3D printing with PLA - printing, sanding, smoothing, gluing

PLA print of bird skull I modelled in Meshmixer and smoothened with resin
After my first article about 3D printing, that focused on use of 3D printing in cosplay, I had a lot of requests to write more, especially about filaments and post-processing, so here you go!

Everyone who buys a 3D printer struggles with the decission what to print first, how to print it and what 3D printing filament is best for it.
And because the last mentioned thing is one of the most important  - let's look at my experience with filaments and some more info and my own research of PLA filament.

Best starting filaments

Everyone who is starting with 3D print is always searching for the same question:
What is the best starting filament?

My story:

I searched for it too and studied different approaches to that theme, but never received complete info I needed. Eventually I bought 2x1kg of black ABS filament, because I've learned from the internet, that ABS is better, because it is easier to smooth afterwards and much stiffer than PLA never allowing your 3D printed parts to break.
And it was a fail from my side. I still have both ABS filament spools almost full - I've used one roll once and never used it again. Always try to search for complete info before buying anything!

PLA vs. ABS

I mentioned these filaments, that were in most videos and articles considered best starting materials. But what are the differences?


PLA 
ABS after and before vapor smoothing with acetone
(source: Allthat3d.com)

  • Easiest material to work with - you have bigger safe margin for making errors by setting your printer. 
  • It's also biodegradable - your failed prints won't burden the mother Earth (they still will, but they will eventually disolve easier than other materials). 
  • Even you can sometimes read, that ABS has better overall characteristics, consider very wisely if your part will be often mechanically under stress and if your answer is yes, then after that start to consider ABS option. I have to admit, that I printed already a lot of stuff and I never experienced any kind of stress related issues on PLA prints. 
  • You do not have to own a 3D printer with heated bed in order to print it.
  • And when I said it is easier to print with PLA, it can handle bigger overhangs and longer bridging than ABS.


ABS  
Thi is how your ABS print
without enclosure can look like
((taken from 3D printing group on FB)

I do not like working with ABS and I'm afraid it will influence my valuation of this kind of filament, but I try to explain why.

  • It is not biodegradable (sorry, mom Earth), 
  • you have to own a 3D printer with heated bed 
  • and having a flawless print from ABS seemed to me harder than having a flawless print from PLA. 
  • The most important thing, that is often forgotten by many is, that ABS produces fumes by printing, that you can actually smell very intesively and people are still discussing about the safety of living in those kind of fumes. 
  • Also, ABS print is relatively sensitive to temperature changes - it has to cool very slowly or it will crack or it can curl and warp during 3D printing, so it is recommended  to have a full enclosure built for your printer or a more expensive printer with it's own enclosure. 
  • And yes, there are also positive sides of ABS coin - supposedly, it is much more durable in terms of flexibility and strenght 
  • and it can also be smoothened with Aceton which is in comparison to PLA's Tetrahydrofuran much cheaper alternative (but you don't have to use neither one).


Maybe you ask why people still try to compare both filaments even that PLA offers better characteristics. It's simple - for some people it is very tempting to get rid of printing lines on the surface with vapor smoothing (and they have often never heard of tetrahydrofuran, since I'm one of the first people to try it) and they are happy with better hardness and (endurance of the material - PLA is not so flexible and strong, but it can handle more weight before breaking). They maybe own an enclosure and they don't get fails by printing like the one on the picture.


If you expect more durability from your print, there are some filaments, that try to combine the best of both, but writing about them would be for too long, so if you want to learn more, try to find more about PLA+ or PET-G.



I choose you, PLA

In the comparison above, I tried to include all the things I thought were relevant for you to decide which filament to use as starting filament, but to be honest, most companies will make this choice for you and you 3D printer will be delivered with a spool of PLA. Good choice!


Best PLA manufacturer

If you are familiar with preparing STL files for printing, in most programs, there is a choice of PLA manufacturer, that will adjust the settings according to a manufacturers recommendations. And I recommend you starting with recommended settings and try a few test prints. With trial and error by printing those test prints, you can learn more about the settings needed for that particular filament and adjust them in the program you use (for example Slic3r, Cura, ...)
The fanciest looking filament
Vertigo Galaxy by Fillamentum

In my short experience, I tried only few manufacturers and I recommend Plasty Mladec PLA and Fillamentum PLA (no sponzorship included). I also tried some cheaper ones, but I wasn't really satisfied with the look of the print and the trial and error time was much longer than I expected. Some cheaper PLA's also do not react well to smoothing with tetrahydrofuran. Be careful also about some really cheap filaments - some may come tangled on the spool and it can then stuck by feeding the filament and the printer will continue working without any filament extruding. Some cheaper filaments can have an uneven surface, so it can clog your nozzle. And some cheaper filaments may come wet, that would cause a really wierd outcome in the print. Invest more money into filament and you will be a happy printer owner.

Adjusting the settings

I cannot give you the right answer to that question, but there are steps you can take always to make your print succesful.
1) If you print a free 3D model, consider  printing settings described by the designer for your build.
2) If you are used to use one manufacturer, start by setting it to that manufacturer's recommended settings and try to print test prints to see which settings are ued for the best results. Test prints can include printing Benchy, 3D printer testing models (picture).
It helps you to find the right settings and know the boundaries of your printer/filament (for example in printing overhangs, bridges, ...)

It is a very wide theme for longer explanation and I am afraid I would have to appel on you to do your own research according to your printer, your used software and your used filament to get your setting to desireable outcomes! I also recommend joining 3d printing group on facebook - I've learned a lot of useful info just by reading people's posts.


PLA and bed = friends?


As I've already mentioned, you don't have to use heated bed if you print with PLA. But if you own one, do not hesitate to use heat according to filament manufacturer you use.
Sometimes it is still hard to find the best balance in "sticking":

PLA doesn't stick to the bed:If your PLA doesn't stick to your bed, it will stick to your nozzle, make it dirty and can cause overheating. And yes, your print won't print. You can enhance the stickyness of PLA by cleaning the bed with some window cleaners (Isopropyl alcohol) or Aceton. Do not touch it afterwards - even you don't see it, your fingers are oily and can cause non sticking of PLA.
If this doesn't work, try to use painter's tape layered on the bed.
Oh and if the problem is still relevant, just ask yourself if your heatbed is leveled well and well configurated.

PLA sticks too much to the bed:
I have this problem all the time. Always try to find solution, that doesn't require you to damage your bed or the print by trying to get it free from the bed (credit card, pressure of your hand). Try to preheat the bed for better result. When I'm really lost, I use shears or a scratch tool or a razor blade and I'm forced to go through the risk of damaging the print/the bed.


The print is done, how do I smooth it?

This is probably the most asked question even I find more important to get the process of printing properly first. Sometimes the post-processing is used to hide flaws during printing, which is okay, but it is really time-consuming. But usually the post processing is here to get rid of the printing lines. The printer works by putting layers and layers of filament on each other and each layer is round. Each layer has round edges and that means, there are layers of material with small gaps inside them. And those visible layers are mostly unwanted, so post-processing is here to help you out!

As I've said in my first article about 3D printing from a point of view of cosplayers, for me as a cosply judge it is really important to see, that the printed part is post-processed well (and that it doesn't have any common printing fails), since I usually do not have much chance to know if the person printed and modelled the part by him/herself.

So, what are your options when it comes to getting rid of the print lines?

1) Finer printing

Choose finer quality(layer height) of the print in your program (Cura, Slic3r, Prusa Control) for finer and smoother outcome. Usually there is possibility to choose between 0,1-0,3 mm. This won't stop you from postprocessing your print, but if you decide to sand your print, this will allow to save time later.

Disadvantage: longer printing time and more filament will be used.

2) Sanding

This is the most time-consuming post processing way (but maybe the cheapest), but if you decide to use only sanding papers for smoothing out your print, you can use tools to help you out - belt sander, dremel. Start by using rough sanding papers and continue to the finer ones. I recommend using  higher quality sanding paper for sanding paints, that are water resistant.

Disadvantage: very long post-processing time.


3) Primer and filler (+sanding)  


If you like the option of sanding, but you want to make your process less time consuming and more effective, use primer&filler. Spray your print with a spray and seal the gaps between layer lines. You just then sand it a little to even out, and there goes your perfectly smooth print. And if you are using good product, you can even print on lower quality (bigger layer height) without worrying about the result.
And if I say good product, I mean primer and filler, that had a grey color (for plastic), not beige. The beige primer and filler doesn't fill as much as we want, the grey one does.
And if you are still lost which product to use, try THIS or THIS.

CAUTION: Always wear mask by spraying primer and filler on your prints. Imagine what happens to your lungs after breathing the cement for filling gaps in the print. Your lungs won't be happy about that.

Disadvantage: more expensive option.


4) Tetrahydrofuran + Aceton


As I've already mentioned by ABS filament, there is an option to smooth the print by Aceton vaporing. But it doesn't work for PLA. I discovered a product, that actually works for PLA - tetrahydrofuran and *methylene chlorid.
Both products can melt **PLA filaments pretty well and even I don't use for vapor smoothing, since I do not want to handle fire next to flammable chemicals, it should be possible to do.
OR you can go my way and just apply tetrahydrofuran on the print with a brush and even it takes several layers and the result is not so shiny, I feel much more safe that way and I feel like I have the fate of my print in my hands :D If you are struggling with finding the needed product, I bought it here.

*I've never tried using methylene chlorid, but it should work according to this video.

*Tetrahydrofuran doesn't work on some filaments. I've experienced it by cheaper filaments, that it didn't work as expected, it just disolved as white colored stuff on black filament. It 100% works on Plasty Mlades filament tho.
Vapor smoothing by joesmakerbot

CAUTION: Always wear mask with chemical filters and gloves when working with Acetone, Tetrahydrofuran and methylene chloride. Read product description and safety instructions. All the chemicals are flammable.

Disadvantage: Tetrahydrofuran is a special chemical product used for welding plastic (for example for swimming pools). It is harder to get and in comparison with aceton much more expensive. If you decide to use aceton, tetrahydrofuran or methylene chlorid, always keep safety on first place.



6) Coating

XTC-3D coating by 3dprinting-blog
There is a special product, that you can use for coating your prints called XTC-3D. It is a special kind of resin, that sticks well to the plastic and makes the surface crystal clear as a result.
There are always at least 2 layers necessary for your print to look good, since the first one functions as a filler and the second one makes the surface smooth.

I've tried coating my prints with resin and it is one of the fastest and easiest ways for achieving crystal clear finish.
If your print is not going to be stressed or bumped in, I think you can use even a crystal resin used for casting or normal resin  or some people are using even nailpolish.


Disadvantage: XTC-3D and resin are not cheap materials and I've never tried using nailpolish. It also doesn't copy the print very truely, so I wouldn't recommend it for functional parts like gears or ball bearing.


7) Heating - heatgun

Some people are even using heat for achieving  smoother results. I personally use heating only when I want to form my print somehow and I have to admit it is really tricky to find the right temperature not to boil or deform your print too much.

Just look at following videos what people thought of:
Heatgun smoothing

To be honest, I don't like heatgun smoothing a lot, but since PLA is reactive to temperature, you can use very hot water to clean out the support material more easily, or use heat whenever you want ot fix some flaws on your print by using soldering iron or woodburning iron.

Disadvantage: Heating is a risky way to smooth out your print. Even it is really cheap, controlling the amount of heating necessary is really hard and you can end up destroying your print.

8) Combination of more ways


I mostly combine more ways of post-processing according to a look I want to achieve and the use of the finished print. Do not hesitate to experiment by yourself, but alway have in mind, that safety must come first ;)


Glueing PLA parts together

Sometimes you don't get to print your print at once and it has to be assembled from more parts. What glue is the best to use with those parts?

There are some glues you can use or you can make your own glue!

1) Superglue 
bigger platic packaging allows you to
use the glue more than once

Is the most use glue for 3D printed parts. I don't like using it since I do not find it so "super" on a lot of occasions, but I  have to admit, that it is the fastest and cheapest choice for 3D prints. I only recommend to buy a bigger package of superglue not wasting your money on smaller tubes, that go hard after first use.



2) Epoxy

If you are not a fan of superglue, any kind of epoxy glue should be fine!


This lightsaber was glued completely by using
tetrahydrofuran paste.

3) Tetrahydrofuran (PLA) and Aceton (ABS) 


As I've said before, both are use for welding plastics, so it means the do not only dissolve plastic, they can glue it too. Just take a small amount of the chemical and mix it with small rests of the filament (for example with supports, failed prints) and let the plastic dissolve in it. Take the develop paste and put it on the glued areas. The chemical will vapor away and it will form an inseparable connection.







--------------------------------------------------------------------------------------------------------------------------

This article was made with the support of my patreon followers and I'm really greateful to them!
If you want to take part in this and support me in making more of the content like this, you can join my patreon here :)
Thank you!


Yours
Germia

P.S. I'm working now on a 3D printing project I call Frankenstein, since it will be made from around 30 different models! Just check out my instagram stories :)

Penulis : germia ~ Sebuah blog yang menyediakan berbagai macam informasi

Artikel 3D printing with PLA - printing, sanding, smoothing, gluing ini dipublish oleh germia pada hari neděle 18. února 2018. Semoga artikel ini dapat bermanfaat.Terimakasih atas kunjungan Anda silahkan tinggalkan komentar.sudah ada 3 komentar: di postingan 3D printing with PLA - printing, sanding, smoothing, gluing
 

3 komentářů: