now that your build is mostly finished, would it be possible to get some details on it? Like bed size, how thick that plate is, extrusion length, the pulley types/idlers/belt ect used. I think ive decided to go with this build but i might make a few modifications to save money, im guessing those pulleys on the lead screws are pretty expensive

 

maybe the hotend cools down because extruding to fast, then the different temps cause it to come out quick then slow, ect? try printing at slower speeds or mess with the hotend temp?

 

another thing i thought of was maybe the temp probe in the hotend can't sense the temp fast enough. These are all just guesses tho, i still havn't built my printer yet, finally ordered most of the stuff i needed to finish it. So im sure ill be running into all these problems soon, so let me know what you find out

 

Judging from the fact that the pattern is repeating I'd bet it's a Z-axis problem.

 

Have you seen this article? It may address why the height of the whole print is slightly off.
TrueUp Glide
To sum up, you pick a layer height that is a multiple of a single Z motor step to prevent small positioning errors on each layer height.

As far as the banding goes it looks really regular. But with the way the walls pulling inward it looks like it might be cyclically under extruding instead of a Z axis issue? I was having a very similar problem. For me, it was an issue with drag on the filament spool.

I just had the spool hanging on pvc pipe. As it fed it would slowly tighten on the spool. Taking more and more pressure to feed, causing it to under extrude. Then the spool would finally slip and turn, loosening the filament for a short time, then repeat.
Switching to a filament holder that used bearings fixed this issue.

 

i almost have my version of this complete, i did things a tad different as i didn't want to have to cut anything, lost a little space doing it that way but not a big deal. I have my acme rods, 2 of them, on one side as ive seen in other builds before, and it looks like the opposite side hangs about 1/4th of an inch lower . going to try and tighten my wheels up and hope that fix's it, i really dont understand how it could be lower the vslot should be straight and not bend.

anyways as i started to think about the electrical part of this build i had a question. on these power supplies, isn't it highly dangerous to just wire a cord up to the screws, i mean u essentially have 120v just sitting there to be touched, and its like that on almost every build ive seen that uses these power supplies. is there any way to set that up, that isn't a huge electrical risk?

ive also seen 3 prong plugs with a switch on them, basically like a computer power supply where u can push the cord in and out, anyone know what those things are called? i imagine they have a fuse built in too, i thought for starters that would be a good thing to get but i have no idea what they are called to even search for them. in otherwords i have a pc cord, i just need the little box with the plug and switch on it. otherwise i might just use a light switch from the hardware store, same thing i guess basically except i might be missing out on a fuse

also of note, this vslot stuff is such a pain, i keep realizing i should have put more T nuts in and have to keep tearing the thing apart. and the brackets to hold it together twist because the holes in them are so big, so its hard to get the vslot aligned with other vslot . my motor mounts that hold the acme screws, they flex when i turn the screws....hoping thats not going to be an issue. oh and the build plate doesn't even have holes that match the heat bed, that might actually be the most annoying issue ive had so far. Sorry to rant but little things like this can save other people alot of time. and my hotend mount doesn't match any holes on the gantrys, that one i expected, but still not sure how to fix it without a printer, maybe some wood? anyways, ill post pictures on what i come up with

 

thx, i read a few reviews and read something interesting, if the plug is rated for 15a, but the switch is 10A, isn't that bad? Most house wall plugs are 15 to 20 A, so won't this thing fry? i read a review on amazon about one of the switches melting?

Also isn't a 250v fuse kind of pointless? shouldn't the fuse be closer to 120v? obviously not 120, or it will go off, but 250 seems like all my electronics would be fried by time it hit that

 

The amperage (A) switch or socket will see is what is rated to flowing through it, not what /could/ be sent to it.
Does that make sense?

Lets say you have a 30A breaker - feeding to 15A Sockets. This is because it is assumed you won't be pulling the full 30A through one socket. That 30A is intended to be distributed over several sockets. And the 10A switch is intended to feed to a lower amperage device.

Example: Lets say you have 5 devices, each pulling 5A each
Socket #1 has 2 devices. That is 5A+5A = 10A total. Still safe for Socket #1
Socket #2 has 2 devices. That is 5A+5A = 10A total. Still safe for Socket #2
Socket #3 has 1 device. That is 5A total. Still safe for Socket #3
And the breaker feeding them all has 5A+5A+5A+5A+5A = 25A total. Still safe for that breaker (and wires in the walls).

And an Example of how not to do it:
Lets say you use a bunch of extension cords to plug EVERYTHING into one socket.
So that 5A+5A+5A+5A+5A = 25A total is running through one socket. This does not exceed the max amperage for the breaker so it is ok, but it is exceeding the max amperage of the socket (and possibly the wires in the walls). Resulting in a potentially dangerous overload. (This is how older incandescent Christmas lights caused fires). This is why all power strips have their own breakers, so they can't be used to overload a single socket

Keep in mind 15A is a lot. If you look on the info sticker on your device it will tell you how much power it uses, but this is usually in Watts:
Watts = Voltage x Amps
Amps = Watts / Voltage
(and usually calculated assuming 110v service. The actual voltage running in you house varies depending on a lot of issues, for the math part I just go with whatever is listed on the label.)
So a 40 Watt power supply:
40 = A x 110
A = 0.36A

Or a 300 Watt power supply:
300 = A x 110
A = 2.73A

So your 10A (1,100 Watts) switch should be more than strong enough to handle it.

I hope that was helpful

Fuses pop at the rated Amperage regardless of the voltage (so you can safely use a higher rated V without effecting performance). I think you see the 250v fuses so that the switch assembly can be used with a 110v or 220v setup.

 

hmm, think ill do that cover without the switch on it, that should add pretty decent protection, still going to do that switch/plug from earlier tho incase someone trips on the cord, then it will just pull out and nothing can get shocked or fire started.

so im at the point of needing to do my belts on the top of the machine, and i tried googling but its an odd question i have. So long question made short, how straight do my belts need to be? Eyeballing what im thinking of doing, looks like my belts will have to go at an angle to hit the pulleys. will that cause any issues?

 

How well does your heated bed work with those wires? I'm designing a project very very similar to yours and was thinking of doing that.

 

Holy quick response time, Batman! Thanks! I may have to go this route. My build is actually a bit bigger, looks like about 18" x 24" build area with slightly larger bed. I don't mind slower heating up times though. My problem is that I don't know much about how to wire something like that, other than snaking the heating wires under the heat bed. Could you shed some light (if/when you have time) on how you connect it to your controller board (if you do at all) to control the heat, and how you hooked it up to plug into i'm guessing the wall (I'm at 110v)? Sadly electronics is not my forte but I'm trying to learn all I can with this, and I certainly am!

 

What made you decide to "upgrade" to belt driven z-axis? I'm trying to make this decision now and like the precision of lead screws, but i know they can potentially have z-wobble problems.