Nylon 6.6 versus Nylon 6 – Are They Really All That Different?
Nylon – one of the most common and best known polymers
Nylon is valued for its light weight, incredible tensile strength, durability, and resistance to damage. Today, nylon is among the many polymer products in common daily use throughout the world. It is the second most used fiber in the United States, since it is so versatile and relatively easy to make.
Basically the crystal structure of the Nylon 6.6 is tighter than that of Nylon 6.
Nylon 6.6 Considered
Nylon 6.6 is made by an extrusion process, this involves the material being pushed thru a die to produce the required size.
This production method helps to increase the mechanical strength, stiffness, heat and wear resistance over cast Nylon 6, the only negative of this method is that it can increase internal stress.
The higher melting point of 260oC, helps to increase the maximum working temperature of Nylon 6.6 to 180oC short term.
How is Nylon 6.6 used?
This polymer is used for mechanical parts such as machine screws, gears and other low- to medium-stress components previously cast in metal.
Nylon 6.6 is frequently used when high mechanical strength, great rigidity, and good stability under heat is required. It is used for ball bearing cages, bushes, gears, profiles and various machined parts.
Looking at Nylon 6
Nylon 6, is a polymer developed by Paul Schlack at IG Farben to reproduce the properties of nylon 6.6 without violating the patent on its production. It was given the trademark Perlon® in 1952.
Nylon 6 is the most common commercial grade of nylon. Nylon 6 is tough, possessing high tensile strength. Smaller diameters and thinner thickness sheets are produced by an extrusion process, while larger diameter and thicker sheets are produced by a casting process.
A lower melting point of 215oC gives Nylon 6 a slightly lower maximum working temperature of 170oC short term.
Nylon 6 applications
Nylon 6 is used in a broad range of products requiring materials of high strength. It is widely used for gears, fittings, and bearings, in automotive industry for under-the-hood parts, and as a material for power tools housings. It can also be used in gun frames, such as those used by Glock, which are made with a composite of Nylon 6 and other polymers.
How they compare
So you’ve decided that Nylon is going to be the best material for the job, now you’re faced with that long term ongoing dilemma of which grade? Am i going to choose nylon 6 or will it be Nylon 6.6. then you start asking the questions like, whats the difference? Why is one more or less expensive than the other? Does it really matter?
Well, lets look at both alternatives and point out some of the differences:
We’ll start with Nylon 6,
- Its available in a huge range of sizes
- Its relatively inexpensive
- It machines ok
So decision made, but hold on a second, lets have a look at Nylon 6.6
- It can operate at around 6% higher temperature
- It‘s around 13% harder
- It’s around 10% more rigid
- Has an 8% better tensile strength
- It will machine that little bit better
So now all of a sudden, nylon 6.6 looks like the better option until you realise that nylon 6 is around 30% cheaper.
One thing to remember is that Nylons can absorb up to 7% (by weight) water, under high humidity or submerged in water. This can result in dimensional changes up to 2%.
If you are on a tight budget and the material demands are within what nylon 6 can deliver, we would suggest that option but if the components are being exposed to some higher temperatures or if some of the performance advantages come in to play then we’d recommend Nylon 6.6