DeFelsko Standards Zero Plates
Zero plates are uncoated steel (1018 steel) or aluminum (6061-T6) disks. A zero plate is included with most coated metal sets. The first gage measurement is on a zero plate to verify that the gage measures zero correctly. Electronic gages can usually be adjusted to “0” if necessary. A zero plate is also a convenient base onto which a plastic shim or polystyrene block can be placed for measurement. Plate Diameter: 38 mm (1.5″)
- Coated metal Standards for magnetic and eddy current gages usually include a zero plate. The first gage measurement is on the zero plate to verify that the gage measures zero correctly. If not, electronic gages can usually be adjusted to “0” on the zero plate. Alternatively, some specifications allow the measured difference from zero to be subtracted from future coating measurements.
- A zero plate is also a convenient base onto which a certified or non-certified plastic shim can be placed for measurement.
- For best accuracy it is important to ensure a coating thickness gage meaures “0” on the uncoated substrate and adjusted to “0” if necessary. This is especially true when the substrate is rough, shaped, extremely thin, or is an alloy. When an uncoated piece of the material is not available for a zero check, some procedures call for the gage to be adjusted to “0” on an uncoated zero plate. A compensation value is then subtracted from future coating measurements.
- Zero plates are also used to provide a substrate where none exists. Large sheets of material such as paper, plastic, fabric and rubber can be measured with a coating thickness gage by placing the material over the zero plate. This is useful when the measured item is too large to access with a micrometer or other device. The screen printing industry uses zero plates to measure the thickness of the “substrate” being printed.