ANSI STM11.13 pdf free download

ANSI STM11.13 pdf free download.For the Protection of Electrostatic Discharge Susceptible Items Two- Point Resistance Measurement.
5.0 GENERAL DISCUSSION
This method is recommended for testing items with irregularly shaped surfaces, and small and narrow surfaces. Conventional concentric ring and parallel bar electrode configurations are used for testing planar items only. However, most packaging items are not planar. Examples include shipping tubes, trays, tote boxes and carrier tapes. The probe described in this standard test method employs springs to apply consistent contact pressure between the electrode and the item. Force created by springs is subject to variance from wear, contamination and manufacturing tolerance. This variance is acceptable for this application. Elastomeric electrodes compensate for uneven item surfaces yielding consistent results between laboratories and test operators.
6.0 TEST EQUIPMENT
6.1 Two-Point Probe
Refer to Figure 1 and Table 1.
This two-point probe consists of an insulated metal body with a Teflon insulator inserted into each end. One insulator holds test leads; the other holds receptacles that accept spring-loaded pins. One receptacle is surrounded by a cylindrical insulator, which is surrounded by a metal shield. The pins are gold plated and have a spring force of 0.465 kg (16.4 ounces) ± 10% at a travel of 4.32 mm (0.17 inch). The pin tips are machined to accept friction fitted 3.180 mm (0.125 inch) diameter electrically conductive rubber electrodes. The rubber has a Shore-A (IRHD) durometer hardness of 50-70 (ASTM Method 0 2240). The electrodes are 3.180 mm (0.125 inch) long. Electrode volume resistivity is < 500 ohms-cm.
6.2 Insulative Support Surface
A surface when used for sample support shall have a surface resistivity greater than
1.0 x 1013 ohms/square when measured per ASTM D 257.
As an alternate method to verify the properties of the insulative support surface, the resistance
shall be measured using the same test instrument and probe that is being applied in this test
method. The average resistance of the insulative support surface shall be greater than
1.0 x 1012 ohms based on a minimum of three (3) random measurements in separate places on
the insulative support surface.
6.3 Instrumentation
The measurement instrumentation, called the meter, whether it is a single meter or a collection of instruments capable of the following:
6.3.1 For Product Qualification
The meter shall have circuit voltage of 100 volts (± 5%) while under load for measurements of
1.0 x 106 ohms and above, and 10 volts (± 5%) while under load for measurements less than
1 .0 x 106 ohms.
The meter shall be capable of making measurements from 1.0 x 1 0 ohms to 1.0 x 1012 ohms.
6.3.2 For Acceptance Testing
A meter meeting the requirements of product qualification may be used, or:
The meter shall have an open circuit voltage of 100 volts (± 5%) for measurements of
1.0 x 106 ohms and above, and 10 volts (± 5%) for measurements less than 1.0 x 106 ohms.
The meter shall be capable of making measurements from 1.0 x 10 ohms to 1.0 x 1012 ohms.
In case of disagreement, the meter used for product qualification will be used to resolve any
disputes.
6.5 Verification Resistors
The low resistance verification fixture will consist of a 1.0 X 104 ohm (土1%) resistor electrically bonded to two isolated metal contact plates. The plates must be of size and shape so that each probe electrode contacts only one plate. The plates shall be affixed to a material with the same properties as the insulative support surface described in Section 6.2. Figure 3 ilustrates one possible configuration of a resistance verification fixture. The high resistance verification fixture will consist of a 1.0 x 1011 ohm (土5%) resistor elecrically bonded to two isolated metal contact plates. The plates must be of size and shape so that each probe electrode contacts only one plate. The plates shall be affixed to a material with the same properties as the insulative support surface described in Section 6.2. Figure 3 ilustrates one possible configuration of a resistance verification fixture. The actual value of the resistors should be measured periodically in accordance with the manufacturer’s recommendation. This measured value should be used to verifty probe operation.ANSI STM11.13 pdf download.