3D Printing Tips and Techniques

[Frank3k]

It isn't obvious how to use the PrusaSlicer. This blog post covers some of the basics. There's an online knowledge base as well.

UVTools is also not obvious, but it does an amazing job at fixing print files and can open most printer file formats.

UVTools comes with printer profiles for PrusaSlicer that have to be installed before you try to slice your file in PrusaSlicer.

There's a UVTools workflow that is helpful... but you'll have to mouse around to find the menu commands in the program.
There's also a series of videos on UVTools, but they aren't tutorials.

[LemonJello]

I may have convinced the Lady LemonJello to acquire a 3D printer for my Christmas gift this year.

I was thinking of going with the Mars 2 Pro, seems like a good starting size for what I think I'll be printing (1/48 and 1/35 bits-n-bobs).

Is the Mercury Plus washing/curing machine a "must have" or more of a "nice to have"?

[Frank3k]

The Mars 2 Pro is a good printer and has a monochrome screen, so it will print much faster and the screen will last longer than the older RGB screens.

Washing and curing is probably one of the most annoying parts of 3D resin printing. You can make your own curing station with UV LEDs or a nail curing UV station (or even putting the print in the Sun) and you can manually wash the part in isopropyl or put it in an ultrasonic bath.

I thought wash & cure stations were just "nice to have" but even though I had streamlined the way I washed and cured parts, it was getting tedious. I bought an Anycubic wash and cure station (at the time it was both cheaper than the Elegoo and in stock) and it really made a huge difference. Now I print, drip of the excess resin, put the part in the wash tank, give it a few minutes wash and depending on the part, either cut off the supports and cure or just cure with the supports. The machine does an even cure and I don't get pockets of partly cured resin.

[LemonJello]

Excellent! I shall send the links to both to the interested parties and hope to find both under the tree this year.

Also, Blender will be downloaded/installed on the home laptop so I can get ahead of the designing curve. 

Thanks!

[robunos]

I can only second what Frank says about the Mercury Plus, with the qualifier that as I've been using the water-soluble resin, I tend to wash my prints in the sink . . .


cheers,
Robin.

[Frank3k]

Uncured resin down the sink isn't a great idea... just wash it in a container of water and set it outside in the Sun to cure the resin.

@LemonJello - there are some excellent tutorials for Blender on Youtube. Make sure they're recent (for version 2.8 or higher).

The Blender Foundation videos are good, up to the chapter where they introduce armatures and they don't mention how to get the test files, or load them. Truly infuriating.

[arkon]

when you draw/design things  will it print them out solid or do you have to design them with thinish walls so your not printing a big chunk of plastic? or is there a progam that will take your big chunky shape and only print the outer most part?

[Frank3k]

It's really up to you. If you draw/design an object and it passes all the printablilty tests, in most cases it's going to be a solid object. This can make an object expensive (if you send it to a place like Shapeways) or expensive and heavy if you print it yourself. A heavy object can cause issues during printing as well.

Most slicing programs have the option to hollow out a solid object. Depending on the object, you may need to add drain holes to allow the resin to flow out during printing.

I design my objects with a wall thickness - 0.75mm is OK for medium sized objects (but can be fragile), 1mm is a good compromise between cost and strength. Bigger objects may need slightly thicker walls.

[LemonJello]

My Mars Pro 2 is set up and running a test print as I type this. 

My laptop is running Win7, Blender requires at least 8...so I'll be using my work computer and AutoCAD for my first few designs, but Chitubox and UVTools had no issues installing.

Excited to see if my test print comes out ok.

[Frank3k]

Great! The latest (2.7, now 3) versions of Blender are a great improvement, especially in the interface.

Chitubox is OK, but get PrusaSlicer as well; UVTools will install the correct printer profiles as well. UVTools finds fewer issues with Prusa sliced objects vs Chitubox. Also, resin is sensitive to temperature - if it's cooler than 68F, you're going to have a lot of issues getting a good print. 70F-78F is better (at least around the printer)

[LemonJello]

Test print was successful. I washed them in Isopropyl alcohol and will have to let them cure in the sun tomorrow. (I won't know if I got the wash/cure station until New Years). 

My son got me three bottles of Elegoo's resin; clear red, clear green, and grey.

[Frank3k]

Counterintuitively, black resin will produce the best details, clear resins will be slightly fuzzier because the UV will spread further in clear resins than dark. Gray is a good compromise and parts come out looking primed. You'll want to do an exposure print (UVTools has one) for each of the resins, because one exposure definitely doesn't fit all.

[arkon]

are stl files specific to resin or extruder  3d machines?

[LemonJello]

The Mercury Wash & Cure station has arrived.  Haven't had a chance to play with my new toys with family here over the New Year's holiday, and dealing with 15 inches of snow dropped on us yesterday.  Lost power for most of the day, restored around 7pm local time.

Weather has us socked in right now, lots of downed trees and unplowed roads, so maybe today I'll get to play?

[Frank3k]

are stl files specific to resin or extruder  3d machines?

STL is just a file format that's commonly used with 3D printers. It defines the 3D geometry of an object. To make the object printable, you have to process the file in a slicer that knows about the printer you're going to use (resin or FDM). The slicer cuts the object into layers for the printer, adds supports, etc. and generates a file that the printer understands. Most FDM printers understand a language called G-Code, which is common to CNC machines and just tells the print head where to move, plus the thickness of each slice.

Most hobbyist resin printers are different - the slicer just generates images that are slices of the object (and added supports) from the STL, with each slice separated by a layer thickness - much like an MRI or CT scan. This is one reason they're often faster than FDM printers; each layer is printed in one go. The resin printers also use G-Code to move the build plate and for setting parameters.

Another type of resin printer uses a UV laser that shines on a mirror and the mirror is moved in XY very quickly by galvos; these are closer to FDM printers in that the slices describe the motion of the laser spot. They're still very fast, since the mirror is much lighter than the printhead on an FDM printer.

[Frank3k]

This is a very technical page - Jan Mrázek does some serious experimenting with resin printers and shows all his steps - but his results are understandable and applicable to most resin printers: https://blog.honzamrazek.cz/category/3d-priting/

[LemonJello]

Update from LemonJello Heavy Industries, 3D Printing Division:

Had some free time to play and found a canoe and mens/womens bicycles that looked useful. 

1st attempt: my scale calculations were off, plus I didn't account for scaling in all 3 dimensions, so the prints were wonky, not usable, but they did print.
2nd attempt: much better results. The bikes are a little tall for 1/35, but could be added to a truck bed or strapped to a vehicle to add interest. The canoe is usable, but a tad underscale and fragile.  but, again, successful prints!

I have an assortment of weapons curing right now: pump shotgun, Saiga 12, AA-12, lever action rifle; again, my scaling may be slightly off/need refining, but they all look usable.

[arkon]

got a crealty halot-one resin printer from the kiddos this christmas. resin has already arrived now just waiting on the respirator.have watched all recommended videos and read all info provided so far from Frank3k.
new territory here so this shall be fun.

[LemonJello]

Here's a couple photos of my first run of prints,  I've got a batch of kegs, weber grills and milk crates washing right now, and a batch of crates and barrels printing.

More photos to come.

[Frank3k]

Nice job! If you can't account for all the missing pieces, make sure they're not stuck to the FEP or the build plate or you'll have a Bad Time. How did you print the rifles? parallel to the build plate?

I'm having some difficulty "dialing in" my Saturn. The larger vat and FEP are a bitch to work with.

[LemonJello]

Thanks! It was pretty fun to get some time with the printer.  At one point I had a batch of prints in washing while another batch was printing. 

Any missing parts are lost to the carpet monster as they flew off as I was removing the supports.

I let PrusaSlicer determine best position for details on the rifles, and they all printed at odd angles with a lot of supports.  I think I'll try it again with more vertical orientation and see what happens.

I give the FEP a good inspection for cured bits at the end of my printing time and a rinse of Isopropyl before closing up shop.

[robunos]

I'm having some difficulty "dialing in" my Saturn. The larger vat and FEP are a bitch to work with.

I was recommended to view this blog, and it does seem to have some good advice, might be worth you looking at it . . .


https://blog.honzamrazek.cz/category/3d-printing/




cheers,
Robin.

[Frank3k]

Robin,
 I'm using some of Jans' ettings! His latest settings and script for UVTools are great. I'm having issues dialing in the best exposure.

[Frank3k]

I should follow my own advice...

I was having weird print failures, even on basic prints like exposure checks. Half would be stuck to the FEP and half to the build plate; it didn't make sense. After many attempts and many re-levels - I took the build plate off, cleaned it well and took a good look at the surface. I gave it a quick pass with a 600 grit sanding pad and a shiny spot appeared. It was a tiny sliver of resin, no more than 5mm x 3mm and much, much less than 1mm thick (maybe only 1-2 layers thick, so around 100 microns) near the edge of the build plate. It was smooth and almost invisible and I could only feel it by its smoothness.

I scraped the build plate several times, gave it a couple of passes with a 400 then 600 sanding pad, cleaned it off, re-leveled and it started printing like a champ.

[Story]

What do you guys do with your misprints?