The care & nurture of a 3d printer...

Started by Wulf, 10 March 2019, 03:46:12 AM

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Wulf

10 March 2019, 03:46:12 AM Last Edit: 10 March 2019, 03:50:01 AM by Wulf
Recently I decided to splash some cash & buy myself a 3d printer. I didn't go entirely wild, I was looking for a good entry level FDM printer. FDM printing is like icing a cake with a bag, squeezing icing out of a nozzle. Move the nozzle around and you can build up a 3d structure. It's not as good at detail or structural integrity as a resin printer the likes of which is used by Shapeways and others, but it's a fraction of the cost and the stuff used in resin printers sounds nasty and hazardous.  While I wouldn't actually try eating the stuff used in my printer, it's bio-degradable and says it's non-toxic...
My intention wasn't actually to print my own minis. I accepted that FDM printing wasn't detailed enough. I'd bought FDM printed buildings and tanks from online retailers, and, while they were workable and useable – I've used them – they were just on the acceptable side.  However, if I could print at that quality for a fraction of the cost of a professional mini (my software to prepare the prints tells me a Jagdtiger in 1:150 scale weighs 12g, which, compared to the cost of a 1kg spool of the material I use at £15 a kg, makes it about 18p... plus electricity, of course).
Anyway, what I discovered was that buying a 3d printer isn't like buying an inkjet or a laser printer. 3d printing is a hobby in and of itself, and one you need to be prepared to commit to to get decent results.  First of all, you have to assemble the printer... this is a £200 piece of kit with tolerances of 0.02 mm, and they gave me a spanner and some alan keys... Oh, and although I knew it was a slow printing process, I had no real idea HOW slow... That Jagdtiger would take about 4 hours to print, some of the buildings will take 3 solid DAYS...
After some initial encouraging tests, I hit a bad patch attempting to improve matters. Sometimes I couldn't get the print to adhere to the print bed at all, sometimes the print would dissolve into a ball of plastic wool after 4 hours of printing... But, eventually, I'm quite pleased with the results...
Initial tests did not produce very good tanks at all, as you can see...


However, I persevered, and got some much better results...

The buildings in the background are also 3d printed, as are the rather superb wattle fences. The tanks are cleaned up, an extensive process I admit, and primed with Hafords spray primer. The buildings only cleaned up. So, some obvious questions...

Q: Can I now home print minis to the same standards as the professionals like Pendraken or even Shapeways?
A: No. Quality is better than I expected, but I can still see the layering on any smooth sloped or curved surfaces, the minis are very fragile, I still get failures in printing and, most important of all, I can't create my own 3d print files, so I am reliant on finding the files online and the work of others. Now, it's amazing what is available (see above...), but there are still limits. Almost every 3d file I found for tanks was either in 1:100 scale and had to be shrunk down to 1:150 (which often made parts like track guards & gun barrels too flimsy and small to print) or 1:200 (which can look a bit crude when enlarged). The only KV-85 I could find was 1:200, for instance, despite every other KV variant I know of being in 1:100 as well. They also take a long time to print, but not as long as waiting for postage... Oh, and they are CHEAP...

Q: Can I then produce minis rivalling the cheap end of professional printing, FDM prints for instance?
A:Yes, I think I'm quite happy to say my prints are as good as theirs, if not better. And cheaper...

Q: So, will I never have to buy minis from professional sources again?
A: I very much doubt if that'll be the case. I am still entirely reliant on finding someone else's work to print, although I have to say I could probably spend the better half of a year just printing what I have found that I like so far... Annoyingly, terrain is probably the most difficult thing to find. I guess most gamers game in bigger scales, so 3d printing whole buildings in 28mm or even 20 or 15mm scale is going  to run into problems of print bed sizes – I think my printer can handle up to 220x220x260mm or something like that – and, like I say, most of the 3d files available are for bigger scales. I also came across some building files marked as 15mm scale which proved way too small when reduced in size to 10mm scale, and were obviously about 10mm scale to begin with. Annoying after a couple of hours of printing, but it only costs 10p or so...

OK, so that's it so far. You have to excuse me now, I have to prepare some fences...

Orcs

They look very good Wulf, an interesting article, I have been wondering about getting a 3d printer, but did not know if their was any real saving when the time taken to clean up prints and the initial printer costs were taken into account.


I would be interested in hearing more about your forage into 3d
The cynics are right nine times out of ten. -Mencken, H. L.

Life is not a matter of holding good cards, but of playing a poor hand well. - Robert Louis Stevenson

Steve J

We have a 'cheap' FDM printer at work and it causes no end of issues, most of which oyu have mentioned. It printing temrs it's damned crude but the advantage is it prints the 'right' material so if useful to engineering tests etc.

Then if you want a good SLA 3D printer, then you need all the chemicals etc to clean of the support materials and a UV oven to cure the printed parts. There are other options on the market, but it's very much caveat emptor. We see loads of new and interesting kit all of the time, but most rarely perform anywhere near as well as advertised.

Another thing to remember is that these materials are for prototypes and are often not that UV stable and can be quite hygroscopic, so barrels can become brittle or distort over time etc.

Hope this helps?

Dr Dave

Wolf, did you make a Pz35T in the end?  ;)

I have to say that I'm a fan of this process. Those look terrific.

jambo1

Interesting read, those tanks look very decent too. :)

Leman

those initial taks would probably be taken off your hands by a fantasy sci-fi player; unique and strange looking.
The artist formerly known as Dour Puritan!

Techno

I think those look very spiffy !!  :)

Steve has some interesting points, though.

Cheers - Phil

steve_holmes_11

Most emerging technologies like this will present three tiers of machine.
Each one better (faster, more precise and providing higher quality output) than the former, but costing at least 10 times the price.

The low end appears in the home, or a small workshop.
The midrange used to appear in a local small businesses.
The big stuff appeared in factories.

Over time the features and qualities of the top tiers migrated down the stack, and entry cost fell.
I get the impression that 3D printing at home has some limited applications for wargaming, but won't supplant our favourite manufacturers for quite some time.
I think we'll be seeing boardgame components, and marker tokens well before figure printing becomes mainstream.

However, I've learned that technology is anything but predictable.
Occasional breakthroughs create massive leaps in speed or quality and render old kit obsolete overnight.
Perhaps the drawbacks will be ironed out and in a couple of years we will all be using this technology.

Westmarcher

On the basis of the photograph alone, most of these tanks look very good.
I may not have gone where I intended to go, but I think I have ended up where I needed to be.

Leman

There is a company that is now producing printed 2mm figures and scenery, and they look remarkably good.
The artist formerly known as Dour Puritan!

Wulf

Quote from: Leman on 10 March 2019, 08:39:56 AM
those initial taks would probably be taken off your hands by a fantasy sci-fi player; unique and strange looking.
You may already know this, but just in case anyone doesn't, the first two are the Bob Semple Tank from New Zealand, and the Odessa or NI tank from... well, Odessa... Both real tanks created on the brink of WWII, and, as far as I am aware, not available in any other way in this scale.

For everyone else's comments, I can't disagree with much if anything said, I am improving my print quality by small steps now I've got the printer functional. It's certainly not a simple process and you do need to spend a lot of time - mostly time sitting waiting for the latest test to print - to get improvements.

Fences, though... fences are lovely...

Wulf

Quote from: Dr Dave on 10 March 2019, 08:02:39 AM
Wolf, did you make a Pz35T in the end?  ;)
I never did (so far...) print a 35t - I bought metal minis from Pit Head, and the campaign has now moved on to Pz IVH and T-34s. However, I will return back to the 35t now you have reminded me...

GrumpyOldMan

Hello Wulf

If you really want to get into the 3d world you could have a look at getting some models from the 3D sketchup warehouse https://3dwarehouse.sketchup.com/, sketch up available as a free version https://www.sketchup.com/plans-and-pricing/sketchup-free. This software exports as STL files as well. The warehouse has both the KV-85 and the Pz 35T available.
https://3dwarehouse.sketchup.com/model/uaeb0a8d2-464a-4168-a52d-1954d2cd44c8/KV-85-Russian-Heavy-Tank


https://3dwarehouse.sketchup.com/model/6b5e78cc4809cdf404885c24bdd02cc/Panzerkampfwagen-35t


Other handy programs would be Meshlab and Netfabb studio for manipulating the stl files, (might also be handy for fixing rescaled meshes too).

Now you can look forward to many hours playing with 3d meshes  :D :D

You've probably already looked at the tutorials available from Shapeways but I'll put some links here for any other budding 3d designers:-

https://beta.shapeways.com/tutorials/3d-software
https://www.shapeways.com/creator/tools
https://www.shapeways.com/tutorials/easy-3d-modeling-for-3d-printing-tutorial-for-beginners

Good luck with your 3d endeavours.

Cheers

GrumpyOldMan

Wulf

OK, I have decided to continue with this, in the hope that someone - either myself or the readers - learn something about 3d printing. Today, I'd like to discuss bed levelling, print adhesion, and associated subjects...

When you get an Ender 3 printer, it comes in a big box which, on opening, appears to be Big Boy's Meccano... The good news is, the base unit, with the print bed, comes pre-assembled. Everything above that you have to put together. Once assembled, switch on and, everything looking good, set the print head to Auto Home. The print head should stop at base level at the left front corner of the print bed.

Now... the factory fitted print head (you can get others with finer nozzles) extrudes filament at 0.4mm in diameter. The finest layer it's designed to lay down is 0.04mm thick. So, if you print at maximum detail, and that print bed is 0.04mm too high, the nozzle is scraping against the print bed. Remember, you assembled this with a little spanner and some alan keys... Because the filament is 0.4mm diameter, if the print bed is close to that too low, the filament won't be stuck to the bed & will either be pulled away by the print head, or will be hit by it next time it passes over that location. So bed levelling is essential... How do you do it? It seems laughably primitive to me, but essentially you position the print head at each corner and slide a piece of paper under it until it can just be moved and no more. There's a wheel under each corner to raise & lower that corner of the print bed by tiny tiny amounts. Keep doing that, since there's a see-saw effect - raise one corner & the diagonally opposite one is lowered. Keep doing it until you're happy. It works, but weeks and many prints later I'm still making tiny adjustments while the first layers print, depending on the look of the filament, too transparent & the bed needs lowered, too lumpy & it needs raised, etc. You can do that while it prints if you're careful. On the advice of someone on a print forum, I have a 10cm square of kitchen foil under the removable print mat you get on an Ender 3 Pro just to raise the centre of the print area. Even that thickness makes a noticeable difference to adhesion! Note that there are various different test prints available to download that will help determining how level your print bed is by how well the print looks at various bits of the print bed. Too thin or missing altogether, the print bed is too high. Too thick or not sticking to the bed, it's too low.

Other things that affect print adhesion are temperatures and print speed. I'm printing with PLA so far, the 'basic' material. Other materials need higher temperatures and have different properties. PLA prints with a nozzle temperature anywhere from 180 degrees Centigrade to about 240 degrees. It will print anywhere within that range, but too cold and it won't stick (and the layers of the print won't stick together making a very fragile printed model), too hot and it dribbles out of the nozzle and makes a mess of the whole thing. Each different spool of filament will, apparently, have a slightly different 'best' temperature, differing between manufacturers and, some say, even between colours... The print bed of the Ender 3 can also be heated. Generally 60 degrees is recommended for the bed, which is fine, but I'm currently running with 210 degrees for the nozzle despite the default being 180.

Now, print speed. The faster the print head moves, the less time the filament has under the pressure of the nozzle to stick it to the bed or the underlying layer of filament. Simple. Slower means more accurate. But a 10mm scale tank already takes 2 hours or more to print at moderate speed... Default speed is 60 m/s, I use 30. If you have patience, 20 is recommended for untrafine detail. Remember, 10mm scale tanks are TINY by the standards of 3d printing, and have a very small footprint to adhere to the bed.

So, last topic regarding getting the print to stick to the bed (it does sound disturbing, doesn't it?), Build Plate Adhesion. The software I use to change my 3d files into print files, Cura comes with 3 methods of Build Plate Adhesion. The Skirt is a ring around the print on the print bed, that doesn't actually touch the print. As far as I can see, it does nothing to help adhesion, but serves very well to warn you if the bed isn't level. Watch that skirt print & adjust on the fly. The Brim is a single layer of printed filament around the print, starting a few mm out and extending in to touch the actual print. I can certainly see that helping, even if the outer rings don't adhere it stands a good chance of sticking the actual print down. Last is the Raft. That's basically a platform, like a Brim, but thicker, and with a miniscule gap under it with it's own support/infil. It's designed to break away from the print easily. It sounds like it would be great at providing a good base for the print so long as the Raft itself adheres... I haven't printed any tanks with Brim or Raft so far, just Skirt, but have tried Brims on buildings and Rafts on fences (basically a Raft that's redesigned NOT to break away from the print, so it provides a base for the fence to stand on). I will experiment with both on tanks to see what effect they have.

OK, so, next time, Supports, Strings, and model cleanup...

Meanwhile, my Pz 35(t) is printing...

fred.

Thanks Wulf

I assume that while a model is printing, you can just leave the printer to it? Or does it need monitoring while its printing?
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