My tips for Starters before you print. (1 month owner here)

[Markedagain]

I have now owned the printer for 1 month , and ran into alot of troublshooting.
here are a few tips to anybody that just bought this printer as there first one as i did.

First off i think these should be included in the kit but are not.
-A portrait that has a glass on it 20cm x 20cm for a level bed
-Kapton high temp tape if your sensor is on the outside
-Flexable coupler to replace Z coupler
-More Filament. there is not even enough to print there practice print

When building following this guide is really a big help
ljwinkler.blogspot.ca/2014/01/ve … -tips.html

-A few extra points i would add to the guide is , the stop screws on your x and y should be tight to make sure good contact with the switch. if not play arround with the angle of the switch to get it to lean forward more.
-Take note that the gear head on the X is flush with the motor pin

-Make sure to buy a spool of filament while getting the printer since what comes in the box is pretty pittiful. I recomend not to buy black as the first one as i noticed the temps on it is a bit off so requires changes.

-You can use a metal screwdriver for changing the voltage on the stepper motors if u did not buy a good pair of calibration tools. just be very careful not to touch anything around
My motors were initially set to 1.5v and i could not for the life of me get them down using my plastic tools, took me some time to realize my tools were to cheap to get the job done.

-Once you run the motors for the first time, make sure you raise the voltage after to around .54 -.55
It took me many weeks before doing this, I fixed it after noticing some layers near the top of big objects completely offsetting on the X (the X motor was set to .44)

-If your temperature sensor is on the outside, use Kapton high temp tape to wrap that baby right onto the brass hole nice and snug
My extruder set was all over the place in parts, i had a mix and match of pieces. so i had to put my temp sensor on the outside.
i only did this after 2 weeks, i kept thinking the filament required less heat cause it kept bubbling and water would even come out. ( i was also thinking my filament got humid) it turned out the sensor was 1mm off the brass and the real temp was always 20 degrees more then what i saw in software

-When filament is broken or you are putting a new one, take close care to make sure the ends going into the extruder are not warped if so try to cut them clean
-Dont jam the filament in, simply allow the wheel to grab it and pull it in. Also dont try to do this during a print, make sure you are manually extruding 100mm or something relative or else the retractions during print will jam things up
I have probably removed the extruder head at least a dozen times so far by not taking the advice above. If needed you can unscrew everything including the white cylinder , usually the jam is in there,use pliers to pull it out ( ironically, i had to take it apart while i was writing this (facepalm) )

-Try to use a the back side of a Kitchen sponge to clean the head of the nozzle after and before prints to make sure no plastic is burning
-If the nozzle gets clogged i used a small needle, using the calipers i made sure it was smaller then .5 mm and at about 150degrees try to poke a bit ( not sure how ok this is for the head, i did not want to use a tiny drill bit in case)
-I recently figured out cutting off a metal wire off the end of a brisstle brush work like a charm in cleaning the end whith pliers
-I have also read about Cold Pull to clean the nozzle of clogs, but have not tried it yet. bukobot.com/nozzle-cleaning

-One of the first thing you should buy, maybe even before your first print is a mirror or glass the size of the bed 20cmx20cm.
I searched a long time as i did not have an ikea that had these mirrors, i eventually bough larger mirror and got the tools to cut it. Tools cost me about 10$ and was easy to cut watching some videos on youtube
I eventually realized i could of used any glass off a picture frame, so eventually i found one at wallmart for the exact size.

-Your glass on the bed will be a bit smaller then the base of the bed, and your nozzles home position will be off the glass
You want this so there is somewhere for the plastic to ooze out of before and after prints or else it gets squished onto plate and wraps around nozzle burning. So dont kill yourself trying to stretch the end screws to there max

-Trying to get the bed without glass level is actually impossible, so glass is essential must
-Once u have the glass, you can actually get closer then the recommended .25mm they are being generous since the default bed is not level
Mine is now set to .1mm level across, i don’t have to level it often as long as knobs on bottom are nice and firm, unless i change something in the hardware of course

-Do not try to match the height you just set as the bottom layer physically in slicer options first layer height.
It took me weeks to realize that the height I set the bed to is not the height it will print at.

-The bottom layer you want it thick, not as thin as possible. your first layer is not printed on the same height you set it too physically
so the idea is with the default option set to .35 , the first layer will actual go up by .35 on on the Z on top of your intial spacing ( so vellmans default means .6mm. so the closer u can get your initial spacing the closer you will get a real .35 height on the first layer
-Take into account nozzle expansion when hot
this is the reason i set it to .1mm ,this is when nozzle is cold, when hot the distance between the glass and nozzle is almost none existant, so any lower and i would push the glass down when its hot and expanded

-Z level screw. I hate it, the design on this is horrible. I ended flipping the screw around so i cna get to the head from the top not the bottom and put the nut also on top.
-Make sure you tighten that little nut, i had to use pliars as i have nothing else that small
-I also super glued a small flat plate on the metal switch. The bottom of the screw is to thin and would miss the moving metal on the switch
(you dont need the flat plate if u print the z adapter that also moves out the switch a bit)
thingiverse.com/make:92576
thingiverse.com/make:92793
I printed the z level with mircrometer, but really was not needed, once the new bracket moves the switch along and with a tight screw for the alignment its pretty spot on with 1/8 turns on the screw to control .1mm height at a time.

-Fix the Z axis wobble issue asap.
-For a couple $ i was able to buy a flexible coupler from the same store that sold me the printer. i bought a couple at that price and saw an improvement right away just by the noise levels being lower.
-Print a new Z bracket. the metal one does not do a good job with only 2 screws holding the motor and 2 screws on the vertical frame

-Make sure your belts on the top and bottom line up, if not then your motor or bracket needs to be moved
-Also another symptom of offset layers i heard was because of loose or to tight of a tension on the belt. i did not know that it can be to tight but make sure to check them if having issues with offset

-If you just got your printer , chances are you got the latest firmware , the only reason you need to update firmware is if you get th lcd attached to do all your prints.

-Figuring out what software to use and what settings to use was actually a long process for me. following the intial guide i ran .084 for a while then i noticed on the download section they had .95 and the settings to go with it.
-I did try installing the newer version straight from repetier but the z motor was making some weird noises when i tried running it. so went back to .95
-Slic3r on the other hand i did get the latest stable from there site 1.1.7, and i point repetier to that folder for slicing work

At first because of my unknown low voltage issue and temp sensor not stuck on brass , i started watching many calibration videos trying to change settings in slicer thinking vellman got it wrong, but after fixing my physical issues, and more troubleshooting cause i changed all the default settings i came to conclusion the default ones really do work best
Even the E steps in firmware are pretty good, the only changes i did, and i did these changes because i was not printing to the .1mm precision i need to make prints usable mechanically . i put the filament size to 2.9 and the permiters width % to 210% vs 170% in the advanced tab
my reference points to these changes were
manual.slic3r.org/advanced/flow-math
reprap.org/wiki/Print_Troublesho … _Excessive
hydraraptor.blogspot.ca/2011_03_01_archive.html

One of the next things i printed was to help the spool turn better, as it stands that little jump it did kept breaking the line once in a while. I also read that its very proan to absorbing humidity , so its important to keep it in a dry area and not open bags that wont be used.

im currently printing a new adapter for the nut that moves the Z plate. i still hear some weird noises from that area, some im hopping this 2 nut with spring adapter will fortify the grip and not slip.

I hope these tips help someone out, if i have made a mistake let me know and i will edit the tips, more then happy to also edit in more tips anybody else might have.

[O918]

Thanks for your tips, I have had mine for a couple of weeks, and You bring up some good points that i should look into (eg- I took your advise and made a new Z-axis coupler, which is terribly misaligned, causing the motor to oscillate/bend the motor mount bracket… it seems like they drilled each end separately, allowing the possibility that the motor shaft and threaded holes to be off-axis from each other).

I have been able to make some successful(ish) prints, but i am still trying to fine tune printing with ABS… the prints stick to the surface just fine (using a piece of glass from a picture frame with a layer of packing tape), but my problem is that the layers do not adhere to each other very well. I increased the layer thickness to 0.4 (it was originally set at 0.25) and that seemed to make the vertical shells adhere to each other better, but now the top layer doesnt look finished at all.

My bed heated bed will not get any hotter than 66 deg celcius, and it takes FOREVER to get that hot (i usually turn on the heated bed while i am designing a part, so it will be ready 20 minutes later when i have the part ready.)

How hot does your bed get? (phrasing!) and does it take >10 minutes to heat up? I have been using a heat gun to speed up the process. once it gets to the target temp, it can maintain the temp fine.

one thing i noticed is that calibrating all of the motors to the recommended 0.44v would not turn evenly, resulting in skipping. On my first print for example, the X Motor would “walk” in one direction, causing each layer to be 1/2", for example, further to the left or right (depending on the voltage) than the previous layer.

The voltages for each motor are all different (and very different from Velleman’s setting of 0.44V, with the exception of i believe the extruder motor.)

I agree completely with you on the Z level screw, it is terrible. i also had to flip the screw and top nut around so i could adjust it. and tightening that stupid top nut is next to impossible.

another issue i have noticed is the two long screws that thread into the standoffs holding the extruder assembly will loosen themselves due to the thermal expansion and contraction.

They also need longer screws used to level the bed.

[frankwim]

Hello and thanks so much for the pre startup tips. I’m new to 3D printing but not kit building. I just finished building and calibrating the printer yesterday (a 19 hour project) but had to make/replace a couple of parts. It helps to have a machine shop. I remade the Z axis coupler and straightened the lead screw. Also made an aluminum bracket to replace the plastic Y axis belt attachment that broke during assembly. I just noticed they sent a couple spare plastic brackets which probably verifies I’m not the first one with this issue. I spent a couple hours trying to level the bed before I saw your post about using a glass. That’s my next add on. I assume the bed temp is not an issue for standard glass or should I consider tempered glass? Also, maybe I am over analyzing but since the bed is not flat and the glass is, will there not be uneven contact therefore uneven heating?
Of course I had to try to print the recommended PB Board cover but had issues. The extruder motor doesn’t seem to have the power needed and would skip steps frequently. I moved the motor and pinion away from the big gear slightly and also checked the tightness of the hob shaft nut. I tried increasing extruder temp thinking I could lower the viscosity of the plastic and even, as a desperate move, slowed the feed rate to about 30%. None of this solved the problem. I will crank up the voltage per your suggestion. Hopefully more power to the X and Y axis will eliminate the layer offset problem I saw as I am sure the motors are just skipping pulses and losing position.
So far I don’t regret buying the K8200 but I certainly hope Velleman looks at these posts and heed some of the suggestions. One I would add pertains to the electrical connections. Can you say T-E-R-M-I-N-A-L-S. I’ve had my fill of soldiering for awhile.

[artcominio]

On my first attempt to print, the extruder motor would not force the filament through the orifice. As recommended in the Velleman instructions, I simply upped the extruder motor voltage from 0.425 V to 0.550 volts. That solved the problem immediately. The stepper motor is not “too weak,” it simply needs more voltage. Increasing the voltage on the other motors can also eliminate missed steps. But don’t go above the recommended voltage of 0.55 volts. If there is axis binding, that must be fixed rather than attempting to overpower it with more motor voltage.

Raising extruder temperature to make it easier to force the filament through the orifice is not a good idea because it creates other problems. Too high an extruder temperature causes a lot of “stringing” during prints, and even worse, a high temperature causes the filament to oxidize. This WILL clog the extruder orifice. If you see any smoke at all, then the temperature is TOO HIGH!

As for the Z-Axis banding problem, there is some truth to the urban legend that wobble causes the problem. But even if everything were perfectly aligned, there would still be some banding caused by the pitch variations in the threaded rod. Bands appear about every four to five layers. The solution to this problem is to replace the threaded rod with a precision leadscrew. BUT, as an interim solution, simply increase the layers to 0.35mm. I know, I know… Everyone wants the thinnest possible layers. But I have photographs of prints at different layer heights, and believe me, a 0.35mm layer looks smoother than a 0.2mm layer because the banding is MUCH LESS APPARENT.

It is true that a bad wobble in the Z-Axis can affect the printed quality of vertical surfaces, but even with no wobble at all thin layers will cause banding due to variations in the pitch of the threaded rod. If you really want the best quality vertical surfaces, then replace the Z-Axis threaded rod with a leadscrew FIRST…THEN you can work with thin layers. until then, the recommended 0.25mm layer is too thin. I routinely use 0.35 mm layers, and for square boxes like the enclosure, I used 0.4mm. Do not go above 80% of the nozzle diameter, so 0.4mm is the highest you should use. Thicker layers with no periodic banding look a whole lot better than thin layers with banding every four to five layers.

If you doubt what is causing the banding, just compare the bands with the pitch of the threaded rod. It is obvious that the bands occur at the same rate as the threads on the threaded rod.

Art

[Paul_Compton]

The hot end needs to be at the RIGHT temperature. You really need to verify that the hot end is actually achieving the temperature you’re asking for. Using a contact thermocouple instrument I discovered that mine was reading correctly at room temperature, but under-reading by about 20 degrees when hot (in other words 20 degrees hotter than I was asking for).

I used an external temperature controller and sensor to heat the extruder and measured the thermistor values to create a new thermistor table.

[artcominio]

My hot end was running about 15 degrees hotter than the 190 it was set for. Too much stringing and dripping as the hot end cooled. I determined experimentally that everything worked fine when I set the temp to 175. I didn’t bother to change anything but the target temperature setting. I don’t care if the number is accurate, as long as my parameters work.

Art