Building a concrete 3D printer - need help with movement

Hello everyone,

We've been working on this for quite a while and finally all the hardware is set up.

We are trying to get Rumba + Marlin working now.
The control software we would like to use is Simplify3D with a custom profile.

Everytime we turn on the motors, you can hear the humming of the motors being energised.
But there is no movement when we try to move the X, Y and Z Axis. Even with the extruder motor, there is no movement.

We have already set Motor current limits (VREF) on the motor driver to 0.9
(Current limits = VREF x 2, the current limits for these motors are 1.8A)

Currently when we try to move the motors via the Simplify3D control panel, the voltage reading on the motor output is 2.8V.

I'm not sure what is going on but I have a few ideas.

1. There may not be enough voltage to the motors - how do we adjust that while still keeping within the current limits?
2. Microstepping settings on the motor driver - although is this were the case, I would assume that there would still be movement albeit it just would not be sufficient.
3. Jerk and Acceleration settings
4. Simplify3D Settings - Don't think Simplify3D is respecting the firmware settings. Is this even possible?

Here is a copy of the Firmware:
[drive.google.com]

Here are the motors we are using:
[www.omc-stepperonline.com]

Here is the motor driver:
[www.panucatt.com]

Here is where we got our RUMBA board:
[www.geeetech.com]

Thank you for the help in advanced! I'm fairly new to this and it's a project that we're just trying out at the moment!

send a m119 to the printer (endstop status) any that are triggered it will refuse to move in that direction.

How have you disabled the extruder thermistor... The printer will just halt if it cant find a thermistor (normally)
I see TEMP_SENSOR_0 1 so you better have something on that port (most just hook up a 100K resistor on it, so it thinks its always 25c)

motors say "24-48V" what voltage are you feeding it? the board says it can be 12v-35v

Why are you using marlin-rc? is new and buggy.. I would stick with release branch, at least till you have it working.
[github.com]

Edited 3 time(s). Last edit at 12/16/2015 02:27AM by Dust.

Hey,

As for thermistors. we hooked up a 100k thermistor, exactly as you mentioned.

I did not notice this was Marlin-RC - Thanks for pointing that out!.

the problem is really with the voltage probably. We're not feeding it enough.
How do I check this?

Also about the m119, will have to do that and rectify it. Don't think I did a very good job with the wiring there though!

thanks for the information! I really do appreciate it. Slight headaches have now eased!

Shafiq

Basically what voltage does your power supply say? The one that’s is plugged into the MAIN-PWR plug this is fed directly to the steppers.

This is probably 12v... for you 24volt is probably minimum voltage

We're using a 24Volts, 14.6 Amp power supply.

When I check the Main-PWR plug on the Rumba, it says 24V.

Its probably not your power supply then, check those endstops.

Yeah I guess so.

But would that affect the extruder too?

Extruder has its own checks, will not extrude unless hot for eg... (you will have to over ride that send M302, to enable cold extrusions)

Ah ok.

sounds like there is a lot of testing and calibration to do.

I shall get to this.

currently redoing all the settings with the older version of Marlin.

Thank you so much for the help so far.

Other things to check...

Stepper wiring, its really easy to get this wrong.
Basically there are two coils. reprap coil A is on pins 1 and 2, and coil B is on pins 3 and 4. color codes should be ignored... check with a multi meter wich wires are a coil.

Ah yes.

That's true also. The color codes may not necessarily be universal.

Although I do hear the motors energising, there is that low hum..

But ok, yet another thing to check.

Shafiq

1. Check the stepper motor wire pairing, as has been suggested already.

2. Reduce the motor current setting on the stepper drivers. You should not run the motors at their maximum current, because they will get very hot. Also, the stepper driver modules may well overheat at 1.8A. The 2.5A rating quoted is a theoretical one for the driver, with better cooling than that module provides. Try 1.4A.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

At the moment, after sending instructions to the motor, when we measure the output it's at 2.8V.

I wasn't sure why this is happening. But then now i realise it may be the wiring. Shouldn't just believe the wires.

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Read our blog at www.everyoneacreator.com

How are you measuring output?
Motor drive is Pulse Width Modulation (PWM) out to each coil (wire pair)

Using a multimeter on AC won't work.
Got to use a scope to look at output signal and measure pulse height (voltage).

Are the dip switches under driver boards set correctly
[reprap.org]

Quote
mekastudios
At the moment, after sending instructions to the motor, when we measure the output it's at 2.8V.

I wasn't sure why this is happening. But then now i realise it may be the wiring. Shouldn't just believe the wires.

Hey cozmicray,

Your thoughts on dip switches were spot on. Ours were all over the place, have switched them all off to Full Step.

I will have to get an oscilloscope, not very familiar with electrical and electronic systems. It's a good learning experience this project.

I checked the wires on the motors as Dust and dc42 mentioned and that was one part of the problem too. The wires were a bit haywire. the way I did this was to put two wires together and try and see if there is any resistance to turning the shaft of the motor. If there was then those two wires are a pair. A bit of a rudimentary method, but it works.

The motors are all moving now. It's now about the axis steps per unit and tuning the axis actually. We are using a gear and chain mechanism for this baby, so it's a lot of trial and error to get it right.

Anyone interested in seeing a photo/video?

Thank you very much for all the help so far.

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Read our blog at www.everyoneacreator.com

Unless you have a large gear reduction, don't use full steps. Use 1/16 microstepping or 1/32 microstepping. Aim for steps/mm of betwee 80 and 200, except that for the Z axis of a Cartesian printer it can be as high as 4000.

Don't bother trying to measure the motor voltage, it's not easy and not necessary if you have the current set correctly.

Edited 1 time(s). Last edit at 12/17/2015 02:01AM by dc42.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Great.
Thanks for the advice.

Here are some photos of our build at the moment.

[drive.google.com]

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Read our blog at www.everyoneacreator.com

PS - my recommended steps/mm of 80 to 200 was based on standard 3D printer nozzle sizes and speeds. What nozzle size are you using, and what print speed do you hope to achieve?

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

You need some serious wire management.
Consider using shielded twisted pair for motor drive lines
the high frequency drive can cause weird things to happen.

Also shield the end stop switch wiring!

consider some drag chain
[www.inventables.com]

@dc42,

We are going to use a 10mm nozzle, designed by us. I guess for the extruder portions, we're going to have to make changes as we go along.

My main concern really is the X, Y and Z movement at the moment.

@cozmicray

Yesh! I'm in need of some serious cable management. Thanks for the suggestion on drag chain. I

As for the endstops, I really just wanted to check everything first than do the cleaning up, but I do think I should shield it.

We're actually gonna re-do all the wiring once the main thing is set up!

Updates:
At the moment, the x axis and extruder are working fine.

the y and z axis are another ball game. We have two motors on each axis wired up together and i'm not sure there is enough power to move the whole axis.

Ah well, just have to keep experimenting.


Shafiq

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Read our blog at www.everyoneacreator.com

How do you have the pairs of Y and Z motors wired? They will probably work better in series than in parallel.

---

Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

Hey dc42,

yeap after some confusions, we've now wired them in series.

It's now probably all about weight distribution and keeping the X-axis straight while moving up the Z-axis.

We're also having a problem with the Z-axis keep it's position. After moving up, the motors will suddenly lose it's toque and the axis just falls. This can be a bit dangerous.

I'm sure there is a setting on Marlin to keep the motors energized. Anyone have any idea what it is?

Shafiq

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Read our blog at www.everyoneacreator.com

Sorry, I don't use Marlin. I expect someone else will be able to help.

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Large delta printer [miscsolutions.wordpress.com], E3D tool changer, Robotdigg SCARA printer, Crane Quad and Ormerod

Disclosure: I design Duet electronics and work on RepRapFirmware, [duet3d.com].

In Marlin

Configuration_adv.h

//default stepper release if idle
#define DEFAULT_STEPPER_DEACTIVE_TIME 60

Default is 60 --- set this high for long hold of stepper

BUT

Motor / driver will be drawing current and get VERY HOT

Consider geared Stepper motor or stepper with a brake
ie

[www.ebay.com]

@cozmicray,

Thanks for the advise.

Yeah I think we'll have to think about using motors with brakes.

In this printer, the bed is stationary. The X, Y and Z axis are moving, this would make it necessary to have steppers with brakes on the z-axis.

Or maybe I can set up a nice little end g-code for the extruder to rest after it has finished printing.

The printer has a build capacity of 640 x 640 x 680 mm.

I still have not got the steps per unit right though, I've currently set it all to 1/16 microstep.

We're just left with confirmation of the movement on the z-axis. There is enough power but it's just that the axis is not moving straight together at the same time.
This may be a weight distribution issue, which i hope it isn't cause that would be quite complicated especially since we have the x-axis and extruder mounted on and moving.

Shafiq

---

Read our blog at www.everyoneacreator.com

[github.com]

// Disables axis when it's not being used.
// WARNING: When motors turn off there is a chance of losing position accuracy!
#define DISABLE_X false
#define DISABLE_Y false
#define DISABLE_Z false

Stepper wiring, its really easy to get this wrong.

@JuliaV,

O yes. It took us a while to get this right.

@Dust,

thanks, but ours is currently already set to false.
Which means it should not turn off.

Had a bit of a disaster the other day when the Z axis came crashing down.

Shafiq

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Read our blog at www.everyoneacreator.com

Hello everyone!,

We've got everything working alright now.

except the Z-axis. Which is such a pain at the moment.

I suspect we our motors are skipping steps, but we can't seem to identify the problem for sure.
One of the things is also that the weight of the motors are a problem.

Would shielding the wires really help?

Here is a video, please let me know what you think.
and how we can do better.

[youtu.be]

Shafiq

---

Read our blog at www.everyoneacreator.com

That is definitely skipping steps.

since you have already tuned your pots. You could try lowering your Z micro stepping a little ie if its on 1/16 try 1/8th as micro stepping does 'steal' torque (as I understand it) and halve your z steps/mm to correct for the distance travelled