It seems like 3D printers can use any material nowadays. Desktop Metal is reinventing the way engineering and manufacturing teams produce metal parts with the ability to print in metal. There are even some printers that can print chocolate, pasta and wait for it— pizza! However, most commercial 3D printers create parts in some sort of plastic. To help you choose which is right for your application, we outline some key material properties below.
How Do You Choose
When choosing which 3D printing material is right for you, even among plastic printers, there is a wide variety of material properties to take into consideration. For example, Stratasys FDM thermoplastics alone can include:
These material families have a number of different characteristics that make them standout, but many people only look at the reported strength of the raw stock. To demonstrate how choosing materials is about more than strength, we compare tensile strength and toughness of 15 FDM thermoplastics.
Unfortunately, Tensile Strength doesn’t always determine if a part will be stronger. If you were forced to make a hammer from either hardened glass (ultimate tensile strength 175 MPa) or 3003 Aluminum (tensile strength 110 MPa), and you chose the glass, then you’d have a hammer that was technically ‘stronger’ but would shatter after just a few blows. That’s because there’s another material property that also affects how long our parts last called ‘toughness.’
A pane of glass will shatter if you hit it with a real hammer. A sheet of steel might either bend or shatter under a hammer's blow, depending on the type and temperature of the steel. Lead is not as ‘strong’ as either glass or steel, but it is tougher than both. Hammer blows that would break glass and steel would deform, but not break, a similarly sized sheet of lead. This is one reason they make bullets out of lead (you wouldn’t want a bullet to shatter when the hammer of a gunpowder explosion hits it).
Relationship of Tensile Strength and Toughness
If you look at the relationship between the tensile strength and toughness of different plastic materials, you start to notice something:
The top five "strongest" materials are not the same as the top five "toughest" materials. As you can see in the chart above Nylon 6, Nylon 12CF, PC ISO, PPSF/PPSU and ULTEM 9085 are the strongest of the group, but PC-ABS, ABS-M30i, ABS-M30, Nylon 12 and ULTEM 1010 are the toughest.
So in summary, there are a wide variety of FDM 3D printing materials to choose from. Looking at their properties will help in deciding which is the best option. Some that are ‘strong’ aren’t necessarily ‘tough,’ and some that are ‘tough’ may not be ‘strong.’ This is why we don’t have glass hammers or high carbon steel bullets.