Da Vinci Junior 1.0

da vinci junior 1.0 came with a metal stick to push filament from the top and thin steal wire to clean nozzle from the bottom. Check the accessories that came with your printer.

the top right two item of the above image is what you need.

slightly smaller than nozzle diameter - most are 0.4mm diameter, but since I have never owned a DaVinci, please verify that with other sources

there are dozens of them - where are you located? USA? Europe? Australia?

LOL, yeah, we have all been there.

Afraid I wont be much help in regards to good suppliers in the UK, but there are plenty of others that should be able to help you out

The actual tool for the tip is piano wire or similar. The issue with the drill bits are they are high carbon steel and will break if they are bent even the slightest bit. If they break off in the extruder it can be a nightmare to remove if you even can.

XYZ sells a service pac kit with the correct size cleaning tool. I'm not sure of the exact size, but it's a bit heavier that a wire coat hanger. The extruder cleaning wires are pretty thin and made of hard, spring steel. For a .4 mm extruder, a .3 cleaning wire would probably be appropriate.

I had the same problem. I've tried to print something, but the filament was jammed inside the extruder before the nozzle.

The XYZ support says, that it is a problem of the z-offset, that I have to make sure, the belt tension is correct and that I have to clean the nozzle.

I dismounted the device partly, to find out, what the real problem could be. So I discovered it, solved it and found, that the support persons of the manufacturer do not have any experience and not any know-how about the function of their machines. Nothing.

Because I bought it more than 6 months ago, there is no warranty left, altough I never used it. So by fact, it is a NEW machine.

I did a lot of work on this printer. Unfortunately I do not have any pictures for documentation.

I lowered the pressure on the feeder mechanism by reducing the tension of the spring. It had a force of about 3 kg. This high tension causes the stepper motor to block, if only a small amount of higher force is required, to feed the filament - hearable as a "clack, clack, clack" with an optical vibration of the filament at the same beat.
I lowered the tension to about 300g, by the use of a screw driver to increase the spacing of the springs windings. The feeder is located on the upper left side of the printer. You have to unmount the half of the case, to be able, to reach it.
The force is estimated by the pressure force on the thumb, to move the feeders leverage.

I also lowered the pressure of the springs in the filament detectors, to allow a smoother guiding trough. There are two detectors, one in the filament feeder, one in the extruder head. To do this, I took the springs out, pulled it to the double of the original length, cutted it in the half and sat it back in.

It is a bit tricky, to open the extruder head. Make sure, not to brake the fasteners out.

I had to fix the entry for the filament on the extruder head with a nylon washer, mounted under the fixation, to thighten it. It was loose and caused a misleading of the filament on entering the extruder.

The metallic cone inside the extruder head had some sharp edges, where the filament was jammed mostly. After smoothening it a bit, the filament was sliding trough without any problems.

Now it prints perfectly.