Eddy Current UPA Dermitron Eddy Current Portable Instrument
The Dermitron EM portable instrument uses a special type of technology (Phase Sensitive Eddy Currents, ASTM B-659-90) that provides unique capabilities for the measurement of plating or coating measurement.
Benchtop Dermitron systems have been used worldwide for over 50 years wherever precise control of coating thickness is required. This is due to their capability to be used on the process line plus, accuracy comparable to X-Ray systems. Most common usage is for the measurement of Zinc/Steel for the fastener markets for determining corrosion protection. But Dermitrons are also used for measuring other plating on steel such as Nickel, Cadmium, Tin and Copper.
The versatile, handheld Dermitron EM instrument accurately measures the thickness of Zinc/Fe, Cd/Fe, Vacuum metalization, Anodizing and many other platings or coatings.
The Dermitron can be used in harsh environments such as directly on the plating line as well as in a Quality Lab or receiving inspection area. Dermitron portable instruments are sealed, limiting the effects of harsh environments.
Calibration is done using a set of certified plated calibration standards provided by UPA. Once the instrument has been calibrated it is ready to measure without requiring additional calibrations be made for differing parts measurement. The specific plating bath affects eddy current measurement accuracy. For example Alkaline Zinc and Acid Chloride Zinc baths require that calibration standards be made from the same type of chemistry. Substantial measurement errors can occur if calibration standards are used from incorrect bath chemistry. This is why UPA provides the correct standards and technical support to insure the closest correlation to X-Ray measurements.
Common Applications
- Zinc/Steel
- Cadmium/Steel
- Silver/Stainless Steel
- Copper/Steel
- Nickel/Steel
- Vacuum deposited aluminum or copper on plastic
- Anodizing/Aluminum, Nitride case depth
Corrosion Protection for the Fastener Industry
Fasteners, nuts bolts and screws are plated to protect against rust and corrosion. The zinc plating thickness corresponds to how resistant to rust they will be. Higher quality requirements and longer warranties require the fastener industry to confirm that the thickness of the plating meets specifications. The rugged Dermitron can be used directly on the plating line or in the lab.
Measure Anodizing on Aluminum
Anodizing is an electrochemical process that converts the metal surface into a decorative, durable, corrosion-resistant, oxide finish. Aluminum is ideally suited to anodizing, although other nonferrous metals, such as magnesium and titanium can also be anodized. The anodic oxide structure originates from the aluminum substrate and is composed entirely of aluminum oxide. This aluminum oxide is not applied to the surface like paint or plating, but is fully integrated with the underlying aluminum substrate, so it cannot chip or peel. Since anodizing is a non-conductive oxide layer over conductive aluminum, anodizing is an easy measurement using Eddy Current.
Vacuum Coatings on Plastic Parts
Very thin metal vacuum deposited metals on plastics or ceramics can also be measured using Eddy Current. Copper and aluminum are commonly applied to plastic as RFI and EMF coatings and each are measured instantly with the Dermitron.
The Method
Eddy Current vs Magnetic Method
Phase Sensitive Eddy Current is better suited than magnetic methods for measurement of Zinc on Steel because of its ability to measure thin platings, even on rough surfaces and small or large parts. It also offers great advantages in measuring small objects since the probe’s measuring area can be reduced so that geometry of the part being measured has little influence on the measurement. Even the thickness of copper on steel BBs can be accurately measured without the need for probe stands or parts fixturing using Eddy Current! This measurement wouldn’t be possible using magnetic induction.
Click here to read an article about the advantages of using Eddy Current for measuring zinc plating compared to magnetic instruments for fasteners.
Probe Selection
| Coating Base | Probe | Range Mills | Range Micron |
|---|---|---|---|
| Zn/Fe (Cyanide) | C | 0-.65 | 0-17 |
| Zn/Fe (Cyanide) | B | 0-1.5 | 0-38 |
| Zn/Fe (Chloride) | C | 0-1.1 | 0-28 |
| Zn/Fe (Chloride) | B | 0-2.5 | 0-64 |
| Zn/Fe (Alkaline) | C | 0-1 | 0-25 |
| Zn/Fe (Alkaline) | B | 0-2 | 0-50 |
| Cd/Fe | C | 0-0.8 | 0-20 |
| Cd/Fe | B | 0-1.6 | 0-41 |
| Cu/Fe | C | 0-0.2 | 0-5 |
| Cu/Fe | B | 0-0.4 | 0-10 |
| Watt’s Ni/Fe | C | 0-0.5 | 0-13 |
| Watt’s Ni/Fe | B | 0-1.0 | 0-25 |
| Watt’s Ni/Fe | A | 0-2.0 | 0-50 |
| Brite Sn/Fe | C | 0-0.9 | 0-22 |
| Brite Sn/Fe | B | 0-2.0 | 0-50 |
| Cu/Non-Conductives | B | 0-0.6 | 0-15 |
| Cu/Non-Conductives | A | 0-2.0 | 0-50 |
| Non Conductives / Non-Magnetics | C | 0-33 | 0-840 |
| Non Conductives / Non-Magnetics | B | 0-40 | 0-1000 |
| Non Magnetic/Magnetic | ASP-3 | 0-32 | 0-810 |
Talk To An Expert
When you call UPA, you will speak with a real person who will direct you to a product or technical specialist to answer your questions, assist with your requirements or provide applications support.
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UPA Technology
8963 Cincinnati-Columbus Rd.
West Chester Ohio, 45069
Phone: 513-755-1380
Email: info@upa.com