3D Bas-Relief Medals
What are 3D medals?
3D (3 Dimensional, 3D Relief or bas-relief) medals are medals with bas-relief carvings. Bas-relief is a kind of sculpture in which shapes are carved so that they are only slightly higher than the flat background and no part of the modeled form is undercut. The projecting image in bas-relief sculptures has a shallow overall depth (1 to 5 scale), as on coins, on which all images are in low relief. In the lowest reliefs the relative depth of the elements shown is completely distorted, and if seen from the side the image makes no sense, but from the front the small variations in depth register as a three-dimensional image. More about bas-relief here.
Your unique vision of how your medal will look like is expressed by our graphic designers. A detailed design reflecting the central theme of your message is further developed from rough hand sketches using graphic software applications. A sculptor uses these designs to produce a first enlarged (3 times the size of the end product) model sculpt in clay using fine cutting and grating tools (view a video about sculpting a bas-relief here). Alternatively, a virtual model can be created using CAD/CAM software. A combination of both techniques, sculpting and utilizing CAD/CAM software, is especially used for human faces. First the sculptor uses conventional tools to produce a bas-relief model, then a CAD/CAM specialist uses a digital 3D scanner to capture the sculpted model and transform it into a 3D virtual model. The 3D model can be edited (manipulated digitally) e.g. scaled up or down or enhanced etc.
The Stamping Die
To stamp an impression on medals you need a steel stamping die. Different methods can be used to produce steel stamping dies.
Classical method for producing a stamping die
Classically, a bas-relief (3D) clay model created by the sculptor will be cast in brass then copied and reduced to the proper size onto a steel die using a manual pantograph or an automatic special 3D reducing machine called Janvier’s Pantograph or Medallion Lathe. After engraving the impression on the steel die, the die is hardened to make it ready for stamping medals. Mr. Mohammed Toufic Absi was the first to introduce a Janvier’s Pantograph to Lebanon and to use it in the early seventies.
Mr. Mohammed Taufic Absi Method
Mr. Mohammed Taufic Absi pioneered a new approach to produce stamping dies. Instead of using the Janvier’s Pantograph to engrave the steel die, he used it to engrave a copper plate, a metal softer than steel and a good conductor that offers a high resistivity to electric erosion, which in turn is used as an anode (or Medal “Master”) in a spark erosion machine known as Electric Discharge Machine (EDM) to transfer the impression onto a steel die (or “Workpiece”).
This approach proved to be not only faster in producing detailed engravings, but it has also enabled Mr. Absi to recycle hardened stamping dies when the impression engraved on their surface was of no further use. Clearly, hardened steel dies are not suitable for engraving by the Janvier’s Pantograph due to the hardness they acquire through the hardening process. The surface of a steel die is cleared from any impression using a surface grinding machine, and a new impression is engraved on its surface using the EDM machine and the copper plate engraved with the Janvier’s Pantograph.
Finishing the Stamping Die
The die goes through several procedures before it can be used for stamping or coining. It may need to be turned off to be accommodated in the minting collar and minting press. The die is heat-treated to harden it. The exact optimum degree of hardness must be achieved in order to avoid cracking the die under strong pressure while striking. The die surface may need to be smoothed in case a proof-like medal is to be stamped.
Stamping Dies for Proof-Like Medals
The impressions (the raised areas or the relief) of proof-like medals are frosted and their backgrounds (medal field) are shiny or brilliant (mirror-like) with minor imperfections. The surface of stamping dies used to stamp proof-like medals must be processed in such a way it is highly polished; also the blanks used for minting must be polished.
Sample Images of Stamping Dies
Sample Images of Bas-Relief Medals
Production of 3D bas-relief medals involves art and technology. Though the process can be time consuming and relatively expensive, the 3D bas-relief medals always stands as an aesthetically appealing product.
So, if you are ahead of time, not so tight on budget, and you require medals in large quantities then this might be the option that you are looking for.