Left of Arc #6 – 3D Printing

Holy cow, what have I let myself in for?!

Not long after my wife and I moved house did she agree to let me buy a 3D printer.  Note, before any ridicule, I had saved up the cash beforehand and so was relatively easy to afford!  This endeavour, along with my increasingly busy workplace and Open University studies, is the reason why I haven’t blogged much in the last few months.  A poor excuse I know, but a justifiable one.  It’s completely true what folk say about amateur 3D printing – it’s a hobby in its own right!

To say there is a wealth of resources on the internet would be an understatement.  Researching this hobby is quite possibly another hobby in itself.  So, why am I intending to add to this?  Because very little that I read or viewed (I prefer the catharsis of writing…) really prepared me for the continual defeats I suffered.  This blog post is intended on showcasing a little of my journey in the hopes that it may help yours.

Why print at all?

Bloody good question.  It’s damned expensive, hard work, smelly, and just what the hell do you print anyways?  For me, it was always about Battletech.  Having used Shapeways for many years with great results, I looked at my Battletech project and calculated I would be spending upwards of £1000, based on average prices.  Not only this, but the idea that I could print something resembling a good approximation of commercial quality products was very exciting!  Based on this alone I convinced myself that a 3D printer was worth it.  Once the decision was made to buy one I started looking at everything else I could print: Babylon 5, Team Yankee, 6mm modern, to name but a few.  “Brilliant!”  I thought, “Sold to the apparently excited Brit (visible displays of excitement are beaten out of us at a young age)!”, I mused.  So off I went, scouring the internet for knowledge on which printer would suit my needs.

Ketchup or Katchup?

Put simply, there are only two real types of printers you want to learn about; FDM and Stereolithography.  There are more types but I won’t go through them, that’s your bedtime reading for another night.  FDM essentially melts layers of plastic, drawn from a thin filament of plastic, to build whatever.  Stereolithography, or SLA, uses light to cure layers of liquid resin.  There’s a lot more to this and I would seriously recommend that any prospective 3D printerer do their homework – seriously, put aside the Mr T attitude of a “fool don’t need no manual” and read up.  Doing said homework will put a lot of things into perspective later.  SLA printers are the domestic king of fine detail, we’re talking machines that see your command to print 0.05mm thick layers and call it Tuesday.  FDM printers are likely to tell you to jog on, but ask it to big something big or in numbers and they will churn away quite happily like a dog with a bone.

So which printer then?  Depends on what you want to do really.  I boiled it down to this; if you want small and you want detailed, where the 6mm scale or showpieces are your domain, then you want SLA.  If you want a production line of decent quality 28mm, at a push 15mm, or perhaps lots of terrain, then FDMs are your baby.  Naturally, I chose an SLA.  I can’t speak to FDM printers right now, but I do know I would like one!  Just don’t tell the wife…

Cool, so burger or hot dog?

Even within the SLA range of products there are more choices and, you guessed it, more research.  Most printers within any range mostly resemble each other.  They work off of the same principles and technologies and mostly function the same way.  Uniqueness comes down to the companies that produce and market the wares, and the little quirks they build into their machines.  Surprisingly, a lot of consumers stick with companies that seemingly have better product aftercare.  In my research, I learned that a lot of folk like to mod their printers and tinker with them.  Some have even broken their printers after exceeding what print-hours the machine was intended for – which by the way is A LOT of hours…  The size of the community of printer owners is also a strong factor for buyers, again for that support network.  I didn’t really detect much difference between communities individually, but actually found my way to project-based communities that were a little more helpful and forward – these being, for example, the Battletech International 3D printers group.

I decided to focus on the technology and innovations that each company incorporated into their products.  In the SLA range, the big 3 companies are Anycubic, Elegoo, and Longer.  All 3 are pretty much the same as one another, all 3 have pretty much the same types of reviews, all 3 are (from what I can tell) built out of China.  I chose the Anycubic Photon S.  It’s the pricer product of all those that are sold by the 3 companies, and whilst Elegoo may have a better reputation for customer service, I was interested in the fact that Anycubic showed continual product development.  The Photon S, specifically, features a second z-axis guide rail which, as far as I’m aware, is the only product to do so (as of Mar 21).  Interestingly, and I wish I had known about this before buying, Anycubic are soon to release a new printer with a different LED light source that has a better lifespan and control compared to everyone else’s.  …Bet you wish you’d done some researching now, huh?…

It’s light, Jim, but not as we know it.

So, here’s a quick SLA101 for you.  SLA printers use UV light of approximately 355 nm to 405 nm, emitted from an LED source at the base of the printer, to cure liquid resin.  Above this LED is a vat of said resin with a thin sheet of transparent Fluorinated ethylene propylene (FEP or short) film as the base of the vat, allowing light through.  A build plate lowers into the vat until it’s just a few tens of microns away from the film.  UV light is then emitted and essentially ‘glues’ the resin initially to the build plate, and then to each subsequent layer.  The build plate raises and lowers after each layer.  Again, there’s more to it than that so it really is worth your time reading up!

Where were we?

What you will learn through your research is that you need more tools and equipment than just the printer and its contents.  A full SLA printer setup would look something like this…

A stable and level table, the printer itself (the white box), a storage box with all the extra gubbins (the green box), and a bin. The only thing missing is my UV oven.

One SLA printer of your choice
1 L or more of resin or your choice (there are probably more brands for resin out there than there are makes of printer, stick with the companies brand, it might be a tad more expensive but you’ll know it works)
1 L or more of 99% isopropyl alcohol (super-proof, smells worse than anthrax, don’t drink it)
A small tub (for the super-proof alcohol)
A pack of nitrile gloves
A face mask
A roll of kitchen paper
A ‘build plate scraper’ (the printer will come with one, you should be able to identify it immediately – otherwise get out)
A funnel
A pack of conical filters
A pack of spare FEP film (again, sourced from the company if you can)
A hobby knife (from the link, use the blade on the bottom right)
Tweezers
A UV ‘light box’

All told this lot will cost you about another £100-£120 if you build the ‘light box’ yourself.  More if you don’t.

A box of light?

Resin is a funny beast, smelly too but you get used to that (wouldn’t recommend drinking it though).  Just because you’ve printed some resin doesn’t mean you’re done.  When you handle your model you’ll feel that it’s odd, bendy, and perhaps soft.  That’s because it is.  It needs time to finish off ‘cooking’, like that last proving before you have delicious bread.  So, you’ll need more UV time, and what better source than the sun.  Stick your model outside or by the window in full view of the sun and within 15-30 minutes you’ll have fully cooked bread.  Note, I’m a bad cook so I tend to leave my models in the sun for a minimum of 2-3 hours.  Some folk say you’ll lose detail but I’m not sure how, nor do I have evidence to prove that.  Regardless, you’ll know when your model is ready as it will feel ‘right’ to the touch.  But… and it’s a big ‘but’… what happens if you’re in the UK and it’s raining?  Then, sir, it’s time to make your own light!  That’s right, spend a day fighting tooth and nail to fix disco-style LED lights inside a box lined with reflective tinfoil and you have yourself the UV power of the sun, only it’s in a box!  If you didn’t guess, building this wasn’t easy…  I tend to use the ‘light box’ for about 30+ minutes then leave the model in the window for a good couple of hours.  If it’s still not ready I’ll rinse and repeat.  The UV ‘light box’ won’t resolve your lack of an intense celestial UV light source, but it will mitigate against it.

One specific electromagnetic spectrum emitting source container, aka a disco box

‘Cutting’ in briefly…

The hobby knife.  I had to learn this the hard way, so don’t be square, learn this from me.  Your model will have to print with supports, they’re like scaffolding for the model to build off of.  Getting rid of these supports is infinitely easier BEFORE you submit the model to its final curing.  This is because the resin is soft and easier to handle than rock-solid cured resin.  Once you’ve removed the model from the build plate, drop it straight into your bucket of super-proof alcohol and then start cleaning your machine.  That will give the model a bit of time to get the excess resin off.  When you’re ready, give the model a damn good shake in the super-proof.  Shake it dry and start peeling off the supports by hand, that way you can better control the pressure so as to not break anything you shouldn’t.  Once the bulk of the supports are off, go at any leftovers with the knife and tweezers – GENTLY!  Expert knife control is advised so you don’t accidentally wedge the knife somewhere you don’t want it.  Once you’re satisfied, give the model a final wash and stick it out for curing.

This is how you build a star ship in a printer, with scaffolding

Just for my own kicks, try removing the supports after the final curing… go on, I dare ya’!

That’s great. but…

Cool, so we know what to do when we’ve printed something, but how do we print something?  Well, the easy option is to look on STL Finder, All3DP, or Yeggi for what you want.  However, even then the model might not be print-worthy.

In general, you’re going to need a “slicing” program – the one that comes with the printer will be ok – this turns a 3D file into something your printer can interpret and work with.  However, there is another “slicing” program called Chitubox that is free, works well with any SLA print, and has better control over the supports that are needed for your models.

Additionally, you’re going to need a third program to tweak your models if you’re that way inclined; Blender is probably your best option as the latest version has a tool specific for 3D printing.  Lastly, and probably most importantly, I use Mircosoft’s 3D Builder.  Even after fully tweaking your model and thinking you’ve closed every gap and flipped the faces the right way, the model might still now print correctly.  3D Builder is such a user-friendly and powerful program that I have yet to see it fail at fixing a model.  The downside is that it’s only available for Windows 10.  There may be other alternatives, but this is the best one I’ve found.

So, my process tends to be to review a model in Blender and make any tweaks I need there.  I then put it into 3D Builder and scale it to the size I want and have the program do any last fixes.  I then throw the model into Chitubox and add the supports I feel I need (I’m probably over zealous with my supports but it works for me).  Once I’m happy there, I save it off, load it into my printer’s slicing software and I’m done!  I could slice the model in chitubox, but I’m paranoid.

The Results

It’s a lengthy process to follow and one that needs lots of patience.  You’re going to have models that seem perfect for printing that just don’t work, and the issue could be one of several dozen reasons; is your model at the wrong angle? are your print settings not sufficient? it is too cold? is there a hidden polygon that’s facing the wrong way? did you not do enough supports? did you use the wrong supports?  Etc… You’ll fast learn to become a good problem solver and with a bit of time and effort, you’ll learn your printer too!

If you can get through all that, you’ll end up with some incredible results produced right on your desktop…

My very first print! First lesson was scale
A close-up of the print, which has a surprising amount of detail for something so small
The test file that came with the printer. In theory, you should be able to print this perfectly without any adjustments, but this only goes to show that each printer needs a bit of tweaking first.  Lesson two… printer settings!
Lessons learned, I moved to trying to print something, but something wasn’t quite right
This shows that the printer was curing resin where it shouldn’t have been. It turned out that the model I had been using had inverted vertices. Lesson 3, fixing models!
A successful print! Hollowed out too!
How small can we get?  about a few millimeters of thickness apparently (10mm L by 5mm H by 4mm D…ish)
This is how my Deimos should look!
This is not how an Omega Destroyer should look…
… second attempt, yet something is missing… Lesson 4, printing at angles.

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