Motor Issue and Uneven HBP Heating

I bought a Prusa i3 kit from ebay last week and got it together this weekend. Wasn't too difficult for my first build and for the most part everything works well.

However, I'm having two issues:

1. The x-axis motor heats up pretty quickly and makes a high pitched whining noise on certain steps. None of the other motors get hot at all or make any noise. I can't see any issues with the wiring and I've tried lowering the VRef on the driver down.

2. The heated bed only heats up on one side. I realize now that I should insulate the bottom of the pcb, right now it just has a glass plate on it.

Any advice would be greatly appreciated! I'm dying to make my first print

for the X axis swap step sticks with one of the othe rmotors and see if it folows the board or the motor. then you can figura out if you have a bad board or a bad motor. My guess is board.

Check the wiring on your board. I am assuming you have an MK2b board? are you running 12v or 24 v?

I tried swapping the sticks and still the same issue. High pitched whine on some steps and rough movement. The linear bearings slide really smooth so that's not the issue. The kit I purchased came with a 2.6kg/cm motor for the x-axis. Could it be that the motor doesn't have enough torque? The y-axis is running on a 4.6kg/cm motor and seems to work much better.

I got the heated bed figured out, I bought a thin piece of thick styrofoam and put it underneath for insulation. I have the MK2b with the 3 solder pads, I didn't realize that the 2nd and 3rd pads are both negative when using 12v, so I fixed that and had no issues heating it up. I even managed to do my first print!

I didn't print a full cube because I'm afraid that the x-axis motor might be bad. Also, I have a direct drive setup and the extruder motor is mounted to the extruder cold end which causes the motor to get pretty hot. It also seemed that the extrusion was really jitterying instead of a smooth continuous pull. I still need to do some more fine tuned adjustments in Marlin, so maybe I can fix it from there.

That X motor seems a bit weak - half as strong again would be better, maybe 56 oz-in.

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Waitaki 3D Printer

Seems odd that the kit would come with motors that are too weak. Would it help to run at 1/8th stepping instead of 1/16th? I have a RAMPS 1.4 and i think i remember reading that only 1/16th was supported

Hi there, which printer kit did you get on ebay?
just wondering if it's the same as mine

mine came with 2.6 motors for x and z and 4.8 for the Y axis.
(clear acrylic prusa i3) just putting it together now... so not quite as far as you

mine was the folgertech prusa i3 kit, very very reasonably priced at $349.00

Cheers.

Quote
Waltermixx
Hi there, which printer kit did you get on ebay?
just wondering if it's the same as mine

mine came with 2.6 motors for x and z and 4.8 for the Y axis.
(clear acrylic prusa i3) just putting it together now... so not quite as far as you

mine was the folgertech prusa i3 kit, very very reasonably priced at $349.00

Cheers.

Yep, that's the exact kit that I got. Really great deal to help you get started, there's a few things that weren't in the kit though. I had to buy about 15 or so M3-.5x20 machine screws because there weren't enough in the kit. I think bought a few other screws too. You'll also need a glass plate, which I got from Lowe's for about $2.50 and they cut it for me. You'll need binder clips, and some insulating material for the bottom of the hot bed. I advise getting some cable management sleeving or automotive cable casing, it makes things a lot easier.

Feel free to ask me anything about the kit, I had to figure a lot of things out on the way.

Thanks, any help would be appreciated.

I contacted the guys at Folgers directly when I got my kit as it was missing plastic parts, which they sent to me free of charge. While they were at it, i had them add a 40mm fan, and a couple of extra bearings, ( I paid for the extra's, but shipping was free).
They were very apologetic and sent out the stuff right away. When I ordered my kit, i also purchased from their website, the full graphics lcd screen with sd card, which they added to my ebay order and did not charge shipping... The construction video's on their site are handy, but it looks like they need to add a few more. This is my first 3d printer build, and it's very very cool. Would you mind posting some pictures of your completed printer? front and back, Just wondering about the measurements, I know the Y smooth rods should be 170 mm appart but wondering how far you have the base inside the acrylic frame... distance from the rear nut, to the nut agains the acrylic frame .

what did you use as an insulator between the heated bed and the acrylic frame it's mounted to: re-read your message, you indicated thin Styrofoam, not too hot for that?

I will post pics of mine when done too... or i could post pictures of the process...

Edited 2 time(s). Last edit at 09/10/2014 09:23AM by Waltermixx.

I didn't realize they had construction videos! I looked for some support on their site and didn't find any. Oh well, the kit went together easy enough without them.

I can post some pictures tonight when I get home, my build ended up looking differently than theirs. I also had to drill a few extra holes in the acrylic. I drilled four holes on side of the main frame panel to hold the power supply using M4-0.5x12 hardware. There were two holes in one of the triangular side support panels that I assume were meant for the power supply to mount to but didn't actually line up to anything. Plus, 4 holes are better than 2 anyways and it makes removing the power supply once the machine is fully assembled much easier. I'll include pictures of that too.

I also had to drill a hole on the y-platter to mount the belt holder piece. The platter I got had 3 holes but the holder needs 2, so I had to drill a new one. Not a big deal but it took me a while to figure out that I needed to do that.

The insulation I'm using is actually a dry erase board similar to this: [www.walmart.com] which is just some polystyrene foam with some plastic front and back panels. So far it's held up just fine the bed going up to 110C. The melting point of polystyrene is pretty low but it seems to be holding up fine for now.

As far as the exact measurements go, I didn't use the measurements from the piece of paper they included. I left the 5mm threaded z-axis rods at the length they came which was fine. Here's the cuts I made:
3x 210mm threaded rod (width-wise base)
1x 280mm threaded rod (width-wise base)
2x 395mm threaded rod (length-wise base)
2x 320mm smooth rod (z -axis)
2x 365mm smooth rod (x-axis)
2x 370mm smooth rod (y-axis)

I also had some issues getting the y-axis linear bearing holders lining up well. I ended up drilling out the holes on both the plastic pieces and the y-plate using a 9/64 drill bit which gives you enough play to line things up properly. Make sure you pack your bearings with grease before you assemble them! They come with a light oil to keep them from corroding but they require grease to operate properly.

For the x-axis idler pieces, you'll need to press in two linear bearings each. If you have a 15mm drill bit, you can try to hand ream the hole so that the bearings will line up well. Otherwise, you can do what I did and first push in a bearing from the top (the side with the z-axis nut holder) and then press the second bearing on top of the other, so you push the first deeper and end up with the bearings right on top of each other. I found this to be a really easy way to make sure that they were lined up properly, otherwise they'll be off axis and will cause a lot of friction.

Besides that, I can't remember any other issue I ran into. I can also provide my Marlin firmware if you'd like. I'm not quite done tuning it yet but it should help you a LOT. The defaults were way off on a lot of stuff and took a bit of trial and error to get things right.

Edited 1 time(s). Last edit at 09/10/2014 11:17AM by dooms101.

Here is a link to my version of Marlin that should help get you started: [www.filedropper.com] It also has support for LCD panels and controllers but you'll need to configure that yourself since I don't use one.

Edit: fixed link

Edited 1 time(s). Last edit at 09/10/2014 04:10PM by dooms101.

Wow thanks for all the info...
I started a thread for this printer... check it out...

to access the video's there is a link in the ebay auction:

[drive.google.com]

the video's state that the hole has to be drilled for the y-axis belt holder, and for the power supply...
they are pretty crude, but they get the job done... I'm hoping they post more videos...

thanks for all the great info

not sure if you want to copy and paste your above post into that thread as well.

Cheers.

looking forward to the pictures.

Thanks for the link! I noticed that they have quite a few changes in their Marlin configuration. I'll have to try those out when I get home.