3D printing tips and tricks
In this page you will find basic things to consider, when designing an object what will be printed out with 3D printer.
Many of them are related and are based on specific 3D printer type and settings you inserted in the slicer program. Also different filaments need different settings. Below you will find the list of only few most common fails what might happen to 3D model or when printing it.
Nevertheless many of them are universal and you can consider them, when making a 3D drawing.
In the material below you will also find universal "benchies" (calibrating and testing tools) to find out your printer capabilities and make fine tuning modifications.
In the end only real way to find out different failures is to try them out personally.
So bon voyage to your way to become master of 3D printing 🙂
Printer settings
As we already know, a lot of 3D printed detail appearance and quality depends on your printer and its settings.
Good comparison in this case are cars- BMW and some cheap car - they drive the same and they have all the same controls. Nevertheless they don't feel the same and drive in same quality. Even same BMW models don't drive the same- they all have some special additions and functions. Also, well tuned cheap car with good driver drives faster than new and powerful supercar with bad settings and driver.
Settings are divided by two:
Settings what you can make in slicer program:
printing layer height
nozzle temp
infill density and type
printing speed*
Settings what you can make on your printer:
nozzle temp
heatbed leveling
draft, wind and sunlight
vibrations
ventilation
Most of the settings are automatic and selected by program. How to use slicer programs, you can learn in "Slicer programs" subpage. Usually program takes input data when you select your printer type. If you are beginner, do not change them. If you are more experienced, you can try different things - every printer needs some fine tuning.
Most of the printer settings are done before printing, e.g heatbed leveling. Of course you can do fast with automatic leveling (turn knobs and/or live adjust Z axis), when you look first layers.
Same is with nozzle temperature. Usually PLA is about 210C. Some printers put it 200C. Then you can easily change it to 210C.
Draft, wind, sun and vibrations are printer environmental things and should be also considered. Because 3D printer is melting plastic, every little wind can change nozzle temp and change printing quality. Same is with vibrations- 3D printer should always be on stable table. It moves and if printer is on moving/shaking table it will be visible in printing layers.
Sunlight is also factor. Most of printer filaments do not like sun. UV beams will start plastic to harden and therefore make it usless for 3D printer. Filament should be always stored in dark, dry, steady temperature environment.
And finally ventilation - most filaments are thermoplastic polymers and when melting, they release volatile organic compounds (VOCs) and Ultrafine particles (UFPs). They are harmful for humans and therefore it is recommended to print in a well-ventilated room.
Where is more sensible to change print settings- in a slicer program or in printer menu?
Slicer program should be first option. Printer menu is for finetuning and small changes.
"Benchies"
"3DBenchy" is a simple 3D model specifically designed for testing and benchmarking 3D printers. It is a small recognizable object that you can download for free in many pages (cults3d, thingiverse, yeggy).
When printing this STL file you will be able to make adjustments to your 3D printer and filament settings and also compare the result to other users' prints and machines.
Use TEST Benchy models to understand your settings and printer possibilities. Then you know maximum angels and bridging capabilities on the model, that your printer will print in good quality.
Most common boat benchy. It is designed by Creative Tools member Daniel Norée (the creator of OpenRC Truggy, printable wrench, etc).
Use TEST model to understand your printer and its settings.
Above are two test printouts from different printers - Prusa MK3I and Creality Ender 3 S1. (it is not official test!)
As you can see, most obvious difference is in details- Prusa (green) can make somekind of writing, as Creality can`t. It is usually "problem" that starts in the slicer program- some slicers don't print details under 0.4mm.
Otherwise quality is almost the same. As you can see, Prusa and Ender both started to have difficulties when printing over 60 degrees angle. But Prusa was better, because it kept almost the shape and top layer was good. Creality ender did better work up to 60 degrees, but then filament started to print in the air and there were loose strings.
Overall Prusa costs about 1100 EUR, Creality 450 EUR. They both did very good job and for everyday users it is enough. We can see, that Prusa is more capable making details, as Ender 3 will do more smooth layers and it costs 1/3 of Prusa price! There are more benefits for user when working with Prusa- more silent, better bearings/parts, less manual adjusting...
So overall all printers are good. You just have to finetune your 3D printer and you have to know what are you looking for.
We use basic settings, 0.2 layer, 10% infill and same prusa filaments. 210C nozzle. Different slicers - Prusa and Crality.
Why are "benchies" used in 3D printing world?
Benchies are special figures with some special qualities. They have some demanding sections and figures. You can use them for finetuning your printer and filament settings or just to compare printing quality on different printers.
Loose object and no sticking to heatbed
Adhesion with the heatbed is maybe most critical and common "mistake" that can happen. You can be sure that it is adhesion problem when:
The 3D print is a jumbled mess
The first layer is becoming messy
Usually it is predictable and avoidable when checking some things before print.
Bed level - use paper/auto bed level/leveling screws
Old residue - clean heatbed well, old printing places are covered with last print "oil" and it may come loose.
Be there for first layers - 98,7% problems will occur in the first layer prints. Check and make adjustments, cleaning and setting changes to your print.
Change nozzle temperature - different filaments need different temperatures. Usually they are written to the sticker, which is on the filament roll. For PLA it is 210 degrees of Celsius. Because every print sensor and program is different you can make adjustments . e.g ±50 C is good starting point.
"Nice" view - object came loose and result is failed print. This was our project DIY printer screen holder.
Different layer height problems - too far/all ok/too close/too fast.
Name 3 reasons why headbed adhesion might be bad and object may become loose?
Old plastic residue. Dirty heatbed.
Misaligned bed leveling.
Wrong nozzle temp/filament settings.
Filament
The main two types of "beginners" filaments are Acrylonitrile Butadiene Styrene (ABS) and Polyactic Acid (PLA).
Besides of them, there are many more different filaments with a lot of different characteristics - chrome/wood/copper. All these special filaments aren't real copper or wood- they are plastics, but they will look and shine like real materials.
Some filaments have special nature like ability to glow in the dark or change colour at different environments of light and temperature.
Using different filaments will give you more exposure to various aspects of the 3D printing process. For example, depending upon the filament you choose, you may find that it takes more time to be layered, more time to cool, more post processing or any number of other differences.
On the right there is just only one example of filament table. Every filament manufacturer has their own. Just use some kind of searching engine and your local vendors to find right for you!
Very good table of different filaments and their properties.
Chamfer versus Radius
In 3D CAD drawing program everything looks nice and smooth. But as you save the file in .obj or .stl format, program automatically generates model using triangular shapes.
That`s why some round objects will look like stepped circles. If that is not important, then let it be. But when radiuses are very small ≤ 2mm, then printer will not make nice edge. In that case CHAMFER will be better option.
STL and CAD file difference. STL tries to do everything in triangels.
Image source: https://bit.ly/3Fx2UaL
As you can see, round grip is little bit "square"
chamfer_radius.mp4Here you can see difference between rounded corner and chamfer. Rounded will be "uglier" same time as chamfer is smooth and nicer.
Use CHAMFER not RADIUS
Exeption.. when doing vertical corners, using radius is better- then printer movement will be more fluent, less vibrations and better overall quality.
Beginners basic modeling guide
In general top or bottom surface of a printed piece will have the best finishing.
PLA should be your first filament. It's cheap, it prints very easily and comes in a vast selection of colors. But it has some disadvantages. First of all, it's quite hard and strong but also fragile. Its mechanical properties become worse with UV exposure (sunshine). That means the material is not suitable for stressed mechanical parts and other things where you expect outdoor use and/or long-time durability. Also, PLA is not too resistant to high temperatures. At 60-70 °C, the material already starts to soften.
Features smaller than 2mm are usually hard to print or they come out in bad quality.
Reduce supports by following the 45-degree rule - Use chamfers to strengthen up your model and remove need for extra supports.
Wall thickness- 0.8mm is strandard in 3D printing world. If you wish to have stronger model then you have to consider the wall thickness. Add thickness according to nozzle size (0.8; 1.2; 1.6...)
Slicer program must be suitable for your printer. G code is universal and printer can handle that, but problems might occur when print will start (40x40cm model will start in one corner when 20x20cm printer is used)
Clean your heatbed - when object comes loose in the middle of printing, then it is failed print. If your printing bed is dirty or even covered with previous printout residue, it may come loose! Please clean your printarea with IPA (Isopropyl Alcohol). Be careful - dont use them on powder coated heatbeds...
When making combined parts, leave room for tolerance. 0.2mm is enough!
Try always to avoid sharp corners. Chamfers add structural strength and all printers can print 45 degrees slope without supports!
Use metal inserts to achive durable polt connections.
Why is added chamfer better than using supports?
Then you don't have to add supports and also 3D printed model will be stronger!
CAD modeling tips
When modeling complex models, use save function often. When your computer crashes, data will not be lost.
Holes. Usually outside diameter of printed parts is almost exactly what it was on your model. But holes and openings are usually 0.2 mm smaller. You should test it! Sometimes smaller hole is even better- you can insert something with little pressure. Connection in that way is very precise and durable.
When you wish to have more post-processing room add wall thickness. Standard is 0.8mm (0,4mm nozzle), but can use 1,2 or 1,6mm instead. Then you have more drilling material. You lose some printing time, but outcome will be stronger.
Connecting parts should be modelled with little extra room. About 0.2 mm is usually enough (nuts and bolts). You can always use "scaling" function to make parts 1-2% smaller against each other to give them some playroom. It also depends on your printer, filament and their finetuning.
Important thing to remember when designing for 3D printing is that your digital design will become a physical object. In the CAD design software there are no laws of physics to affect your model. When printing, you have to consider filament, temperature, printer and even cavity. Almost anything could be "drawn" in 3D object, but not everything can be 3D printed. Knowing the key factors that go into designing 3D models will ensure that you produce digital designs that can be successfully printed.
Before inserting linear bearings, we use drill to make round hole.
Below are some main design principles to consider when you are designing 3D object for 3D printing.
Image source: https://bit.ly/3Uxs6m7
3D Printing Forums as Your Advantage
3D printing forums are developed by hobby users mainly. If you have some kind of problem or you use new filament, you can be sure that someone has done it already and can give you answers and solutions.
Just goolgle it and you find answers for most of your questions. Very good places are on all printer (Prusa, crality...) and filament makers webpages- they all have troubleshooting pages.
You can find a lot of free .stl/.obj models cults3d; thingiverse; yeggy webpages and there are many more of them. Just be wise and careful when downloading things in the Internet - use only pages you trust!