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Folger Tech 2020 Prusa i3 Build Log

#41
if the bottom layer is ok, and the rest not, double check your Z axis steps per mm. A quick ballpark check is just lifting the extruder say 100mm and measuring how much it actually moved. If your firmware is misconfigured (like for an M5 rod instead of M8), you'd notice this way.

The filament curling, is pretty common and no cause for concern.
 

markyoe

Senior Member
#42
if the bottom layer is ok, and the rest not, double check your Z axis steps per mm. A quick ballpark check is just lifting the extruder say 100mm and measuring how much it actually moved. If your firmware is misconfigured (like for an M5 rod instead of M8), you'd notice this way.

The filament curling, is pretty common and no cause for concern.
I checked the Z axis. When I told it to go up 100mm it only moved about 96mm. How do I change the Z axis steps per mm?
 
#43
Interesting thing!

Looking at the firmware image you provided, you are getting exactly what you should be getting (even though it is wrong).

The firmware is using 3840 steps per mm on the Z axis, but you should have it set to 4000. I am pretty sure you can do this in Repetier. If not, go to configuration.h and edit this line:

#define DEFAULT_AXIS_STEPS_PER_UNIT {80, 80, 3840, 90}

change the 3840 to 4000 and reupload the firmware. Test the motion again and you should be good to go.

The required Z steps is calculated based on the thread pitch of the 5 mm rods, the stepper driver, and the stepper motor.

A 5 mm rod has a pitch of 0.8 mm per revolution (or 1.25 rev/mm). The drivers have 16 x microstepping, and the motors turn 1.8 degrees per step. So the calculation is (1.25 rev/mm)*(16)*(360/1.8).
 
#44
I checked the Z axis. When I told it to go up 100mm it only moved about 96mm. How do I change the Z axis steps per mm?
Hmm.. 4% seems too little as deviation to explain completely messed up prints like that, and much of it may be measurement error. But if you want to verify the settings, have a look here to calculate your steps per mm:
http://prusaprinters.org/calculator/#stepspermmlead

Edit: wilsonb meanwhile already did the math for you.

But its probably something else. As others suggested, speed might be a factor, the bottom layer is normally laid down slower than the rest. As you speed up, lots of things can go wrong, like the stepper motors missing steps. It might be helpful to see some video.
 
#45
If all of the prints since that one have turned out the same past the first layer, it is likely a speed issue as everyone else has noted.

A couple of other things you may want check: Make sure your hotend isn't partially clogged, or another likely issue, check to make sure the tension on the extruder idler is set correctly (if adjustable, can't tell from the pics or the product page)
 

markyoe

Senior Member
#46
Hmmmm. I made the changes according to Wilsonb's directions. Now, when I connect the printer to Repetier Host, it says "Extruder switched off. MINTEMP triggered !" The extruder thermistor just reads 0 degrees now. It then proceeds to not let me anything except home the axis. Before this, the extruder thermistor would read something like 305 degrees and give a MAXTEMP error. I checked the thermistor and it read 102k ohms. Any suggestions?
 

markyoe

Senior Member
#47
If all of the prints since that one have turned out the same past the first layer, it is likely a speed issue as everyone else has noted.

A couple of other things you may want check: Make sure your hotend isn't partially clogged, or another likely issue, check to make sure the tension on the extruder idler is set correctly (if adjustable, can't tell from the pics or the product page)
Can you tell from this picture if the extruder idler is adjustable? When I would heat it up, it would slowly leak out the nozzle.

IMG_20151015_151723.jpg
 
#48
If it is oozing some then it is probably not a clogged extruder. I can't tell from that pic either.... If it is adjustable, there is going to be a screw near the lever that you move to insert the filament. It doesn't look like there is a hole on top other than the filament path so if adjustable it would be on one of the sides or from the bottom.

Here is a decent guide on getting the extruder calibrated as well:

https://www.youtube.com/watch?v=YUPfBJz3I6Y
 
#49
Hmmmm. I made the changes according to Wilsonb's directions. Now, when I connect the printer to Repetier Host, it says "Extruder switched off. MINTEMP triggered !" The extruder thermistor just reads 0 degrees now. It then proceeds to not let me anything except home the axis. Before this, the extruder thermistor would read something like 305 degrees and give a MAXTEMP error. I checked the thermistor and it read 102k ohms. Any suggestions?
Woah. Definitely time to talk to Folgertech on this. There is a problem with the connection on the thermistor. It loses connection and the heater doesn't register a temperature rise in the thermistor so it keeps on heating (up to 305C in this case!) and the firmware recognizes the problem once it reconnects and shuts the machine down.

The connection issue could be in the wiring of the thermistor (a static reading like you did doesn't always help because it needs to be a good connection with temperature and motion) or something in the connector. I would request a replacement from Folgertech.

Until you get this taken care of, do not do any unattended printing. The intermittent connection of your thermistor can cause serious issues beyond just the printer (like a fire!).
 

markyoe

Senior Member
#50
Woah. Definitely time to talk to Folgertech on this. There is a problem with the connection on the thermistor. It loses connection and the heater doesn't register a temperature rise in the thermistor so it keeps on heating (up to 305C in this case!) and the firmware recognizes the problem once it reconnects and shuts the machine down.

The connection issue could be in the wiring of the thermistor (a static reading like you did doesn't always help because it needs to be a good connection with temperature and motion) or something in the connector. I would request a replacement from Folgertech.

Until you get this taken care of, do not do any unattended printing. The intermittent connection of your thermistor can cause serious issues beyond just the printer (like a fire!).
The weird thing is that I don't think the thermistor barely heated up (if it even started) when it read 305 degrees. Do you think it is a connecting near the hot end or the ramps board?
 
#51
I wonder if you mounted the thermistor properly and if its not shorting out intermittently. I used to have problems with that. I finally came up with a fool proof way: first I wrap all 4 sides of the heat block in Kapton tape. Then I poke a hole in the tape where they predrilled the temp sensor hole. Insert the thermistor, bending one leg around each side of the block. Cover the thermistor legs in more kapton. Then connect them using fishing crimps to the wires.
 

markyoe

Senior Member
#52
I wonder if you mounted the thermistor properly and if its not shorting out intermittently. I used to have problems with that. I finally came up with a fool proof way: first I wrap all 4 sides of the heat block in Kapton tape. Then I poke a hole in the tape where they predrilled the temp sensor hole. Insert the thermistor, bending one leg around each side of the block. Cover the thermistor legs in more kapton. Then connect them using fishing crimps to the wires.
So I should be able to pull the thermistor out from the hot end?
 
#53
Last edited:

markyoe

Senior Member
#54
Did it come preassembled? I was glancing over the documentation and wondered why I couldnt find anything on that.

edit: nevermind, you have a screw-in thermistor, that should prevent most of the trouble I ever had. Would still be worth double checking, but I wouldnt disassemble it. For the record, this is more like I had to do it:
http://greymatterdroppings.com/prusa-i3-build-log-part-8-assembling-the-e3d-v5-hotend/
It is not loose or anything. Should I risk trying to pull it out by the smalled crimped metal piece or is that unnecessary? I have emailed Folger Tech regarding the thermistor.
 
#55
I would just measure the resistance while wiggling the wires, but thats probably as far as id go. Ive never used one of those, so Im not sure how they are assembled.
 
#57
Another thing you could try to isolate the problem; connect a 100Kohm resistor directly to the ramps board. Obviously dont turn on the heater then, or at least not for long. If the ramps board then registers a reasonable temperature, its likely a problem with the thermistor. More likely however, I fear the problem is with the ramps board. You already had to move it to another pin, something you shouldnt have to.
 

markyoe

Senior Member
#59
Wow! The board arrive today. I switched it out with the older one and fired up the printer. Here is the log that shows up on Repetier Host

11:42:37.446 : Printer reset detected - initalizing
11:42:37.446 : start
11:42:37.446 : echo:Marlin 1.0.0
11:42:37.446 : echo: Last Updated: Oct 15 2015 5-20-15 15:00:03 | Author: (FOLGER TECH, 8 i3 Prusa Config)
11:42:37.446 : Compiled: Oct 15 2015
11:42:37.462 : echo: Free Memory: 4519 PlannerBufferBytes: 1232
11:42:37.712 : Error:0
11:42:37.727 : : Extruder switched off. MINTEMP triggered !
11:42:37.727 : Error:printer stopped due to errors. Fix the error and use M999 to restart. (Temperature is reset. Set it after restarting)
11:42:39.868 : echo:SD init fail
11:42:39.899 : FIRMWARE_NAME:Marlin V1; Sprinter/grbl mashup for gen6 FIRMWARE_URL:http://www.mendel-parts.com PROTOCOL_VERSION:1.0 MACHINE_TYPE:FolgerTech EXTRUDER_COUNT:1
11:42:39.915 : X:0.00Y:0.00Z:0.00E:0.00 Count X: 0.00Y:0.00Z:0.00
11:42:39.915 : echo:Active Extruder: 0
11:42:39.930 : Begin file list
11:42:39.930 : End file list
11:42:39.930 : echo:Active Extruder: 0

I was disappointed to see that the MINTEMP error came up again. The thermistor extruder is the problem then?