Before going into detail we must be clear what is hydrographic printing? It’s the process of applying decorative finishes to 3D products. Any hard, non-porous surface that can be submerged into water can be decorated. A reference used in this process is that if the normal paint adheres to the material you can apply the hydrographic process. The most commonly used materials are: plastic, glass, hard woods, fiberglass, ceramics and metal.
In the printing world this can be a little known process and therefore not many people use it. There is not much information about the history of this printing process, we only know that the first registered hydrographic device for a US patent UU was made by Motoyasu Nakanishi of Kabushiki Kaisha Cubic Engineering on July 26, 1982.
Hydrographic process is used to decorate items ranging from complete all-terrain vehicles and automotive dashboards to small items such as bicycle helmets or other car trims.
The process uses a water-soluble film that contains complex patterns printed with ink. The film dissolves in the water and leaves the ink on the surface. Something that I found interesting about this process is that in a normal process the object we want to paint is first covered with a glue base or adhesion that serves as a basis for the process.
The question that we all ask
Before telling you a bit about this process, we will try to answer a question that we all surely had when we heard about this printing process and that is: How long does the print on the objects last?
Throughout my experience in the world of printing and as surely many of you, we know that according to the type of project, place, materials or operation today we have a wide variety of materials, inks and printers that can help us in our process. If we need material for the experiment we have inks that are resistant to the sun, rain, gases, smoke, etc. This type of printing is commonly used in parts for cars, either mechanical or for decoration, helmets, glasses, wood, metals, weapons, etc. So, I ask you a question … What do these kinds of pieces have in common? That they are exposed to the elements at all times. The first impression I get is that manufacturers must offer materials and inks and processes that are resistant to anything or as we commonly say ” all-terrain materials ” because, imagine … we will not want our carbon fiber textured rings damaged in the first round.
Answering the initial question, if we perform the whole process correctly and add the correct coating, it can last a long time.
What do I need if I want to do Hydrographics?
Depending on the type of business in the market there are equipment and materials to do it at home or with specialized machinery. Some of the elements are:
- The first thing we need is a place to trained on the subject, since there are some basic concepts that we cannot ignore.
- Water transfer printing film.
- Activator, it is a product that goes hand in hand with the ink and helps it adhere to the surface.
- A manual sanding device.
- A spray gun and air compressor.
- A selected base coat, and a transparent acrylic paint.
- A water transfer printing system. It will depend on the workflow, the type of system that we will need for the business, from a conventional one of some plastic material and manual system to one of stainless steel and automated systems.
A quick guide to the process
- Film Selection: An important point of this process is that most of the designs that are used are patterns so that when adhering to a surface the design is not damaged.
- Base Coat: A base color layer is applied to the objects that are being processed. The distributors of materials offer us a guide for these colors since depending on the design; the base coat can make a big difference.
- Film Transfer Preparation: The hydrographic film is placed on the surface of the water in the immersion tank. The material dissolves, leaving only the pattern floating in the water. The combination of chemicals and water will allow the pattern to curve around any surface.
- Activation: The floating image is sprayed with a special activator that dissolves the components in the pattern’s colors without affecting its structure and appearance.
- Transfer: The element is immersed in the water through the floating layer. The pressure of the water will cause the pattern to adapt around the object in all places and adhere to it.
- Washing & Drying: The printed parts are washed to remove any residue from the printing film and allowed to dry. Printed objects can be coated transparently to protect the surface and provide a shiny appearance.
Answering our initial question, it is a transfer printing process. That gives us the opportunity to decorate our pieces in an easier and long-lasting way.