service from threaded rod in previous printers, a real leadscrew is so very smooth in action.

Things that could be better:
-wiring looms would be nice; I cleaned up the wiring a little with zip ties
-LCD display could use a rear support. When you push the 'Select' button, the board flexes. But once the printer is connected to the PC, you don't need to use the controls on the LCD...
-After 3 hours of use, the LCD display got garbled (visually). Resetting the machine after the print fixed it and in any case this did not affect the print in progress.
-I would've liked a holder for a sponge on the inlet of the extruder (to wipe the filament as it goes thru), but that's a very very minor ding.

Overall, a solid 9/10. I still have some settings to tweak, but that's true of any new printer.

 

Removed all the posts related to Google not wanting anyone to see the pics Problem should be solved, as now they are on the RCWC server and thus if they don't show NOW, we know who to complain to

 

I bought mine from the link above. If you're buying from EBay, you may not be getting the same thing from the same people, so YMMV.

 

I am really liking what I am seeing at that price point.. I may have to pick one up in a few months

 

If you don't have a pair of cats jumping on anything box-shaped or furniture-shaped, the foamboard should actually do pretty well for printing purposes.

 

I recommend putting BLUE locktite on the threads Not critical at all, but it will keep anything from coming undone, and means that you don't have to risk cracking the acrylic while torquing down nuts to keep them in place...

 

Are you sure that the X-axis endstop is wire to the right location? It sounds like its not seeing the endstop going closed.

One way to test it is to manually move the x-carriage to the far end, then hit 'Home X' and press the endstop as soon as the carriage starts moving. If it doesn't stop, it's in the endstop switch or wiring.

 

Yay for easy fixes I'm home sick today (nothing dramatic) so if you have more questions, post 'em