Rheology Gap Settings

It's Tech Tip Tuesday! 🤩 Let's set the right gap in rheology!

This is #1 question I am asked whenever I teach rheology to someone new: "Nicki, how much material should I put in between the plates?" or "Nicki, what gap should I set it to?"

And while some may not think too much about this, it actually does make a difference in your end result! And what I commonly say is "It's easy to run rheology! It's also easy to get bad data in rheology!" This is a scenario where, if you don't set the gap right, you will get bad data.

So, what gap should you set your test to? My answer... "It depends!".

I typically go between 50 - 2000 um, but that value really depends on the material I'm testing, especially if it's filled, has high normal stress, or is one that easily dissipates thermal energy. I will keenly observe the raw data on the rheometer (axial force, sinusoidal wave, etc...) during my initial discovery test, and will adjust my gap from that information. The slides below shares some tips on rheology gap settings that you should bear in mind to NOT get bad data.

Need help in running your rheology? I have been running rheology for over 16 years, testing hundreds of materials ranging from polyethylene, polypropylene, rubbers, epoxy, lubricants, paints, coatings, & so much more! I've used rheology to solve many formula, processing, and application problems. Hit the Schedule Call Now button to connect with me!