There are two major differences between a polymer plate and a thin steel plate:
- Etching method.
- Printing Plates are etched by means of a UV exposure unit whereby a series of steps are taken to burn the image to the surface of the plate while exposing the surrounding area. Depending on the type of polymer (alcohol or water wash) the unhardened material will be washed away to leave a positive impression of the image.
- The Printing Plates process is similar however to get to the end result the steel must see an acid bath for the etching process.
- Production life.
- There are many different types of polymer plate materials and associated estimated production lives. This speaks to the importance of selection of a material that is cost-effective for the anticipated production run. There are plate materials that are rated anywhere from 10k – 15k impressions with higher end materials can provide an estimated 60k – 70k impressions.
- The thin steel plate material has been estimated in the 500k+ impression range for durability.
The above factors have bearing on the cost of the material. As you might imagine, the photosensitive polymers tend to be much cheaper, in particular on the lower end of the durability scale, while the thin steel plate’s durability tends to be a bit higher.
Thick steel plates are another option. Thick steel plates are usually about 10mm thick and rated for a production life of close to one million cycles.
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