south jersey additive manufacturing

Let's grow 3DPrinting Adoption in South Jersey

Reading Tech Data Sheets for Dummies
kd
November 9, 2023
11:43 pm
PLA vs Carbon Fiber PLA

Materials = Applications

Additive Manufacturing is getting new materials all the time, and variants with specific use cases of existing polymers.  Some examples may be Zymergen Z2, a Polyimide with exceptional Z strength and heat resistance.  Ultimately, datasheets help discern the properties of the polymers you can chose from, and it may be confusing to use a datasheet practically to drive your application.

Before we start, we have one big caveat: there are testing standards such as ISO 527, and you must be apples to apples to compare them.  Also if one number is in MPa(megapascal pressure unit) the other must be as well to keep it even.

Most materials are tested with an ASTDM D638 specimen type 1 or 2, this may be called a dogbone.  Companies who are utilizing sophisticated applications often ask for printer manufacturers to print dogbones in three configurations and test them - to get an idea what machine has the best process control to produce a strong part.  Companies often characterize their material data sheets using this as well - but it can vary from machine to machine - quite drastically in some cases even where it seems like per spec sheet it should be comparable.

donebone testing

Information a sheet may show you

  • Tensile Strength - how much force, tension is needed to break the dogbone
  • Tensile Elongation - When the material is pulled in tension - how much does it stretch
  • Flexural Strength - How much does the material resist breaking when bent
  • Flexural Modulus - How much will a sample resist bending when a load is applied - Higher#= Stiffer / Lower# = More Flexible
  • Young's Modulus - How much will a sample stretch when a load is applied - Higher# = Stiffer
  • Impact Strength - How much can the material impact energy/absorb shock - Higher# = Tougher
  • Glass Transition Temperature (Tg) - The temperature that materials change to a glassy/crystalline state.  Going above the Tg materials tend to get "rubbery" (Please note UV resistance is separate)
  • Heat Deflection Temperature (HDT) - The temperature which a sample deforms under load, at a high level - when does it begin to soften
  • Elongation at Break - the amount of deformation (typically in % of original length) a material can have before the sample breaks.
  • Shore Hardness - Measures the hardness of a material and its resistance to indentation.  Refer to the chart below, note that there are overlap such as 30D is comparable to 100A.  In FDM(filament) the low end is typically 85A, where in FGF and SLS it may be as low as 35A.  
  • Density - how many G/CC^3 does the material weigh.  Heavier = less material per Kg.
shore hardness chart
Data Sheet Comparison - PLA  vs CF PLA(carbon fiber)
PLA vs Carbon Fiber PLA

Above is a comparison of datasheets from 3dxTech.  While I have not printed PLA in years this should serve as a good comparison as these are popular hobbyist materials.  What can be discerned quickly is:

Carbon Fiber Adds a considerable amount of stiffness.

Standard PLA is more resilient as it has a higher tensile strength and higher flexural strength.

If you wanted the material to be more rigid, I would choose the Carbon Fiber variant.  If you were going to abuse the part knocking it around - Standard PLA would serve you better

There is no "best material" and most people try to balance cost and properties.  The key is to identify the use case, and then make a part out of a polymer that is best suited for the use.

Category : Uncategorized