Extruder only working when testing, not during printing.

Hi all,


This is my first post. I don't usual come to forums for help, I normally like to figure things out for myself, but this time it's driving me nuts.

I have a little problem with my extruder not extruding when printing. This is a freshly built custom printer. It has never printed before. I built it myself and I sort of made things up as I went along...
All motors are Nema 17 steppers. All Axis(es) have a direct timing belt to the motors (meaning: if the motor turns 1mm, the axis will move exactly the same amount, no calculations of threads needed).
The bed is fixed because it's quite large (500x600mm), and I have limited space, so the whole rig moves backwards and forwards for the Y-axis.

All motors are rated at 200 steps per revolution.
I'm using Arduino Mega + Ramps 1.4 + DRV8825 drivers and a RepRapDiscount full graphics smart controller display.
I have the 3 jumpers installed under each motor driver, allowing 1/32 microstepping)

1.75 PLA filament.
0.4mm Nozzle

I have the minimum extrusion temperature set to 200ºC in Marlin

Everything works fine. I can boot up into Marlin, and use most of the functions there (I say "most" simply because I haven't tried them all, but everything I tried, worked).


So I can move all axis motors from the LCD controls or from software (I have both Cura and Repetier - on an iMac), and I'm mainly using Repetier with Slic3r. I can heat up the hotend and I can manually extrude the filament. If I give an order to extrude 10mm, that's exactly how much comes out (I measured the filament).

If I try to print a 10x10x10mm cube, the printer heats up the hotend to 205ºC, then homes perfectly, moves to initial position and starts doing all the movements as if it were printing, but no filament comes out.


In the G-Code I can see values for the Extruder being sent. Here are the top few lines:

; generated by Slic3r 1.3.0-dev on 2018-06-04 at 16:58:40

; external perimeters extrusion width = 0.44mm (3.38mm^3/s)
; perimeters extrusion width = 0.48mm (7.54mm^3/s)
; infill extrusion width = 0.48mm (10.05mm^3/s)
; solid infill extrusion width = 0.48mm (2.51mm^3/s)
; top infill extrusion width = 0.48mm (1.88mm^3/s)

M107
M104 S205 ; set temperature
G28 ; home all axes
G1 Z5 F5000 ; lift nozzle

; Filament gcode

M109 S205 ; set temperature and wait for it to be reached
G21 ; set units to millimetres
G90 ; use absolute coordinates
M82 ; use absolute distances for extrusion
G92 E0
G1 Z0.400 F7800.000
G1 E-2.00000 F2400.00000
G92 E0
G1 X39.827 Y40.720 F7800.000
G1 E2.00000 F2400.00000
G1 F1800
G1 X41.583 Y39.220 E2.27422
G1 X43.743 Y38.405 E2.54845
G1 X45.000 Y38.286 E2.69842
G1 X55.000 Y38.286 E3.88607
G1 X57.275 Y38.683 E4.16029
G1 X59.280 Y39.827 E4.43452
G1 X60.780 Y41.583 E4.70874
G1 X61.595 Y43.743 E4.98297
G1 X61.714 Y45.000 E5.13293
G1 X61.714 Y55.000 E6.32059
G1 X61.317 Y57.275 E6.59481
G1 X60.173 Y59.280 E6.86904
G1 X58.417 Y60.780 E7.14326
G1 X56.257 Y61.595 E7.41748
G1 X55.000 Y61.714 E7.56745


I have tried messing with the Extruder's FEEDRATE settings. In fact, I have tried several values from 5mm/s to 45mm/s and the result is always the same.
I'm also a bit confused at the part about motor speeds. Initially I had set DEFAULT_AXIS_STEPS_PER_UNIT to 6400. I calculated that each motor does 200 steps per revolution, and each step can be subdivided into 32, so 200x32 = 6400 right?... Well, no. Eventually I found that I had to set DEFAULT_AXIS_STEPS_PER_UNIT to 200. And strangely enough, I had to set X_MICROSTEPS, Y_MICROSTEPS, and Z_MICROSTEPS (in configuration_adv.h) to 16 (I have no idea why the hell it works like this). Only then (after playing a lot with all these values) did I finally get the printer to move in a sensible way (ie. when I issue a 10mm command, it finally moves just 10mm instead of trying to go all the way to the end of the axis, which in my case is quite far - 600mm).

So this is basically 2 questions:

1. What's up with these stepper values, and how the hell can it work like I have it set up? (motor steps at 200, jumpers set for 32 microsteps, and microstepping set to 16 in configuration_adv.h)
2. Any idea why extruder won't extrude when printing?

I have attached my Configuration.h file and my configuration_adv.h file.
(I also messed around with some acceleration settings. I want this printer to be slow, because it wobbles a bit at high speeds. This first build is supposed to be just good enough so that I can print my own parts and build a more stable printer. I am happy with the speed I am getting now. I do not want to make it faster.)

I also attached 3 photos. 1 of my extruder and hotend, one of the RAMPS 1.4 connections, and one of the little rig that allows me to use a timing belt on the Z-axis instead of using a long threaded rod.

I hope you guys have a few suggestions that I can try, or better still, if you can spot where I messed up in my configuration file.


Thanks in advance


P.S.

What ever happened to Y-Axis being the vertical one? All my life, in 3D apps, the X is width, the Y is height and the Z is depth. Suddenly in Marlin Y is depth and Z is height... Strange? (or is it just me?).

First thing I note

"// Microstep setting (Only functional when stepper driver microstep pins are connected to MCU."
On a ramps microstepping is set via the jumpers under the stepper drivers only. No need to set it in configuration_adv,h That does nothing.

Steps/mm depends on belt tooth spacing and number of teeth on pullies

200 steps per revolution (1.8 degree per step)
1/32 microstepping
16 tooth pulles (guessing)
2mm ptch belts (guessing)

Steps per mm = ((360°/Motor step size°) * (1/Driver microstepping))/(Belt pitch * Tooth count)
=((360/1.8) * 32)/(2 * 16)
=6400/32
=200 steps/mm

"What ever happened to Y-Axis being the vertical one? All my life, in 3D apps, the X is width, the Y is height and the Z is depth. Suddenly in Marlin Y is depth and Z is height... Strange? (or is it just me?)."

Its never been that

Z has always been Up/Down in reprap (at least for the 8 years ive been doing this)

Edited 1 time(s). Last edit at 06/04/2018 09:02PM by Dust.

Re e not moving...

Is temperature reading correctly? (as in reading to high and filament hasn't actually melted yet)
what does m503 say about E acceleration and steps/mm (as eeprom may be different setting from firmware)
Does it try to move? vibrate at all?

Edited 2 time(s). Last edit at 06/04/2018 09:07PM by Dust.