Printer head location, ink dispersal

[ajn9494]

Thanks again for the help with the Arduino problem, everyone. Now, my next roadblock...

When I go to print something, the printer head is depositing ink in a haphazard fashion. For example, I loaded a model from Thingiverse called 'SmallHelperDisk'. Here's what it looks like as its converting:

The problem is, the printer is nowhere near the circle shape. It's depositing ink all over both bins. Here are some sheets of paper I put over the bins:

Is there a way to fix this? A way to calibrate, in a sense, the printer?

[Pwdr]

For me, it's not very clear what the printer is doing. For printing on
paper, try a saturation (drops of binder per position) of 1. You can change
the saturation in the PWDRCONF.TXT file, inside the PWDR folder on your SD
card. Change the value of the fourth number to 1 in order to set the
saturation.

Most probably, your wiring to the print-head is not correct.

On Tue, Jun 10, 2014 at 7:16 PM, ajn9494 notifications@github.com wrote:

Thanks again for the help with the Arduino problem, everyone. Now, my next
roadblock...

When I go to print something, the printer head is depositing ink in a
haphazard fashion. For example, I loaded a model from Thingiverse called
'SmallHelperDisk'. Here's what it looks like as its converting:

[image: 1]
https://cloud.githubusercontent.com/assets/7737437/3233860/af612fa4-f0c2-11e3-9961-f733091b0d94.jpg

The problem is, the printer is nowhere near the circle shape. It's
depositing ink all over both bins. Here are some sheets of paper I put over
the bins:

[image: picture024]
https://cloud.githubusercontent.com/assets/7737437/3233871/d9fe7172-f0c2-11e3-8d2f-66ba77409f79.jpg

Is there a way to fix this? A way to calibrate, in a sense, the printer?

—
Reply to this email directly or view it on GitHub
#29.

[ajn9494]

I'll check the wiring, but to make sure, this is the proper circuitry, right? Or should it be one of Boreaz's diagrams that show the rest of the printer head? There are a few schematics floating around and I want to double check.

[Pwdr]

Yes, that layout is correct.

This one might be a bit more helpful, including numbering:

[image: Inline image 1]

On Wed, Jun 11, 2014 at 8:58 PM, ajn9494 notifications@github.com wrote:

I'll check the wiring, but to make sure, this is the proper circuitry,
right? There are a few schematics floating around and I want to double
check.

[image: printer scheme]
https://cloud.githubusercontent.com/assets/7737437/3249501/21dd69d0-f19a-11e3-98f1-02a42b635079.jpg

—
Reply to this email directly or view it on GitHub
#29 (comment).

[ajn9494]

For some reason, the picture you posted isn't showing up. Is this the one?

The wiring one this one looks different than the wiring above. Also, with SD card wiring, right now
it's wired with resistors based on another schematic. Is this correct?

[Pwdr]

Oops, I meant this image:

[ajn9494]

Ok, so I've been playing around with the wiring. I think I got the printerhead all sorted out. Now, here's the thing. Before, when I hit "Initialize position", the printer would think the initial position is opposite the motors (like its supposed to be). When it did that, however, when the roller when I move as if to deposit a new layer of powder, the roller would activate when it moved from the build bin to the powder bin, NOT from powder to build. Also, it would move as if building in the powder bin. I played with the wiring to the motors. Switching the y-axis motor around allowed the roller to turn and move as if to deposit powder like its supposed to (powder bin to build bin), but now its thinks the initial position is at the opposite end of the printer, the same end as the y-axis motor. If I DONT hit 'initalize position', and keep the printerhead where its supposed to start when I go to print a file, it sometimes tries to print in an area not even on the bin.

Regarding my pictures posted above of the ink splatter: regardless of what design I loaded, the printerhead would just deposit ink in short lines. The very dark area is just several layers of that. After changing some wiring, it won't do it all over the place. It'll just seem to do that in a specific spot (an improvement, but still...).

Now, I'm wondering if part of the problem is how the SD card is wired. Now, its wired in using a schematic from Boreaz with resistors. If I'm using the wiring to printhead like you just gave me, should I use the version without the resistors? Or does it not matter?

I'll put it this way: Is mixing elements of the schematics (the SD card wiring in one, printhead wiring from another) ok? or strictly stick with one schematic?

[Pwdr]

So, there are two problems: direction of the printhead and the deposition of the printhead.

Concerning the direction of the carriage/printhead; it’s not completely clear to me what’s happening. Looks like your y-motor is turning in the opposite direction. You can alter this by editting 'PwdrFirmware2_0.ino’, change stepperY.setMaxSpeed(stepperMaxSpeed); to stepperY.setMaxSpeed(-stepperMaxSpeed);

Maybe we have a different declaration of the powder and build bin. Would it be possible to post a video or schematic overview of what’s happening?

Concerning the deposition of ink; it would be very strange when the wiring of the SD shield would influence you print results. Please post some pictures of the print result and a screenshot of how it supposed to look.

On Monday 16 June 2014 at 22:24 , ajn9494 wrote:

Ok, so I've been playing around with the wiring. I think I got the printerhead all sorted out. Now, here's the thing. Before, when I hit "Initialize position", the printer would think the initial position is opposite the motors (like its supposed to be). When it did that, however, when the roller when I move as if to deposit a new layer of powder, the roller would activate when it moved from the build bin to the powder bin, NOT from powder to build. Also, it would move as if building in the powder bin. I played with the wiring to the motors. Switching the y-axis motor around allowed the roller to turn and move as if to deposit powder like its supposed to (powder bin to build bin), but now its thinks the initial position is at the opposite end of the printer, the same end as the y-axis motor. If I DONT hit 'initalize position', and keep the printerhead where its supposed to start when I go to print a file, it sometimes with try to print in an area not even on the bin.
Regarding my pictures posted above of the ink splatter: regardless of what design I loaded, the printerhead would just deposit ink in short lines. The very dark area is just several layers of that. After changing some wiring, it won't do it all over the place. It'll just seem to do that in a specific spot (an improvement, but still...).
Now, I'm wondering if part of the problem is how the SD card is wired. Now, its wired in using a schematic from Boreaz with resistors. If I'm using the wiring to printhead like you just gave me, should I use the version without the resistors? Or does it not matter?

—
Reply to this email directly or view it on GitHub (#29 (comment)).

[ajn9494]

Actually, since i rewired the printhead, I'm not getting any ink. Guess I might have to switch back.

I made a few videos, but they are too big to post here. Can i email them to you? If so, email me at NAJFACAJ@miamiOH.edu and I'll reply with an attachment.

[ajn9494]

So, yea or nay on the email?

[MasseyAlbany]

Hi Guys,

I have everything working properly on my PWDR printer except the print head is not depositing any ink. I have followed this circuit diagram https://cloud.githubusercontent.com/assets/7737437/3249501/21dd69d0-f19a-11e3-98f1-02a42b635079.jpg and have designed and made a PCB from it. After doing some more research I realised that in that circuit pin 9 on the ULN2003 is connected to ground, shouldn't it be the power input? Should I have done this instead? https://cloud.githubusercontent.com/assets/1730691/3281767/10564322-f4c3-11e3-94e8-13815cda7d43.png

[Pwdr]

You're aboslutely right. I was recently notified about this error in the
drawing, but didn't find time to fix the drawing.

Could you please perform a pull request on the PDF and SCH files?

On Wed, Mar 4, 2015 at 9:21 PM, MasseyAlbany notifications@github.com
wrote:

Hi Guys,

I have everything working properly on my PWDR printer except the print
head is not depositing any ink. I have followed this circuit diagram
https://cloud.githubusercontent.com/assets/7737437/3249501/21dd69d0-f19a-11e3-98f1-02a42b635079.jpg
and have designed and made a PCB from it. After doing some more research I
realised that in that circuit pin 9 on the ULN2003 is connected to ground,
shouldn't it be the power input? Should I have done this instead?
https://cloud.githubusercontent.com/assets/1730691/3281767/10564322-f4c3-11e3-94e8-13815cda7d43.png

—
Reply to this email directly or view it on GitHub
#29 (comment).

[MasseyAlbany]

Thanks. I updated my circuit and I am now getting the print head working some of the time. I'm trying to figure out if it's an issue with the print head connections or the SD card and the file it's reading.

I have wired the print head like this https://cloud.githubusercontent.com/assets/7737437/3274785/2ff4e4c6-f334-11e3-8261-a1cbfe779800.png The problem is as it's printing, there is 3 or 4 passes before the ink sprays, then a few more passes afterwards, and the part it's printing should be bigger. So I am unsure if it is reading the correct file or a print head issue. I have designed and cut a PCB to house everything, pictures here https://www.dropbox.com/sh/ftttijcstzfvxao/AADmaTgWJSQOypBgm0luFfmUa?dl=0 (ignore the unused connectors at the top, they are so I can add limit switches later).

The SD card board I am using is like this one http://cdn.instructables.com/F6V/F1OJ/H5ENQ08B/F6VF1OJH5ENQ08B.LARGE.jpg and connected using the Arduino SPI connections (pins 50,51,52,53). I was wondering what you did for the SD card, looking at the pictures on the PWDR website there is no SD card on it.

Also, I had a look at performing a pull request on the PDF and SCH files but for some reason it would not let me.

[MasseyAlbany]

I have just done a test with a larger part and now I believe it's the print head not the SD card as it looks like some nozzles are not firing. I have added an extra picture to the dropbox link showing this. Yes I also need to adjust the Y-axis step size.