Quality 3D PrintsIf you’re at all familiar with what 3D printing or ‘additive manufacturing’ is, you’ll be aware of some of the advantages it has over traditional ‘subtractive manufacturing’.

Some of the obvious ones are less waste, Environmentally Friendly (besides a few fumes) and good strength to weight ratios (varying infill patterns and densities).

There’s also the potential to print previously un-manufacturable objects, easy rapid prototyping and most importantly for me, you can do all this stuff in your own home. I think Forbes Magazine put it really well in the following quote:

“Just like the Industrial Revolution, assembly line, the internet and Social Media, 3D Printing will be a game changer” ~ Forbes

So if 3D printing is so amazing, what are the downsides and what is this blog post all about?

Besides some little known Dangers of 3D Printing, which can mostly be mitigated with a bit of common sense and basic education, the problem most home 3D printing enthusiasts face on a daily basis is quality.

Unfortunately desktop 3D printers are not like toasters. Although they both get a little warm sometimes, that’s where the similarities end.

What I mean by this is that toasters, TVs, and other household electronics generally work out of the box day after day until one day they give up (usually after at least 5 years) and you throw them away, replacing them with a newer model.

That’s just the way the consumer society we live in happens to work. In fact many products are designed to break after a certain period of time, so this cycle of years of reliability, then total failure, then replacement is no coincidence.

3D printers are nothing like this. Just check out my Beginners Series where I document everything from ordering my first 3D printer, right through to 3D printing stuff like RC Model F1 Cars.

If you do, you’ll realise the journey wasn’t smooth. It was fun, but certainly not without it’s ups and downs. If my 3D printer was a toaster I would have sent it back within the first week and just ate bread from that point on.

3D printing is an art, a science a hobby and even a lifestyle for many people. When a large 3D print takes 20+ hours to complete and may fail a few times before you achieve success, that does impact your day to day life.

Assuming we have overcome the Cost of Acquiring and Running a 3D Printer hurdle, the next biggest issue is how to consistently produce high quality 3D prints, without wasting too much plastic, time, energy and money.

It’s exactly this problem, which I intend to address here. This article is aimed at beginners, so some of the real technical and rarely used stuff will be mentioned but not explained in detail. Such unnecessary technical details might just confuse some people and I intend to solve problems here, not create them.

Just quickly before we move into the main meat of this article, here’s a few of the issues us 3D printing people face daily, when trying to create high quality 3D prints:

  • The resolution of FFF printers is limited
  • Support structures, rafts and warps impede the quality
  • Appearance (partly due to the above) can be rough and plasticy
  • Achieving strength for functional applications is tricky
  • Failure rates can eat up plastic, time, energy and patience

These are just some of the issues I’ll address in this article and when you’ve read and understood it, I can promise you that you’ll be producing far more reliable and high quality 3D prints. I cannot promise 100% success, but I can promise a noticeable improvement.

One assumption I must make for this article is that your 3D printer is a Fused Filament Fabrication (FFF) printer, basically meaning that it works by adding layer after layer of melted thermoplastic. This is by far the most common type of desktop 3D printer and although I don’t like making assumptions, for the purposes of this article I think I have to make an exception here.

Let’s start with the 3D object file you intend to 3D print, as this in itself can be the root of many problems you might face further along the 3D printing process.

3D Object Files and Good Design

Bottle Opener DesignThere are a few different ways you can obtain 3D printable designs.

You might choose to download them from a website like Thingiverse, you might scan a 3D object or you may choose to design something yourself.

If you’re feeling ambitious you could even combine some of these, but either way your 3D printing task will start with a design of some kind.

Of course if you design your own objects then you will have far more control over the process, enabling you to produce designs with 3D printing in mind right from the beginning. If you download them all then you can still produce high quality 3D prints, but you’ll be a little more limited in how you do it. Let me give you some examples of what I mean.

Avoiding Support Structures

If you want to avoid rough surfaces on your 3D prints, then you’ll also want to avoid rafts and support structures where possible. Desktop 3D printers don’t often print well in mid air, so they struggle a lot with overhangs, where there’s no previously laid down material to print onto. An example of this is the letter T, printing upright in 3D as you see it here.

It would print fine until your 3D printer reached the horizontal bar at the top, but then with nothing to print on the bar would sag and you’d end up with a tangled mess of filament. Removable support structures would solve this, but then you’d have to break them off after printing, creating rough edges and generally reducing the quality of the print.

I created a YouTube video demonstrating the YHT example, which shows you what your 3D printer can and cannot print without supports…

You’ll see it can cope with the Y, as it has slopes of 45 or more degrees from horizontal. It can cope with the H, as it can bridge between the two vertical pillars. The T on the other hand as I just explained will fail without support structures.

You should probably watch this video (but feel free to skip forward to the actual slope, bridge and overhang parts) until you understand what’s going on here. After you’ve created/3D printed a few designs that need supports you’ll be able to look at any design and instantly visualise where they’d be required and how you might redesign it to best avoid them.

You’ll find it almost instinctive after a while and this alone will enable you to create much better quality 3D prints with a lower failure rate too. For best results you’ll also need to understand slipping, warping and rafts and how you can avoid all of these. That’s what we’ll talk about next.

Slipping, Warping, Rafts and Orientation

Once you understand slopes, overhangs and bridges you’ll not only be able to design objects that avoid supports where possible, you’ll also learn how to orientate your objects to 3D print better. Imagine 3D printing the T upside down, you no longer have overhangs and it will print without problems and without the need for nasty support structures.

You can also orientate your objects to prevent warping and reduce the need for removable rafts. Large square areas on the build plate are notorious for warping, as the plastic cools at different rates, pulling the surface (usually starting at the corners) from the build plate. We’ll talk more about this later, but good design and smart orientation of the design whilst printing can help improve your print quality.

Warped PrintNot only are removable rafts sometimes required for large areas on the build plate, they may be required for the opposite scenario, small areas on the build plate.

If you have a tall, thin object then it’s likely to topple over or slip on the build plate. This will result in a failed print and a tangled mess of useless plastic.

Adding a raft will increase the area on the build plate and reduce the chances of your object slipping or tipping over. Of course, a better solution may be to orientate the object by 90 degrees so that it’s lying down on the build plate. This might improve things or it might introduce warping or the need for supports, so judging this for the best quality 3D print is a bit of a balancing act, sometimes literally.

Something else to consider when orientating your objects for 3D printing is strength. For example I have 3D printed some coat hooks, but they just keep breaking. The reason is that I orientate them so they print upright. Where the most stress is on the hook (due to a heavy coat and gravity) is along the grain or along the layer lines, where the 3D print is weakest.

Simply spinning the object by 90 degrees before printing will make it much stronger for it’s intended purpose. From now on I will try to print them rotated by 90 degrees, but I also need to consider overhangs, supports and build plate contact area when I change the orientation. With all things considered (which could reduce the print quality) it may be best not to orientate it at all, we’ll see.

Not long ago I wrote a very detailed blog post called How to Design Objects for 3D Printing, so although I’ve given you an overview of some design considerations which affect quality, you’ll find much more detail about design in this other blog post, just click its link above. You’ll notice that in this other post I cover some design issues (including bacteria of all things) which you’d probably never even thought of.

There is another thing worth considering here, which can cause your designs not to 3D print at all and that’s non-manifold objects. Let me explain what these are, how to identify them and how to fix them.

Non-Manifold Objects

The mathematical theory of non-manifold objects can become a little tricky to understand, so for the sake of our sanity I’ll try to keep this simple.

If you have a 3D model which you designed, downloaded or scanned and you see some strange behaviour whilst slicing or 3D printing it then there’s a chance it’s non-manifold. What does this mean in simple terms?

Non ManifoldWhen we create 3D models using mesh modelling we’re only modelling the surface of the object, so this surface has to be very consistent, mathematically correct and watertight for it to be 3D printable.

If you imagine the surface of your object to be made up of thousands or millions of tiny flat surfaces with straight edges, each edge has to be shared by exactly two surfaces. Again, imagine two 2D square surfaces pushed up against each other to make part of your objects surface. The edge where they touch is shared by both squares and only those two squares. This is good.

However, if you have any edges that are shared by more than two surfaces then you have a mathematical problem and your object cannot be made. The same goes for your object if any edges are shared by less than two surfaces, as this would mean you have a hole and your object isn’t watertight.

A similar issue can arise if you have inverted normals. Imagine a ‘normal’ being an arrow on the surface of your object which is perpendicular to your surface and facing outwards. All normals must point outwards as they represent the surface of your object. You may have normals which somehow have managed to point inwards, in which case you have an object which is theoretically impossible to 3D print.

The symptoms of the above mesh issues are that your object may fail to 3D print, fail to slice, have excess fill and supports, walls that are very thin or loss of surface details. The reason is that in theory your object is unprintable, but some software may make assumptions about what your object should really look like. Assumptions are not good, because they’re often incorrect and can result in a 3D print that isn’t what you expected.

So, if you have such issues and conclude that maybe your object isn’t manifold you can use various tools to identify and fix these problems with your model. If your 3D modelling tool doesn’t have any tools to fix non-manifold objects, then check out Magics, MeshLab or Netfabb, all of which will help you fix your objects so you can obtain good quality 3D prints from them.

Filament Types and Quality

Besides having a good 3D design and using a decent 3D printer which has been set up correctly (more on this later), there’s something else which can affect the quality of your 3D prints and that’s your filament.

In the old days of 3D printing filament quality was a big issue. Low grade plastics, inconsistent diameters, impurities and moisture were just some of the issues people faced. This was mainly as a result of purchasing cheap filaments from suspect online sources. To be honest this isn’t as much of an issue as it used to be as most filament is better quality than it used to be.

I’ll talk about filament diameters in detail later as inconsistent diameters can cause a whole load of issues. Firstly though, let’s just mention impurities and moisture for a minute.

Impurities and Moisture

Impurities can cause many issues including differing melting points, inconsistent viscosity, a visually rough/discoloured finish or total nozzle blockages. None of these are favourable and quite often ‘cheap’ filament ends up being false economy as your Failure Rate increases, costing you more time and money.

Blocked nozzles are particularly frustrating as I found out when I suffered a number of Blocked Nozzle Issues myself and even had to resort to cooking the nozzle a few times to clear it.

Moisture in your filament can become an issue if the filament has been poorly packaged or left out of the packaging for too long. Plastics absorb moisture from the air so after some time exposed to the atmosphere you might find that your print quality is compromised.

Now would you spot this? Well, if you’re hot end is around the 230 degrees mark and water boils at 100 degrees, you can imagine what happens to the moisture in your filament as it passes through the hot end. It super heats, turns to steam, then pops and splutters within the filament, often leaving bubbles internally in your 3D prints, and tiny craters on the surface. It can even result in complete failure of your 3D prints.

To avoid impurities and moisture issues, buy your filament from a reputable source and make sure you store it correctly. Storing it in a cool but dry atmosphere, preferably wrapped up in cling film or polythene will help keep out the moisture and ensure your 3D prints are as good a quality as possible. If you’re feeling ambitious you could even try vacuum packing it using a normal household vacuum. Lastly, adding a little silica gel to the inside your packaging can help absorb any moisture already in there.

Filament Diameters and Extrusion

Any FFF desktop 3D printer will be designed to use filament of a specific diameter. More specifically it’s the extruder which needs to be matched to the filament diameter you’re using.

The two most common diameters are 1.75mm and 3.00mm. It seems that 1.75mm is the most common amongst these two, partly because the filament is more flexible so it flows better from the spool, though the extruder to the build plate/object where it’s needed.

FilamentRemember that your 3D printer is really a precision instrument and the filament diameter has to be matched to the extruder, so any variations in filament thickness can cause you problems when 3D printing.

Variations can cause under extrusion or over extrusion, which will result in gaps in your print, bulging at the edges and sometimes extruder stepper motor slips (a noticeable clicking noise) if there’s no-where for the extra filament to go.

Also, if the filament diameter variations exceed a reasonable tolerance the excessive diameter will not flow through the extruder hot end at all and will result in a blockage. Basically, filament diameters which are out of tolerance will cause bad quality prints or even compete failures.

Opinions vary, but a reasonable tolerance for 1.75mm filament would be +/-0.05mm. How do you know if your filament is out of tolerance? You buy yourself a Vernia Calliper. Trust me, even if you don’t think you need these they’re an awesome piece of kit for any 3D printing enthusiast. I write about the basic tools required in my Free Beginners Guide to 3D Printing at Home so download and have a read of that for more information.

There’s a few things you should do to ensure your filament is in good shape. As we mentioned above, the main one is to to purchase your filament from a reputable source. If you haven’t already, you should read the section above about moisture, as excessive moisture can also cause your filaments to swell. Some filaments are worse than others, but this is another reason to consider moisture as your filaments enemy.

Later on in Part 2 I’ll talk more about extrusion and explain how to set up your extruder to match the filament you’re using, even if it’s diameter is slightly out of tolerance. This will form part of your 3D printer so it’s more fitting to talk about this later on where you’re setting up your 3D printer for the best quality 3D prints.

Using Flexible Filaments

When you’ve been 3D printing with ABS or PLA for a little while you might feel the need to branch out a little and try flexible filaments like NinjaFlex. These filaments have a rubber like strength and flexibility, making them great for 3D Printing Tyres. For all their benefits they also have a few downsides and are tricky to 3D print with if you’ve never used them before.

To save me going into great detail on how to achieve great quality prints with flexible filaments, I will run though a few basics here, but I’ll also refer you to a blog post I wrote a few weeks ago called How to 3D Print Using Flexible Filaments Like NinjaFlex. In this blog post I also included a 12 minute YouTube video of how I designed a custom chocolate mould in OpenSCAD, setup my printer and then printed it using flexible filament.

3D PrintHQ TyreThere are a few things you’ll need to know about flexible filaments.

You won’t have any problems with warping as they flex so well they generally won’t pull off the build plate.

Also, imagine how tricky it would be to ‘push’ elastic though your extruder. This is effectively what your 3D printer will be trying to do so you need to make this process as smooth as possible or else your filament will just bend, double up and block your extruder in seconds.

A slightly higher temperature helps to keep it flowing as well as helping the layers adhere to each other. Also most people (myself included) find it absolutely vital to slow down the extrusion rate to about 1/3 of your normal speed. 30mm/s works very well for me.

Actually, when I 3D printed the OpenRC F1 car I listed the Flexible Filament Settings I used for 3D printing the tyres, so you might want to take a peak at this too.

We mentioned filament diameters earlier on and that 1.75mm seemed to be the most popular. Well, for flexible filaments it might be more sensible to use 3.00mm if possible, as this would reduce the flexing though your extruder and reduce your failure rate dramatically. Of course if your 3D printer isn’t designed for 3.00mm filaments then unfortunately this isn’t an option for you without replacing/modifying the extruder.

Lastly, if you have a Bowden extruder then using flexible filaments might seem impossible. The simple reason is that your extruder stepper motor is no longer located in the extruder, it’s on the main body of your 3D printer. This setup has many advantages but one of the disadvantages is that the extruder has to push your filament much further creating more flex even with ABS or PLA.

This makes 3D printing with flexible filaments difficult, but I have heard of people who manage to create great quality 3D prints using flexible filaments and Bowden extruders so anything’s possible, if not easy.

Special Composite Filaments

As well as pure ABS and PLA filaments there are many different special (or composite) filaments on the market. I’ve written before about ColorFabbs Wooden and Bronze filaments and have had some success with them. I’ve also tried some ‘strong’ filaments like XT Colpolyester, which is strong and FDA food safe.

These are just a few of the special filaments available but each has it’s own unique properties which will affect your 3D print settings and the quality of your final prints. Obviously there are too many special filaments out there to discuss them all, but I’ll just summarise some of the qualities and downsides of some of these interesting filaments.

woodFill WatchThere are quite a few strong filaments out there, which you might want to use for functional applications like replacement parts.

These often have higher melting points and can warp more on the build plate. Also, don’t be fooled by filaments like bronzeFill, thinking that if it contains bronze, which it does (80% I believe), then it will be stronger.

The reality I found is that it’s weaker than normal PLA, as the weak link is still the PLA, not the bronze. The same goes for woodFill. This contains 30% real recycled pine and is a great filament. It looks like wood, sands like wood and even makes your house/office smell like a woodworking shop as it 3D prints and heats to 220+ degrees.

Objects 3D printed using metal infused filaments can be polished to look a little like the metal itself and wood infused filaments can be sanded too. I love using these special composite filaments, one of my favourites being glowFill, which glows in the dark. This is great for Halloween!

I do find that these special filaments are a little stringy and require more post print work to clean them up, but it’s worth it. I even 3D Printed This Functional Watch in woodFill after I’d written this initial blog post about it.

These filaments are fun, so why not buy some and try them out. ColorFabb even do a sample pack where you can try one of each of their special filaments, without having to buy a whole spool of each. That’s how I started my journey with these cool filaments. For many applications they’ll improve your 3D print quality simply because they don’t have that plasticy finish which we’re all so used to.

What to Expect in Part 2 Next Week

When I started to approach 4,000 words in this blog post I realised that I needed to split this blog post into two parts. This’ll give you time to absorb what I’ve talked about so far and maybe try out some of what you’ve just learned.

There’s much more to come in part 2, which I’ve already planned out and started to write. This’ll include:

  • Setting up Your 3D Printer – build plates, temperatures, extrusion and calibration.
  • Post Print Finishing – sanding, trimming, removing supports/rafts, vapour polishing and dry brushing

Maybe I’ll talk a little about outsourcing too, because for the really high quality stuff where you need to use materials like metal it’s often great to prototype your designs at home and then outsource the final production so a company with a specialist 3D printer. I’ve done this a lot, so can help you out with this.

Anyway, this was quite a large blog post and you’ve done well to read up to this point. Now is as good a time as any to congratulate yourself for getting this far. Reading this and Part 2 will be a good investment of your time, so stick with it and your 3D prints will be so much better as a result.

I’m really looking forward to finishing off Part 2 and publishing it for you. In the mean time if you want more free information about 3D printing then Download my Beginners Guide to 3D Printing at Home eBook, then Join my 3D Printing Facebook Group to discuss your goals, your projects and to have any questions answered, by myself and the community.

Finally, feel free to Like and Share this article if you found it useful.

Thanks for reading and see you soon for ‘How to Produce High Quality 3D Prints – Part 2’.

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