Ormerod 2 extrusion has never really worked

Hi there,

I bought and assembled an Ormerod 2 unit back in February. Ever since first getting it up and running, I've been fighting with the extrusion. I've had correspondence with RepRap, but it seems like none of the troubleshooting steps have solved the problem. I can feel pretty good pull by the extruder motor on the filament, but whenever I try to print, the extrusion is stuttery, and invariable there reaches a point where, if left alone, the extrusion simply gives up part-way through the project. I have managed to print a few parts by baby-sitting the printer and maintaining the pressure on the filament input by hand throughout the print, but I would love to be able to get it working as designed.

So far, I've followed all trouble-shooting steps, and on multiple occasions rebuilt the hot end. One concern I have right now is that the Bowden tube may have become too short due to these attempts. The other interesting thing I've found is that my kit came with an extruder with the teflon sleeve already cut and inserted.

Is this a common issue with this printer, and does anyone have any ideas for what I should try next? I'm utterly flummoxed.

Cheers.

A few suggestions:

1. Make sure that the hot end fan is the right way round so that it blows air continually through the heatsink, all the time. Don't be confused by backwash from the front of the fan.

2. If the extruder drive stutters (i.e. skips backwards), you can increase the motor current a little, to 1000mA or 1200mA - although I find the default 800mA sufficient on my Ormerod 1.

3. What extrusion temperature are you using? Maybe you need to try a little higher.

4. If you have a multimeter with a thermocouple probe, check the hot end temperature calibration by feeding the probe into the hot end in place of the filament.

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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].

Thanks for the reply! Interesting... it does look as though I have the fan backwards. I'll check and see if reversing it makes a difference!

I have indeed attempted higher temperatures, and I'm fairly confident that the temperature is high enough, as if I go much higher, the filament slides out in a less controlled-fashion as it's extruded. I haven't experienced the extruder drive stuttering, it's more the fact that the extrusion is "flaky." It will be extruding, then it won't (the knobbed insert with start scraping the filament instead of pushing it along).

Quote
williamf
Thanks for the reply! Interesting... it does look as though I have the fan backwards. I'll check and see if reversing it makes a difference!

The side of the fan with the label on it should normally go on the inside. Do you have it on the outside instead?

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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].

Yes. If I compare it to the pictures on the documentation, it's backwards. I think this probably occurred during one of my rebuilds of the hot-end. I would've had it right when I first built it.

If this does not work please give us your printing temperature and the material. Which version of the Ormerod 2 you got? Maybe your bed is not leveled correctly which may also result in skipping or the nozzle height is wrong.

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Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

There's also the possibility that you have a partially blocked nozzle. That has happened to me twice - both times after the plastic was inadvertently left "cooking" in the nozzle with no extrusion taking place.

Dave

Quote
Treito
If this does not work please give us your printing temperature and the material. Which version of the Ormerod 2 you got? Maybe your bed is not leveled correctly which may also result in skipping or the nozzle height is wrong.

The bed has been repeatedly levelled by the procedure in the documentation, and the extrusion issues also persist even when trying to extrude well above the bed level as a test. So I don't think that's it.

Not sure about the version of Ormerod 2, but it was purchased in January. The material is still he orange filament that came with the printer.

Quote
dmould
There's also the possibility that you have a partially blocked nozzle. That has happened to me twice - both times after the plastic was inadvertently left "cooking" in the nozzle with no extrusion taking place.

Dave

I wonder about that. What do you do in order to remove a blockage like that?

Quote
williamf
I wonder about that. What do you do in order to remove a blockage like that?

There is a hit & miss process you can try, but I never succeeded with that so I bought a replacement nozzle (not expensive). The procedure should be documented in the troubleshooting section (or do a google search).

Dave

The procedure to extrude a tiny amount, let it cool slightly, then withdraw it has never worked for me. Maybe a replacement nozzle is the simplest course of action.

This sounds like a similar problem which I have had recently. The first few prints are usually okay but after a time the print will fail, the extruder drive is still visibly running but no filament is being extruded.

In my case the problem was that the bolt which goes through the large extruder gear and holds the hobbed bolt was loose. This caused the hobbed bolt to move off line slightly and no longer drive the filament. So I tightened it up and problem solved.... Or so I thought. I managed two prints in the same session without issue then the same problem occurred again. This time the bolt was a little loose but on closer inspection of the large extruder drive gear it appeared it was not rotating in a perfectly straight line and therefore neither was the hobbed bolt.

I dismantled the extruder and the pla extruder block appears slightly warped!

Then it hit me, this problem only occured when I was printing ABS where the bed is 110degC and hotend is 220degC or when the Ormerod was running for longer periods. Also the Ormerod is semi enclosed to help maintain bed temperature. So I suspect the warping is due to the sustained higher temperature over the duration of the print. Also the stepper motor which is in direct contact with the extruder block gets quite hot (as do the other 2 motors) so the extruder block may be expanding/warping during the print causing the hobbed bolt to move off line. I suspect the heat from the extruder stepper motor is the most significant cause of the warping.

My plan is to print and replace the extruder drive block but in ABS not PLA as it will be more thermally stable at higher temperatures. I'll try this on the Ormerod "from cold" so the stepper motor is at it its coolest but fortunately I have a Huxley which I can print on as well.

I plan to do this in Thursday this week and will report back.

This sounds like a similar problem to yours but if not apologies for the ramble.

Ross

If you would have read the manual there is a hint that you have to replace the Extruder parts with ABS printed parts if you want to print ABS regularly or often.
For me this was not an easy task as the ABS often warped. In my case the x-carriage slightly begin to fail or it wanted to get rid of the linear bearing.

---

Slicer: Simplify3D 4.0; sometimes CraftWare 1.14 or Cura 2.7
Delta with Duet-WiFi, FW: 1.20.1RC2; mini-sensor board by dc42 for auto-leveling
Ormerod common modifications: Mini-sensor board by dc42, aluminum X-arm, 0.4 mm nozzle E3D like, 2nd fan, Z stepper nut M5 x 15, Herringbone gears, Z-axis bearing at top, spring loaded extruder with pneumatic fitting, Y belt axis tensioner
Ormerod 2: FW: 1.19-dc42 on Duet-WiFi. own build, modifications: GT2-belts, silicone heat-bed, different motors and so on. Printed parts: bed support, (PSU holder) and Y-feet.
Ormerod 1: FW: 1.15c-dc42 on 1k Duet-Board. Modifications: Aluminium bed-support, (nearly) all parts reprinted in PLA/ ABS, and so on.

Yes, if you are planning to print in ABS, you must reprint all the hotend parts (fan, nozzle mounts etc.), the X-carriage and the extruder parts (housing & gears) as the first few ABS prints you do. These parts will all fail before too long if left as PLA. My suggestion is that before switching to ABS, you print a set of these parts in PLA. That way, if any fail before you manage to print a good set in ABS, you have a spare and are not stuck with a non-working printer in a chicken-and-egg situation.

Dave