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RMA TOLERANCES FOR EXTRUDED PRODUCTS

 
   

The closer tolerance classes outlined below should not be specified unless required by the final application and they should be restricted to critical dimensions. The closer tolerances demanded, the tighter the control must be exercised during manufacture, resulting in higher costs.

When particular physical properties are required in the products, it is not always possible to provide them in a combination which is capable of fabrication to close tolerances. It is necessary, in these circumstances, that consultation take place between the customer and supplier. In general, softer materials need greater tolerances than harder ones. Where close tolerances are required, a specific technique of measurement should be agreed upon between purchaser and manufacturer.

 
 
Tolerances for outside (O.D.) diameters, inside (I.D.) diameters, wall thickness, width, height, and general cross sectional dimensions or extrusions.

RMA Class

1
High Precision
2
Precision
3
Commercial

Drawing Designation

E1 E2 E3
Dimensions (In Millimeters)  
Above Up to
0 1.5
1.5 2.5
2.5 4.0
4.0 6.3
6.3 10
10 16
16 25
25 40
40 63
63 100
 
± 0.15
± 0.20
± 0.25
± 0.35
± 0.40
± 0.50
± 0.70
± 0.80
± 1.00
± 1.30
 
± 0.25
± 0.35
± 0.40
± 0.50
± 0.70
± 0.80
± 1.00
± 1.30
± 1.60
± 2.00
 
± 0.40
± 0.50
± 0.70
± 0.80
± 1.00
± 1.30
± 1.60
± 2.00
± 2.50
± 3.20
RMA Class
1
High Precision
2
Precision
3
Commercial
Drawing Designation
E1 E2 E3
Dimensions (In Inches)  
Above Up to
0 0.06
0.06 0.10
0.10 0.16
0.16 0.25
0.25 0.39
0.39 0.63
0.63 0.98
0.98 1.57
1.57 2.48
2.48 3.94
 
± 0.006
± 0.008
± 0.010
± 0.014
± 0.016
± 0.020
± 0.027
± 0.031
± 0.039
± 0.051
 
± 0.010
± 0.014
± 0.016
± 0.020
± 0.027
± 0.031
± 0.039
± 0.051
± 0.063
± 0.079
 
± 0.015
± 0.020
± 0.027
± 0.031
± 0.039
± 0.051
± 0.063
± 0.079
± 0.098
± 0.126

Note: Tolerances on dimensions above 100mm (3.94) should be agreed on by supplier and user. General cross sectional dimensions below 1mm (0.04) are impractical. In general, softer materials and those requiring a post cure need greater tolerances.

 
Why use Silicone Rubber?
Typical Properties for Silicone
RMA Tolerances for Molded Products
RMA Tolerances for Extruded Products
RMA Tolerances for Cutting to Length Extrusions
General Compatibility Chart for Various Rubber Materials