If you are a user of Nylon materials do you use extruded or cast nylon? Do you always use one vs. the other? Material testing shows there are differences between extruded and cast nylon materials that may warrant a good look at a Technical Data Sheet before you make your material selection.
The Top 5 Differences between the more traditional extruded nylon and cast nylon materials are:
5 – A cast nylon material inherently has less stress than extruded nylon
4 – Lower moisture absorption gives cast nylon a higher dimensional stability than extruded nylon
3 – The more crystalline structure of cast nylon gives it a higher strength than extruded nylon
2 – Cast nylon is available in smaller diameter rod than extruded nylon is when looking at premium bearing grades
1 – Cast nylon has a 20 degree higher operating temperature than extruded nylon
The table below shows a comparison chart between a typical cast nylon and a typical extruded nylon. In this case we are looking at Property Comparison of Nycast® 6pa – Natural versus Extruded Natural Nylon 6/6
| Property | Units | ASTM Test Method | Nycast ® 6 pa Natural | Extruded Nylon 6/6 |
| Specific Gravity | g/cm3 | D792 | 1.15-1.17 | 1.15 |
| Tensile Strength | psi | D638 | 10,000 – 13,500 | 11,500 |
| Tensile Elongation | % | D638 | 20 – 55 | 50 |
| Tensile Modulus | psi | D638 | 400,000 – 550,000 | 425,000 |
| Compressive Strength | psi | D695 | 13,500 – 16,000 | 12,500 |
| Compressive Modulus | psi | D695 | 325,000 – 400,000 | 420,000 |
| Flexural Strength | psi | D790 | 15,500 – 17,500 | 15,000 |
| Flexural Modulus | psi | D790 | 420,000 – 500,000 | 450,000 |
| Shear Strength | psi | D732 | 10,000 – 11,000 | 10,000 |
| Notched Izod Impact | ft.lbs./in. | D256 | 0.7 – 0.9 | 0.6 |
| Hardness, Rockwell | R | D785 | 115 – 125 | 115 |
| Hardness, | Shore D | D2240 | 78 – 83 | NV |
| Melting Point | deg. F | D789/D3418 | 450 +/- 10 | 500 |
| Coefficient Of Linear Thermal Expansion | in./in./F D696/E831 | 6.1 x 10 (-5) | 5.5 x 10 (-5) | |
| Deformation Under Load | % | D621 | 0.5 – 2.5 | NV |
| Deflection Temperature: | 264 psi deg. F | D648 | 200-400 | 200 |
| Deflection Temperature: | 66 psi deg. F | D648 | 400-430 | N/A |
| Continuous Service Temperature | deg. F | 230 | 210 | |
| Intermittent Service Temperature | deg. F | 330 | NV | |
| Coefficient Of Friction: Dynamic | D1894 | 0.22 | ||
| Water Absorbtion – 24 Hours | % | D570 | 0.5-0.6 | 0.30 |
| Water Absorbtion – Saturation | % | D570 | 5.0-6.0 | 7 |
| Dielectric Strength | 500-600 | 400 | ||
| Dielectric Constant 60 Cycles | 3.7 | 3.6 | ||
| 1000 Cycles | 3.7 | 3.6 | ||
| 100,000 Cycles | 3.7 | 3.6 |
(The facts stated in the above table are based on experiments and information believed to be reliable. No guarantee is made of the accuracy, however, and the products are sold without warranty, expressed or implied, and upon the conditions that purchaser shall conduct their own test to determine suitability for their intended use.)
Although it may not always make sense to choose a cast nylon over an extruded nylon material, characteristics of cast nylons can ultimately mean longer wearing parts and in applications such as bearings, nylon wear pads, or gears, that can mean less downtime of equipment, less maintenance and improved operating costs over time.
See you in the blogosphere again soon!
Lisa Anderson
Marketing Manager
ThyssenKrupp Materials, NA
AIN Plastics Division