Extruded or Cast Nylon – Material Testing Shows Differences

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

www.tkmna.com

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