HOW TO SELECT
Thickness meter
classification
classification
Coating thickness meters have various types of methods roughly listed below and select a type depending on material of coating film of a measuring object.
They are non-destructive types (either electromagnetic/eddy current, electromagnetic, eddy current, permanent magnet) and destructive types (wet gage, cut).
They are non-destructive types (either electromagnetic/eddy current, electromagnetic, eddy current, permanent magnet) and destructive types (wet gage, cut).
Measuring method
Measuring object
Substrate
Coating
Electro-magnetic / Eddy current
Magnetic metal (iron, steel, etc.),
Non-magnetic metal (aluminum, copper, etc.)
Non-magnetic metal (aluminum, copper, etc.)
Non-magnetic coating,
Non-conductive coating
Non-conductive coating
Electro-magnetic
Magnetic metal
(iron, steel, ferrite stainless steel, etc.)
(iron, steel, ferrite stainless steel, etc.)
Non-magnetic coating
(painting, plating(excluding nickel), resin, etc.)
(painting, plating(excluding nickel), resin, etc.)
Eddy current
Non-magnetic metal
(aluminum, copper, austenitic stainless steel, etc.)
(aluminum, copper, austenitic stainless steel, etc.)
Non-conductive coating
(painting, resin, anodized coating, etc.)
(painting, resin, anodized coating, etc.)
Permanent magnet type
Iron, steel
Nonmagnetic coating film
(coating, plating, resin lining, etc.)
(coating, plating, resin lining, etc.)
Wet gage type
Metals, plastics, etc.
Undried coating film, adhesive layers, etc.
Cut type
Metals, plastics, wood, concrete, etc.
painting, resin coating、plating, etc.
Measuring method
Measuring object
Substrate
Electro-magnetic / Eddy current
Magnetic metal (iron, steel, etc.),
Non-magnetic metal (aluminum, copper, etc.)
Non-magnetic metal (aluminum, copper, etc.)
Electro-magnetic
Magnetic metal
(iron, steel, ferrite stainless steel, etc.)
(iron, steel, ferrite stainless steel, etc.)
Eddy current
Non-magnetic metal
(aluminum, copper, austenitic stainless steel, etc.)
(aluminum, copper, austenitic stainless steel, etc.)
Permanent magnet type
Iron, steel
Wet gage type
Metals, plastics, etc.
Cut type
Metals, plastics, wood, concrete, etc.
Measuring method
Measuring object
Coating
Electro-magnetic / Eddy current
Non-magnetic coating,
Non-conductive coating
Non-conductive coating
Electro-magnetic
Non-magnetic coating
(painting, plating(excluding nickel), resin, etc.)
(painting, plating(excluding nickel), resin, etc.)
Eddy current
Non-conductive coating
(painting, resin, anodized coating, etc.)
(painting, resin, anodized coating, etc.)
Permanent magnet type
Nonmagnetic coating film
(coating, plating, resin lining, etc.)
(coating, plating, resin lining, etc.)
Wet gage type
Undried coating film, adhesive layers, etc.
Cut type
painting, resin coating、plating, etc.
- ① Select a measuring method according to the above classification.
- ② Select a type depending on measuring range, probe type, measuring object, etc.
PRINCIPLE
Electro-magnetic
When iron is moved toward or away from a steel core coil, self-inductance changes in accordance with distance and can be read with an ammeter / signal connected as shown in right figure.
This principle is utilized to measure the thickness of non-magnetic surface treated coating on magnetic metallic substrate.
Nonmagnetic
coating film
coating film
- square
- resin lining
- plating (except electrolytic nickel)
Eddy current
By utilizing the relativity between eddy current induced on the surface of metal by high frequency field of coil and distance to metal from probe, the thickness of insulating coating applied to non-magnetic metallic substrate can be measured.
Insulating film
- coating film
- resin lining
- anodized aluminum