3D Printing - whether to buy, what to buy and how to use it?

[Big Train James]

As noted in the US Dabblings thread, I have recently gotten an Elegoo Mars 3 printer. GrahamMc has suggested I might contribute my insights here since Simon and others are considering the Mars 3 as well.

First I'll list out the specs of my setup, then move on to discuss the general printing experience and my impressions of the Mars 3, cleaning/curing station, and resin choices.

Elegoo Mars 3 printer ($350 from Elegoo, via Amazon, cheaper at the moment apparently )
Elegoo Mercury Plus v2.0 2-in-1 wash and cure station ($150 from Elegoo, via Amazon, cheaper via Elegoo direct but not available in the US at the time)
Siraya Tech resin - Fast ABS-like Navy Grey (~$35-40 via Amazon)
Siraya Tech resin - Build Sonic Grey (~$35-40 via Amazon)
Siraya Tech resin - Sculpt Grey (~$35-40 via Amazon)
99% Isopropyl Alcohol for secondary and tertiary cleaning in tubs
91% Isopropyl Alcohol for primary cleaning in a spray bottle
Paint booth - for ventilation
Chitubox Pro slicer (1-year free subscription included with the printer)

Various other sundries used to varying degrees, include respirator, lots of nitrile gloves, lots of paper towels, scraper, flush nippers, x-acto, hair dryer or heat gun (but I don't use the heat function), silicone mat, silicone spatula or scraper, paint brush, funnel, paint filters. What you have on your "other supplies" list can vary based on your process, as usual there is more than one way to do things. Somethings should not be negotiable, like the gloves, it would be really imprudent not to use them.

Running through Simon's bullet points from Post #1:

There are all sorts of resins available, and yes they most often exist for a specific reason. They can be formulated for fast cure times, or as water soluble clean-up (which does not mean wash off in your sink though), plant based, heat resistant, for investment casting, flexibility, hardness, strength, in short pretty much all the reasons most other types of plastics exist. For our purposes, usually, we want something that mimics the plastics we already typically use, which are ABS and styrene. Finish quality is also important, as is precision. Some other factors are in play, like smell and price, but there are enough options that those things need not have much impact on decision making.

Grey ABS-like resin is probably fine for 99.99% of what we do, so it's a good place to start, and is also one of the cheaper types of resin available. No point in spending big on test prints. Save that for later, when you are printing masters for burnout. The other two resins I listed above, the Sculpt and the Build, will be tested for print finish quality against the ABS-like Fast, and the Sculpt will also potentially be tested for it's qualities in mold making at some point.

For printer resolution, at this point I would only bother with a 50 micron machine if you want one of the larger form factor printers like the Elegoo Saturn. If you are going to get one of the typical small format printers, there is really no reason to not get a 4k version like the Mars 3 or similar. The difference in price between the Mars 3 and the Mars 2 Pro is currently about $50. There's just no point in choosing the old technology unless your budget is extremely tight.

Similarly, there's also no point in getting any printer that doesn't utilize a mono screen. The mono machines cure faster, so print faster. This will make a huge difference in print time, by a factor or 4 or more. The other advantage to mono screens is that they last longer. The screens are a consumerable, they will eventually wear out, so screen life cycle does matter. One thing I don't know, is whether color screens have anti-aliasing capability, if they do not, then that would be another plus for the mono types.

Curing and washing stations are often considered together, it might be more accurate to think in terms of post-processing stations. The printer manufacturers certainly think of them in that light, and with rare exception market cleaning and curing capability as 2-in-1 units that can do both. There are 3rd party options for curing enclosures, and both curing and cleaning stations can be home-built as well. Are either required? Explicitly, no, you could use the sun to cure your prints instead (don't). But the processes are required. Prints will need to be cured after cleaning, and prints will need to be cleaned of excess resin after printing and prior to curing.

Options for curing stations are any of the 2-in-1 units from the printer manufacturers, 3rd party options as linked above, or build your own. There are plenty of examples on the web for the latter. Get some UV LED light strips off of Amazon, some aluminum foil (I would use mylar instead), and build an enclosure from foam-core or a cardboard box, or find a nice sized bucket or bathroom trashcan. People often say to get a small turntable as well, to rotate the part and get exposure to all sides, but I don't think it's necessary for home-built units. The UV strip typically wraps around and around inside the enclosure, so the light comes from all sides anyway. One disadvantage of home-built units is that they lack timers, although I feel confident that something could be incorporated into the assembly to handle that task. You must make sure to get the proper wavelength LED's.

Cleaning stations, I wouldn't have paid for one if it wasn't part of the curing station I chose. That being said, I'm not disappointed that I have it. But honestly, a couple of food storage tubs with lids would suffice equally as well. The difference is that the commercial unit has an agitator that moves the cleaning fluid, as opposed to jiggling the part about in the tub of alcohol, and of course the same timer as used with the curing function. There's really not much more to it. Using the washing function also doesn't explicitly mean the model is fully clean. So when I do encounter stubborn liquid resin hiding in holes or tight spots, the small paint brush is used to brush and dab about in those areas to clean it out. In my opinion, a washing station is the epitome of "your mileage may vary", but I also think it should be the last criteria you consider when assembling a 3d printing "system".

As to what you use to clean, water or IPA or other, it depends on what type of resin you are printing with. Water would be the obvious choice for water-based resins, but it is also sometimes recommended in the curing process for various types of resins. Alcohol or Ethanol (NOT Methanol) are the options typically recommended for most other resins. The alcohol is usually recommended to be 95% plus IPA, although 91% seems to work okay as well. Methanol, or denatured alcohol, is a cheaper option, but can have other chemicals in the blend that are potentially more hazardous to our health. Then there are other cleaning agents like Simple Green, that have been discussed online. They came to the fore during the early days of Covid, since IPA was either impossible to get or outrageously expensive. I voted for 99% IPA for the most part, but more on that later. The short answer here is start with the manufacturer's recommendations and processes. Choose from there if they list options.

Smell? Depends on the resin. Many are being developed to have low odor, Siraya Tech emphasizes this feature for many of their resins. I've been using the Fast, and I haven't found the smell to be overwhelming at any time. I typically run the paint booth fan when I'm printing, and I typically wear a respirator when handling the liquid resin. However, I've forgotten to do one or the other or both at least once or twice, and didn't notice any particularly offensive odor when that happened. Also, in between print jobs, liquid resin sits in the vat in the printer, with the lid on, and I never notice any obvious smell. I can't speak to any other resin at this time, as I haven't used any others.

Conversely, I do have an issue with the odor from the IPA. I also find that the fumes from the IPA can irritate my throat with extended exposure. Again, the odor and fumes can be tolerated for a short time, but ideally as a best practice, I wear the respirator while I'm dealing with either the liquid resin or the alcohol.

Noise, yes it can be noisy. The Mars 3 is supposed to be quiet, but it's actually not especially so. It's not terrible either, but definitely noticeable. The real noise culprit is the spray booth fan. Mine is an older model, and it's quite loud. I don't know if newer units are quieter. If you had the printer running in a back room, I doubt the printer noise would be a concern by itself.

Space requirements, about what other people have suggested already. My work space is about 24" x 60". That includes the printer, wash and cure station, paint booth, several tubs of alcohol, and open work surface area. I could do with a bit less space, but not much, and more would always be nice but not necessary. It is nice if you have a cabinet underneath or shelving to hold supplies and tools.

Are there disadvantages? None that I can think of unless you would use the printer only very rarely, and by rarely I mean statistically equivalent to never. Then it might not warrant the cost of purchase. Better in that case to know a friend that has one. I guess the other consideration might be access to and fluency with the 3d cad needed to create the models. But in all other aspects, I'd recommend a 3d printer as an extremely useful and powerful tool. I would even argue paradigm shifting, and I don't think that's an exaggeration for myself.

I'm going to wrap this up for tonight. I'll come back tomorrow to talk about slicers, and other thoughts and observations about my experience to this point.

Jim

 

[simond]

Well, it’s very nearly a year since I started this thread, and I’m just about to splash out.

the choices of printer have changed, of course, over the year, and there larger devices available, and better resolution too. Price/capability seems to have come down, if anything, which is surprising.

The entry level units appear to be Anycubic, Elegoo & Creality, of which I‘m tending towards the Elegoo Mars3 or Saturn2. I’ll read up in detail about these over the weekend. I’ll get a wash/cure station too.



if anyone has experience which suggests doing something different, do please shout up!

cheers
Simon

 

[Big Train James]

3D Printing Waste Handling - One Man's Journey

There's been some discussion recently on Mickoo's thread regarding waste alcohol from cleaning 3d prints, and what to do with it. I'm one of those who sees some value in cleaning and reusing the contaminated alcohol for certain steps in the print cleaning process, so I thought I would detail what I go through. I'll also briefly discuss what I do with the other non-alcohol waste from the 3d printing process, meaning the gloves, paper towels, supports, and any other items laden with uncured resin.

Actually, I'll start with the handling of the peripherals, since it's very simple to explain. I'm of the opinion that uncured resin is uncured resin, whether it be in the bottle, on your print supports, your gloves, or soaked up into the paper towel used to wipe the work mat. As such, I think those leftover items should be processed to cure any resin, before they are disposed of. Beyond any sort of discussion about the necessity or merits of doing so, the reality is that it's a very easy thing to do, that errs on the side of caution by default.

I have on hand any number of quart/liter size round storage containers, bought at the local dollar store. Simply fill one with the gloves or paper or support waste and cure it in the wash'n'cure for 30 minutes. Then throw away and do the next batch, repeating as necessary. One workflow I use frequently is to cure the peripheral waste for 30 minutes while I let my cleaned prints air dry before curing. I use an air source to dry my prints, but I like to let them sit for additional time to make sure they are fully dry. The 30 minutes max time on the curing station is a good interval. Or course there are plenty of other opportunities for curing waste, if nothing else it can be done while prints are running.



Moving along to cleaning and filtering the contaminated alcohol, there are a few caveats. This method is not intended to produce 100% clean alcohol, which would probably require distillation. Some people are doing that, but I am not one of them. This method instead is intended to produce a mostly clean alcohol that can be used in the primary stage of the common two-stage cleaning process that many people follow. The goal is to reduce the consumption of alcohol by extending its usable life. It will not fully eliminate waste or the need to occasional resupply with fresh alcohol.

First up are the tools. There are a handful of items that I've settled on.

• Quart/Liter storage containers with lids, or any other clear(ish) container that fits in the curing station and rotates freely
• (2) large funnels of the same size, that nest in such a way that the bodies don't touch - I'm using 5" diameter funnels
• Coffee filters - I'm using #4's, which fit well in the size of cone I'm using
• 1 gallon net type paint strainers, intended to fit over a bucket of paint
• 1 gallon bucket or similar larger container with lid, for use with the paint strainer

Some people will use the paper cone paint strainers as the first filtering step, to remove bits and pieces, but I don't find that necessary.

Obviously, it all begins with a container of contaminated alcohol. Something like this.


There is something to consider with respect to what sort of resin you are printing with. Many of us have advocated for and taken up use of the Siraya Tech Fast Navy Grey resin for printing. One issue though is that there are multiple pigments added to the resin and the various components tend to settle out over time. This happens with fresh resin in the bottle or vat as well as the resin that is initially suspended in the alcohol after cleaning a part. I think it's important when cleaning this sort of waste to remix the components before curing, as I think it leads to better results in the end. I suspect that this is less of an issue if using other types of resin that only involve a single component. More on that as I go through the process.

Don't bother filtering the solution as the first step, it's a waste of time. Cure first, then filter solids after.

Step 1 is to recombine the resin/pigment/alcohol solution so that everything is fully integrated. Then pour into one of the containers and cure in the curing station for the full 30 minute max time.* The idea with mixing to recombine components is to catch pigments in the cured resin solid, rather than curing only the resin itself and leaving the pigments in the alcohol.

*The 30 minute time is normally sufficient unless the resin content in the alcohol is very high. If so, additional steps will be needed. More on this later.

Step 2 is to let the container of cured resin/alcohol sit for a while. Just as the uncured resin will settle out of the alcohol, the cured and solidified resin will do the same. After several hours or a day, you should end up with something like this.


Step 3 is to then filter the alcohol using the funnels and paper coffee filters. But first a few words about the funnels.


These are cheapo funnels from the dollar store, sold in sets of three different sizes. I use the largest funnels for filtering, 5" diameter opening at the top. As can be seen, I've used a drill to modify the white funnel to add numerous holes around the body. This isn't my idea, although I probably would have figured it out eventually. Credit goes to the Veg Oil Guy, who 3d printed a version and offers the stl for sale if anybody wants to go that route. If anybody has tried to use a funnel and the paper cone paint strainers to filter alcohol from the gooey cured resin, they know that the resin clogs the filter and funnel very quickly. The modified funnel increases the open area for alcohol to pass through the filter, including openings above the mass of resin goo. One thing to note, it's important that the two funnel bodies don't touch, so that there is a gap between them for the alcohol to flow through. These nest in such a way that the gap is maintained. I can see where truly conical funnels may not accomplish that, so a spacer may be needed.

I've used #4 paper coffee filters. They fit nicely in the large funnels, except they are a bit tall. However, after opening them, I invert a section in the center of the filter. This does two things, it increases the surface area that is above the resin goo, and it makes the overall height of the filter a bit shorter so that it sits cleanly in the funnel.


In action. I often have more than one container to filter, so I start with just the clear liquid from all containers. The alcohol drains quite quickly at this point.


Sometimes the solidified resin will settle to the bottom of the container and form a sort of pancake like blob. This is the best situation, because there usually aren't any bits and pieces of loose cured resin that want to flow out with the alcohol when you pour into the funnel. Also, the filter can be used again later, it will dry out as the alcohol flashes off.


But sometimes there will be loose parts. In that case, once the bulk of the clean alcohol is processed through the filter, I pour the rest in and let it slowly filter and drain. That can take a short while as some of the filter surface area is blocked by the goo. But it will eventually run through leaving the resin in the filter. You can see the difference between this resin and the single blob pictured above.


Once filtering is complete, you end up with a contaminated filter. Let it sit for a while until all the alcohol flashes off. I will cure this once more and then dispose of in the trash.


Here are some examples of the cured and filtered alcohol. There is the wash'n'cure tub, which I only use infrequently for initial cleaning of large volume parts. It's a perfect use for the recycled alcohol, as a large volume is needed. There's a second shot of a large and small tub, the clear liquid is fresh 99% alcohol, the large tub is recycled 91% alcohol. I use very little 99% IPA now, but that's due to changes in my print cleaning process. That's a story for another day. You can see the tint to the recycled alcohol, I've had other batches that were much clearer, but never fully clear. I attribute the tint to the dark pigment that is part of the Siraya Tech Fast Navy Grey formula. I think it's the same dark pigment seen sitting on the top of the resin in the vat after a bit of time. I believe that the more thoroughly mixed the resin/pigment/alcohol is before curing, the more pigment gets trapped in the cured resin and thus the clearer the recycled alcohol will be. All a guess of course, but it sounds plausible. The last picture is just to give a sense of the clarity of the alcohol, despite it having a tint to it.



That completes the process, unless that asterisk way back in the post applies. I'll get to that in a moment though. To reiterate, I'm not proposing that this process will yield truly clean alcohol equivalent to fresh out of the bottle. Or that it will leave prints fully clean. To be fair though, I've never tested to see how it actually does behave, so maybe I should do that. But it could very well reduce the total amount of alcohol consumed in the printing process, for those that consider it an important factor. If you want to use recycled alcohol, then I'd suggest doing so until it no longer performs to expectations, then flash off and start fresh.

Now if the alcohol is particularly contaminated with resin, then it takes a bit more effort to get it clean. If the goal is to reclaim the alcohol, then I use the following additional steps. If the goal is simply to cure the resin for immediate disposal, then the passive method of setting a container outside, allowing the alcohol to flash off and the resin to cure in the sun, is probably the easiest thing to do.

For those that want to recycle alcohol, I highly recommend that you clean your alcohol regularly, and don't let it get excessively contaminated. It makes the process significantly more protracted, which could be avoided simply by cleaning more often. I'm actually considering changing my workflow so that I clean and filter my primary print cleaning container after each use, rather than after several uses, as I think it will yield the best results for recycling the alcohol.

Curing waste resin frequently is easy. Mix everything up, put the container in the curing station, and hit go. The amount of resin in the mix is still low enough that the solution remains translucent, and the UV light can penetrate fully through the mixture. Curing a heavily contaminated mixture creates a problem where the resin is dense enough that it cures to an opacity that blocks UV light from fully penetrating through the mixture. The result will be a layer of cured resin to some depth from the walls of the container, say 13mm or so. Inside of that cured membrane will remain uncured solution, with uncured resin included. The cured resin will not settle out of the solution until the membrane is pierced. It's sort of like the yolk of a fried egg once you jab a fork or a piece of toast in it. The remaining solution must then be cured again, and sometimes even a third time. It's not hard to deal with but takes considerably more time to do a complete job.

Once cured, filtering the alcohol from the blob of resin is impractical through the typical funnel and paper filter combination. The volume of resin would fill the entire funnel body in some cases. Also, the resin will hold a lot of alcohol even though it's cured, that will leach out over time and drain off if given the chance.

I use the net type paint strainer in this case. Stretch the strainer over the top of a large container, with some sag inside. Pour the cured resin/alcohol mixture into the net, put the lid on, and let it sit for a day or two. The large surface area of the net and larger container will allow any liquid to immediately run through, and the remaining alcohol held in the resin blob will drain through over the next day or so. I would then cure the remaining liquid again and then filter through a coffee filter.

Pictures of that will be added in a second post. I've hit the limit in this one.

One last note about curing outside. I prefer to do my curing indoors. I tried the outside let-it-sit method, and it didn't work so well for me. I'm sure I used the wrong container, a quart container with relatively small surface area instead of a bigger flat pan, but it took forever. I also was leery of leaving the uncovered container outside, thinking that an animal might find it interesting and sample the contents. I may be daft, but then dogs and cats will drink antifreeze if you let them. So if anybody wants to ask me, "why go to all that trouble?' that's my reasoning.

I hope people find this useful, as a tutorial or at minimum an extra data point in the decision-making process. I may do a similar post about how I clean prints, since I use a slightly different process than is typical for that as well. Net strainer pictures to follow in the next post.

Jim