Extruded filament analysis - Microscopy

I started today wanting to print something other than a test cube so an Octopus was first up, but half way through just as I popped in to make a cup of tea my Filament bundle got jammed and the extruder snapped it clean in half. The machine was still printing Mr Octopus in mid-air without any filament.

So I decided so take the opportunity to look at the already extruded Filament from in the PTFE delivery tube.

And also slice open one of my test cubes with a knife to take a closer look under a microscope - (the red ring is where we will be looking at in the next photos below)

At least I know my extruder has a powerful drive, even though this is only 1.75mm PLA I would not have imagined it would have just snapped.

   

I am very happy with the drive marks, the filament is not mangled as much as I would have expected.

I have not compared this to a filament driven with a hobbed bolt, but I imagine that looks more dramatic.

This is the close-up of my test cube, the red line indicates the box edge and at it's 1 0.25mm layer, 4 of them make 1mm.

 The infill is +/-45 degrees to the Box and at 1.75mm spacing so you get a nice criss-cross pattern.
It's also a 0.35 nozzle that extrudes 0.42mm filament in open-air.

That a nice picture if I do say so myself.

I would be grateful if any experts can comment if that is a good fusing of filaments or not? 

I was expecting them to be more squashed down so maybe my flow is not enough?

I think they must be stretched as they are thinner than extruding just into air.

Looking down the stack, and you can see the blue 'sharpie' ink at the end.

Cube side at the top, cube bottom on the left.

This is just a close-up of the cube outside edge, it feels very smooth to the touch, only a very slight ripple as you draw a finger nail over the surface.

This was the closest my microscope would go, this is a picture of the foreground filaments.

And the same shot with change of focus to the background vertical filaments.

I only got to this point with my Octopus and tomorrow I know exactly what I'm printing - 

A Filament spool holder ! - I'm off to select one from the many fine offerings on Thingiverse.

Until next time, thanks for reading and I hope you liked the close-up photos.

Rich.