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Re: PowderMaker1 3DP printer

Posted: Fri Apr 26, 2019 2:12 pm
by maxt
hello, this is my first post on this fantastic forum, and I take the chance to explain why I'm here. I'm operating a 3DS Projet 660 since a few years, so I have quite a bit hands on experience with this technology. Problem is that this printer (the one I own) sucks so much that I'm seriously considering developing my own.

This PowderMaker1 design show here looks really nice, I'm wondering what commercial price level are you aiming at, and when you think it would be ready for sales, even single modules (e.g. heads controller)

A couple of advices though:
1. the main problem of these printers is, as dragonator points out, the powder. 80% of the issues of the 660, and half ot the aborted prints, are due to the powder going litterally everywhere, dirtying electric contacts, ruining printheads, falling from the axes and making a rough build surface. So don't underestimate the powder mess... in particular, the desing is missing a sort of cover that protects to some extent the room were the printer operates.

2. build volume. These printers have three axes, the Y axis (where the printheads move) is the fastest and should be the largest dimension, as it is in your design. The X axis is the slow axis, and should be the second largest dimension. The Z axis is by far the slowest, and should be the smallest dimension.

In this case the difference between X and Z axis is only 1cm, so not a big deal, but consider inverting the X and Z sizes if you still can. Every print job you will do will always be oriented so that largest dimension is along the Y axis and the smallest on the Z axis, because doing otherwise can turn a 2 hours job into a 15 hours job, printing the same part !

3. consider a vacuum system. The build volume is deep enough that you wont be able to extract the parts without it.

Now something about the materials:
for the powder I suggest you to start with 3dsystems PXL, at least for the experimental stages. It's really the only one that spreads really smoothly. If you can't spread that one smoothly you know you have to fine tune the spreader, while with normal plaster you may not know if the issue is the roller or the plaster. It costs a fortune but has the proper granulometry mix and, especially, the grains (I have a few microscope photos I'll post later) are fairly smooth, nearly spherical (as opposed to the plaster you can buy at LeroyMerlin or similar places) and spread really smooth. I suspect this is the main reason for the high cost.

for the liquids, transparent: just plain demineralized water added with the necessary percentage of IPA will do. I use this since long time and half an hour after the print is completed the parts are perfectly cured and hard, they do not even need to be infiltrated with CyanoAcrilate, which is otherwise mandatory using the usual mix of water/glicerine/surfactant. Getting rid of CA is a big, big, BIG advantage.

I can't tell you the % of IPA because it is head dependant, if your head could print pure water, pure water would be perfectly OK, because IPA is only necessary to render the necessary viscosity and surface tension for the head to jet, but the solvent (for plaster/PXL) is just the water.

For colors is a bit more complex ;) , it requires procuring inkjet color (amazon is fine) and to find the right dilution with water. That's it....

good luck with the project, seems really promising

Re: PowderMaker1 3DP printer

Posted: Tue Apr 30, 2019 10:41 am
by maxt

here's a photo of the "official" powder grains taken with an electronic microscope. See the surfaces are fairly smooth (within reason) which gives a very appropriate rehology.

kind regards, Massimo

Re: PowderMaker1 3DP printer

Posted: Tue Apr 30, 2019 4:16 pm
by dragonator
How does this "official" powder behave compared to what I have in Oasis right now.

The stuff in Oasis is an older Zcorp "official" gypsum. If you just pour it it can keep angles between 45 and 60 degrees, but is loosely bound. It can then be compressed to what feels like between 2/3 and 1/2 its original size. Based on this behavior I always though that the powder would be exceptionally jagged. Once packed, it retains it shape up to 90 degrees of angle (straight up) without much hassle. When dropped it creates a fine mist of powder containing the smallest particles.

Re: PowderMaker1 3DP printer

Posted: Wed May 01, 2019 6:16 pm
by maxt
I don't think there's much difference between the old zcorp stuff and the new one. Brand is the same and it behaves similarly to what you describe, though probably does not compress to 1/2 it's original size. At most they have just changed slightly whatever additive they add to the plaster and labelled it "NEW" but I wouldn't be surprised if they didn't change an atom.

The 660 is exactly the same machine as the zcorp 650, they stopped developing it (besides the model tag) several years ago, even if they still sell it, and I don't think they have invested a penny in researching the material.

But mind you, this powder can withstand only so many print cycles, it start degrading after some, while it looses the smaller grains (which fly around everywhere) and start collecting humidity. So, if you don't see a billiard table flat bed (it should look solid), this may be the reason.

Re: PowderMaker1 3DP printer

Posted: Wed Jun 05, 2019 7:47 pm
by david

Sorry for my slow update. I'm working on the electronic part. The project is still going and I'll definitely make the first print during this summer.

maxt, thanks for your input. Re the commercialisation, it is a bit early to tell as I'm not sure about the total cost and the actually performance it can deliver. In this design the X, by which I mean the direction the printhead travels most, is supposed to be the fastest axis, the speed should be around 100mm to 500mm per second, just like an ink printer. For better spreading performance the roller and the printhead connect to different belt along the Y axis. The printhead firstly being installed has 6 channels, the idea is to have two channels to print major 'glue' and other four channels for colour with minor glue. The 'glue' is ECO solvent type. The powder may contain PMMA, ABS, PVA, PVB, etc, which will be melt by the solvent and can solidify afterwards. BTW, what's the price range of the official powder you mentioned? and where to get it? Due to the simplicity and cost, this version does not have a vacuum, instead a cover can be used during the final collecting stage. Actually I was thinking to put a vacuum underneath the powder bed to make it firmer but that should be the next stage. The humidity vibration etc all play certain roles in the powder spreading, We'll see when I get there.



Re: PowderMaker1 3DP printer

Posted: Mon Jun 10, 2019 3:11 pm
by maxt
Hi david
david wrote:
Wed Jun 05, 2019 7:47 pm
maxt, thanks for your input. Re the commercialisation, it is a bit early to tell as I'm not sure about the total cost and the actually performance it can
pls keep us posted on the progress.

Regarding the powder, it's pretty expensive, unfotunately. List price is around 80€/Kg and it's only sold in packages of 14Kg. It's only sold by 3dsystems resellers. If you're in Europe you may try this site in the Netherlands ... et-ve.html
I can't tell you if they are fast/reliable because they accept order from the entire EU (and a few non EU countries as well) except from my country :evil: unfortunately, otherwise they stock a few spare parts that I would be happy to buy from them.

Regarding the ink... using solvent ink is something I've been considering as well (since the XAAR doesn't seem to swallow anything else) but I don't have a clue what kind of solvent is used in the inks and does it actually solve.

The powder above is plaster with added (most likely) PVA powder, the solvent used is plain water wich solves both the PVA and the plaster. If only the additive (PVA, PMMA, whatever you will use) is solved then most probably you will get brittle parts and will need to infiltrare them in CA. However don't take my words for gold because I've never tested such ink/powder combination. In the past I got some nice surprises when testing new clear binders, so you may never know.

Re: PowderMaker1 3DP printer

Posted: Thu Aug 15, 2019 11:14 pm
by david
It has been sometime. I'm still working on the printhead to implement a proper driver. For someone might be interested, a driving waveform has been enclosed.
waveform.png (63.33 KiB) Viewed 2159 times

Re: PowderMaker1 3DP printer

Posted: Sun Aug 18, 2019 6:17 pm
by david
so far so good ...
DS2_QuickPrint3.png (40.73 KiB) Viewed 2142 times

Re: PowderMaker1 3DP printer

Posted: Tue Aug 20, 2019 11:03 am
by maxt
thank you for sharing the updates.
May I ask you where did you get the technical info about the epson printhead ? or are you reverse engineering it ?

Re: PowderMaker1 3DP printer

Posted: Thu Aug 22, 2019 1:13 am
by david
that's mixed of literature study, reverse engineering, wildest guess and some of good luck. My plan is to try it with the real head in a few days. There is still some firmware work and ink set up. so fingers crossed.