𞋴𝛂𝛋𝛆

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Joined 2 years ago
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Cake day: June 9th, 2023

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  • You can just slap a dial gauge on the gantry and move the X/Y manually to see exactly what the deviation is. A decent second-hand dial gauge on eBay will run you $20 shipped.

    If you get into the weeds, there is not an accurate method of triggering any form of mechanical stop that involves touch or a hall effect probe. You must get into optics for real accuracy, but that is nonsense for the materials and scope of printing. You would need to eliminate many other variables like the filament accuracy and how backlash and step accuracy are eliminated as issues.

    As a former owner of an auto body shop with employees, most people do not know what clean is or how tooth is required. Like isopropyl alcohol has its place but is ultimately extremely weak at real cleaning problems. In automotive paint, silicone is a major problem. It primarily comes from tire dressing that makes them look slick black. The amount of effort it takes to remove that junk for automotive quality work is insane. Most chemicals just push the junk around but leaves or dilutes the issue often making it worse. One of the big tricks in automotive stuff is (to use a chemical cleaning step first but -) a few drops of dish soap in the wet sanding bucket. The light soap will keep the sand paper clean and working longer, but makes most work also cleaning work. Anyways, dish soap can be very effective. Acetone occasionally on a surface is also effective. Virgin lacquer thinner is the strongest common solvent but it can react with lots of stuff and you are unlikely to find true virgin solvent. The recycled stuff has a paint stripper component in it that will cause epic nightmares and reacts with almost all plastics. Acetone is much cleaner and consistent unless it is sold for junk like nail polish.

    The general rule of thumb is to assume a mechanical tooth adhesion is the primary form of bonding unless there is a catalyst involved (2k urethane/epoxy primers/clear). That rule can easily apply to 3d printing and bed adhesion. I see a lot of the same types of effects from different surfaces and filaments. In automotive paint, there are even special adhesion promoters like Bulldog for spraying plastic parts ahead of other finishes. I had other adhesion promotion tricks too, like a mist coating of clear coat. The main trick with all automotive paint adhesion is to know what grit or “tooth” each thing you’re spraying wants to grab onto and prep accordingly. So in 3d printing I use a similar approach with the general safe bet of sanding my smooth build plates to 600 grit. With sanding, do not start dirty, like you’re trying to embed junk into the surface. Start clean, then knock off the shine to a smooth and consistent matte finish on the entire surface. When it comes to sanding like this, edges and any anomalies are absolutely forbidden to sand. Never touch your edges until last when everything else is done. Edges are always thinnest and most vulnerable to causing issues especially for the inexperienced. You match them to the rest of the matte surface carefully at the end.

    Clean a smooth build plate with acetone like once or twice a year and then sand it to matte, clean that with dish soap, then alcohol with each print. That will completely eliminate contamination as a cause. If you have old skool clean glass with no coatings as a build plate, sanding is optional because you can use something like lacquer thinner or less effective acetone to get it absolutely clean.

    Perfect first layers are possible with enough fussing with the software. If you really want to level the bed with hardware, use a dial gauge clamped to the extruder. That will remove all of the averaging and inaccuracies from probing if it is a quality gauge that is smooth and not sticky. You would need to get into optics for true accuracy like with closed loop control systems that are an order of magnitude more expensive than 3d printers. 3d printers are precision machines with no accuracy. The 0,0 home location is always slightly different, but all measurements are based upon this location. This issue becomes relevant with IDEX and CNC. Going well beyond these – in optics accuracy requires a defraction grading and alignment of light wave patterns. I so want to get into that one to grind my own telescope mirrors. Typically accurate machines use a flag of metal sticking out somewhere at a known location and an optical encoder switch that gets interrupted without anything touching as this is typically the closest you’ll get to real accuracy down to the clock and instructions timing of the interrupt routine in the microcontroller.

    If you have v-roller wheels on extrusions, one other major potential issue is that extrusions have a relatively large twist tolerance component in their specification. It is extremely difficult to detect this kind of twist, but it is a major potential issue. It generally requires a high metrology grade granite surface block and parallel sticks to measure twist in a precision instrument’s linear bearings… as far as I understand it. I have seen such things being measured but have never done so myself.


  • Very cool. I was thinking about ways of making a potentiometer knob on an audio amp more visually interesting. The moire effect might be one to play around with.

    I don’t think I would trust this one in practice, but the effect is interesting. I found it far more necessary to learn the vernier scale with micrometers. It felt much more useful understanding the practical limitations and scope of when to use calipers versus a mic. While there are super accurate calipers, relatively cheap calipers and micrometers are far cheaper and easier for most people to access.

    When it comes to radius gauges I trust these more than any of the others I have tried:

    I know this kinda isn’t the point, but using it as an excuse to share – the fishing leader line to hold a set like this is key to making them super handy. Unfortunately I have only used micrometers on a few 3d printing projects. Those are more used within the machining realm.





  • 𞋴𝛂𝛋𝛆@lemmy.worldBanned from communitytoAsklemmy@lemmy.mlAre we going to refer to americans as "orcs" now?
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    8 days ago

    US is not supporting Russia, but Iran is. Israel is atrocious and it would not surprise me at all if they absolutely know about Oct 7th well in advance. It was the result if their prejudice and Palestinian concentration camps before Oct 7th in either case that caused the initial attack. However it was not entirely without cause like with Russia in Ukraine. Everywhere is complicated. The USA is super polarized and in pretty bad shape, but it us not exporting suicide bombers. Is it better to target with 10 million dollar munitions remotely no, but those are not targeting crowds of people as the primary goal


  • 𞋴𝛂𝛋𝛆@lemmy.worldBanned from communitytoAsklemmy@lemmy.mlAre we going to refer to americans as "orcs" now?
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    8 days ago

    It was the change in Syria and the mountain on the boarder that Israel now controls that changed the geopolitical situation and strategy. The radar shadow of that mountain was what prevented Israel from having an opportunity to stop or influence Iran’s nuclear policy. Some deeper depth geopolitical youtubers have done uploads on this change and implications. The position will likely end up back in Syrian hands eventually… or it might. Again like I have said elsewhere, I don’t support Israel or their escalations but Iran is shit. They are supplying arms to Russia, exporting terrorism, and run by a disordered misogynistic group of men that kill in the name of fantasy and a collective imaginary friend that no one has ever had a real conversation with. That is fucking cave man level bullshit from anyone anywhere.



  • 𞋴𝛂𝛋𝛆@lemmy.worldBanned from communitytoAsklemmy@lemmy.mlAre we going to refer to americans as "orcs" now?
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    8 days ago

    If you can take out all nukes, hell yeah. Bomb all of them into oblivion. I’m for first do no harm and live and let live.

    If my neighbor is talking about shooting up a school, and no one I report them to seems to change the situation, and I see them loading up the car to go shoot up the school, I’m not going to feel bad about shooting my neighbor then and there, if I have no other option. I don’t care to wait until they pull the trigger at the school to confirm their intentions.

    I mean you’re ultimately talking to a physically disabled guy living in the USA where I face homelessness and a terrible future. I despise this country and know the lack of ethics better than most. Still, the primary exporters of jihad are still the primary exporters of jihad.

    Israel should not exist, and is a crusader state. The boarders of the middle east were absolute garbage and the result of the colonial era of cartel like western criminality. I don’t support any of that crap. That does not change the fact that Islam has no reformation to stop jihad like how separation of church and state and the christian reformation put an end to church based crusades. People can try to tone down the message but fundamentalists will always draw power from the most ignorant using this element of teaching. That can never and will never go away.