Printing a reuseable heated enclosure
In order to progress my project of making a surfboard fin, I need more heat around the printed object.
I came up with the idea to print an enclosure along with the fin, that worked well, but I want to improve on that and reduce the material waste that it causes.
Also, I want to print with polycarbonate if possible, because Polymaker PC-max is a bit too floppy.
So my next idea was to print parts that I can stack around the print manually as the print progresses. I call it the Reuseable Heated Enclosure, or RHE.
I have printed a pile of segments for the RHE and now I want to also actively heat the air inside of that space. I'm still making adjustments to the stackable segments, main problem is that they have a 1/2mm play each and it accumulates so that the higher layers tend to drift apart.
So the latest version of the RHE segments has a clip-together feature (see Slic3r preview below), it's not tested yet, still printing in PC at 295C nozzle and 134C bed temp.
Below is the SCAD code for V 1-6-4-6-4-5Enclosureonly.scad. It does not have the clip together feature. I cannot easily share the design for the next version, because I used the "import STL" function repeatedly, so it's no longer just SCAD code.
$fn=180;
rotate([0,0,-39.5])
// differencing halve-separators
difference(){
// Union of entire ellipse segment of reusable enclosure:
union(){
// Tounge ellipse 2mm wide:
// differencing groove from tounge:
difference(){
// Union of tounge ellipse:
union(){
translate([0,0,5])
difference(){
scale([159,34,0.1])
linear_extrude([0,0,0.5])
circle(1);
scale([157,32,0.1])
linear_extrude([0,0,0.5])
circle(1);}}
// Groove ellipse differenced from tounge ellipse:
translate([0,0,-4])
union(){
difference(){
rotate([0,0,0])
scale([159.5,34.5,0.1])
linear_extrude([0,0,0.5])
circle(1);
rotate([0,0,0])
scale([156.5,31.5,0.1])
linear_extrude([0,0,0.5])
circle(1);} }
}
// Inner wall segment
difference(){
union(){
difference(){
rotate([0,0,0])
scale([159,34,0.1])
linear_extrude([0,0,1])
circle(1);
rotate([0,0,0])
scale([153,29,0.1])
linear_extrude([0,0,1])
circle(1);}}
// Groove ellipse differenced from inner wall:
translate([0,0,-4])
union(){
difference(){
rotate([0,0,0])
scale([159.5,34.5,0.1])
linear_extrude([0,0,0.5])
circle(1);
rotate([0,0,0])
scale([156.25,31.25,0.1])
linear_extrude([0,0,0.5])
circle(1);} }
}
// Outer half of wall segment:
difference(){
union(){
difference(){
rotate([0,0,0])
scale([163,38,0.1])
linear_extrude([0,0,1])
circle(1);
rotate([0,0,0])
scale([159,34,0.1])
linear_extrude([0,0,1])
circle(1);}}
// Groove ellipse differenced from outer wall:
translate([0,0,-4])
union(){
difference(){
scale([159.75,34.75,0.1])
linear_extrude([0,0,0.5])
circle(1);
scale([156.5,31.5,0.1])
linear_extrude([0,0,0.5])
circle(1);} }
}
}
// object being differenced to cut segment in halves:
color("blue"){
translate([-10,24,0])
linear_extrude(0,0,15)
polygon([[0,0],[10,0],[10,10],[20,10],[20,20],[19.5,20],[19.5,10.5],[9.5,10.5],[9.5,0.5],[0,0.5]]);
translate([10,-24,0])
rotate([0,0,180])
linear_extrude(0,0,15)
polygon([[0,0],[10,0],[10,10],[20,10],[20,20],[19.5,20],[19.5,10.5],[9.5,10.5],[9.5,0.5],[0,0.5]]);
}
}
Re: Printing a reuseable heated enclosure
I hope that I can modify the heated bed connector so that 12V DC can be supplied to 10W ceramic resistors mounted in some of the RHE segments.
Do I need to add more cabling for this purpose, with 12V DC supplied from the additional 12V outlet on the power supply, or could I just piggieback the resistors on the heated be cables?
What is the limit for power output of the power supply if I use the additional outlet on it?
Thanks for any help, Mik 😛
Re: Printing a reuseable heated enclosure
How are you going to attach these around the part while it's printing? Pause the print? Will this not have a detrimental effect on the printed part? Also, how are you going to keep the enclosure from moving on the bed during printing?
Re: Printing a reuseable heated enclosure
How are you going to attach these around the part while it's printing? Pause the print? Will this not have a detrimental effect on the printed part? Also, how are you going to keep the enclosure from moving on the bed during printing?
I print a 'sacrificial tongue' with each print, which is firmly attached to the bed. It is exactly the same size as the tongues on the segments that get added later on and fits into the groove on the bottom of the half-ellipse segments.
I hope I will be able to add half-segments without pausing the print, but I might have to pause it. I don't think that would matter much.
The segments with clip-together feature are now ready, unfortunately it is a lot harder to assemble them than the ones without clips.
Maybe I'll just have a clip on one segment per layer, and then alternate their sides.
Re: Printing a reuseable heated enclosure
After many small adjustments, made after learning from various failures, the segments now clip together much more easily and I can assemble the pre-printed parts around the print in progress without messing it up every time.
However, this was still not enough to prevent the fin tearing itself apart and causing several layer shifts in the progress. I nursed the print along long after I knew that it was a 'failure', otherwise the layer shifts would have resulted in a birds nest, rather than a very bad fin.
Re: Printing a reuseable heated enclosure
I need to move on to using active heating of the reusable enclosure.
For adding segments, I either just placed them on while the extruder is going about it's business, or stop it by selecting "Change filament" via the LCD knob control.
One of the main problems is that opening the printer enclosure (to add reusable enclosure segments) causes a sudden temperature drop, resulting in a few audible cracks emanating from the print. The temperature in the printer enclosure was reaching around 38C when closed, room temperature was about 27C. Temperature of upper parts of the printing part inside of the reusable enclosure was about 60-70C, hard to measure.
Printing from Polymaker PC-Plus clear at 270C nozzle and 120C bed temp.
Re: Printing a reuseable heated enclosure
Here is my latest half-baked plan to pull this off:
Build a fan-forced heater for the Actively Heated Reusable Enclosure (AHRE).
Using 12V impellers (same as the ones blowing at the nozzle), I want to blow air into a chamber filled with 1ohm 10W resistors. The exhaust air will be fed at an angle into the AHRE so that the heated air forms a vortex around the printed part, and escapes out of the top, flowing around the parts that are being built up by the extruder as it is doing it's job. That way, power consumption (and temperature in my garage 🙁 ) will increase, but the need to enclose the printer, and (more importantly) to open the enclosure, will disappear. The 12V fans / impellers will only be exposed to room temperature air, but I think I can get the exhaust air temp to reach 120C or more.
Powering the heater box from a variable voltage (and current limited) lab power supply, and measuring the temperature of the air where it enters the AHRE and at a few more spots further up by k-type probes, should give me good control over the printing part's temperature.
Re: Printing a reuseable heated enclosure
I applaud your fortitude. I would have given up long ago.
Re: Printing a reuseable heated enclosure
What looks a bit paradoxal is that to add a layer of enclosure, you have to open your enclosure which will cool it.
I do not want to tell you that you do not have the right approach, but what about using a ceramic heater in the enclosure to reach a higher and stable temperature ? There is a OctoPrint plugin that help to regulate enclosure temperature, using a DHT11/22 to get air temperature and a relay to switch on and off a heater.
The electronic parts (PSU, Rambo) may then needs to be moved outside of the enclosure.
However, maybe it could be used as a complement to your approach
https://github.com/vitormhenrique/OctoPrint-Enclosure
I'm like Jon Snow, I know nothing.
Re: Printing a reuseable heated enclosure
The main problem is that the components of the i3 MK2 are not suitable to be operated in a 120C + environment, but that is what I am aiming at.
I'm planning to build a small ceramic heater that only heats the area around the printing part, and hopefully leaves the extruder cool enough to survive. If the AHRE is under positive pressure with hot air, then I do not need to close the enclosure around the entire printer any longer. That will make my life a lot easier when adding successive layers to the AHRE.