Researching the extruder was a bit frustrating, as I could not print one, and to make anything like the wades extruder would be quite a task to complete. I researched the way the extruder work and started to design my own. First attempt had spring loaded filament guide like the wades, but I realised soon that it would take a lot of time and trial and error to pull this one off. Not impossible, but there must be a simpler solution.
And there was!
My extruder is a single block of wood. Yep, it has a hobbed bolt going through the middle. I drilled a hole for the filament to go through the block and past the hobbed bolt. I then drilled another bigger hole right next to it for a bolt to go in. The holes sort of blends into each other and form an oval-shaped hole. I put a bolt/screw down the hole with a brass shim between the bolt and the hobbed bolt. Look at the photos, I am sure you get the idea by looking at them.
When the filament is pushed down it get pressed between the hobbed bolt and the brass shim. By turning the screw/bolt up or down I can adjust the pressure that the shim puts on the filament against the hobbed bolt. Quite good I reckon. And the beauty of it is, it actually works! As a matter of fact, it works fantastic. It is also very simple to make. But make sure to clean it out well. No saw dust must be allowed into the nozzle…it will block. I have not sealed it in any way, just blown off any dust.
It may not be the most sophisticated extruder, but this printer I am building is going to be used to make parts for my next. All I want is a working printer made from what I have got.
In the photo above you can see my first hot end. It was a complicated design, but it did work. It had brass tube and carbon fibre tube going through the inside of the heat sink. Nightmare to clean when blocked. 🙂
Photo above shows the complete extruder assembly. It can easily be removed from the printer and serviced. It can be replaced with a pen for plotting if needed. Works great (may not look the best but….)
It also shows the current hot end I am using. MKIIb with holes drilled in the cooling pipes.
The following photos shows the same but from different angles.
The photo above shows the filament entry hole. I have 2 shims at the moment between the hobbed bolt and the adjusting bolt. Note that the screws are there to hold down the shim when reversing the filament. Sometimes the filament can catch on the shim and force it upwards. The screw head stops that.