The Best Way to Scan Coin Reliefs for Minting Perfect Coins


The accuracy of a coin is completely dependent on how well the reliefs or molds are created.

If this isn’t done just right, you risk:

  • Poor quality coins
  • Coins that are not all identical
  • Enabling counterfeiting

Clearly official mints are under a lot of pressure to create measured and traceable mints.

Measuring Coins and Minting Reliefs

Here’s how to they turn a coin relief into digital data.

  1. A 10x scaled version of the coin is created in plaster mold
  2. The relief (and coin made from it) is measured by a laser distance sensor, such as Optimet’s ConoPoint-10 sensor

Okay, that doesn’t sound so hard, does it?


Unfortunately, this isn’t quite so simple.  There are a number of things that make plaster reliefs particularly difficult to measure:

  1. Plaster is translucent which causes the laser to partially penetrate the relief, causing beam spreading.  This leads to a much higher level of noise than usual.
  2. Plaster is delicate and can’t be measured with touch sensors.
  3. Due to the nature of the application, very high precision (2-3 μm) is necessary.
  4. Depending on the coin design, there are often parts which have sharp angles that cannot be measured with standard triangulation sensors.

One Solution

But I won’t leave you hanging.  There’s a way to solve all these problems in one go.
It’s called ConoPoint-10.

Here’s how each of the above can be addressed by just using the Optimet ConoPoint-10 sensor:

  1. Unique polarization scanning technique was created in order toimprove the signal to noise ratio when scanning translucent materials.
  2. Optimet’s sensors use laser technology and don’t come into any contact with the object being measured.
  3. Depending on the lens uses, ConoPoint-10 has sub-micron level precision.
  4. Optimet’s unique collinear technology allows measurement of sharp angles and deep holes without a problem.

Contact us for more information on your particular application challenge.

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