Things to think about if you are going to buy a Anet A8

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Peter Bermingham
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Things to think about if you are going to buy a Anet A8

Post by Peter Bermingham » Sat Aug 05, 2017 2:23 pm

Problems with the Anet A8

1. To call the PSU cheap and nasty would be being polite No Quality control on the PSU in mine it had Dry solder joints and wasn't earthed to the Case.

2. The PSU is only 20A 12V throw it away and get a Good 30A 12V one.

3. You need to put an IEC connector with a fuse and switch on the PSU.

4. You need to terminate the wires going to and from the PSU.

5. You need to take off the Connector at the heat bed and solder the wires on.

6. Solder the headbed wires and hotend wires to the main board.

I have done this to mine and it's a great Printer, my second favourite after my Prusa.

I have seen people put mosfets on the printer as they were going up in flames and most people think that it’s the boards fault.

I think it’s because they don't know anything about electrics it’s the crap connection of the heatbed and hotend wire throw bad connectors...get rid of them

I have printed around 600 hours with mine PLA and ABS and it has not had a problem with the electrical system at all; BUT I have done what I said needs to be done.

I think it's a Great printer just not for a NOVICE and that is the Market it’s aimed at.

Well that opinion hope it helps

Jim JKla
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Joined: Mon Jun 26, 2017 12:01 pm

Re: Things to think about if you are going to buy a Anet A8

Post by Jim JKla » Thu Sep 07, 2017 11:53 am

I am looking to buy an Anet A8 as a first printer as I have the tinkering skills and tools to do the required upgrades and fire protection.

I am also deeply atracted to the idea of having a printer that can print its own upgrades for the cost of the filament plus some electricity.

Those upgrades will also provide useful experience in larning how to use the printer.

Down the line I will be using Mosfets and at some point a 30A PSU and I can see myself also eventualy going for a genuine E3dv6 hotend

My second choice would have been the A6 but the lower cost of the A8 and the upgradeability of the A8 just give it an edge. I would probably consider a Tronxy if the Anet was not there.

I did look at the Dolly Printer that Tom did and started down that route but for me cost has to be a consideration, and the A8 is about %40 cheaper and everything is in one box.

At some point I will probably finish the Dolly and donate it to my neice at the moment she's into Minecraft, Spinners and Unicorns (go figure).

MattNewman
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Joined: Wed May 24, 2017 1:52 pm

Re: Things to think about if you are going to buy a Anet A8

Post by MattNewman » Fri Sep 08, 2017 2:44 pm

I had a lot of problems with reliability/reproducibility of print quality. What's left of mine has become spares or parts to finish my Dolly i3 project which has already been more reliable.

My advice to anyone with an A8 is don't trust it, I came home to mine once and found the hotend so hot it was boiling PLA and had melted the Teflon tube and it was still chugging along just fine. Flashing latest Marlin with runaway protection is a must

telanoc
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Joined: Fri Sep 08, 2017 4:35 pm

Re: Things to think about if you are going to buy a Anet A8

Post by telanoc » Fri Sep 08, 2017 5:00 pm

Peter Bermingham wrote:
Sat Aug 05, 2017 2:23 pm
Problems with the Anet A8
...
I have printed around 600 hours with mine PLA and ABS and it has not had a problem with the electrical system at all; BUT I have done what I said needs to be done.
I agree with all of those. I replaced the power supply right away for a 30a one, and dealt with the power connectors and my A8 has been working great. I've only tried printing PLA with it so far, bit it does that reliably. But then again, my A8 isn't anything at all like a stock machine.

The few additional things I've done:

a). Frame brace for the front top area
b). X axis tensioner,
c). Y axis rework with tensioner (uses a pair of threaded rods to keep the frame from bending),
d). Inductive levelling sensor,
e). e3dv5 carriage/extruder,
f). a fan over the mainboard,
g). new z-motor mount plates with slotted screws for adjustment,
h). a z-axis syncronizer (belt and gears up at the top of the Z rods),
j). replaced the non-straight X and Y smooth rods with some nice ones from Misumi.
k). replaced the noisy bearings with Igus drylin ones.
l). replaced that 'H' abomination with a proper one-piece, thick aluminum heatbed carriage.

Since I gave it my delta's old hotend I was tempted to give it the RAMPS board too, but the stock controller has been working fine.

Also: Marlin. There's a nice linux tool on github called 'marlintool' which takes care of 99.9% of the work of getting Marlin (or Skynet) onto the Anet controller.

Best regards,
Pete Cervasio

hillct
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Joined: Fri Sep 08, 2017 7:05 pm

Re: Things to think about if you are going to buy a Anet A8

Post by hillct » Fri Sep 08, 2017 7:48 pm

My Anet A8 was my first 3D printer build. I received the Revision B model (a far as I can tell) which has the separate, tabletop spool holder. I almost did a live stream of the build but thought better of it when I saw the number of acrylic pieces with adhesive paper on them.

I had no issues with the build itself but as part of the build, I replaced the stock screw-down plates belt holders, with printed versions (X with tensioner) found here https://www.thingiverse.com/thing:2425783 and https://www.thingiverse.com/thing:2386809 both of which I've very happy with. There are plenty of other lists of Anet parts replacements, so I'll spare you that, but electrically, days after the build I encountered the electrical problems many have reported. My PSU upon close inspection seems to have reasonable build quality, no bad solder joints, properly grounded etc, but I had the heatbed adapter (on the headbed end) burn out, so soldered the wiring directly to the bed, to address that. Rather than removing and replacing or directly soldering the wires on the board end, I went the mosfet route. I also had the hot end cartridge heater die. There was no visible damage/burn marks, no excessive heat on the connector end although, it turned out the grub screws in the heat block has loostened, fallen out and been lost, so the heater was not making full contact with the block. That doesn't fully explain it dying, but still worth pointing out. Make sure you tighten them up after a few heating/cooling cycles.

Somewhat more interesting, was the discovery that the AVR/ISP header on the A8 mainboard uses an improper combination of header and pinout. As discussed here http://www.batsocks.co.uk/readme/isp_headers.htm there are two standard pinouts, one for a 6-pin header, and one for a 10-pin header. Apparently, the Anet A8 board was designed with the appropriate pinout for a 6-pin header, however, in production, it dawned on someone that they could save a half a cent per board if they used a 10-pin header on the board, as they use a 10-pin header elsewhere on the board so could buy in larger quantities. As such, the board uses a 10-pin header, but simply has no connection to the outer 4 pins as described here: Image

The only reason I discovered this was because I needed to flash a bootloader to my Creality CR-10 and didn't have a spare Arduino with which to do so. IN the end, it worked perfectly, using Nick Gammon's bootloader flashing sketches http://www.gammon.com.au/bootloader.

Monkeh
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Joined: Fri Sep 29, 2017 11:56 pm

Re: Things to think about if you are going to buy a Anet A8

Post by Monkeh » Sat Sep 30, 2017 12:24 am

Having been pressing on with my A8 for a few months now, I thought I'd add my experiences regarding the points above.

The power supply, althrough a pile of crap, is adequate - I've pushed mine up to 14.5V and it still only gets moderately warm when holding the bed at 100C for an extended print. No problems there, no need to overrate it by so much. Buying a better supply is somewhat advisable, though.. I'm quite comfy repairing one of these and well familiar with the potential risks, most people (no offence) shouldn't even be connecting the cable, let alone opening one and fiddling.

The harness from PSU to controller came (badly) preterminated for me, but it honestly needs uprating anyway - it's typical 50% undersized Chinese wiring. Big pile of surplus 14AWG (that's 2mm² in real money) came in handy there.

Bed connector is definitely a problem. Slowly cooking mine, but I'm hopeful to keep it there by using the extra pins (they're connected in parallel just not wired). We'll see how that goes when the crimps arrive. Might end up having to solder it.

Bed and hotend do NOT need to be soldered at the board. Terminate the cables properly (fork crimps for the main supply and bed, ferrules for the hotend) and the existing connectors, if not great, are adequate. If you solder everything down you'll just find yourself with a headache when you need to disconnect them, and these PCBs are REALLY CHEAP, I wouldn't want to rework them several times. The twisting when torquing down is a little disconcerting though.

Other issues:

Frame screws work loose quite easily even if torqued, thread locker is wise - this improves massively with the various frame braces added, though.

Stock screw holes for securing the X belt are out of line and don't work well, printing a better belt holder is advised, as well as a tensioner - this needs more belt. The stock stuff is horrible thick steel cored anyway, so it's worth replacing.

Stepper drivers get quite hot without cooling, so a fan arranged over the controller is good. FETs for the bed and hotend don't seem to get particularly warm, though.

Existing debounce (if you can call it that) circuit for the limit switches is.. not good for probes. 10k pullup over 10uF cap - crazy, especially with an active high probe. That, I'll be reworking, and then my Z probe speed can be at least quadrupled.

Bearings are, frankly, terrible, and the rough cuts on the rods do not help (goodbye balls, it was nice not getting a chance to know you..). Nothing bent, though, including the lead screws - positions of the motors and nuts, on the other hand, require careful adjustment.

Oh, and the heater cartridge crimps fail every few dozen hours, which is intensely aggravating. Hopefully my replacement will be more reliable when I get around to stripping the harness again.

By the time I'm done with this thing, little will remain.. but it gets you started with a little thought put into it!

johnhodgson1111
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Joined: Fri Oct 20, 2017 12:04 pm

Re: Things to think about if you are going to buy a Anet A8

Post by johnhodgson1111 » Fri Oct 20, 2017 12:38 pm

I bought the Anet A8

Things I have done.

1. Added 12v to 14v 30A Powerr Ssupply dedicated to heat hotbed. that PS has a fan. Adjusted to 14v, quickly goes to 110c easy

2. Ywo mosfet installed 1 for hotbed running 14v, 2nd for hotend

3. installed 2 z end radial bearing to help with z wobble

4. Taken out hotbed connector, direct wired/soldered to board

5. Replaced hotbed wiring with 14ga stranded copper, 14ga wiring from motherboard to mosfet.

6. Have two power strips w switches , 1 going to extra 14vadjusted 30A power supply, other going to stock power supply

7. Installed 3mm high temp insulation cotton sheet to underside of heatbed

8. Used the Kapton Tape to insulate the underside, and used tape on top of heatbed.

9. installed z wobble end parts with radial bearings, printed out case assembly for motherboard,mosfets,y chain, x chain, t support, front
and rear stabilizers , x and y tension mounts for belt and tension adjustments

10. I completely insulated the hotend. using leftover 3mm cotton insulation and Kapton Tape. the hotend used to cycle between 240c up to 245c and backdown to 240c. after insulating hotend (all sides) the temp is 240 plus or minus 1c. the filament output is very consistent

11. I will print the adjustible z motor mounts, the z wobble ripple is still there. Once I get the new belts, I will installed the adjustible z motor mounts.

12. have bought a lack table, and setup a plexiglass enclousure.

13 soldered and tinned all connections and added connector hardware for good current flow.

I think insulating the hotend on all sides is a good idea, getting verystable print temps.

Monkeh
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Re: Things to think about if you are going to buy a Anet A8

Post by Monkeh » Fri Oct 20, 2017 4:36 pm

Two power supplies is, uh.. unneccessary. Again, stock one has all the power needed, and your extra one.. even more so.

Restraining the leadscrews will just make wobble worse - make sure your leadscrews are straight, adjust the motor and nut positions to get them to run parallel to the guide rods, and fix the X axis tensioning so it's not trying to pull the two carriages together.

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lowfat
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Re: Things to think about if you are going to buy a Anet A8

Post by lowfat » Fri Oct 20, 2017 7:53 pm

Not sure I agree about the stock PSU being capable. The PSU on my first A8 died within 2 days.

If you are using an external mosfet for the heated bed, soldering wires to the control board is 100% not required. You could easily run 24AWG and not have an issue here.

Mosfet for hotend is also absolutely not required.

As @Monkeh said, you shouldn't restrain your lead screws. It could prevent wobble but it also could cause consistent layer shifting and binding if both rods aren't 100% straight.

You also shouldn't tin any connector that goes in to a screw terminal. Because the tinned wire can't compress, there is less surface to surface contact between the wire and the terminal. Either use blade connectors, ferrules, or bare wires.


My first Anet A8 I ended up using for parts after I finished a new printer. 2 weeks ago I just bought another (kid didn't have patience to finish building) for $100 CAD ($80USD), had most of it built, but the acrylic frame was warped pretty bad, so it like the previous one will be scraped for parts.

Monkeh
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Re: Things to think about if you are going to buy a Anet A8

Post by Monkeh » Fri Oct 20, 2017 8:03 pm

lowfat wrote:
Fri Oct 20, 2017 7:53 pm
Not sure I agree about the stock PSU being capable. The PSU on my first A8 died within 2 days.
Assuming no crib death, anyway! Mine only gets moderately warm when holding the bed at 110C and printing, especially once you get up to temperature and the bed resistance goes up, 240W is enough power. Crap supply, adequate rating.
You also shouldn't tin any connector that goes in to a screw terminal. Because the tinned wire can't compress, there is less surface to surface contact between the wire and the terminal. Either use blade connectors, ferrules, or bare wires.
Eh, contact area's really not an issue - tinned wire compresses fine. The problem is the tin flows under pressure and the contact pressure weakens, especially with thermal cycling.

The existing terminals are really badly suited for bare wire or ferrules (except the pluggable hotend, that's suited only to ferruled wire (IMO)), suitable fork crimps are the way to go. Alternatively, rings, but that's more fiddly.

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