How Strong 3D Printed Products Are
How long a product will last is a question all of us ask when buying anything new, whether it is an electronic device or just a decorative item. But when it comes to a 3D printer, you create your own items.
So just how strong are 3D printed parts?
It depends. From the material you use to the type of printer in operation, everything factors into the strength and durability of your prints.
Here is a quick rundown on how to craft the strongest 3D printed items.
Strength or Durability?
Before diving into the different materials used in 3D printers, it is important to understand the distinction between strength and durability.
When we talk about material strength, we are usually referring to tensile strength. Without going into numbers or equations, you can understand tensile strength as the amount of weight a hook made of a given material can lift.
Naturally, the higher the tensile strength, the better it is at handling physical pressure.
Durability, on the other hand, depends on many other things besides physical strength alone. Heat, for example, is the bane of many 3D prints. Others might be sensitive to UV exposure (sunlight), making them unsuitable for any outdoor application.
Usually, the really strong materials tend to be pretty durable as well.
Which Type of 3D Printer Gives Stronger Prints?
Selective Laser Sintering is probably the process for obtaining the strongest prints.
In SLS, a laser is used to selectively fuse a powdered material, resulting in incredible accuracy and quality. This is because lasers, in contrast to UV lights or extruders, are capable of melting even metals, allowing an SLS printer to use metals or metal derived substances in printing.
SLS printers are expensive, however, and much harder to use than your usual 3D printer. These printers are thus exclusively found in industrial or scientific settings, where the cost is no bar and the highest quality of the 3D printed product is required.
Obtaining Strong Prints at Home: The Right 3D Printer Type
Stereolithography generally creates higher quality prints compared to conventional printers like FDM
The main reason for this is the printing process itself. Stereolithography printers use UV light to ‘cure’ material in a vat of liquid resin, creating very smooth, cohesive prints.
The other reason is the material; some tough resin variants can result in very strong and durable prints, immutable to both heat and pressure. For 3D printing hobbyists serious about their craft, stereolithography is probably the way to go.
Fused Deposition Modeling or FDM is the most common form of 3D printer found in homes and small offices. And with good reason; FDM printers are affordable and easy to use, even for complete beginners.
FDM also has the greatest variety in materials used for printing. From PLA to ABS, PETG to Polycarbonate, you have many plastic filaments that can be used with an extruder. And while the cheapest filaments aren’t particularly strong, there are plenty of good options that give a much better performance.
How Strong are the Various 3D Printing Materials?
Polylactic Acid is the cheapest filament material that you can use with an FDM printer. As such, it should come as no surprise that its products aren’t that strong.
PLA has a low melting point, which means that even constant exposure to harsh sunlight can deform your prints. Even when kept away from heat, PLA products tend to degrade over time.
This seriously hampers the ability of PLA to function as anything more than a material for printing prototypes, although its tensile strength is actually quite high.
Acrylonitrile Butadiene Styrene or ABS has a well-deserved reputation for strength and durability. ABS is notoriously hard to work with, requiring very high temperatures and slow print times to be able to set properly.
But when it comes to tensile strength, ABS is actually weaker than even PLA.
The only reason ABS is preferred over PLA is its overall durability. ABS is highly resistant to heat, making it a good choice for printing everyday objects that are meant to outlast normal wear and tear. Most people print a little thicker than normal to make it more durable.
For fabricating objects that can survive physical impacts and pressures, you need something even better.
Polyethylene Terephthalate Glycol behaves somewhat differently from other filaments. It is a denser, more rigid plastic, making its prints heavier but also stronger.
Better yet, it is a food-grade plastic, allowing to print plastic containers for storing edible items safely.
PETG is a great option for creating simple prints that can take the extra weight. It can be a little tricky to work with at the start, but is easier to use than polycarbonate.
Polycarbonate is hands down the best filament you can use for 3D printing. Not only does it possess the highest tensile strength of all the filaments we have reviewed so far, but it is also incredibly heat resistant.
Products printed out of polycarbonate are almost indestructible and are suited to all kinds of applications, no matter how harsh.
The only problem is that it needs very high temperatures to work with, which not all FDM printers support. But if your printer can take it, polycarbonate should definitely be your material of choice for printing the heavy-duty stuff.
Used with stereolithography printers, resins are liquid polymers that solidify on exposure to UV light. Once they are ‘cured’, however, they are rather resilient.
Tough resins, especially, are great for printing miniatures and other small objects where you need smoothness and detailed features along with strength and durability.
Metal filaments are quite rare, owing to the temperatures required. More usually, metal-based materials are used with SLS printers, where a laser melts powdered metal to print the object.
This is obviously the strongest material for 3D printing, creating products that can even be used in machines or automobiles.
Printing Techniques for 3D Printing Stronger Products
When starting out, most people tend to print designs completely hollow to save material and speed up printing. While that is alright for experimental prints you do not intend to keep for long, you need a different approach for creating things to last.
Infill is a pattern or design that is used to fill up hollow spaces inside a 3D printed object. Situated between walls, infills strengthen the overall structure while using the minimum material possible. Grids and honeycombs are two of the most common infill patterns used in most 3D prints.
You don’t have to fill up every inch of space either; for an object meant for everyday use, 25-40% is enough. Use 100% infill only on those prints meant to bear weight or withstand impacts.
Number of Walls
Just like an infill, increasing the number of internal walls in a 3D print can also boost its strength. This tip is particularly useful for larger objects, where a greater fraction of the object tends to be hollow.
In such a scenario, inserting additional walls and using more infill can shore up its support capacity considerably. Keep in mind though that increasing the number of walls also increases the print complexity, requiring more time and material.
At this point, many of you must be thinking, “Why don’t we just print a solid block of material?”
Because it is inefficient, and frankly, unnecessary. After a certain point, just throwing more material at the print only makes it bulkier, not stronger.
What you need to do is to avoid flimsy walls that cave-in at the slightest pressure. Create thick walls supported with plenty of infills to obtain a 3D object that surprises you with its strength.
Of course, the size of the object in question determines how thick the walls must be, so adjust things accordingly.
It is a myth that 3D printed products are any less durable than those produced by ‘traditional’ manufacturing. Like always, the strength of the final product depends on the materials used and the design of the object.
Cheap filaments like PLA are mostly meant for experimentation – pick something better, like ABS or even polycarbonate for creating stuff meant to last. The same goes when working with resin printers: use tougher resins if you don't want your prints to fall apart easily.
Pay attention to features like internal walls and their thickness to ensure that your printed object has enough support. Don’t hesitate to use infill freely whenever you need some extra strength.
By following these simple tips, you can create 3D printed products that last a lifetime.