Things that still suck about the V1 printer - according to the founder

I definitely can't see these being a big problem for such a cheap printer, as MagicDan said. The normal problem for other cheap (ie three times the cost of the Peachy) printers is along the lines of "doesn't actually print" - in comparison, these issues are trivial.

For (2), would it be practical to solder the coil wires to some much thicker (more robust) wire? Even 28AWG should be fine, and that's big enough to use with standard crimp connectors. Then, to prevent the thicker wire putting stress on the super-fine coil wire, 3D print a "coil holder" that keeps it all together.

Edit: hmm, suppose you soldered the thicker wires to the coil, then put maybe 1mm of resin in a small container, placed the coil + wires flat in the container (ie partially immersed in the resin), and left it out in the sun? Ideally, that should result in the really delicate wires and the joint to the thicker wires being firmly embedded in cured resin, but with the coil right at the surface of the resin. This has the advantage that you don't need a working Peachy printer to do it.

hmm.. if you cant flame the wire, there's always the molten caustic soda method, but thats pretty dangerous - take some sodium hydroxide (powder) and mix it 4:1 with some non-iodized table salt, then melt it with a torch, then insert the wire you want stripped into the molten soda mixture for 1-5 seconds, then quench in water.

If you have a laser cutter, you could experiment with the strength needed to just burn off the insulation without melting the wire. - There are special machines that do this, and can supposedly strip higher than 50 gauge wire without damaging the wire.

It is unfortunate you could not go with the PCB coil method I suggested, it would make for much more secure interconnections (and more consistent coil inductances).

As for the remaining issues, I think that the most significant bug is that the final prints are not accurate, and it pretty much throws anything I would use the printer for out the window.

I'm sure that you guys can find a better calibration method, and as a backer, I hope that you prioritize this as soon as possible.

-UD

Quote:

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Originally Posted by User_Defined

It is unfortunate you could not go with the PCB coil method I suggested, it would make for much more secure interconnections (and more consistent coil inductances).

As for the remaining issues, I think that the most significant bug is that the final prints are not accurate, and it pretty much throws anything I would use the printer for out the window.

I'm sure that you guys can find a better calibration method, and as a backer, I hope that you prioritize this as soon as possible.

-UD

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Ya that PCB coil idea was really great, I dont think we can get the power ( turns ) we need out of it tho. Our coils have many hundreds of turns in them
and they are rather small. Ether way fundamentally is a perfect idea. I want to use it somewhere. And I can see a good place for it in peachy 2.0 galvo system :)
As for calibration, it is coming soon, after we implement variable laser power, and acceleration, Calibration is next on the list.
One step we have taken toward better calibration is we have come up with a better UI for entering the calibration points.
You can now move the laser beam around with your mouse and click on various places on grid paper to set calibration points. Its much faster than our previous method and I can now imagine it being reasonable to enter in 100 plus calibration points.

PS UserDefined
quite some time ago you asked a REALLY good question, something that is constantly on my mind and still is.
Why is the peachy printer able to print perfectly smooth columns but dose not achieve the same smoothness on other prints?
This has botherd me ever since I saw that first green column print.
I still don't have a definitive answer for that, I have tested and disproved many theory's so far, and I still have more theory's to test.
When I find out why I will make a thread on this. My apology's for not answering you with a simple, I dont know. I remember composing a rather in depth
answer in my head including all my theory's at the time, but Im sure I never went back and actually typed out a reply to your question.

Quote:

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Originally Posted by rylangrayston

Ya that PCB coil idea was really great, I dont think we can get the power ( turns ) we need out of it tho. Our coils have many hundreds of turns in them
and they are rather small. Ether way fundamentally is a perfect idea. I want to use it somewhere. And I can see a good place for it in peachy 2.0 galvo system :)
As for calibration, it is coming soon, after we implement variable laser power, and acceleration, Calibration is next on the list.
One step we have taken toward better calibration is we have come up with a better UI for entering the calibration points.
You can now move the laser beam around with your mouse and click on various places on grid paper to set calibration points. Its much faster than our previous method and I can now imagine it being reasonable to enter in 100 plus calibration points.

PS UserDefined
quite some time ago you asked a REALLY good question, something that is constantly on my mind and still is.
Why is the peachy printer able to print perfectly smooth columns but dose not achieve the same smoothness on other prints?
This has botherd me ever since I saw that first green column print.
I still don't have a definitive answer for that, I have tested and disproved many theory's so far, and I still have more theory's to test.
When I find out why I will make a thread on this. My apology's for not answering you with a simple, I dont know. I remember composing a rather in depth
answer in my head including all my theory's at the time, but Im sure I never went back and actually typed out a reply to your question.

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No worries about not answering the questions. Naturally I assumed that your team is trying to make the best possible prints and would be pursuing that goal if you could.

The question was more to catalyse some thinking. I found the stairs of the purple rook to look very glassy, and thought it had just been a question of layers.

It might simply be that the glass columns were printed from high up and were straight, so the laser was interacting less with surrounding resin and produced a consistent surface as it went.

It could simply be a question with laser power, spot size, layer numbers, and print time. If you print it slow and take your time it may come out better?

In any case, Im already super impressed with the prints so far, and with better calibration for accurate parts, the peachy will have surpassed my expectations (which were still high) by far.


-UD

If the shrinkage for a particular resin is deterministic and repeatable, could it not be stated on the supply vessel label? Then could the print software have an automatic allowance for each resin type, so that after shrinkage, the dimensions would be more accurate. Not sure whether shrinkage is omni-directional though, so it might have to be an allowance per axis.

Quote:

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Originally Posted by User_Defined

It could simply be a question with laser power, spot size, layer numbers, and print time. If you print it slow and take your time it may come out better?

-UD

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"It could simply be a question with laser power, spot size, layer numbers, and print time. If you print it slow and take your time it may come out better?"

yes longer print times small spot sizes and slower laser seems to help, but more than 100 layers per mm dosent seem to make any difference.
No matter what settings I use there is often some subtle oscillation leaving rings on a print, it seems to happen with a period of about 50 layers.
You can see it in this rocket, pronounced near the tip.

Attachment 6564

more layers per mm probably would eliminate the patters you can see on the tops of each stair here( altho you cant see these with just the human eye) :
Attachment 6565

my latest Theory's are things to do with the way resin flows during the print, as well as how air may be affecting the surface of the resin.
Im coming up with test prints that can help support or disprove what I think is happening. I feel like we are very close to really nailing perfectly glossy prints( as far as the human eye is concerned).

Those attachments are invalid?

I've been thinking about the ridges in prints..... I reckon it is the wetting/surface tension effect. The way to prove this is to watch a print and time between the points where the resin overcomes surface tension and re-wets the surface of the printed object. Then take the time between wetting events and compute the increase in Z for that time. If the thickness of the ridges in the print correspond to this Z value, the ridges are caused by the surface tension effect.

Incidentally, this effect can be removed by bottom up printing i.e. shine the laser through the bottom of the tank. The worry about sticking to the bottom of the tank can be removed by adding 5 mm of brine first and floating the resin on it. A floating platform is raised using ordinary water and pulls the print upwards from the resin. The print never sticks to the tank because there is a 5mm gap between the resin and the tank bottom.

This method removes any focus problems (distance is fixed) and power problems (fixed). Not sure how the galvos would behave when pointing upwards !!!!

Oh and the other advantage is that the distance to the print never changes, so no mathematical correction for x and y in relationship to Z required. No calibration for z required, it would be the same for all prints, because the distance to the print could be identical for every print.