nzo
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Posts posted by nzo
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Hi kman. How are your bronze/copper filament experiments going? Have you been able to solve the problems you were having?
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short answer - printed part won't be brittle.
Tell me more. How do you know? What tests have you done? Yes I do realize you have a great deal of experience
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Thanks for that info @geert_2'> geert. Moist PLA might have enough H20 molecules to work. The last batch of PLA I tested in the MW certainly responded by softening. No moisture = no softening @ 70C.
We had this BS marketing hype last Black Friday in NZ and I kept an eye on deals for bench top ovens marked down to around $50. Today they were up to $145 -$180 again. I'll wait until mid December and look again. An oven like that could be useful for cooking filament, backing bread, heating pizza and roasting a chicken
I'll stick a pottery pyrometer in through the oven shell to more accurately monitor internal temp. I'll keep you updated.
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@SandervG'>SandervG...I'll start testing filament loops again soon. Microwaves heat the water molecules in humidified filament. I have no ABS or Nylon but my sense is that it could work. In my first PLA tests loops were exposed to a maximum of 1100 watts. They got hot quickly but not evenly and cooled very quickly at room temp. I feel it needs a slower process.
Next I would place the filament on a flat surface and run the microwave at a 50% on/off cycle, to give the plastic time to soak. Microwave ovens tend to have low thermal mass and uneven heat, and when the door is opened cooling is rapid.
Added thermal mass, such as a dense piece of firebrick or unglazed tile placed in the MW for a pre-heat phase would even out the temperature and hold the heat for longer. There's probably a sweet spot where the heat hovers around 60 to 70C where the annealing is happening.
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@kmanstudios'>kmanstudios...I printed this tiny forklift by agepbiz a few days ago, using the UM 0.25mm nozzle and yellow PLA. I decided to sacrifice the print in the microwave @ 2mins on the high setting to see any resizing effects.
Top to bottom of chassis before MW=17.28mm
Top to bottom of chassis after MW=17.22mm
I need to test this more for consistency.
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Gobble gobble gobble! The forum just ate my reply to kman :(Aaargh!
Hi @kmanstudios'>kman...
I'm heating the raw filament so far.
When the MW heating cycle ends @ 2mins for a bunch of 6x single PLA loops in different colors, one has only a few seconds to manipulate the filament before it hardens again. The loops straighten easily. No more finger bending!
I cross-sectioned the red PLA with a scalpel after heating and cooling and what I saw reminded me of a tree-ring structure. The inner core appeared glassy (like those red gelatin-filled chocolates) and was surrounded by a ring of normal 'crystallized' PLA. Maybe the center was still crystallizing. I tried to photograph this but it really needs a microscope. Mine is in pieces at the moment. I'll repeat this when it's resurrected.
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How does microwaving work?
From Scientific AmericanChad Mueller, assistant professor of chemistry at Birmingham-Southern College in Alabama, replies:
"A microwave oven cooks food because the water molecules inside it absorb the microwave radiation and thereby heat up and heat the surrounding food. Microwave radiation will similarly heat up skin and other body parts. In fact, people stationed at big microwave towers in cold climates used to stand in front of the microwave generators in order to warm themselves. The radiation is harmful mostly to the parts of the body that cannot conduct the heat away very effectively---the eyes especially. I think that heat transfer could explain why one sometimes hears about people (fast-food workers, for instance) getting headaches when exposed to leaking microwave ovens."
David E. Hintenlang, associate professor nuclear and radiological engineering at the University of Florida at Gainesville, adds some further details:
"Microwave ovens cook food by generating intermolecular friction between the molecules of the food. The microwaves cause water molecules to vibrate; the increased friction between the molecules results in heat. Microwaves could affect your tissue in a similar way if they were able to escape from the microwave oven. Modern microwave ovens are designed to allow essentially no leakage of microwaves, however. The only time for concern would be if the door is broken or damaged, in which case the oven should not be used.
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Something strange is going on
I've not seen any mention of heating filaments in a microwave.
I've just tried it with several loops of orange and blue PLA in a 1100 watt microwave.
Results:
- 30 secs=about 35C - the orange relaxed and not so brittle, the blue still snapped easily.
- 60seconds=both colours heated to about 50C
- 1m30seconds=both colours now softish and when held by one end relaxed into straight vertical shape. Both colours no longer snapped but bent without breaking.
More experiments on a larger quantity soon. Probably a 'softer' (50%) microwave setting may be beneficial when a whole reel is processed.
- 30 secs=about 35C - the orange relaxed and not so brittle, the blue still snapped easily.
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I cut a few meters of a spool, few seconds in hot water and the filament becomes soft, let it air cool (in the right shape) and it is "good as new"
This has got me beat! I'll try it.
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Would coating a new PLA print with a clear fixative or polyurethane spray delay the onset of brittleness? Or baking the print to make it harder and denser?
Maybe what we need is extrudable granite...or maybe not
.A quality of PLA I like is that it is said to be non-toxic and biodegradable - unlike the Great Pacific Plastic Garbage Gyre that is killing huge numbers of ocean-dwelling species every second. I don't want to contribute to that!
I also don't want to make endless PLA stuff that sits on a shelf...monuments to my ego
. I also don't want to make PLA toys that put children at risk. Usefulness is high on my list of priorities.Then again, everything disintegrates. Filament, printers, us. The balance seems to be somewhere between usefulness and disintegration?
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Just wondering. Thanks.
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I enjoyed this short but very important sharing between you and kattyisis, sandervG.
Language; the words we use; can range anywhere between wasted mouth noises and clear, clean and accurate. I say this with all respect to those for whom English is not their mother language. (Google Translate is quite good these days).
We also have brains that are widely different in how we interpret the world. Some of us are mainly visual, some are auditory, kinesthetic, olfactory, gustatory or a combination of modes. "I see what you mean" is a different mode to "I hear what you say", or "I don't feel comfortable with that" or "I don't know what you're talking about".
In my years of learning about therapy and counseling, I frequently came across couples where one seemed to be speaking French and the other in Russian. And they wondered why they were not communicating!
.I've mis-communicated like this many times and sometimes still do. The problem is amplified in the field of 3D printing and forums like this one. How many time have you read something and wondered what the heck they were talking about. The wider internet is like a dog's breakfast in this regard. Everything gets mixed up together, especially when it comes to teaching, learning and imparting understanding.
I may be correct in saying that 3D printing is very visual: videos, images, watching and visual terminology. But it's also olfactory (what the hell is that smell!) and auditory (I hear a grinding, spitting noise) and (touching that nozzle made me fall off the chair).
I frequently look at a post I've just carefully (or not) composed and think "What the heck have I just written!?". The requests for more information from responders to posts on this forum is huge. "Can you post a pic, a video, show me what you're talking about".
I'm aware whenever I learn a new field I need to learn the language of that field. This often comes slowly to newbies and can be immensely frustrating for those already very skilled in that language. And there's nothing worse than an experienced member snapping tersely at the author of yet another newbie question "Have you tried Google?". Or RTFM!!!
I'm particularly impressed by sandervG, Geert and others who make a real effort to communicate. Yes, telepathy would make it simpler, but then we would have to put up with the self-talk head noises as well as the critical information
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I use a UM2+ and my solution is to wait for that special moment when the extruder finishes its filament dump and grab it with some surgical tweezers. I have to pay attention, otherwise I miss the magic moment and the dump gets dragged into the first layer. But I'm pretty good
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Geert - have you tried any of the PLA/PHA filament blends using your salt-water method?
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Good to get your methodology and video gr5. They're very useful.
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Thanks SandervG. It must have been cosmic circumstance that Backspace usually propels my posts to whirl forever in cyberspace
The "tunnel" must be like the "toob" ex US president George W Bush was fond of calling the internet. Like those pneumatic message pipes they used to have in big department stores.Is it true that a new forum is just around the corner?
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Thank you Geert, for your wonderful work. Much appreciated.
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I sometimes forget to check this box, get involved in writing a post, the forum times out and I lose what I've written which is a PITA
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I'm assuming that since you're a Windows (version?) user, you create regular system backups to extract you from a messy situation when one strikes? I use Aomei Backupper Standard which is free and excellent.
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May I ask a question kman: what is it about red-clay-colored copperfill that drew you to want to experiment with it?
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Very cool kman. I guess you need special nozzles for that type of filament.
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kman...these 3mm spools sell for $NZ28.00 from the supplier, plus freight and rural delivery @ $12.00 per roll/rolls. Out of about 10 spools bought from them, the orange PLA is the only one that has given me problems. OTOH, the place I bought my UM2+ from has better filaments starting at $55.00 up to $110.00 a spool + freight. Maybe sometime I might buy from them what I can't find elsewhere.
In hindsight I think it was probably friction in the bowden tube that caused the problem. The filament was well sealed and had a desiccant packet in the spool hub. The slight bit of spitting on the brim may be due to the residual oil in the bowden tube. That doesn't explain the brittleness.
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I found the culprit (I think). I discovered the following about this orange filament:
- It is very brittle - snaps easily
- Diameter is about 3.03 to 3.04mm
- Very tight in bowden tube...friction prevented passage through extruder
- Lubed b-tube with a drop of light machine oil
- Inability to slide easily created a PLA 'blob' in front of the nozzle
- Extrudes with what look like moisture bubbles
Now it's printing the robot
- It is very brittle - snaps easily
Does brittle (easily snapped) PLA filament equate to less strong prints?
in Materials & profiles
Posted
Won't this type of cracking be eliminated in the "furnace" of the hotend?