I was thinking about how the prusaNozzle supposedly has a mirror like finish inside the feed barrel to make plastic removal easier. I got a E3D recently and wanted to see if I could improve the finish inside the barrel by polishing.
The adventure so far:
I’m able to take 3 woven nylon cords and pull them through the hotend. I make a loop knot at the end of the cords, leaving about a foot of travel before hitting a knot.
From there I apply the polish to the cords so I can move the hotend back and forth… 20 or so minutes later rinse/repeat…
Filament appears to pull through the tube a little easier. Not having something to measure the force needed to push/pull filament through the hotend before or after polishing make it anecdotal…
I’m going to keep working on this for a little more and I’ll post what I found if anyone is interested.
So jealous…wish I had the time energy and money to tweak and refine and potentially innovate with 3d printing…do not stifle or hide your talents/gifts…
We don’t go in for polishing because the benefits, while real, are small, and the cost is high.
What you have to remember about the E3D is that the area where filament is not liquid, but also not rigid is extremely small.
It’s not the friction from cold filament running against the walls of the tube you are looking to reduce, its the stiction of the rubbery portion of filament in the transtion zone that you want to reduce.
The E3D tactic for making an all metal hotend that ActuallyWorks®™ is to reduce the amount of rubbery filament to the absolute minimum. We also take pains to ensure the holes in the stainless heatbreaks are drilled in a particular manner, with particular bits, which gives a really nice internal finish.
This reduces stiction to the point that it’s easily overcome by the extruder. Once extrusion begins, the rubbery portion actually shifts down ever so slightly into the hot melt zone, and slips along easily because as soon as it touches the walls it liquefies and so can’t adhere.
If you want to make an E3D hotend have less stiction upon extrusion-restart polishing might have some impact, but I think your best bet would be to add a small taper that begins to open out from the top of the constriction in the heatbreak downwards.
A taper is something we are considering for production models, but it means getting a set of custom machine reamers made up, which is not a small task.
I’ve found that leaving filament reels stored without protection from the environment in the house has added about 2kg of force to filament extrusion. This is with filament left open over a period of 4-5 months.
So I’ll be looking out for Xmas sweets and biscuit containers that I can convert to filament reel magazines.
@Sanjay_Mortimer I’m using A Mendel Parts V9 0.4mm modified clone, more than 18 months old now and no servicing during that time. I only use PLA filament, the cheapest I can find and it’s worked well for me so far.
On new filament, 1 kilo of force is about average with this hot end with settings 220c temp, 24mm/s feed rate & 0.25 layer height.