User avatar
By Andy
#4379
ddelgrande wrote:So I have everything I need to build the pre-treater, so a few more questions: 

1.  I'm building the base out of OpenBuilds V-Slot Gantry Set and V-Slot Linear Rail coupled to 1 1/2" PVC Schedule 40 pipe.  I will T the pipe to build the riser extensions but wonder where I should place those extensions in relation to the the V-Slot which is 39" long.  I'll be using/making a platen that is 18" wide and 24" long.

2.  The Start and Purge buttons.  Does the polarity matter when connecting to the Pre-treater board?

3.  bStop = Limit Switch?

4. Length and Speed buttons.  With the buttons facing with the terminals up, from left to right, would that be minus, ground, plus?

Thanks, 
1: I put the nozzle towards the front of where the Epson printer would be if this was a printer base.
2: Polarity doesn't matter on those
3: This is the back stop limit switch
4: I will look and upload something soon but you just want to keep them in order. 5v - Signal - Gnd. If you keep them in a order the worst case is they are backwards and your knob operates opposite.

Sorry for the lack of documentation. I'm working on more documents and videos 
By ddelgrande
#4778
IMG_1754.JPG
Need verification if I had the pins labeled correctly.  I think I may have the 5V and GND reversed. 

Thanks
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User avatar
By Andy
#4779
I have the 5v and GND opposite in my notes. Worst case your knob works backwards and you then flip the wires.
By ddelgrande
#4780
Yeah, I thought I had it backward.  I looked at the diagram for the potentiometer but could make heads or tails of it!

Thanks 
By ddelgrande
#5157
OK, so I got my pretreater up and running on the first try now I just need to tweak a few things!

First off, priming the pump is a bit of a pain and I'm wondering what is the best way that will not use a lot of pretreat solution.   I'm just using water at this point to dial things in but would like to know the best placement of the gallon jug of pretreat with respect to the pump—how short can I make the tube run from the gallon to the pump.  Should the gallon be at the same height as the pump, or higher, lower or does it matter?

Right now with the speed and length knob set to their highest levels, the spray will cover about 12".  How can I make that longer?  I'm looking for a length of 18".

FYI, this is a really easy build compared to converting a P600.  If you've gone through that labyrinth of "gotchas" building/converting a P600, building a pretreat machine with the OpentDTG kit is a piece of cake!

Thanks
User avatar
By Andy
#5158
ddelgrande wrote:OK, so I got my pretreater up and running on the first try now I just need to tweak a few things!

First off, priming the pump is a bit of a pain and I'm wondering what is the best way that will not use a lot of pretreat solution.   I'm just using water at this point to dial things in but would like to know the best placement of the gallon jug of pretreat with respect to the pump—how short can I make the tube run from the gallon to the pump.  Should the gallon be at the same height as the pump, or higher, lower or does it matter?

Right now with the speed and length knob set to their highest levels, the spray will cover about 12".  How can I make that longer?  I'm looking for a length of 18".

FYI, this is a really easy build compared to converting a P600.  If you've gone through that labyrinth of "gotchas" building/converting a P600, building a pretreat machine with the OpentDTG kit is a piece of cake!

Thanks
Haha yeah the pretreater is a whole different level. 
Code line 215 you can change the maximum length by changing the 6400 step number
There are some side effects of going too short between the pump and the nozzle so keep the pump at least a couple feet away.  To prime remove the nozzle and hold the purge button, this should pump the air out.  Height of the pretreat gallon shouldn't matter too much.
By ddelgrande
#5159
On code line 215 I upped the step from 6400 to 11400 which gave me 18" of spray length.  Now I just need to lower the height of my spray nozzle.  It's currently at 8 1/2 above the platen and is spraying beyond each side of the platen by a couple of inches.  The platen is 18" wide so the spray is currently 22" (or thereabouts) wide.  

I going to reduce down to 7 1/2" and see how that works.  It's PVC so easily done. 

What I am going to build to keep the spray from going all over is an enclosure.  Should be easy enough to do build a frame out of PVC, but not sure what type of sheets to use for the sides/front/top.
By ddelgrande
#5162
I adjusted the spray height to 7 1/2" from 8 /2" and that seems to be the perfect height for an 18" wide platen.  
Now on to building the spray enclosure. 
By ddelgrande
#5222
Yes I need to post some videos and I will . . . promise! 

I had some time today to adjust the setting since my platen at times was getting stuck and I had to give it little push to get it going.  Now I built a rather large platen for my pre treater:  18" wide by 24" long using 3/8 HDPE plastic, so it has some heft to it.

To get it to work reliably I change the default setting in the settings.h file to the following: 

------------------------------------------------------

const int homeSpeed = 390;   // Step delay that controls platen speed when homing at startup. Lower is faster.  Default is 200
const int ejectSpeed = 300;  // Step delay that controls platen eject speed. Lower is faster.  Default is 200

const int maxSteps = 16900; // Maximum steps the motor takes to get from the back to the front. Controls where platen stops on eject. 
                      // NOTE: This max steps is on a base with 26.5 inches of travel, 30 teeth pulley, and 800 steps per stepper motor revolution.  Default is 17500

---------------------------------------------------------

One of the gotchas to note is the pre-treater should be level (that's obvious but you really need to get it level) and given the speed of the platen hitting the limit switch you should fasten the pre-treater to the table.  I didn't do this and given the size of my platen, and the speed that it hit's the limit switch, the whole pre-treater would move just enough to cause a failure 1 in 10 times  I just held the pre-treater with my hand so it wouldn't move and for 20 passes every was a go!

The other adjustment for me is the max steps.  It took me awhile to figure out where I wanted the back edge of the platen to stop (that would be the non limit switch end).  To long of a run and the belt would skip on startup but I wanted it as long as possible to get away from the sprayer.  I didn't shorten it much; from the default setting of 17500 to 16900.  

I'll try to post some video tomorrow.