G_T's build log - trials of an insulated hotter Trident

[G_T]

I had some things get in the way of working on the printer for the last few weeks so there hasn't been much progress.

However, I do now have the Sanyo 9GAX0412P3S001 fans installed in the Bento Box II. They are suitable for use in a vacuum cleaner! Loud and a little whiny, with tremendous ability to move some air.

I am mis-using these fans. I cut out the yellow and brown wires, and are providing them 12V max through a 2 pin connector on the Octopus controller. With most fans this still allows throttle control. With these though they don't work at much under 12v. On my fan speed slider the usable settings are 98%, 99%, and 100%. 97% has the fans turning, but not doing much. At 98% I'd say they are running half speed and are a fair bit quieter. But even then they move more air than other fans I've tried.

I have the fans oriented to produce suction through the filters. I'd be concerned if they were oriented to blow air upwards that at full power it could result in disassembly of the Bento Box if the magnets aren't quite strong enough. Probably not really, but I don't want to test it.

So, if you can tolerate the noise, and want the filter to really do its job, these are a viable fan choice. They are an order of magnitude more effective than what you can get from Voxel for instance.

They would probably work better - be more readily throttlable - if they were wired correctly rather than just giving them power.

I expect the filters will need more frequent changing, now that they will actually be able to do a lot more cleaning of the air in the box.

These fans will produce some air motion in the box. That will probably alter the temperature profile and likely make it more uniform. TBD whether the air motion is enough to affect printing. If so, well, the activated charcoal and scortch blend I'm using is only about a quarter full. More than that and the old fans wouldn't move any air. I can fill those up a lot more now!

Gerald

 

PS - Yep, definitely loud, and a bit whiny. But it's doing the job. Forget about speed control for the most part. One can have either rather slow at 98% 12v where it isn't doing enough to matter, or might as well run 100% where it is  doing a lot.

Edited September 1, 2024 by G_T

[G_T]

I've completed a test print. 45 minutes roughly for machine warmup, then 1:15 printing. Fiberlogy PA12-GF15 @ 255-250 extruder, 125 bed, ~70 chamber. So medium temperature for this printer. Not hot, not cold. I did employ a draft sheild which I do when printing nylon.

I ran the new Bento Box fans full speed during the print after the base layer was down, and for a few minutes after the print was done. I only ran the fans intermittently during warmup.

The printer is in my living room. I do keep one window opened a little while printing, and a bathroom fan running. So there is some small air draw but not noticable.

I'm using a Temtop air quality monitor for testing: https://www.amazon.com/dp/B08DNJ8L55

The printer is still smelly, but not as smelly as it was before the fan change. However according to the air quality meter, the room readings stay essentially unchanged during printing - at least with this nylon. Particulate hardly rises at all. VOC stay the same. Really they don't move beyond normal changes in the room.

Even when I opened the printer after about 10 min cooldown with the filter running, the room numbers didn't change when the meter was next to the printer. So either this nylon is doing nothing, or the new filter fans are working.

I think it is the latter. On previous prints with this material and basic settings I've had to open an outside door about every 15-20 minutes to vent air. Even though the printer is pretty well closed in compared to most any other printer, it isn't perfectly sealed. It is sealed well enough that the exhaust filter fan on the back is useless unless the door is cracked open (which I do for PLA).

Anyway I think the air quality meter is nice for the price, and the new fans are definitely loud, and definitely work.

BTW, my particulate pm10 and pm2.5 stay in the healthy range while printing. I think walking across the carpet has more effect than the printer at this poiint. VOC in my place is a little into the unhealthy range. But that's right where it sits even if the printer hasn't been run for two weeks. I've yet to locate the source - carpet? Wallboard? The printer is not hurting my air quality for what this device measures.

I will increase the quantity of Scorch and acid free activated charcoal in the Bento Box filter though, so I won't have to change it as often.

Gerald

Edited September 2, 2024 by G_T
Ugh, 125C bed not 325C!

[G_T]

The fans do the job well but are loud. I can and have put more filter media in the filter, and the odor has decreased from the printer. But, using just two wires the fans are essentially not speed controllable. As the printer (therefore fans) get hotter, the speed drops too much if not giving full voltage. They really are designed for 4 wire setup. My misuse as 2 wire fans controlled by voltage works but is not ideal.

IMHO 1 fan at full speed is probably enough. The BentoBox II could probably be redesigned to use only one fan. That would make it a little quieter - and cheaper.

Gerald

[G_T]

I've finally replaced the last ABS parts. The replacement RamaLama II tensioners are Fiberlogy PA12-GF15 printed bed 130C nozzle 250C chamber at least 64C, hotter is better.

In the process I had to take the head off the gantry so I could re-run the belts. I found one pin of the extruder motor controller had pushed out of the housing and was making a weak electrical contact. Perhaps that is why I'm still getting occasional patches of non-extrusion. Time will tell.

I took a picture of the ceramic paper above the heat block as extra insulation, after it has had a fair number of hours print time. It's about what I expected. A little toasty where it contacts the heat block and pristine otherwise... Unlike the dirty nozzle and heat block!

Anyway I no longer have a restriction of keeping the chamber temp no more than about 81C. I can go higher now.

THIS COMPLETES THE FIRST PHASE OF THE HIGH TEMP TRIDENT UPGRADES!

The next significant step will be adding the chamber preheater. This will hopefully accomplish two goals. First, to reduce printer warmup time. Now it is about an hour. I'd like to cut that down a chunk. Second is to allow controlling the chamber temperature somewhat separately from the bed temperature.

An example would be for this nylon I've been printing. With the current printer configuration, if I drop the bed temperature to 125C the lower chamber temperature results in the start of weakening of the layer lines. Not weak, but beginning to weaken. At 130C it is better. 135C is like a solid block of plastic.

But the bed doesn't need to be over 125C for good adhesion. So what I need is to put enough extra heat into the chamber, through another  source, to warm it up as if the bed were running hotter. For this nylon, I think I'd like the bed at 125C, the print head at 255/250C, and the chamber at about 80C. I don't need to put a lot of extra heat in to make this happen.

In my experience the higher chamber temperature should also reduce parts warpage. Warpage is a big problem with nylon! I feel sorry for those printing it with just an enclosed printer without insulation!

I've got everything to make the base heater which is essentially a small 300W bed heater plus a heat sink mounted to an insulated stainless steel plate, that the Bento Box will be blowing air across (method to my madness). I haven't decided how to control the temperature. It could be as crude as a rheostat outside the printer. Initially, that is likely what will be done.

I'm also not really sure 300W is enough but I'm only going for 90C chamber in the next round of updates. That's only 9C higher than the highest I've printed so far (CF-PC, not nylon). It's quite possible the fans will be the next limiting factor. Too many fans use ABS impellers and they'll top out at about 85C.

Gerald

Edited September 8, 2024 by G_T

[G_T]

I didn't take many pics for it, but I've replaced the BentoBox with a redesigned version of my own.

It uses a single server fan rather than the pair of fans. One fan is still plenty of air motion for the job. I have the fan orinted for sucking air down from the top rather than blowing it upwards.

Above that is the HEPA filter holder. But I modified it to be taller, and use a convergent and a divergent section.

At the top is the filter media. I should have either removed the magnet holes, or made it about 2mm taller. One can't use the top cover. And honestly, you're better off without it. It does nothing constructive.

I did all the mod work in superslicer rather than in a CAD program. So certainly these STLs could be cleaned up. But here they are if anyone wants to do the same sort of conversion to using a single high static pressure server fan to make a much more effective filter. These are mods of the original BentoBox II STLs. Not elegant, and could be done better. But they should print and work. Feel free to improve them!

Sorry the last one is a superslicer project. I couldn't get it to save out the STL. If you can't work with it, just take the original carbon filter case, cut out the cross web that is in the middle of the bottom since it is useless and blocks air flow, and clip off the mounting rim at the top since this is now the top section.

Gerald

GT_MODBOX_Fan_Case.stl GT_MODBOX_HEPA.stl GT_MODBOX_carbon.3mf

Edited September 23, 2024 by G_T

[G_T]

Too bad nobody is interested in the filter mod detailed above. It filters much better than the original design though it is loud due to the single high static pressure server fan used. I'll take the health vs noise tradeoff in this case. Admittedly my chopping and splicing method of generating the files was far from ideal. But it works well anyway.

I've had no remaining notable issues running the printer at elevated temperature. All the mods are working. Main issue IMHO is it gets smelly when hot. Printing not required, just have to get it hot. I think it is outgassing from cheap made in china insulation being used. I plan to address that in the future.

Bur for now...

I've started the next printer mod, the preheater. I've had the parts for most of this year just haven't gotten around to it. It is a controllable 300W independent heat source that goes into the bottom of the printer to help get it up to temp more quickly. It will also allow having the warmer chamber desired for some materials without having to get all the heat from the bed. So chamber temp and bed temp can be independently set (within reason)...

It doesn't use a fan. Instead it uses a large square low profile copper heatsink with a 6" square 300w bed heater attached, mounted to a heavy stainless plate with insulation between. Stainless is pretty fire resistant in case something goes wrong sometime. Thermal fuse at 135C, and essentially a high power dimmer circuit for control. It will just sit inside on the bottom of the printer. If I have the spare connection on the Octopus I'll also have temperature readout available.

Essentially there is a fan available though. The filter unit detailed in previous posts will move air across the heat sink and help distribute the air around the printer. It isn't necessary though. Given dimensions and location, it  will generate its own convection while the printer is warming up.

This additional heater could be used to run the chamber temperature even hotter than I already run it. I think a little hotter chamber and a slightly cooler bed would be good with the nylon I typically print. From my tests, the numbers on the box are a long long way from the best settings! I think the box numbers are more for selling filament (yes you can print at those numbers, but print well?) than for making engineering prints. Having a hot chamber greatly reduces or eliminates warping issues, and greatly increases layer adhesion. But run the bed a little too hot and you start to get dye discoloration in the nylon - at least for some colored nylon. 135C seems to be the step just a little too hot.

What I'd like to be able to do is have the bed and the chamber at closer to the same temperature. The only way to do that is to have an auxiliary heat source. So that's what I'm making. Then I can lower the bed temp down and raise the chamber temp, to get them closer.

That's a secondary goal at this point. The primary goal is to hopefully cut a half hour out of the printer warmup time!

Gerald

[G_T]

Finally got back to this printer after a long absense.

I got the preheater bed installed and it works. It doesn't put out as much heat as I'd wanted, though it does improve how long it takes this printer to get up to temp. But only by perhaps 20%. I think it will be more useful for adjusting chamber temp when running hot, and keeping less of a vertical temperature gradient in that situation.

I have added the final layer of insulation into the top but only there. I wanted to see how much difference it made. The top used to get very hot but it is noticably cooler now. Less heat loss. I need to add insulation further down now.

Tonight's testing I had the chamber temperature up to slightly over 85C then turned up the print head. I walked away for a bit and came back to find it had crashed. I had the bed near the max I'd set; ditto the print head. I suspect one tripped the shutdown. I bumped the temps a few degrees after this test. I had the printer hot for a couple hours, gradually ramping up the temp once above 80C since that's the highest I'd run it previously.

Motion seems fine at the elevated temps.

Next step is to add a little more insulation. I expect to get 90C chamber at least.

It's about time for me to get some filament to test this range with. I'm not quite up to where I want to be to print CF-PEKK which I have, and above where I want to print anything else that I have on hand!

Gerald

PS - The modified Bento Box I posted about previously works extremely well as an internal filter. It will circulate the air and move it through the filter and filter media just fine. It is loud though. It has had a whole lot of use.

 

Edited Sunday at 02:17 AM by G_T