Today in Blakeyrat is always several years behind in every tech trend news...
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Polygeekery Yes.
Edit: Here's a link to the printer in question. https://www.velleman.eu/products/view/?id=438412&country=us&lang=en. I hope "bushing" is the correct term for those little brass bits that run along the steel rails. It's a bit outside of my day-to-day vocabulary.
Depends on the age of the rod. On rods made more than 18 years ago (14 in Alabama), they're correctly referred to as
bushings
, yes. This was again, most common in the 1970s. Some modern designs don't use these at all.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
I hope "bushing" is the correct term for those little brass bits that run along the steel rails. It's a bit outside of my day-to-day vocabulary.
Bushing is the correct term, and that is a pretty crappy design. That will introduce play in the kinematics. They really should be running a linear bearing or linear bushing. Those are just plain bushings.
Of course it might not be too bad, those bushings are really long and if they run a close tolerance it might be acceptable, but that is getting a bit too far past "cost optimized" and into shitty design territory.
You mentioned that you replaced them with
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
special plastic ones
Were they IGUS polymer bushings?
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Were they IGUS polymer bushings?
Yeah. Those were among the recommendations from other people with the same printer.
I found them to be a bit wobbly by themselves, so I ended up cobbling something together where each rail gets two, spaced approximately 2cm from each other. Having them take a bit of extra space on the rail didn't really matter. There were some parts on the rails that the original sliders didn't reach due to how the end stops were placed / how the delta printer works.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
I found them to be a bit wobbly by themselves
Interesting, they must not be using a standard sized linear rod. Or, now that I think about it, they probably aren't using proper linear rods at all and are using some sort of mild steel instead. I was going to ask why you did not use linear bearings, but if the rods are not properly hardened then the linear bearings would rub grooves in them and trash the rods. IGUS bushings can run on plain mild steel or even anodized aluminum rods.
IGUS bushings come in different types, including ones that have a tighter fit than normal. But even if the rods are properly sized I would not be surprised that they might fit a little loose. IGUS bushings are designed in such a way that when they are fit in to place their mounting should slightly compress them and tighten their fit. That is hard (or impossible) to do with printed parts. They also have a model (RJUM?) with an aluminum sleeve around the bushing that pretensions them, but they're pretty expensive.
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
I ended up cobbling something together where each rail gets two, spaced approximately 2cm from each other.
That's a pretty good solution to the issue. I know that you're probably tired of fucking with it by now and just want it to work, but if it ever comes up as an issue again you could probably order appropriate linear rods cut to length and drilled and tapped on each end and then use LM_UU bearings (Looks like they are 8mm rods? So LM8UU.) You might also try some lithium grease on the bushings which can help take up the tolerance and prevent any oscillation from loose bushings. With FDM printing you don't have to worry about grease attracting abrasive particles, but you might have to worry about getting grease on you.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
might also try some lithium grease on the bushings
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Or, now that I think about it, they probably aren't using proper linear rods at all and are using some sort of mild steel instead. I was going to ask why you did not use linear bearings, but if the rods are not properly hardened then the linear bearings would rub grooves in them and trash the rods. IGUS bushings can run on plain mild steel or even anodized aluminum rods.
Mild steel is probably a good guess (they're not aluminium, that I can tell). The assembly instructions mention that one should take care not to scratch the rods. Assume that would be less of a problem with hardened ones.
FWIW- part of the switch was also the original brass bushings leaving minor marks on the steel rods, so there's that.
IGUS bushings come in different types, including ones that have a tighter fit than normal. But even if the rods are properly sized I would not be surprised that they might fit a little loose. IGUS bushings are designed in such a way that when they are fit in to place their mounting should slightly compress them and tighten their fit. That is hard (or impossible) to do with printed parts. They also have a model (RJUM?) with an aluminum sleeve around the bushing that pretensions them, but they're pretty expensive.
Yes, I remember there being talk about them not being compressed by the printed part. The ones with the aluminium sleeve were mentioned as well, but I couldn't find them with reasonable shipping at the time.
The other recommendation was to use zip-ties to tension them. I briefly tried that, but I essentially found two modes to that: no difference and too tight to have them freely slide (which I at the time suspected was part of the problem with the original brass bushings).
I know that you're probably tired of fucking with it by now and just want it to work, but if it ever comes up as an issue again you could probably order appropriate linear rods cut to length and drilled and tapped on each end and then use LM_UU bearings (Looks like they are 8mm rods? So LM8UU.) You might also try some lithium grease on the bushings which can help take up the tolerance and prevent any oscillation from loose bushings. With FDM printing you don't have to worry about grease attracting abrasive particles, but you might have to worry about getting grease on you.
IIRC, somebody had tried using linear bearings but found them to be a bit heavy compared to the IGUS ones, which apparently required compensating with slower printing speeds (for today's standards, the printer isn't exactly super fast to begin with). They also mentioned extra noise, which is a bit of a concern when you have the thing in your living room (not having to oil/grease the thing with the IGUS polymer ones is another plus in that regard).
Not sure I will invest into major upgrades at this point. It's been a neat starter model and ultimately a lot of learning from tinkering with it (despite being frustrating at times). But, next major upgrade is likely going to be a new printer - who knows what you can get in a year or so.
(Although I have to admit that I'm finding the delta printers to be more aesthetic than the "XY plotters". Stupid reason, but whatever. Also, want to see if I can make use of the fact that the delta head can move in 3d in more interesting fashions - doubtful if I ever get to that, though.)
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@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
might also try some lithium grease on the bushings
You're spending too much time with @Tsaukpaetra, he's rubbing off on you.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
might also try some lithium grease on the bushings
You're spending too much time with @Tsaukpaetra, he's rubbing off on you.
Some people say that if you go too far, you'll never get back to where the rest of us are.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
The other recommendation was to use zip-ties to tension them. I briefly tried that, but I essentially found two modes to that: no difference and too tight to have them freely slide
You'd probably be better off with printing the carrier in such a way that you could clamp them with screws, but then you're likely to run in flowing of the plastic over time. That's something lots of people don't realize, that plastic will flow when put under continuous load, like with screws.
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
IIRC, somebody had tried using linear bearings but found them to be a bit heavy compared to the IGUS ones, which apparently required compensating with slower printing speeds
I would be surprised if the weight difference caused the need for a reduction in printing speeds. Yes, they are significantly heavier, but the weight is in the area where it matters least as those blocks don't move nearly as fast or accelerate as much as the print head itself does. But I don't have a delta printer so I don't know for certain..
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
They also mentioned extra noise, which is a bit of a concern when you have the thing in your living room
Yep, they are definitely noisier, but properly packing them with grease helps quite a bit. But they are still noisier than IGUS bushings.
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
Although I have to admit that I'm finding the delta printers to be more aesthetic than the "XY plotters". Stupid reason, but whatever.
You're not wrong, I really dig the delta printers. I had intended to pick up one of the Monoprice delta printers when they were marked down for no other reason than to have it on my desk for printing small parts because they look really cool. I get it.
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
Also, want to see if I can make use of the fact that the delta head can move in 3d in more interesting fashions - doubtful if I ever get to that, though.
Yeah, that is another cool thing about them, but I'd have to imagine that would take a lot more processing, and delta printers already require a lot of that due to their design, and I have no idea how you go about slicing for stuff like that.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
he's rubbing off on you
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
I would be surprised if the weight difference caused the need for a reduction in printing speeds. Yes, they are significantly heavier, but the weight is in the area where it matters least as those blocks don't move nearly as fast or accelerate as much as the print head itself does. But I don't have a delta printer so I don't know for certain..
Can't confirm either way, so mainly repeating what random people said on the interweb. You're probably right that it doesn't matter too much.
Yeah, that is another cool thing about them, but I'd have to imagine that would take a lot more processing, and delta printers already require a lot of that due to their design, and I have no idea how you go about slicing for stuff like that.
True. Though there has been some work in that direction. I remember reading about somebody developing a non-planar slicer, with some success. IIRC that one even worked on the standard XY printers, as long as they could smoothly move the Z plane up and down.
Hmm. Unrelated question. Any tips for a reflective/mirror-like finish? Somebody mentioned sanding (lots), sandable primer and chrome/mirror finish spray. Not a lot of experience with especially mirror finish, so happy for any thoughts. (Would like to stay away from vapour smoothing for practical reasons, even if it involves a lot of manual sanding.)
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
Any tips for a reflective/mirror-like finish?
There may be an excuse for fire here. If you have the appetite for it, 3 or more roughly equally spaced nuclear blasts should glaze a surface nicely.
Have you considered an acid or enzyme dip?
A few passes through a large intestine, or some time in moving natural water, also have been observed to smooth a variety of objects.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
that one even worked on the standard XY printers, as long as they could smoothly move the Z plane up and down
Yeah, and you need sufficient clearance around the nozzle to be able to negotiate the curvatures, which I definitely do not have. Nonplanar printing is somewhat trivial on cartesian printers. I'm interested in how they go about doing that with delta printers by articulating the head. Typically your gcode only gives XYZ movements to the firmware which handles the kinematics from there while keeping the delta print head flat. I'd be curious to see if they are adding additional gcode instructions to handle the tilt of the head and what that looks like and how much longer it takes to compute in the slicer. Or my foolish assumptions may be more foolish than I thought and I'm overlooking a much simpler way to handle all of this?
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
Hmm. Unrelated question. Any tips for a reflective/mirror-like finish? Somebody mentioned sanding (lots), sandable primer and chrome/mirror finish spray. Not a lot of experience with especially mirror finish, so happy for any thoughts. (Would like to stay away from vapour smoothing for practical reasons, even if it involves a lot of manual sanding.)
Not really, except the methods you already mentioned. If I need smooth then I print in ABS and smooth with acetone vapors. But with the exception of architectural prints I don't usually bother. Other than those almost all of my prints are functional in nature and I don't care about later lines and such.
Vapor smoothing isn't difficult or too dangerous, but definitely do it outside. If you're outside then smell isn't much of a concern either. But to each their own.
If you only need smooth finishes top and bottom you can print on glass for the smooth bottom side. Up your first layer extrusion multiplier and you can get pretty much glass smooth there. For the top you can play around with ironing on the top layer. On top layer ironing I usually run 5% flow with a ~30% stepover between passes. That will get your top very smooth, but I wouldn't say it is glass smooth.
I'm going to guess that you have sanding and paint in your future. Get a set of files, those help a bunch. I have a cheap set of needle files that I keep in my printing area for knocking down edges and cleaning up brims and such. They help a ton. You might be able to also use a larger smooth cut file on flat surfaces to do most of the rough work.
What are you wanting the glass smooth surface for?
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Typically your gcode only gives XYZ movements to the firmware which handles the kinematics from there while keeping the delta print head flat.
From what I've seen, the mechanical construction keeps the head fairly level. Even manually moving the sliders around to relatively extreme configurations won't tilt the head very significantly.
Vapor smoothing isn't difficult or too dangerous, but definitely do it outside. If you're outside then smell isn't much of a concern either. But to each their own.
Inner-city living has it's drawbacks. Not much outdoor space. (Balcony might be an option. I'll see about that if/when I get to the spray painting part.)
What are you wanting the glass smooth surface for?
Was discussing mirrors/reflectors at work. Basically, you can get some good ones custom made for $$$$. I'm curious if I can even get into the somewhat-usable region. In theory there's some amount of leeway in the particular application, but it's still mainly a test for fun/challenge - I don't have too high expectations. Extra challenge is that the surfaces in question won't be flat.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
Was discussing mirrors/reflectors at work. Basically, you can get some good ones custom made for $$$$. I'm curious if I can even get into the somewhat-usable region. In theory there's some amount of leeway in the particular application, but it's still mainly a test for fun/challenge - I don't have too high expectations. Extra challenge is that the surfaces in question won't be flat.
Smooth is one thing, mirror finish is another thing. Actual mirrors and optical quality glass are difficult/impossible with FDM manufacturing. It can be a precise process, but I don't see it being that precise. I can print parts with smooth top surfaces but I don't think that any amount of tuning and process manipulation can get to mirror quality of finish.
You should look in to how mirror quality finishes are made. Grinding two surfaces together with progressively finer abrasives in such a way that the two surfaces grind down each other's high spots without forming a convex/concave surfaces. With FDM processes you could probably grind them against a known flat surface with abrasive compounds. But doing that would require equipment much more expensive than the custom mirror.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Actual mirrors and optical quality glass are difficult/impossible with FDM manufacturing.
That sounds like a wager. I'm'a bet you can't do it.
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@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I'm'a bet you can't do it.
We're betting the same way, who pays out?
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I'm'a bet you can't do it.
We're betting the same way, who pays out?
Canada.
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@Gribnit I'm in. Fuck Canada.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
I'm in. Fuck Canada.
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@TimeBandit said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
I'm in. Fuck Canada.
(stab stab stab) Whoo, good thing there's no Canadian spies in here.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Smooth is one thing, mirror finish is another thing. Actual mirrors and optical quality glass are difficult/impossible with FDM manufacturing. It can be a precise process, but I don't see it being that precise. I can print parts with smooth top surfaces but I don't think that any amount of tuning and process manipulation can get to mirror quality of finish.
That does seem to be the general opinion out there.
I did find somebody who claimed reasonable success with just sandable filler + lots of sanding + glossy chrome/mirror finish spray paint. Mainly curious to try it out, and see how good/bad it gets.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Smooth is one thing, mirror finish is another thing. Actual mirrors and optical quality glass are difficult/impossible with FDM manufacturing. It can be a precise process, but I don't see it being that precise. I can print parts with smooth top surfaces but I don't think that any amount of tuning and process manipulation can get to mirror quality of finish.
That does seem to be the general opinion out there.
I did find somebody who claimed reasonable success with just sandable filler + lots of sanding + glossy chrome/mirror finish spray paint. Mainly curious to try it out, and see how good/bad it gets.
That sounds like something where the finishing paint just fills in any imperfections and leaves a smooth surface.
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@cvi Any odds I could convince you that a Foucault pendulum is needed for this task? If so, are they decent odds?
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@mikehurley said in Today in Blakeyrat is always several years behind in every tech trend news...:
That sounds like something where the finishing paint just fills in any imperfections and leaves a smooth surface.
That's the general idea, from what I've understood. Technically there is the sandable filler, which is also supposed to be sprayed on, to fill up small imperfections (and the excess is sanded away). Whether or not this will translate into something useful in practice I don't know yet.
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@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
Any odds I could convince you that a Foucault pendulum is needed for this task?
Those are fun. There was one where I was studying that spanned 6 floors IIRC. The space downstairs was definitively not large enough, and the walls around the pendulum showed the signs. Unfortunately, my current apartment does not span 6 floors, which would make the pendulum less impressive and more lame.
If so, are they decent odds?
Based on the above assessment: 0%. I don't deal with lame Foucault pendulums at this stage in my life.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
@mikehurley said in Today in Blakeyrat is always several years behind in every tech trend news...:
That sounds like something where the finishing paint just fills in any imperfections and leaves a smooth surface.
That's the general idea, from what I've understood. Technically there is the sandable filler, which is also supposed to be sprayed on, to fill up small imperfections (and the excess is sanded away). Whether or not this will translate into something useful in practice I don't know yet.
Are the reflectors gonna be used in a fashion sensitive to curvature distortion? Cheap mirrors are gravity flattened (iirc) maybe with rotation (iirc) and then past that polishing must continually preserve or enhance overall flatness (or curvature, if you spun it). It's a hellabitch. Assuming it's non-flat, there's only one perfect convex hull, and you can't get it by gravity, and you can only approximate it initially AND your degree of error vs the hull is not going to be constant across the surface assuming any regular voxelization.
Do you, by any chance, have rotation to work with? Rotation can be exploited some way here maybe...
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@cvi this morning I was looking at one of the electronics enclosures I have on my 3D printers and you could probably get pretty close to a glass smooth finish by printing on glass. Some of them I printed on glass and they are pretty close to perfectly smooth. The key is to increase your first layer height, increase first layer extrusion width and increase first layer extrusion rate.
If you normally print with a 0.4mm nozzle at 0.2mm layer height you could try first layer settings of 0.3mm first layer height, 0.5mm extrusion width and 105%-110% extrusion rate/multiplier.
After that you would have to work on getting the metallic/reflective finish on it so that it is actually a mirror. NFC about that. I am skeptical on paint being good enough to get that done.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
I am skeptical on paint being good enough to get that done.
A lot (citation needed) of residential mirrors are just silvered paint on the back of glass. Not as good as vapor depositing silver layers, but way cheaper especially at scale. And the silver might not even be silver.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
@cvi this morning I was looking at one of the electronics enclosures I have on my 3D printers and you could probably get pretty close to a glass smooth finish by printing on glass. Some of them I printed on glass and they are pretty close to perfectly smooth. The key is to increase your first layer height, increase first layer extrusion width and increase first layer extrusion rate.
If you normally print with a 0.4mm nozzle at 0.2mm layer height you could try first layer settings of 0.3mm first layer height, 0.5mm extrusion width and 105%-110% extrusion rate/multiplier.
After that you would have to work on getting the metallic/reflective finish on it so that it is actually a mirror. NFC about that. I am skeptical on paint being good enough to get that done.
The glass-facing side, or the non-glass-facing side? I expect the side that was essentially extrusion molded onto glass to be rather flat.
@cvi What about the curvature, if any?
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@Benjamin-Hall said in Today in Blakeyrat is always several years behind in every tech trend news...:
A lot (citation needed) of residential mirrors are just silvered paint on the back of glass. Not as good as vapor depositing silver layers, but way cheaper especially at scale. And the silver might not even be silver.
I get that, and I knew that, but it is also applied as a colloidal solution to the rear of the mirror and cured in place. If it were easy to print perfectly transparent objects I would have even suggested that, but we can't.
The "painted on" silver also isn't very durable. They coat it afterwards with copper and then paint it with a durable paint.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Benjamin-Hall said in Today in Blakeyrat is always several years behind in every tech trend news...:
A lot (citation needed) of residential mirrors are just silvered paint on the back of glass. Not as good as vapor depositing silver layers, but way cheaper especially at scale. And the silver might not even be silver.
I get that, and I knew that, but it is also applied as a colloidal solution to the rear of the mirror and cured in place. If it were easy to print perfectly transparent objects I would have even suggested that, but we can't.
The "painted on" silver also isn't very durable. They coat it afterwards with copper and then paint it with a durable paint.
Yeah. Front-silvered mirrors require some different techniques. Not all of which will work on plastic.
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@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
The glass-facing side, or the non-glass-facing side?
The glass facing side.
@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I expect the side that was essentially extrusion molded onto glass to be rather flat.
It is, but if you do not have adequate extrusion (you actually want to overextrude a bit, but not so much that it causes issues in following layers or gums up your nozzle) or do not have good adhesion and melt-in between your passes you can get very noticeable lines between your nozzle paths.
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@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I expect the side that was essentially extrusion molded onto glass to be rather flat.
One addendum to this: You have to be picky on your material choice or be setup to print in a temperature controlled enclosure. ABS for instance has a fairly high expansion coefficient so it tends to curl on the edges. As you work your way up from the initial layer the remaining layers are cooled by the ambient air and will shrink causing your part to become convex at the edges. It is similar to how you can warp metal by heating it up to high temperature and then quenching one side. It introduces stresses in the material which manifests as warping.
PLA on the other hand has a comparatively low glass transition temperature and lower expansion coefficient so it is much less prone to warping so it is much easier to print parts without curling or significant internal stresses.
Once you get past printing pretty things off of Thingiverse and start designing functional parts and such, material choice for printing can become pretty important.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I expect the side that was essentially extrusion molded onto glass to be rather flat.
One addendum to this: You have to be picky on your material choice or be setup to print in a temperature controlled enclosure. ABS for instance has a fairly high expansion coefficient so it tends to curl on the edges. As you work your way up from the initial layer the remaining layers are cooled by the ambient air and will shrink causing your part to become convex at the edges. It is similar to how you can warp metal by heating it up to high temperature and then quenching one side. It introduces stresses in the material which manifests as warping.
PLA on the other hand has a comparatively low glass transition temperature and lower expansion coefficient so it is much less prone to warping so it is much easier to print parts without curling or significant internal stresses.
Once you get past printing pretty things off of Thingiverse and start designing functional parts and such, material choice for printing can become pretty important.
For a constant curvature assuming several things that may not hold, you could get a decent convex mirror by exploiting the warping. the things that could break this are, material inconsistency, cooling time differences, discontinuities, etc..., kind of a lot. a spiral path might get closest.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
I am skeptical on paint being good enough to get that done.
Yeah, that is my worry as well. There are some specialized paints; the "best" one that I've found so far seems to be made to be sprayed on glass, with the mirror surface being created on the glass interface (and not the opposite side, from which you paint). That obviously won't work for the 3D printed surface.
OTOH, not really worried about durability at this point.
@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
What about the curvature, if any?
Good question. Yes to curvature, but probably not on the first attempt.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
Good question. Yes to curvature, but probably not on the first attempt.
Ahhhhh, so your endgame might be some sort of concave lens? Like for a telescope or whatnot?
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
Good question. Yes to curvature, but probably not on the first attempt.
Ahhhhh, so your endgame might be some sort of concave lens? Like for a telescope or whatnot?
I hope it's a solar oven. Everywhere should have a handy 3000o point within easy reach.
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@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I hope it's a solar oven. Everywhere should have a handy 3000o point within easy reach.
There are easier ways of doing that at the scale needed to reach those temperatures. Go find an old rear projection big screen TV:
https://www.youtube.com/watch?v=XFw7U7V1Hok
Or an old satellite dish:
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Ahhhhh, so your endgame might be some sort of concave lens? Like for a telescope or whatnot?
Fair guess, but no. I doubt the quality would be sufficient for a mirror in a telescope anyway.
In short, I have a program that computes a bumpy surface with some special properties in the reflection. Currently it's modeled with a fairly good(*) mirror in mind (thus the $$$$ third party manufacturing). However, I could in theory change the way the reflection is modelled to simulate a more shitty mirror. Hence the question of "how bad is the best mirror surface I can make on the cheap".
This falls under the category of "why attempt to fix it in hardware if you can painstakingly work around it in the software". I'm told that's not the right approach, but since I know software more than hardware ... well, you work with what you have.
(*) Fairly good = perfect at the moment, but that might be a bit of a strong assumption anyway.
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@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I hope it's a solar oven. Everywhere should have a handy 3000o point within easy reach.
Combining 3000 oC with 3D printed materials ... you better enjoy the smell of burning PLA.
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@cvi AIUI, much less unpleasant than the smell of burning ABS.
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@Polygeekery said in Today in Blakeyrat is always several years behind in every tech trend news...:
Go find an old rear projection big screen TV:
Oooh, big Fresnel lens.
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
@Gribnit said in Today in Blakeyrat is always several years behind in every tech trend news...:
I hope it's a solar oven. Everywhere should have a handy 3000o point within easy reach.
Combining 3000 oC with 3D printed materials ... you better enjoy the smell of burning PLA.
Eh, the hot part is not very close to the primary mirror. Ship it.
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@HardwareGeek said in Today in Blakeyrat is always several years behind in every tech trend news...:
@cvi AIUI, much less unpleasant than the smell of burning ABS.
At 3000 oC the choice of plastic hardly matters anymore in terms of mechanical performance, so might as well go for the one that fails in a less toxic way.
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@cvi If and when I ever get my off its knees and buy a printer, I will be buying it, in large part, specifically for the purpose of turning PLA into CO2 and H2O. Not at 3000°C, though; 800–900° will more than suffice for my needs (lost-
waxplastic casting).I might not use PLA, though. I remember seeing a very high-res UV/resin printer, and the manufacturer offers a resin specially formulated for that purpose. I might get that instead of a filament printer, depending on the price. I don't remember what it was — obviously significantly more than a starter filament printer — but it didn't seem too outrageous. At least I think I'd remember if it was enough to scare me off the idea of buying it.
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@HardwareGeek said in Today in Blakeyrat is always several years behind in every tech trend news...:
lost-waxplastic casting
you are going to drive yourself insane trying to get the insides of the mold right. I look forward to this.
some people think you need a tap and die set to thread things, but they're probably wrong
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@cvi said in Today in Blakeyrat is always several years behind in every tech trend news...:
the smell of burning PLA.
Which due to what PLA is made of, smells almost exactly like burning sugar.
I had a print go horribly wrong for what could have been any reason but was most likely because I sliced the model while drinking entirely too much and decided to print entirely too fast and ended up entombing a hotend in burnt PLA. It took a while to air out the basement and it gave me a splitting migraine when I cleaned up the mess.