We were planning to build a new 3D printer. The heart and lungs of any 3D printer are the electronics and the hotend. Since we got our first very promising pre-series electronics, we wanted to have a suitable hotend. This is why I spend the last days in testing a new arcol.hu hotend. It was sent to us as a prototype with the request to test and try out the improvements.
It is maybe version 14 or something - and you can really see this.
The improvements in comparison to the arcol hotend 3.0 are:
* A screwable peek tube:
Now you can screw it on one side into the nozzle and on the other side into the thermal barrier.
Between the two windings there is a thicker part shaped in a way to fit into a screw wrench.
The version 3.0 peek tube had a round end. There was no way to fix it with a screw wrench or pliers without damaging it a bit.
But you have to screw the nozzle really tight to be sure no plastic will squeeze out of the screw windings.
* An improved shorter thermal barrier:
This thermal barrier is not only shorter. It has a chamber with winding inside on the top.
Inside this chamber you can put a grub screw to fix the PTFE tube inside and to push it down into the bottom of the nozzle.
Of course the grub screw has a 3.5 mm hole inside.
In version 3.0 the PTFE tube was pressed into the nozzle only by fixing the wooden plates on top of the hotend.
With the grub screw inside the thermal barrier it is fixed more tight.
Because it was a prototype, I didn't had any idea in which way I should assemble this new peek.
Combining the parts in different ways quickly showed that there are two possibilities.
One possibility was to put it from the top through the steel triange. The other possibility was to put it the other way round from the bottom into the steel triange.
In version 3.0 it's consequential possibility one, because it is needed as anchor.
But in this prototype it seemed to be better to screw it into from the bottom, because the other side would be less accessible.
After an assembling test I had to disassemble and recombine it sometimes to be sure to have a working hotend.
Here you can see the assembling test without tightened screws:
So I first combined the thermistor and the power resistor with the nozzle mount and let the cement dry.
Meanwhile I screwed the peek into the noozle using two pipe wrenchs to be sure it is fixed tight.
Then I put it through the steel triange and the attached wood plate and screwed the thermal barrier on top also using two pipe wrenchs.
After this I pushed the PTFE tube through the thermal barrier into the nozzle by hand and fixed it with the grub screw.
The rest was very simple because it was well described in the assembly manual. The hotend comes with a 0.35 mm nozzle and was installed on my one year old Wades extruder first generation.
The big mess begun when trying to put this hotend into a mendel x-carriage:
The wooden plate at the bottom of the hotend didn't fit through.
We designed the x-carriage about one year ago to fit to the early models of the arcol hotends, which only had the steel triangle at the bottom.
The round wood plates at the top fit to the space in the upper part of the modified x-carriage.
But with another round wood plate at the bottom, you can't push it through the lower part of the x-carriage.
So the only way to install this hotend on a mendel was to assemble x-carriage and hotend simultaneous on the x-axis.
It was a bit tricky, because this way you can't fix it at the extruder.
But this was no problem, since I had several additional wood plates on top which were big enough to overlap with the x-carriage.
The Wades extruder was screwed on top and works as clamp for the hotend.
Another way could be to omit the wooden bottom plate. The wood works as additional thermal barrier but the peek screw already separates the hotend from the "coldend", so perhaps there is no need for the wood anymore.
But since the delicate parts of the hotend were already screwed together, I didn't want to test this.
Here you can see the result of the assembled hotend on the mendel x-carriage:
The printing results of the first test prints at 0.3 mm layer thickness were promising:
After tweaking the flow and feed, I tried a print at 0.19 mm layer thickness:
(This part is only 3 cm long and 4 mm tall)
Now I will have to further improve my skeinforge setup to get very good prints.
By the way: Last week I had the privilege to take a look at parts printed with the commercial and professional HP 3D printer in ABS with a layer thickness of about 0.2 mm.
These parts looked the same as my prints with arcols new hotend.
This was a new drive in further improving the abilities of the DIY 3D printers which can compete with 10'000$ machines if calibrated properly.
Greetings from the lake of constance and special thanks to Laszlo from arcol.hu hotends for providing us one of his prototypes!