DIY DTG - Build your own Digital T-Shirt Printer

 
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Andy
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Re: OpenDTG Pretreater Control Board

Mon Feb 27, 2017 8:16 am

MetalGuru wrote:
Great!

I changed the code and now it is working very well!

Thank you!

Will we get to see the beast in action?
 
MetalGuru
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Re: OpenDTG Pretreater Control Board

Tue Mar 28, 2017 3:01 pm

Here are some pictures of the pretreat machine so far.
Still in prototype stage for looks, but it works well.
Assembled it with openbuild parts I had lying around.
May need to change the pump I have, not sure tho.
I have a 60psi pump and the spray pattern is dense in the middle and lighter on the edges. Not too bad, but want to have a more perfect spray pattern.
I am waiting for a new nozzle tip to see if that will fix it.
If not, I will try to increase pressure.


pretreat22.jpg

[attachment=1]pretreat33.jpg[/attachment]
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MetalGuru
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Re: OpenDTG Pretreater Control Board

Tue Mar 28, 2017 3:04 pm

One recommendation I would add is to turn off the motor when it is resting at the front.

Similar to the DTG code.

Not sure if I could just copy that part from the dtg code, or if there would be a more specific way to do it.
 
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Andy
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Re: OpenDTG Pretreater Control Board

Tue Mar 28, 2017 3:16 pm

MetalGuru wrote:
One recommendation I would add is to turn off the motor when it is resting at the front.

Similar to the DTG code.

Not sure if I could just copy that part from the dtg code, or if there would be a more specific way to do it.

That is a good idea so it doesn't get hot. 
// Motor Off
digitalWrite(motorEnable, LOW)

// Motor on
digitalWrite(motorEnable, HIGH);
 
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Andy
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Re: OpenDTG Pretreater Control Board

Tue Mar 28, 2017 3:17 pm

How is that solenoid working out? The ones I get work great but are $110 ish. I've seen those like you have for cheap on amazon.

I notice a much more even spray with a 100 psi pump vs 60 psi, also its better (I think you do) if you have a decent amount of line between the pump and solenoid. If you got to 100 psi use a braided line so it doesn't blow up like a balloon.
 
MetalGuru
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Re: OpenDTG Pretreater Control Board

Tue Mar 28, 2017 3:59 pm

The solenoid works well. Not sure how long it will last, but it does work.

The assembly does drip a little bit after shutoff sometimes. Not enough for me to worry about it tho.
 
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Andy
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Re: OpenDTG Pretreater Control Board

Tue Mar 28, 2017 4:15 pm

MetalGuru wrote:
The solenoid works well. Not sure how long it will last, but it does work.

The assembly does drip a little bit after shutoff sometimes. Not enough for me to worry about it tho.

Take the nozzle off and do a purge to flush the air out of the lines. If I have air in the lines I get a trailing off of drips, but without air in the lines it's a quick off.
 
ddelgrande
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Re: OpenDTG Pretreater Control Board

Tue Apr 04, 2017 3:52 pm

MetalGuru wrote:
Here are some pictures of the pretreat machine so far.
Still in prototype stage for looks, but it works well.
Assembled it with openbuild parts I had lying around.
May need to change the pump I have, not sure tho.
I have a 60psi pump and the spray pattern is dense in the middle and lighter on the edges. Not too bad, but want to have a more perfect spray pattern.
I am waiting for a new nozzle tip to see if that will fix it.
If not, I will try to increase pressure.

Nice build!  Where did you get the box to house the electronics?  I'm just about to wire mine up and was thinking of using a Tupperware box.  Also, where did you house the pump.  I'm not sure where to place/mount.  Does it matter?
Thanks! 
 
ddelgrande
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Re: OpenDTG Pretreater Control Board

Tue Apr 04, 2017 4:44 pm

I was trying to find info on how high to place my nozzle above my platen which is  18" wide by 24" long.  I came across an article from UGA (Universit of Georgia Ag) which show for a 95 degree Even Fan Banding Nozzle (which is used in the OpenDTG Pretreater kit) the ratio between nozzle height and bandwidth is 1 to 2.

Question is this correct information correct?

Go to the following link since the table that shows the height to bandwidth ratio did not display correct on this forum. 

http://extension.uga.edu/publications/d ... mber=B1158

Even flat-fan nozzles apply uniform coverage across the entire width of the spray pattern (Figure 3). This type of nozzle is used for banding chemicals over the row. The recommended operating pressure for even flat-fan nozzles is between 20 and 30 psi. The width of the band produced is determined by nozzle height. The band widths produced for various nozzle heights are shown in Table 2.




[table][tr][td]Table 2. Nozzle height for 80- and 90-degree even flat-fan nozzles in inches.[/td]
[/tr]
[tr][td]Band Width (inches)[/td]
[td]80 degree[/td]
[td]95 degree[/td]
[/tr]
[tr][td]8[/td]
[td]5[/td]
[td]4[/td]
[/tr]
[tr][td]10[/td]
[td]6[/td]
[td]5[/td]
[/tr]
[tr][td]12[/td]
[td]7[/td]
[td]6[/td]
[/tr]
[tr][td]14[/td]
[td]8[/td]
[td]7[/td]
[/tr]
[/table]
ImageFigure 3. Even flat fan procedures uniform spray deposition.
 
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Andy
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Re: OpenDTG Pretreater Control Board

Sat Apr 08, 2017 3:49 pm

I'm not sure how accurate that is. I found that I got the most consistent spray pattern at 100 PSI.

I figured with all of the different variables it was easiest to just turn the sprayer on at different heights and measure the width of the spray until I get what I desired.

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