These discussions and information change between braille experts took place during the EBU Braille Workgroup meeting in september 2022 in Madrid. Each discussion lasted one hour. This article represents the notes of the discussion with useful information and resources gathered during the meeting.
Moderator: Michal Tkáčik
In this part of panel discussion we will talk about several materials and techniques of the braille production.
Materials:
Materials for matrix (mold) creation:
- Resin (spanish resina), which is more suitable for pictures with a different hights of the relief being created.
- corian®, something we use in the kitchen as serving plates or against the heat as well. It works perfectly for the braille and flatter surfaces. It can be used also for higher relief, but it serves best for flat surfaces. For both materials, Resin and Corian the same CNC can be used, with different drilling heads. For flat surface, such as political map, with relieves not so high and without so many different hights, In Germany, the corean reliefs are used even for outside use, and usually hold at least for 10 years.
Materials of tactile graphics production: different materials can be used for mold-to-plastic production. - One example is PVC material, recently it is more ecological to use PET material (such as for PET bottles). PET tends to be less flexible than PVC, but it feels more durable and in-takes less static electricity.
- Kroma Cardboard: hardened paper, it is cardboard pressed and hardened, with kroma overlay. It has a feeling as wood, but is paper actually. It can hold braille print with UV. But it is also possible to laser-cut the cardboard. It tends to be less expensive than plastic PET or PVC.
- SYNAPS Synthetic Paper: Synaps Offset Matt (OM) is the versatile synthetic sheet that prints, handles and finishes just like paper. Can be used for UV printing.
Machines and mold creation:
- CNC routers, milling machines, laser cutters,
(Note: example of Scanning software for CNC: https://www.scan2cad.com/blog/tips/how-to-convert-an-image-for-cnc/ )
To create the matrix (mold) with CNC is very laborious not only for converting the picture in the vectors and preparing it for CNC software, but also to cut the relief takes several hours, days or even week. The mold made by CNC is though very durable and long-lasting. It is possible to make hundreds of copies of this mold with Vacuum thermoforming machine. - The 3D printing: 3D printing can be used for mold creation, but also for accessible models of 3D objects, beginning with maps, orientation plans, models of the buildings, monuments, city centres and so on.
- Vacuum thermoforming machines: Used to emboss the mold relief into the plastic sheet/plate/foil. There are different Vacuum thermoforming machines, some able to create relief in hight of few centimetres, some tens of centimetres, even meter and more. These machines are used in standard market for packaging production.
- UV printing: possible to print tactile surface, braille and pictures as well. It is important to choose good UV ink for printing, according to the material we want to print on. For example, PVC is not working well with UV printing. Sometimes is needed to use special material for UV-ink to hold on the PVC. Better is to USE PET materials for UV printing.
- Standard Colour Plotter Printers: They are used for printing the colour picture on the plastic sheet, to achieve a picture of relief + colour surface. It is though necessary to find the right mix of colours and colour types which will stand the heat of the Vacuum thermoforming.
Map or picture production
Maps can be created by different machines, CNC drill machines to create the mold, ink-print plotters and Vacuum thermoforming machine.
In Spain, official special maps are usually created in SBO after being approved by the Braille Authority of Spain (Spanish braille commission).
Mold creation: coding the picture in the computer, usually design created in Corel Draw, then forming it with CNC drill machine or similar machine for mold production and related software. Deciding of the material for the mold, resin or Corian, depending on the final product and its relief hights.
Colouring the map: It is very difficult to match the colour picture and the relief. First the material to be printed on has to be run through the plotter wit ink-print picture with colours. Only then it is possible to use Vacuum thermoforming machine to emboss the mold picture into the plastic PET material. To match the colour of the picture in a way, it will not destroy or discolour and mix after embossing the mold, is the most difficult task. Usually in the mold, there are special points for colour matching. It is a position of two square marks, to help in this colour matching process. The colours has to be very precisely chosen to withstand the heat of thermoforming. In &ONCE maps are not printed with foto quality, but rather flat coloured areas of the picture for better eye distinction.
Thermoforming: Embossing the mold into a plastic sheet – PVC, or nowadays better PET sheet/plate, is a process of using the Vacuum thermoforming machine. There are several possibilities of thermoforming machines. For example Formech machines. Depending on the mold relief, we have to choose appropriate thick PET sheet/plate. For standard maps or picture 300 micro metre plate should be used. For flat pictures with lower relief, 200 micrometres.
(Note:)
We were able to touch and explore:
- a colourful tactile + braille map of Spain. Rivers made by distinct lines, different surfaces created by the relief of different structure;
- a political map of Europe with flatter surface but with different colours distinguishing states and creating boarders;
- astic picture of 3D car with height of 15-20 cm, created with new thermoforming machine.
- education materials: pictures of skeleton, with a low, flat surface relief (there can be different education materials like this, such as architectures, historical content, phonetic symbols in relief and so on );
- different materials – PET sheet, resin mold, corian mold,
- a sheet of 5 different techniques for tactile pictures: 3D print, standard thermoforming, braille graphics (actually dots shaping the picture on paper), swell-paper, UV printing
Closing thought:
We had seen many materials and techniques. The ideal thing is to use all techniques together depending on the need of the specific, special product we are creating. For example books combining all the possible techniques and materials depending on the picture, what it needs to be precise and understandable for reading.
When we speak about braille and tactile production, at the end, what mostly differs country to country, is number of people working in this area. Machines can be bought more or less expensive, but real breakpoint is the number of people we can employ, teach and train to become braille and tactile graphics technicians. And this human resources is in fact the most expensive cost in this area.