the anet a8 is my second 3d printer. i got it from the onlineshop gearbest and my part of the deal was crating this review video. in my second video about 3d printing machines i will talk more about how to setup such a device for the first run and show that printing parameters have a large impact on the results. the frame is nearly identical to that of the tronxy p802, which is my first 3d printer ever. both devices have a build volume of 22x22x24cm, a maximum extruder temperature of 250 degrees and both can print directly from sd card. the anet a8 comes also as a kit and the frame is cut from 7mm acrylic plastics. the tools included are a side cutter, a wrench, four hexagon tools as well as two screwdrivers - it's all that's needed for the assembly. the documentation is on a micro sd card that's inserted in an usb reader. not all of the text is in perfect english - which is also true for the text of this video - however there is nothing to find fault with the illustrations.
with that you will be able to manage the assembly in a couple of hours. if you buy a printer kit, you should not fear to disassemble structural components in order to eliminate an error you made and reassemble it all in the correct way. check if the guiding rods fit through the right mount point of the x axis before putting it all together - i had to widen the holes a bit with a round file. after the assembly of the mechanics comes the wiring - there is no soldering iron needed. same as at the p802, the insulation of the power supply isn't sufficient. i used two of the cable straps to get an improvisational strain relief mechanism for the mains cable. this power supply is noiseless - there is no fan; as a disadvantage, the casing is perforated to cool the electronics which worsens the insulation of the device. the screws of the clamp connectors on my board were tightened with a torque that only a titan can generate! loosen those screws before assembling the board and hold the clamps with a caliper to avoid ripping off the soldering points.
note the correct polarity of the input voltage - the red cable runs to plus of the power supply, the black cable to ground. the plug connectors are protected against reverse polarity, which makes the rest of the wiring an easy job. the cable spaghetties are tided up with spiral tubes and cable straps. three stripes of adhesive tape are used to keep the prints sticking on the heated bed. it's a good idea to buy tape thats wide enough to cover the bed in one stripe. after the assembly, move all axes by hand from end to end. you must hear the click of the end switches. have a close look at the cables, also - they should not rub against moving parts. during that test i noticed that the y axis did not move as smooth as it should:
the belt is not fixed in line with the pulley of the motor. same is for the ball bearing at the other end. that's why i changed the mount of the print bed. the h shaped plate is now mounted the other way round, by what the mount of the belt gets 6mm deeper than before. with that, the belt is almost in line with the pulley and the ball bearing. while moving the z axis manually, the end switch must be triggered before the tip of the extruder touches the print bed. adjust the height of that switch to have a gap of 3 to 5mm. put the printer on a flat ground - i am using a 60 times 60cm floor tile. if there is a gap between ground and one of the corner points, loosen the nuts and realign the frame.
the power supply has no switch, thus it is a good idea to use a switchable socket, so that you can turn off the printer quickly in case something goes totally wrong. if the display lights up and no magic smoke appears after turning the printer on for the first time, you have taken another hurdle in starting a print. as a frist test you can drive the motors with the printer controls. if both motors of the z axis start spinning into the same direction... ...the y motor moves the heated bed... ...and the x motor moves the extruder, the cabling was done correctly. test the end switches next, starting with the x axis... ...than the y axis... ...and finally the z axis.
if one of the axes doesn't stop as soon as the switch is triggered... ...inspect the cabling of that switch. the joints in the shrink tubing could be broken... ...or the plug isn't inserted correctly or simply in the wrong place. you can turn both spindles of the z axis in different directions whenever the motors are disabled, by what the frame of the machine bends noticeably. because of that, you must align both ends of the x axis to the same height using a ruler. next thing to be done is adjusting the print bed in parallel to the x y plane and that procedure starts by driving the z axis to the end switch with the printer control panel. disable the stepper motors, next. after moving the extruder to one of the corners of the print bed...
...you can adjust the size of the gap between extruder nozzle and heated bed; 2 or 3mm in the first run. repeat that procedure at all four corners of the bed. reduce that gap to 1mm in a second run and finally use a paper sheet as reference for the target size of the distance between extruder and print bed. adjust the hight, until the paper sheet fits tightly between nozzle and print bed. do that in all for corners. if the height of the print bed is adjusted correctly after several runs, lock the position by tightening the wing nuts. next thing to be done is preheating the printer. i am using pla, thus the extruder is set to 190 degrees celsius. move the extruder to the left...
...and lift the z axis a couple of millimeters through the control interface to avoid the x axis from getting missaligned by handing on the extruder with the steppers being disabled. as soon as the target temperature is reached, you can feed the printer with filament. press the lever and insert the filament from top of the print head. pull in the filament until plastics exits the nozzle without bubbles. now, the printer is prepared for it's first job. if you are new to 3d printing, you should select one of the files that are stored on the sd card that came with the printer. after inserting the sd card... ...you must mount the storage device with the printer control. you must select "unmount card" whenever you want to remove the sd card from the printer or else you might loose all data stored on it.
to start printing, mount the device again... ...and select one of the files. as soon as extruder and heated bed reached the target temperature, the printer starts the job. usually a strand of plastics is extruded round the print area, first. with that you can see if all objects are arranged correctly on the bed. furthermore, gas bubbles in the extruder nozzle are pushed out and you can see if the print bed is adjusted correctly. the first layer is usually printed with a higher temperature to get good adhesion on the bed and with a larger layer hight to balance the roughness of the surface. the object is printed layer by layer. all parameters such as extruder temperature, print speed, layer height or fan speed are stored in the file on the sd card.
the used file format is gcode. if you are a beginner, it is highly recommended to print from sd card, because communication through the usb interface can cause trouble. error free software doesn't exist and you should avoid all possible causes of error. with a single mouse click you can delete all parameters stored in the memory of the printer by what the device won't print any longer. so keep the usb cable away from your 3d printer. after approximately one hour and 4m of filament, the item is printed and you can remove it from the heat bed after cooling down. the result isn't perfect - the edges of the character are very rough. that chinese character means "commander in chief" and to become the commander of your 3d printer, you must learn how to handle and adjust all parameters stored in hard and software. printing sculptures or characters isn't what my printer is made fore, thus the next piece is more useful.
it is a link of a cable chain. there are many strings coming out of the extruder nozzle that are not part of the software model. those strings are very solid and you need a knife and a file to remove those unwanted excess of plastics. the parts don't fit together, thus a higher tolerance must be set in the cad model. furthermore there is a error in my design: the cylinder shaped pin doesn't fit into the hole of the hinge... so back to the virtual drawing board and reprint. you must learn to fine tune the correct parameters to avoid that oozing - more than one print is needed to adjust a printer and get optimal results. after a few prints, the output is obviously better than before.
there are fewer strings and those still there are clearly thinner. oozing occurs more, the higher the print temperature, which leads to a problem when printing one file on different 3d printers: the microcontroller senses the extruder temperature through a thermistor, which is a device whose resistance is dependent on temperature. electronic devices are never free from error and a thermistor with a tolerance of 1% is a quality part - up to 3% tolerance is anything but scrap. with 1% error at a printing temperature of 200 degrees we get a variation of up to plus minus 2 degrees, thus the extruder temperature might differ for 4 degrees when using two different printers. having thermistors with 3% tolerance, we get up to 12 degrees in the most unfavourable scenario. temperature isn't the only parameter that is specific for a certain printer, thus calibration has to be done by try and error. more about that is treated in another video and on my pages. while talking about temperature:
none of the driver chips exceeds 41 degrees celcius and the power transistors of heated bed and extruder are below 35 degrees. the microcontroller is the hottest device reaching 42 degrees. the stepper motors heat up to no more than 35 degrees. 3d printing means prototyping, thus success is never granted, especially not in the first run. with a methodical approach, the results will get better with each new iteration of the printing parameters. when printing the links of the chain one after the other you can vary the parameters step by step until the optimum is reached - even the non perfect prints are usually not total scrap and can be used in the chain. i designed the cable chain in openscad, so printing links with a new aspect ratio or another size is done quickly by changing nothing but a view variables. which printer is better, the tronxy p802 or the anet a8? well, that's hard to say since there isn't a huge difference and i haven't printed very much with the devices, yet.
both printers are at the low end of the price scale, thus you must lower your sight on build quality, print speed or precision of the mechanics. when operating the printers with expert knowledge, the results are comparable - the output of both devices is definitely usable and that's what counts to my mind. you can't expect high performance from cheap printers, however having a working 3d printer opens a new world to workshop designers and home constructors. after removing the filament strings, you can assemble the printed parts... ...by what you get a working hinge. this cable chain is composed of links made with both filament printers and as you can see it works fine. on my project pages you can have a close look at full resolution photos of those and more samples printed with both devices, by what you get an impression of the output quality of the printers.
what are the advantages and disadvantages of 3d printing,both devices are a good point to start experiments in 3d printing and so to learn how fused deposition modeling works with no risk of damaging expensive components. you can read all about my experiments with the 3d printers on my pages.
for now, all i can tell is that the main difference between both devices is that the anet a8 can print in blue... thanks for watching and: "i'll be back!"
