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New Build: Anet A8 Prusa i3 variant

Posted by dlc60 
New Build: Anet A8 Prusa i3 variant
January 19, 2018 05:00PM
I got an Anet A8 for Christmas and have been building it, an hour or two at a time over the last couple of weeks. This is my experience and my impressions.

The box is impressively packed and sorted. The best that I have seen in a 3D printer kit (This is my fourth).
What is very weird to me was that the metric screws were almost all "Phillips" and not hex. No problem, just kind of odd to me.
The build instructions are a very good set for folks whose first language is not English. They are mostly pictures with some added helper text. Mostly, this works just fine, those of us with more mechanical knowledge or more 3D printer knowledge are well off, a newcomer may scratch their head at the "missing" bits that are implied. I did fine.
The controller is already flashed with the firmware and unlike other printers that I have built, needed absolutely no tuning (so far).
The USB cable is, as usual, too short to be very useful, but hey, don't we all have 20 USB cables lying around anyway?
I didn't bother to read the setup instructions, I just went right in checking M119 end stop commands, hooked up pronterface and after figuring that the bit rate with 115200, used the stepper jog section and hand entered gcode to level the bed.
But first...
As an astute poster somewhere once said: "3 points define a plane, 4 points define a potato chip." I had no interest in a four point bed level. So I hacked the hot bed that came with the printer. First I bought the RepRap Champions Anet A8 upgrade Y carriage. and used that to mark a centered hole on the hot bed to set up a three point leveling system.
WARNING, the following instructions are NOT for the faint at heart! If you fear damaging a printer part by hacking, do not do this at home!
*****
Looking at the hot bed I immediately saw that there was only one place to reasonably drill a hole to create a three-point level. On the edge opposite the hot bed's wire connector. Anywhere else risked a short that would be hard to bypass. So I drilled a 3mm hole on that edge. This cut through two traces, actually one trace that was a "U" at that end. I then scraped away the metal where the hole was as well as 2mm past the hole. I then scraped off the solder resist on those traces and soldered a 3mm piece of 12 gauge house wire to patch the heater trace back up. When I tried to install the bed I found that the "3rd hole's" wing nut hit the front Y-post mounting. So I rotated the bed so that the hot bed electric wires now faced the side of the printer (see pictures). This means I need a more creative wire harness setup to avoid interference, but whatever - There are flexible wire-tray "Things" all over Thingiverse. Because I now feared that the springs would scrape and eventually short out the heater traces on the hot bed, I printed out "spring cups", which are an Anet A8 upgrade on Thingiverse. These insulate the bed from the springs and add the extra bonus of keeping the springs standing up straight!
*****
NOTE: You can buy an upgrade mk3 hot bed with a three-point leveling hole in it, but I didn't see a need to spend another $25-$30 when I could just drill a hole...
My next mod was a borosilicate glass plate that is 200x220mm, held down with office clamps (see pictures). Placed carefully, these don't interfere with the print nozzle. Placed not-so-carefully, they will. Just sayin'.

The only other upgrade that I installed right away was an X-belt tensioner. I was going to add a Y-belt tensioner but I immediately saw that there will be issues with the way that Y-belt is tensioned between two mounting plates that are not supported against the pull of the belt. THAT will be a soon-to-add upgrade.

I then added a custom PSU cover that gives me an XT-60 plug for the 12V power. I do this on all of my printer supplies to make them easy to disconnect and move. Then I added a nifty controller board cover that allows a fan to be mounted so the stepper drivers and heater MOSFET's get proper cooling.

I spent an hour leveling the bed for the first time using the sheet of paper and pronterface method. I then created a simple profile in Simplify3D for the printer, fired up the heaters, loaded filament (which was very easy) and printed a 20mm XYZ calibration cube. My IR non-contact heat sensor said that the 60C I set for the printer bed was 60.5C. Wow. That was good. The 20mm cube came out to be (X,Y,Z): 20.03x20.03x20.0mm. Again, wow. The A8 nailed it right out of the gate! It had a little bit of "elephant's foot" so I dialed back the nozzle height 0.03mm and printed a "Cute Dragon". I like to test with this model because it has a lot of overhangs, points and islands. It is my "go to" test print after a calibration cube. Again, a perfect print!

I have to say that I am impressed and give the Anet A8 kit 5(*****) stars. It was well packed, the parts were well done, the instructions were easy to follow and fairly complete, and the printer came up and worked fantastic on the first go. Even if the manuals were in "Chinglish", they worked well and did the job admirably. The build files, firmware and software were on a thumb drive that worked and made the build easy. The controller board was well made, well labeled and well laid out. It even has heat sinks on the heater FETs which no other controller I have gotten did. I can find no flaw with the parts and fit of this kit. I needed no hammers, files or saws to assemble it all. The kit even has a part cooling blower that works great. No other kit I have built has had this essential component!

I have read others tell stories of the hot bed connector overheating and burning - I see no evidence of this. I had the printer on and running for an hour and a half with no issues. I will monitor this over time, but the connectors and wire that I got in my kit looked perfectly capable of handling 10A of current. So far it has. I have seen projects and upgrades to correct "tower wobble" on this kit too. I don't see a problem with my kit. I will do a Z Resonance test to see if this is really an issue. And I have seen folks put things on the top of the Jack-Screws to stabilize them (again for Z-wobble) but I don't see the need for that. The Z axis speed is so much lower than X/Y that it seems adequately damped to me. Again, I will keep an eye on this potential.

We all like to upgrade our stuff, and I plan to do some. I will not likely upgrade the firmware, it works flawlessly right now and I don't see any need to do anything with it. I have used both manual and automatic mesh-leveling on my printers and prefer the manual one. So I am not likely to find a way to get a Z-min sensor on the head for this. However, there are some future problem areas that I have identified that I WILL be addressing.
* The Y-belt applies stress between the front and back mounting plates with no support. I _know_ this will eventually flex those parts and cause belt tension and bed leveling issues. I will be creating or finding someone else's creation that physically links and stiffens the front-to-back bottom bracket connections in the center. What I really want to do is directly link all the bottom parts together so that there is no frame torsional flexing allowed. Heck, I could bolt them all to a piece of MDF for that matter...
* Add a Y-belt tension adjuster to make it easier to remove this belt.
* The Z-endstop is very clumsy to adjust when setting the Z head zero point. I have seen a couple of nice Thingiverse fixes for this.
* I need a better clamp to hold the glass plate to the bed. One that won't interfere with the print head.
* Need to add cable tray chains for the bed wires and the head wires. Leaving them flopping in the wind will not end well...
* Add filament guides
* Add a spool holder. Doing this will probably necessitate some sort of frame stiffener though.
* The butterfly nuts are a stinker to adjust, need to put a good set of thumb screws on instead.

These are the upgrades that I added to my kit during the build: (spring cups, controller cover, RepRap Champion Y-bed, borosilicate glass plate.
[www.thingiverse.com]
[www.thingiverse.com]
[www.amazon.com]
[www.amazon.com]

Here are pictures of my build that show most of the stuff that I talked about.
three-point bed hack


Spring cups

The printer completed


The prints



Edited 1 time(s). Last edit at 01/19/2018 06:25PM by dlc60.
Re: New Build: Anet A8 Prusa i3 variant
January 19, 2018 06:11PM
Great write up ! There is no denying that these budget friendly printers
are more than capable of producing fine prints. I've been leaning towards
buying either a Creality or Anet I3 style printer for the past few weeks.

Thanks for the upgrade suggestions.
Re: New Build: Anet A8 Prusa i3 variant
January 20, 2018 03:09PM
I can't believe such praise for a machine so flimsy that just adjusting the belts bend the frame !
And this is just one issue. It doesn't just bend, it often cracks ! (
Note that luckily it bends otherwise it would freeze due to poor guides and alignment.

Just a cheap clone of the Prusa that brings nothing, no innovation, no improvement, just the opposite in fact.

Oh yeah, plenty of people liking it and designing "improvement" for it. Most are cheap gimmicks.
About the only one bringing REAL improvement is a metallic frame ! Amusing. Why not start directly with one ?

Oh yeah, is it cheap !


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: New Build: Anet A8 Prusa i3 variant
January 20, 2018 10:20PM
Wow, that's bitter.
I call it as I see it. I got the kit as a gift and built it carefully. It worked brilliantly, but had a couple of flaws.
It IS a cheap kit. Why on Earth would you expect high quality components in a cheap kit? If the family could have afforded a $600 kit, that would have been awesome and would have deserved vitriol.
This kit is hardly a crime.

DLC
Re: New Build: Anet A8 Prusa i3 variant
January 21, 2018 02:28AM
Here is the kind of "improvements" people do to just the frame : [www.thingiverse.com]

Poor guy was bending the frame just by playing the controls smiling smiley

And all the other issues, for ex: [www.thingiverse.com]

So people reading this thread get fully informed, in fact warned.

Edited 2 time(s). Last edit at 01/21/2018 11:29AM by MKSA.


"A comical prototype doesn't mean a dumb idea is possible" (Thunderf00t)
Re: New Build: Anet A8 Prusa i3 variant
January 21, 2018 01:07PM
Makes it look like a old-style Mendel... This looks like the ultimate fix for perceived wobble. So, what's your point?
It looks like a pretty cheap fix for any Prusa that isn't built on an extruded aluminum frame.
It sounds like you and others have had a bad run-in with this kit. I didn't. If all that is reported are the bad experiences this place will look like "Yelp", where people bitch, and almost never praise.
Well, to me it looks like Anet have been listening and upgrading their kit over time because I am having a very good experience with my kit and I don't mind sharing.
SO, here is a followup report.
(Edit)
I found a problem with my Anet A8. CURA 3.1 won't control it properly. It randomly shoots to Y max or Xmin or retracts 10mm while printing - which kind of makes a print take forever and leaves dribbles all over the bed. Anyone know why?
I use Simplify3D as my slicer, which is what all of these prints used. But it still bugs me.

I have run my printer for several hours with no wobbles, no fires, no explosions, just good prints. I have done the Maker bot action figure, Benchy, Marvin, and some jointed fish. Every single print came off the bed nearly perfect. Here are the results:



Having fun,
DLC

Edited 1 time(s). Last edit at 01/21/2018 11:09PM by dlc60.
Re: New Build: Anet A8 Prusa i3 variant
January 22, 2018 12:03AM
One of the updates I plan on with my kit is pretty simple. Some people have had the hot bed connector fry after use. The connector is capable of handling the current, but the stiff wires used can, with use, compromise the integrity of that connector. I will not have that problem because I secured the cable to my Y carriage so that wire movement won't strain the connector to the board. I plan to get some RC car battery wire, which has WAY high current capacity, much higher than this needs, and is super flexible so it makes the cable less stiff and clumsy. My current fix is fine for now though.

So, yeah, it does seem odd that they don't fix this obvious issue - My kit has a heavy enough wire to carry the current, but its stiffness creates another problem. The FET on the controller board can handle the current so there is no need for nor advantage to using an external FET driver (unless you also change the cable and wiring to the bed.)

This kit isn't perfect, but for <$200, who expects that? The fun of hacking it is most of the reason that I wanted one in the first place. smiling smiley

DLC
Re: New Build: Anet A8 Prusa i3 variant
January 28, 2018 11:48AM
I'm interested in the 3 point level plane you spoke of. How exactly is that accomplished?

I have two anet a8's that I have modded and I am thoroughly satisfied. They are cheap kits price wise but are awesome overall.

I also am still using all stock electronics (motors, motherboard, heat bed, psu) and no extra electronics like mosfets.

I honestly think alot of issues that pop up on most hobby items are down to user error but most people today are quick to blame the equipment than themselves.

Anyways, I modded my a8's with steel frames but needed to have motor mounts and top plates custom cut to keep the a8 x-axis at the same distance. With the e3dv6 and bowden extruder along with some motor mods I can print flex/nylon to carbon and wood pla (infused fibers).

I also recommend the a8 to fellow hobbyists and help them set it up when possible.



Edited 1 time(s). Last edit at 01/29/2018 01:37AM by jaded.
Re: New Build: Anet A8 Prusa i3 variant
January 28, 2018 04:05PM
I too think that these are a brilliant cheapo intro kit! CURA makes them act a bit funky until you get used to it. I usually use Simplify3D for my slicing/printing.
When building, there is no substitute for careful execution of the steps and looking up the bits that don't make sense.

My description of the 3-point hack that I did is in the first post of this thread. Look for the trigger words "WARNING, the following instructions are NOT for the faint at heart!". I included pictures that hopefully help see the steps along with the description.

thanks,
DLC
Re: New Build: Anet A8 Prusa i3 variant
January 29, 2018 01:40AM
Ahhh I see now. You basically mounted the bed with three points for manual bed level.

I have been using autolevel with inductive sensors for so long I don't touch the bed anymore. And even if the level seems off I just reset the plane and save and print again.
Re: New Build: Anet A8 Prusa i3 variant
January 29, 2018 09:21AM
I have over 200 printing hours on my Anet A8, and have been very happy with it.

Early on I had the heat bed connector issue - fixed by soldering the wire directly to the connector. Just recently, I had a bad crimp on the hot-end heater. Re-crimped it and I'm up and running again.

I agree that 3-point bed adjustment makes more sense, but the "H" frame the bed is mounted will flex long before the bed does, so I think it doesn't matter.much.

My biggest problem with the kit is the lack of a home sensor on the second Z axis. Depending on how the steppers lock in a power up I've seen as much as 0.15mm error. Since I started checking both side after power up and home, I've had much more consistent first layers.
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