Nylon

Properties:
Very good physical properties, however moisture has a significant effect on properties, very good heat resistance, excellent chemical resistance, excellent wear resistance, moderate to high price, fair to easy processing.

Applications:
Electrical connectors, gears, slides, cams and bearings.

Descriptions:
The family of nylons consists of many different types. Nylon 6/6, nylon 6, nylon 6/10, nylon 6/12, nylon 11, nylon 12, and nylon 6-6/6 copolymer are the most common. Of these, nylon 6/6 and nylon 6 are the common ones readily available as sheet or rod.

Tips for machining:
Nylon has a high coefficient of thermal expansion (about three times that of aluminium) and low heat conductivity.
Make sure that it has been exposed to normal room temperature for several hours before it is machined into finished parts.

Saw cutting:
Nylon can be easily sawed on standard metal working equipment. Wood working equipment may be suitable but the high cutting speeds may cause excessive heat build-up. A blade that has been used for cutting metal is usually not sharp enough for nylon. Use a new coarse tooth blade with good set. Coolant may be used to control heat build up and to prevent melting the nylon.

Holding:
Keep in mind that nylon is not as strong as metal and can be deformed by improper chucking methods. On small accurately sized rod, use standard spring collets. On larger parts, use a 6-jaw universal chuck instead of a conventional 3-jaw chuck to distribute the holding force more uniformly. For thin walled tubular shapes, machine soft jaws so that the part is almost entirely confined.

Turning:
Satisfactory finishes can be easily obtained on nylon over a wide range of surface speeds. Use tools that are honed sharp and have high rake and clearance angles, to minimise cutting force and reduce heat build-up. Chips will be continuous and stringy. They should be directed away from the cut and prevented from winding around the work piece. Coolants are generally not necessary for lathe work unless there is excessive heat build-up.

Milling:
Milling cutters should be honed sharp and should have high positive cutting angles. Care should be used in clamping the part to prevent distortion. Cutting speeds and speeds will be determined by the finish required and will be limited by heat build-up.

Drilling:
Use conventional twist drill or flat type drills. Polished flutes will aid in the removal of chips. Do not use metal cutting reamers with nylon. They do not cut freely enough. Drill small holes to size in one operation. Rough drill large holes and finish by single point boring.

Thread cutting:
Use only sharp taps and dies on nylon parts. Don't use tools that have been used to cut metal. H5 or even larger oversized taps may be required because a threaded hole in nylon closes in when the tap is removed. Threads to close tolerances can be easily single point chased.

Grinding:
The large amounts of heat generated by grinding, together with the low heat conductance of nylon, usually dictate that liberal amounts of coolant he used in most grinding operations. Through-feed centre less grinding of long, flexible parts of nylon can be easily accomplished, and tolerances as close as .01mm are possible. Cylindrical grinding on nylon is usually not required because it is easy to get good finishes and close tolerances on a lathe. Surface grinding of nylon is usually not necessary. If a flat surface with close tolerances and good finish are required, the best approach is fly cutting in a mill.

Stamping:
Thin pieces may be stamped with standard equipment. Thick sections will require high shear angles if good edges are required. Steel rule dies may be used for some parts.

Measuring:
Use ordinary measuring equipment. However, use a light touch because the material is not as hard as metal. A micrometer anvil can deform a nylon surface as much as several thousandths. Homemade, soft plug and ring gauges are useful on thin walled parts. If extremely close tolerances are involved, ensure any temperature changes that the part will see are taken into account.


Typical properties of Nylon 6           

 Specific Gravity:  g/cm³    
1.14
Continuous Operating Temperature 5: °C   
85/70
Tensile Strength: Mpa   
80
Hardness:
Rockwell M
84
Impact Resistance Charpy Notched
KJ/M²
5.5
Co-efficient of thermal expansion: m/(m.k) x 10¯6  90
Dielectric Strength: KV/mm 25
Surface Resistivity: Ohms >1x10¹³
Flammability ul94
25
Food Grade: FDA Yes natural only




Typical properties of Nylon 66           

 Specific Gravity:  g/cm³    
1.14
Continuous Operating Temperature 5: °C   
95/80
Tensile Strength: Mpa   
90
Hardness:
Rockwell M
88
Impact Resistance Charpy Notched
KJ/M²
 4.5
Impact Resistance Charpy un-Notched KJ/M²  No break
Co-efficient of thermal expansion: m/(m.k) x 10¯6  80
Dielectric Strength: KV/mm 27
Surface Resistivity: Ohms >1x10¹³
Flammability Oxygen Index
%
26
Flammability UL94

HB
Food Grade: FDA Yes




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