Flexystruder v2 Jamming

I have been unable to print anything using black NinjaFlex 3mm filament with my new Flexystruder v2.

It is installed on a TAZ4. Trying to print a simple washer at 230C using Slic3r 1.2.9 and Printrun 2014.03.10 This setup has worked fine for more than a year using the standard extruder with ABS, PLA, and some other special filaments. I used the NinjaFlex-0.5nozzle.ini downloaded from the Lulzbot website.

I don’t think the gcode is the problem as the first step of trying to extrude 10 mm of filament ends up in a jammed hotend. This even happens at hotend temps up to 250C. It pushes out maybe 1 mm and then the stepper motor begins to lose steps trying to push more filament out. I cleared out the hotend and feed tube and found a curled piece of NinjaFlex with scrape marks from the drive hob bolt.

What is the magic thing I am missing? Do I need to convert to Cura or reflash the Rambo card?

A taz 4 uses a buddaschnozzle, a flexistruder uses a hexagon nozzle. The thermistor and heater core are different in the Rambo firmware. You will need to change the firmware, or use curia to update that part automatically, and change it back to use the other one.

I would recommend getting another hexagon hotend and printing a v2hexagon standard extruder when funds permit to allow for easy switching.

You can load the stock taz 5 firmware to set the hexagon hotend correctly on your taz 4.

Thanks, that makes some sense. I assumed that the thermistors had the same TC curve; and the heater core resistance was not that important as the heater control is duty-cycle modulated and the closed-loop would simply handle that. Silly me… :smiley:

That also explains why when I tried to verify the hotend temperature with a thermocouple I was getting lower readings than displayed on the TAZ4 display. I wrote that off as being a problem caused by the hotend blower fan cooling the outside.

So, my problem shifts to how to re-flash the Rambo firmware based on my particular shop computer setup.

Question is, does the Rambo need to be re-flashed with each extruder design change? Can the second extruder interface be configured for an extruder that is different? I’m wondering if I can re-flash the Rambo to have a budaschozzle configuration on extruder 1 and a hexagon configuration on extruder 2. Then when printing select which extruder to use?

I looked at using two different types of extruder on the same machine, and the current firmware doesn’t make for easily adding two different extruder hotend models. You can set different variables for each extruder, but they share the thermal setting variables to a certain degree. You probably could do it, but you would have to define a second set of variables for the second extruder and work it that way, which would be a fair amount of coding.

To reflash firmware I usually just use the Arduino IDE since it makes it easier to tweak the actual firmware values before upload. but you can also use the precompiled versions or Cura to do the same thing. Assuming your shop computer can talk to the 3d printer, you should be able to copy the firmware in via USB to the computer and flash it that way if nothing else.

I think that your suggestions will solve the problem, but I am being delayed by such distractions as filing Federal Taxes, repairing the household clothes dryer and rebuilding the failed carriage gear drive on my lathe… :frowning:

I was able to look at the datasheets for the two thermistors used by the Hexagon and Budaschnozzle hot ends. Big difference!

I also, reran the thermocouple sensor test with the blower fan off and found that the indicated hot end temperature on the TAZ4 was actually about 30 degC higher than actual. So, setting the hot end to 230C would only get up to about 200C and could cause jamming.

Reflashing the firmware using Cura is not that easy if you have older computer hardware and OS system. I have decided on a MacBook with MacOS 10.7.5 which will run Cura; but have not been able to get it set up so far.

As a long time friend in the high tech semiconductor industry once said… “nothing is easy!”