I’ve been in resin printing for over two years now. I have always refused to get a curing station. I disliked the available solution and was happy with my setup of several Lock’n’lock containers with IPA and a simple curing box made out of IKEA Lixhult. If you are wondering why I disliked the current solutions, read the ending of this post where I describe my dream machine.
However, my containers got small and I was considering getting bigger ones. It was at the time when Elegoo announced Mercury X pre-order. I thought “Ok, let’s give it a shot”.
I received my unit in September and I’ve been using it on a daily basis. Current experiences? It works pretty well and I am happy about it. I wouldn’t go back to my “dumb containers with IPA”. If you would like to see a full review that lists all the features and gives you the basic idea, please refer to other reviews: e. g., a nice review by Thomas Sanladerer.
In the rest of the post, I will show you what I dislike about the machine and how I improved it (at least a little) to make it suitable for heavy and convenient usage. Please note that overall I like the machine and I would advise my old me to buy it.
Problem #1: Only a single cleaning container
This is the biggest flaw of the machine – there is only a single container for IPA & cleaning. Do you ask why you would need more containers? It is more economical.
Resin 3D printers are awesome, however, the whole process is extremely messy. Especially when an accident happens and the resin leaks from the vat all over the printer.
When this happens mid-print, it usually means one thing – the resin will leak onto the precious LCD of the printer and cure. This means one thing – the UV light will be blocked by the cured parts and you will probably experience holes in your printed parts.
Damaged LCD
Damaged LCD
Usually, the people on Facebook advise you to scrape the resin away with a plastic razor. This usually works for small leaks, but it doesn’t work well on large leaks.
I experienced a resin leak recently on my Elegoo Saturn. Scraping the resin was not leading anywhere and I managed to scratch the polarizer film on top of the LCD. Therefore I stopped and I decided to make a (successful experiment): use acetone to dissolve the cured resin. It worked flawlessly!
The method is based on the observation that resin softens in an acetone bath, but the polarizer film seems not to dissolve in acetone.
Today, I want to talk about an interesting phenomenon I noticed when printing hollow objects. A simple procedure can drastically improve the surface finish of your prints:
Recently, I noticed in the Elegoo Saturn Facebook groups that many users report a broken Saturn. The symptoms are that the UV backlight is always on. Elegoo has been really helpful and it seems that when a user reports the problem, they send a replacement mainboard.
I was wondering what causes the problems, so I reached out to a few of them if they would be willing to send me the broken motherboard. One of them did (thank you!) and I started to investigate what’s wrong. TLDR: The fix is easy and costs you nothing if you know how to solder.
Back in high school, I wrote SOČ (student-paper) about designing and building a small horizontal wind turbine (available here, only in Czech). It was an interesting experience and I learned a lot about aerodynamic. Ten years passed and I decided to revisit the idea of having a small DIY wind turbine. However, with a modern spin on it in the form of 3D printing the whole full-scale turbine on an SLA printer. Spoiler: it turned out perfectly!
Having a reference model of the printer is suitable when I design new components to tune my printer. I publish the model, so the others can benefit from it! You will find the model below:
If you like the model, you can consider supporting me on Ko-fi or buy something from me on my Tindie store.
PS: Be sure to follow me on Twitter and Instagram if you are interested in knowing what I am up to.
Recently, I discovered Resione resins. They have a wide variety of resins. They also have a series of tough and flexible resins. They also have an EU distribution center, so the resin arrives quickly and you don’t have to care about customs. Overall, the resins seemed nice. I might make a separate blog post about their resins in the future.
When I was working on a big project (blogpost upcoming, sneak-peaks on my Twitter and Instagram) I decided to use Resione M68 — tough snow-white resin. The parts I printed were thin-wall parts (wall thickness of 0.5–1 mm). They also have a lot of internal cavities where a liquid can be trapped. After printing, the pieces looked great! However, it was a rainy day and the air humidity increased up to 80 %. The next day I found my parts deformed like this:
Parts after 24-48 hours in high humidity
Parts after 24-48 hours in high humidity
I soaked one of the parts for 20 hours in water. This happened.
It seems that the Resione M68 absorbs a lot of moisture and the large flat areas between infill of the component expand, thus they form bumps. So I took one piece and soaked it into the water for 20 hours and it even cracked.
It is a well-known phenomenon, that some plastics absorb moisture. There is even an ISO standard 15512:2019 for measuring this (which I don’t have access to, unfortunately). Since my components will be exposed to the weather condition, I decided to make an experiment to determine which resins would be suitable and which not.
I use my beloved 3D printers Elegoo Saturn and Mars to produce various functional components. However, resin is usually not the ideal material for me as I need stronger, less brittle or flexible components. Therefore, most of the time I print molds and cast my components either out of polyurethane or silicone.
Let me show you the easier of the two – silicone molding – in this post. I will demonstrate it on piece I designed last week – the cleaning kit for Elegoo Saturn’s resin vat.
The component
Swapping resins is not a pleasant experience. Evertyhing that touches resin becomes sticky and potentially iritating for your skin. On Mars, I bought multiple 6 vats and avoided swapping resins if possible. However, Saturn vats are not available for purchase yet.
The design of the vats is not ideal for pouring – it does not feature a single sharp pouring edge which does not drop. Instead, if you pour the resin, it will flow on the outside walls of the vat, making it messy. So there is the obvious solution – let’s attach a spout that will direct the resin and also, it will feature a sharp pouring corner that does not allow the resin to flow on the walls.
I have already experimented with making the screen monochrome, however, due to lack of resources (dead screens) I abandoned the idea. The second way is to tune the light source. You can already buy LED lamp replacement, but what hobby would it be if just bought everything? Also, their parameters are not as good as my aims.
One disclaimer – the whole build was performed during the lockdown period during COIVD-19 outbreak, so many manufacturing and supply options were limited. Therefore, some of the approaches presented in this post are rather hacky and I would make them differently during normal times.
I decided to build a 7×4 LED array. The reason for going for such a high number of LEDs is to limit their radiation cone – the goal is to produce as parallel rays as possible. With fewer LEDs, I would need a wider cone. When you have rays under an angle, it leads to a side exposure and imprecisions in the print. I used LG6565 – 10W LEDs which emit peak wavelength 405nm. That’s 240 W. Original Mars is roughly 30 W.
I created a simple PCB. I used copper-clad with an aluminium substrate to provide better cooling. Normally, I would buy sodium persulfate and etch the board. However, during COVID outbreak all the drug stores were closed so I just cut the board with an X-acto knife and peeled the excessive copper. Soldering the LEDs on the aluminum substrate was not an option and reflow oven was out of the reach – so I just cut pieces of solder wire, put them on the PCB, put some flux on it, and put it on a gas stove on a thick piece of steel. After 2 minutes, the solder melted, the LEDs nicely arranged. After attaching some wires, the PCB was ready. To improve the cooling I also mounted a beefy heatsink to the backside of the PCB and I added two 60 mm quiet fans.
To drive the LEDs, I decided to go with a separate power supply. I used a switching boost constant-current DC/DC converter bought on Aliexpress. I decided to power it from 24 V to make it as efficient as possible. I added a MOSFET for switching the LEDs. To make things simple, I attached wire on the gate of the original on-board MOSFET for LED switching. One note – the LED array is really bright! There was also a lot of heat coming out of it – but not the excessive heat in the heatsink – the blue light itself carries a lot of energy and you could feel warm even when you put your hand nearly meter from it.
Drawing the PCB layout by hand
I didn't have single clad large enough, so the final panel is composed out of two pices
COVID outbreak = no chemicals available. Trying to make PCB by cutting the pattern
Cutting the PCB and peeling the copper is surprisingly easy
Recently I got in touch with the customer support of Siraya Tech – my favorite resin brand. I love their Fast Grey resin – it is easy to work with, it is low viscosity resin, which is not brittle. The only downside is that you cannot easily buy it in Europe. I hope it will change soon!
They offered me to test their Tenacious resin – the resin I wanted to try for a long time. You can find a lot about the resin on line. But I wanted to have the first-hand experience.
The resin comes in 500g bottles
Tenacious is marketed to be flexible, rubber like with high impact resistance. The exact opposite you are used to with standard resins like Elegoo or Anycubic.
The resin is light yellow and semi-transparent. When you open it, it smells similar to Siraya Blu. The smell isn’t bad – to be honest, I find it quite pleasant. It is is a viscous liquid.
To test it, I decided to print tips of legs for a walking robot. The tips should be soft and provide friction for the legs to not slip on the floor. Since Tenacious is marketed as rubber-like, I thought it could be a suitable option. The resin was easy to print on my Elegoo Mars and the prints came out great. However, I was disappointed with the results. The parts were quite hard and did not provide enough friction. Even when I hollowed them to have a 3mm wall, a 2mm wall, and a 1mm wall they were still too hard for this application. And too slipper. Note that this is not the fault of the resin, rather my mismatched expectations. I revisited all the reviews and videos about tenacious and I found the cause of my mismatched expectations – when you see tenacious prints to be flexible, they are really thin lattice structures. Not beefy pieces.
