Anet A8 Double Heat Bed (220x440x220) by EllisDee

Last crawled date: 3 years ago

Anet A8 Double Heat Bed
At first i have to say thanks to SmallArtFly for making the Anet A8 frame in useable CAD files
All links are just samples
Warning!!!
not possible with 20A Power supply you will smoke it up
you need around 30A for this. Every Heat bed has 10A and start to use mosfet boards,
its not useful to send so much ampere over the Mainboard
Also i suggest you to solder the wires directly onto the heat bed, my plug smoked up.
as far as i know, they all do sooner or later. for second heat bed u have to remove the plug, and solder the wires directly onto the heat bed.
also you need to add additional lead, the 8mm steel is too weak and starts bouncing on print
sry im no instructions guy hope it will help what i wrote and is understandable ^^
feel free to ask, and maybe u get answered ;-)
Parts Needed
1x Heat Bed 220x220
(must be the same like the other one, cause u cant temperate them alone and have to use 2 beds parallel with just 1 PTC. But works pretty well they have nearly same temperature the difference here is around 2°c maybe with firmware changes it will be possible but still did not figured out how)
2m GT2 Belt
2x heat bed springs
(they are needed for the middle u need to arrange the print head distance there too
so you will have 6 points to level the bed after extending)
2x aloy or carbon plate 440x220x4 for heat bed carrier stability and as print bed
(i used Carbon around 170€ but u can print directly on it and its rly stable at 4mm)
2x 1m silver steel rod 8mmhttp://www.ebay.de/itm/Silberstahl-8mm-Rund-1-2210-geschliffen-poliert-Länge-1000mm/172521494796?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
2x 1m VA screw 8mm
2x I-Typ Profile 40x16x1000 With Drillholes through the whole lentgh of profilehttp://www.ebay.de/itm/Aluminiumprofil-40x16S-I-Typ-Nut-8-Zuschnitt-50-1190mm-11-50-EUR-m-min-1-EUR-/282225635697?var=&hash=item41b5f57171:m:m_hMGu-VQluYoLY24kAYgxw
(needed for Stability if not used or something like this the heat bed starts bouncing prints get ruined for sure and the silver steel rod / bearings maybe gets damaged this profiles are rly stable)
16x bearing 3x6x2,5mm (for the sleds)http://www.ebay.de/itm/10-x-Kugellager-Bearing-63-ZZ-3x6x2-5mm/151965772109?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
M3 x20mm screws
for the i typ profile, make sure u screw some m3 screw through the plastic
before trying to make them in place, else they break, they are weak and just
for holding in place. if everything is ok threy dont get any forces on the I-typ
Profile just pressure from top cause of heat bed
8x M3 x 20mm screws
for the sled, to hold the bearings. Let them stand out some mm that the screws / sled
cant get over the linear bearings u will see that at assembling
the sleds dont get screwed at the heat bed carrier u can do it but i didnt, on this way the sleds cant leave place when pressure from bed is too low or not 100% parallel.
Also make sure u cleaned the bearing holes well from plastic the bearings must be able to turn very well, make some points with water proof pen on it is u had problems like me to see it turning. the screw holes should be drilled with 2.5mm then the screws make their own thread but u could use also a 3mm thread drill
Also i would suggest u to change the common linear bearings to plastic ones, maybe i just got bad bearings but they already destroied a silver steel rod and the new one has a scratch too
have them here but still not in usehttp://www.ebay.de/itm/8x-DryLin-Igus-RJ4JP-01-08-Gleitlager-anstelle-LM8UU-RepRap-Mendel-Linearlager/272135737892?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649
there gets nothing rly screwed together it holds by its own thats why i cant help with the front holders, you need to create them by yourselft they depend on how long your i-typ profiles will be.
my silver steel rods are 77cm
my VA screws are 82 cm (yes i know i still didnt sawed them.... too lazy to disassamble )
my I-typ Profile is around 84 cm and 78 but as u can see in picture i messed it up^^ need a course in how to measure :-) and thats why you need to make the front holders by your own ;-) the front holder i posted is just a suggestion how to
to build the new heat bed carrier take the old one and mark the holes of it on the 440cm aloy or carbon 2 times that u have the holes for the linear bearings you just need the middle bearing holes and 4 bearings, but u need the holes at the side for endstop, be creative to make sure you reach it, i used a 2cm linearbearing spacer and the small block. u can compensate it in firmware also but if no endstop blöck is used heatbed carrier maybe crashes at the wall not good for your belt. Could be used to expend the heat bed a lil but there still should be heat at the edges of bed ^^
you need to place the 2cm blocks between linear bearing and heat bed carrier to make space for the i typ profile.
place the i typ profile spacers on 1/4 and 3/4 of travel way. place the i typ profile on the spacers and top /back acryl plates. the other one gets holded under the stepper. there should be now around 1mm space between bearing blocks and profile. put the sleds on it in the middle of carrier. if the sleds are too low, use some thick paper between sled and carrier (sand paper sand side on sled)
use the screws from the 8mm steel rod holders to add the additional i typ profile holders at the back u can use one of the spare part holders, this prevents the i typ proile from sliding backwards at the other side u take the ones i made to prevent the profile from sliding forward.
Made some spacers today for the profile to prevent them from bending and to keep them parallel, you should be able now to arrange the i typ profiles now easy between the linear beerings. be sure to put the sleds in before assembling the heat bed carrier, i dont think it will be possible later with spacers to get them into the middle
you should use some additional plate now were u screw the heat bed at i would suggest a material were you can print directly on it else use alloy, this is needed to have a plane surface with no edge coming up from one heat bed, i used 6x 30mm and 2x 12mm screws but i would suggest you to use 35 - 40mm makes it easier for the knurled nuts to get on
assemble the carrier like the old one only difference u will level the carrier not from top now, so u need some knurled nut, or cut a m3 thread into the alloy like it was made at the old carrier, not possible with carbon i think but i think its a bad solution cause u cant screw the heatbeds under the print surface tight with nuts. also u have now 6 points to level the Heat bed
Electric:
i use 3 mosfets for the reason that i use an ATX power supply with 60A double rail
2x 12v 30A so i can separate one heat bed to each rail, extruder on rail 1 mainboard on rail 2, and maybe later its possible to heat the bed separate and measure its temp
need to say it again!
solder the wires directly on bed, this plug is a real danger!!!! he can cause fire and burn down your house i saw it to the right time, plug got molten, some cm from the cables too, i think next print he had burned with luck just a shortcut
will post details on electric later if someone needs it
I am using the skynet firmware, works for Arduino 1,0 board and ramps 1.4 board very well
but since i have a diamond hotend im using a ramps 1.4 with cnc shield
Firmware:
You need to tell the machine that it has now the double Y axis length to do so change in
Configuration.h under "// Travel limits after homing (units are in mm)" for "#define Y_MAX_POS 220" and change it to 440 or how long your heat bed is.
feel to be inspired its all just a suggestion :-)