Jammer's Ord Hadron build - Help Appreciated

Topics Related to the ORD Bot Printer

Z-axis

Postby flickerfly » Mon Nov 25, 2013 1:42 pm

I think I'd just turn up the pot on your Z just a little. It won't hurt to be a bit high. You may just get extra heat and noise, but it won't hurt them.

The endstops are used before every print to determine what 0 is on each axis so adjusting the position in software is always relative to that. I have an issue right now where my Y-axis won't home when I send the command and have to manually move it to the home position. I believe there is a place in slic3r to instruct it, using some G-code at the beginning of every print to home and you can probably find G-code to to home just the x and y and not the Z. That'll probably be the easiest way to toggle that on and off.

Once you have your Z endstop operating, you'll also want to use the Z offset to finesse the positioning. .1mm precision on the endstop is a bit tricky to attain.

Also, you'll want to know about the M119 G-code. You can enter that manually to see the current state of the endstops.
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Re: Jammer's Ord Hadron build - Help Appreciated

Postby jb92563 » Mon Nov 25, 2013 3:30 pm

I'm just wondering why its of any importance how accurate the endstops are?

I figure that as long as your print job completes successfully in one session and it does not have to go home and then continue where it left off, the precise location of 0,0,0 to 0.1mm is of no importance unless you want to print to within 0.1mm of the edges of your print bed.

The Z location relative to the Print bed surface is of course important because it needs to start at the surface, not in the air or worse below the surface.

The Auto bed leveling feature is a great innovation for this as I imagine it also sets the Z axis home?

Am I missing some important point to the preciseness of the Home location for the x and Y axis?
I am still new to all this so I thought I would ask.
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Re: Jammer's Ord Hadron build - Help Appreciated

Postby flickerfly » Mon Nov 25, 2013 3:38 pm

Oh, no. You can actually set in repetier to have your X and Y homes be at negative values. My X home is at something like -20 and my print area starts at 0 or you can set you home to 0 and your print area to 20. I'm more concerned with the precision on the Z due to the importance of where it starts. The rest just impacts your print area. You may end up running off one edge and not coming close to another on the X or Y, but like you said, that doesn't matter until you print something that approaches the edge.
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Re: Jammer's Ord Hadron build - Help Appreciated

Postby jammer » Tue Nov 26, 2013 4:30 am

jb92563 wrote:I'm just wondering why its of any importance how accurate the endstops are?

I figure that as long as your print job completes successfully in one session and it does not have to go home and then continue where it left off, the precise location of 0,0,0 to 0.1mm is of no importance unless you want to print to within 0.1mm of the edges of your print bed.

The Z location relative to the Print bed surface is of course important because it needs to start at the surface, not in the air or worse below the surface.

The Auto bed leveling feature is a great innovation for this as I imagine it also sets the Z axis home?

Am I missing some important point to the preciseness of the Home location for the x and Y axis?
I am still new to all this so I thought I would ask.



I am a noob as well and haven't printed anything successfully yet so take what I say with a grain of salt. All I know if from trying to get it set up. The x and y endstops precision is not a big deal at all as you said. It doesn't really matter where you print on the bed as long as it does't try to print off the side. The issue for me came from not being able to accurately set the z min endstop to where the extruder was at the proper height above the bed. I thought I could adjust the end top to where the hotend was just at the bed level and that I could manually set the home location using the "Set Home" button on the print panel in Repetier-Host with the z axis being a sheet of paper thickness above the bed. That would work fine until I hit the print button. The Home All command in the G-Code would send all of the axis searching for the endstops regardless of where I set the z-axis to using the "Set Home" button. This would try to drive the hotend down through the bed. Thank goodness I had springs on my bed because it would compress them. As soon as I disconnected the endstop and disabled it in the firmware then everything functioned as I thought it should. I would use the "Set Home" button when I had the hotend just above the bed and when I hit print it would work fine.
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Re: Z-axis

Postby jammer » Tue Nov 26, 2013 4:34 am

flickerfly wrote:I have an issue right now where my Y-axis won't home when I send the command and have to manually move it to the home position.


Flicker,

Try setting the following in the configuration.h in the firmware:

#define Y_HOME_DIR -1


Since I was using your firmware as the starting point I was having the same issue with the y-axis not homing. I was trying everything and when I changed the above line from

#define Y_HOME_DIR 1

to

#define Y_HOME_DIR -1

It started working.
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Re: Jammer's Ord Hadron build - Help Appreciated

Postby jammer » Tue Nov 26, 2013 4:46 am

It is amazing how much you learn after you can put some power on your printer. I tried to print the test cube a couple of nights ago. The z-axis moved fine when I would move it using the position buttons in the "Print Panel" of Repetier-Host. As soon as I hit the print button the z-axis motors would intermittently stop and make a loud buzzing noise. I did some research and thought the issue might be that I wired my z-axis motors in parallel so I made up a new serial harness and connected it tonight. Same issue. I kept repeating the problem and noticed that it happened every time at the same point, just after I hit the print button. In looking at the G-code that was generated by Slicer, I noticed that there was a

G1 Z5 F5000 ; lift nozzle

In researching this command I found that the F5000 was telling the z-axis to move at a ridiculous speed that it was simply unable to do. Changing it to:

G1 Z5 F200 ; lift nozzle

completely eliminated the problem for that command. I also had to set the EEPROM Mode to 0 since I couldn't figure out where in the EEPROM settings the z-axis max feedrate setting was. After setting the EEPROM Mode to 0, I set the

#define MAX_FEEDRATE_Z 200

Now everything works beautifully. I just need to get the ABS to stick to the glass bed and I will be cooking!
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Re: Z-axis

Postby flickerfly » Tue Nov 26, 2013 1:52 pm

jammer wrote:Since I was using your firmware as the starting point I was having the same issue with the y-axis not homing. I was trying everything and when I changed the above line from

#define Y_HOME_DIR 1

to

#define Y_HOME_DIR -1

It started working.


Thanks! Currently with my FT321X chip burnt out I can't seem to program. I'll need to fix that first. I'm resisting because I can't find a place that'll ship it for less than twice the cost of the chip. :-) I'll break down eventually. I wonder when I managed to flip that. Clearly it's been awhile.
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Re: Jammer's Ord Hadron build - Help Appreciated

Postby jammer » Fri Dec 06, 2013 5:58 am

I was finally able to get some ABS to start sticking to the bed. I cleaned the glass about 4 or 5 times with dish soap, then acetone and then two heavy coats of Aqua-Net. The test cube came out to be about 9mm square but looked funny. I had put off calibrating the extruder and that was a mistake. I have a Wade Reloaded with a gear ratio of 47/9 and I had the 1.8 degree/step motor set to 16 micro steps. Initially I had calculated 709 steps/mm but when I went to calibrate it I had to bump it up to 946.135 to get it to feed an accurate amount of filament into the extruder. The first cube print following the extruder calibration is shown here (bottom side up):

Bed Temp: 120C
Extruder Temp 235C

calibrationcube.JPG


It started out fine but I soon noticed that it was twisting the cube as it added layers. It is hard to see since it is upside down but the corners looked higher than the rest of the perimeter. I had read that too high of an extruder temp can cause that. I changed the extruder temp and tried it again:

Bed Temp: 120
Extruder Temp: 225C

calibrationcube2.JPG


It still twisted but not as much. The printer locked up after my RV heater kicked in almost half way through the print.

What would cause the twisting? I am wondering if the bed is too hot. Also I found that two thick layers of Aqua-Net stinks like crazy when heated to 120C. That smell was much worse than the ABS smell that I could hardly detect. I was like having someone spray the hairspray up my nose. I did have all of the windows & door open in the trailer. Looking at the bottom of the first print I think it looks pretty good except for the twisting. Overall pretty happy that something stuck to the bed after a few days of not being able to get anything stuck. I think the extruder was not putting out as much filament as it though and it ended up dragged and stretching the molten filament. Ideas of what to change next?
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Re: Jammer's Ord Hadron build - Help Appreciated

Postby flickerfly » Fri Dec 06, 2013 1:47 pm

Yeah, my ABS extrusion tempertatures are much lower and on a small block like that, the heat won't have time to escape. The twist may simply be related to the whole things being warm enough to slide the layers around. I print ABS around 200C. It's early so I can't remember exactly.
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Re: Jammer's Ord Hadron build - Help Appreciated

Postby DonaldJ » Fri Dec 06, 2013 5:54 pm

What is your print speed?

You could try slowing it down, allowing a bit more time for the layers to cool. Or, you could print multiple copies, allowing more cooling time for each piece.

I can't tell if you're getting good layer adhesion. Is your layer height about half to 2/3rds the nozzle diameter? You may have to tweak that a bit, too.
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