How to resolve the height difference between metal and plastic dots?

The raised dots on metal and plastic surfaces are made in different ways, and this often leads to problems with differences in height.By analyzing the characteristics of materials, processing techniques, and tactile optimization schemes, we can provide practical solutions that meet the standards for the height of Braille dots, helping to resolve the problem of tactile recognition of Braille on metal and plastic. This will ensure the effectiveness of the barrier-free facilities.

Why are the heights of the dots different in metal and plastic braille?

We all know that the properties of metals and plastics are completely different when they are being processed.Metal is hard, and it is easy to leave sharp edges when it is stamped or carved. The height of the finished product depends on the precision of the mold. Plastic is softer, and it can shrink when it is molded, so that the final height is less than the design height.This difference in feel "drastically reduces the value" of the dots in Braille. When two different textures are used, the user feels the bumps as "sometimes high, sometimes low.

Three steps to solve height disparity.

Choosing the right processing techniques is the key.

He suggests using a laser to engrave metal, as this allows one to precisely control the 0.5-0.7 mm height of the characters, and also gives them rounded edges.With plastics, you have to calculate the shrinkage rate. For example, with ABS plastic, you have to leave an extra 0.15 mm of material, which will then shrink into place when the piece cools.

You can't be lazy in post-production.

When the braille dots are completed, remember to use a sandblaster or polishing wheel to smooth out the edges.Plastic components require two rounds of baking to set the shape, especially in areas with large temperature fluctuations, to prevent the plastic from becoming brittle in the winter and soft in the summer, which would cause deformation.

The most reliable test is in the field.

Instead of just looking at the data, they asked visually impaired users to actually touch the screen and recorded their feedback.For example, when a certain subway station was renovated, it was discovered that although the stainless steel Braille characters were up to standard, their surface was too smooth. Later, a fine sandblasted texture was added, and the recognition rate rose by 30 %.

What about mixed materials?

In some cases, such as outdoor signs, metal and plastic are mixed together (metal for the support structure and plastic for the sign). In such cases, it is suggested that the two materials be brought to a common height, then "differentially compensated.For example, the plastic part is intentionally made 0.1 millimeter higher; in actual use, wear and tear brings it closer to the height of the metal.The frequency of regular maintenance checks must also be increased. In the rainy season, they should be carried out once a month, while in the dry season they may be extended to every three months.

Answers to users 'most common questions.

Many people ask, "Why not just use metal?In fact, it depends on the situation. For indoor locations like hospitals and libraries, plastic is more appropriate, because it won't chill your hands in winter. For outdoor bus stops, metal is more durable, but remember to treat it to prevent slipping.I suggested using metal for the key positions, and special engineering plastics for areas that are frequently touched. This is the most cost-effective solution.