Newbie needing help!!

Hello fellow reprappers,
I am currently building my first reprap, and I'm having some problems.
I'm using RAMPS 1.4 with an Iduino Mega 2560.
Basically, I connected all the stepper motors, drivers, and boards together, and opened Pronterface. I can control the Z, X, Y motors, but when I try to get the extruder motor to move, nothing happens. I can't even hear any current going through the motor.
I tried adjusting the pot, and I've experimented a lot, so I'm pretty sure it's not the motor, the stepper driver, or the Mega.
I am using arduino 0023 with Sprinter.
I am stumped as to what's wrong. Any ideas? I don't know a whole lot about adjusting the firmware, so if there's a way to fix it that way that would be great.
Thank you in advance for your help.
3D-ME

This may sound like a dumb question... but are you trying to move the extruder motor by hitting "Extrude" button when the hot end is not heated up by any chance?

If I try to do that, the following message comes up in the Pronterface message window:
"echo: cold extrusion prevented"

I tried hitting "Extrude" button when it was cold and nothing happened, so I heated my hot end up and then I hit the "Extrude" button, but nothing happened that time either. I'm not sure if my hot end was at its target temp or not when I hit the button, so I might try that again.
When I hit the "Extrude" button while the hot end is cool, I don't get any message, Pronterface just says "Extruding 5mm of filament". Maybe there's something wrong with Pronterface then. I'm not sure.
I have another quick question: I have a 6.8 ohm 3w heater resistor for my hotend, but it seems to be a little under-powered for my hot end design, so I'm wondering, will a 12v 40w ceramic heater cartridge provide more heat?

I used to have 6.8 ohm 3w heater resistor in the hot end I currenlty use. I now have a 40w ceramic heater in it. The difference? Actually, I have not noticed any.

I think 40W resister must heat up the hot end more quickly, but I never had any problem with quickly reaching to the needed temperarue with 3W resistor, either. The hot end reaches to the operating temperature long before the heated bed does (I usueally preheat the hot end instead of letting Proterface heat up the heated bed first and then turn on the hot end), so I haven't really been paying attention.

By the way, at what hot end temperature did you try to extrude? You said your hot end reached the target temperature, but didn't mention what that target temperature was.

In my case, I think the minimum temperature for extrusion is 175C. With anything below I get the error message I mentioned, which is one of the settings defined in the firmware.

Okay, well I inadvertently solved the problem with my extruder, but created a bunch of other problems! The extruder motor turned when I hit the "Extrude" button, but the motor its self actually felt pretty hot. (not sure why.) I've spent all afternoon fixing the other problems, and I'm now back to square one: the extruder is now not working, but everything else seems to be working. I have a suspicion that it is not working because either my firmware (Sprinter) is configured wrong, or my Iduino Mega 2650 isn't properly working. I think the former is more likely.
As I said earlier, I know little about firmware or coding, so if anyone knows how to fix the problem via code, I'd be a happy camper!
I have only the five motors attatched to my Ramps board right now, and I'm "printing" a file. The X and Y motors are moving, but the two Z motors and the extruder (E) motor aren't. I know this sounds like a dumb question, but could it be a problem with my slicer? (I'm using Slic3r.)
I also tried moving the extruder while my hot end was at 180 C, (the target temp,) but it still didn't move even though Pronterface said "extruding 5mm of filament".
Any suggestions?

Info... If you have no filament going to the extruder, then you can test the motor cold.
Also, a 6.8 ohm resistor generally takes longer to heat the hotend but should still work fine.

Ok, on to the problem..
What did you alter/change in Sprinter before you uploaded it?
Have you plugged the extruder motor into the X or Y port and checked it for operation?
Ditto for the Z motors?

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Waitaki 3D Printer

3D-ME Wrote:
-------------------------------------------------------
> I have another quick question: I have a 6.8 ohm 3w
> heater resistor for my hotend, but it seems to be
> a little under-powered for my hot end design, so
> I'm wondering, will a 12v 40w ceramic heater
> cartridge provide more heat?

It will, but requires precautions against fire, as if it becomes stuck on it will get much hotter than a resistor.

@Waitaki
I have plugged all the stepper motors in different ports, so I am pretty sure It's not any of my motors that are the problem. I did the same to my stepper drivers, so I doubt they're the problem, either.
As for altering Sprinter, I changed:
#define BAUDRATE 115200
To: #define BAUDRATE 250000
I commented out #define SD support
I changed #define THERMISTORHEATER 1
To: #define THERMISTORHEATER 7
I also changed #define _AXIS_STEP_PER_UNIT {80, 80, 3200/1.25,700}
To: #define _AXIS_STEP_PER_UNIT {80, 80, 3200/2272.7272}
I wonder if that is the problem...
I also have another problem: my fans won't respond to my M106 commands any more. Can this be fixed in the firmware? And if so, how?

I think I just solved the extruder problem!!
As I was checking over the Sprinter file to see what I changed, I realized that I had changed:
#define _AXIS_STEP_PER_UNIT {80, 80, 3200/1.25,700}
To: #define _AXIS_STEP_PER_UNIT {80, 80, 3200/2272,7272}
I then changed that code back to what it originally was, then re-uploaded it to the board.
The extruder motor now seems to respond correctly to my commands!
The motor its self is getting really hot to the touch, though. I tried another motor, but got the same problem. Any advice?
The Z motors are now also moving when it is "printing", too!
I still have a problem, though.
When I am "printing" a file (I'm not actually printing, only my motors are hooked to RAMPS,) the X and Y motors move, but it doesn't look like they are moving like they should. Sometimes they will just sit still for like 30 seconds while the extruder motor is still going, but Pronterface will show that the object is still being filled, then one of them might turn some more, then stop.
Is this something I can fix in the code?
Thanks for your help, input, and advice!
Now if I could only use that hot stepper motor to heat up my hot end...

Crikey, no wonder the extruder didn't work >>{80, 80, 3200/2272,7272} How did that happen?
3200/1.25 (which is 2560) refers to the Z steps. Don't change that setting if you have 8mm threaded rods.
"700" refers to the initial setting for extrusion - its just a ball park figure, you will need to play with that when you're ready to try actual printing.

Did you select "33" for your board type?
I would set baud rate to 115200 for the time being

Set the voltage on all the pololu drivers to 0.4 volts and see how that goes - motors should only really get warm.

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Waitaki 3D Printer

If your extruder motor is too hot, turn the current down (trimpot on the stepper driver). If it's set too high the motor will heat up.

I have NO idea why I ever changed it from {80, 80, 3200/1.25,700} to {80, 80, 3200/2272.7272}! I think I must have inadvertently changed it when I first uploaded it to my board.
I have my board type as "33". I'll change my baudrate back to 115200, too.
I turned the trimpot down, and now the stepper motor doesn't heat up so much. (Hooray!)
My fans are now working! I realized that my cooling fan mount was disrupting my Ramps' board connection with my Mega.
Is it possible that the X and Y motors are acting like they are because I don't have any endstops attached?

Edited 1 time(s). Last edit at 09/07/2013 04:05PM by 3D-ME.

You didn't say whether you've adjusted the "X and Y" trimpots to see if the motors come to life..
Your motors may move without endstops connected but may crash into the frame looking for them! (Mine are normally open which is not usually the way they are connected by other builders.) Perhaps someone who does connect them normally closed can report here.

Edited 1 time(s). Last edit at 09/07/2013 08:34PM by waitaki.

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Waitaki 3D Printer

Okay, so I was able to fix the X and Y motor problems by changing:
const bool X_ENDSTOP_INVERT = false;
const bool Y_ENDSTOP_INVERT = false
To:
const bool X_ENDSTOP_INVERT = true;
const bool Y_ENDSTOP_INVERT = true;
I don't exactly know why it works because of that, and I may need to change it back when I put endstops on my board, but at least I know the problem now!
Thank you to everyone who has helped me and offered advice, I really appreciate it!

The way the endstops work is that the switch is either open or closed. If you're only using two wires, this usually means that you've connected wires to the COM connection on the switch (common pin) and either NC or NO.

With two wires, most people use pins 1 and 2 on the board. These are the signal (pin 1 - the one the software looks at) and the ground (pin 2 - 0 volts).

(For this type of 2-wire config to work, pullup resistors need to be enabled in firmware - this pulls the signal up to 5V unless a connection brings it back down to 0v).

Now, whether you need to invert them depends on if you wired that second wire to the NO or NC contact on the switch.

I usually recommend using the NC contact. This way, if the wire is broken (or the connector falls off) it appears as though you've triggered the endstop when you shouldn't have.

As a test, before I use a machine, I always send code "M119" to the printer to see what state the printer things the end-stops are in. This way, I know that they're working before I attempt a print. I also use this if I move the machine from place to place, as it's easy to bump or break something in transit but not notice till it's too late.