Surface roughness

 

1. Testing principle

 

There are always uneven surfaces on graphic overlays. Use the stylus (or probe) of the instrument to test the surface roughness Ra.

 

2. Test instruments and supplies

 

a. Testing instruments that meet the testing range and accuracy requirements are available. The instrument error is not greater than ±10%.

 

b. A little acetone and cotton swab wrapped with absorbent cotton at the end.

 

3. Specimens

 

Take three specimens each vertically and horizontally from the sample. The size shall be such that it can completely cover the small test plane matched with the instrument. The surface of the specimen must be clean and free of damage and wrinkles.

 

4. Test steps

 

Use a cotton swab dipped in acetone to clean the test surface of the instrument. Place the specimens on the test plane. They should be completely close to the plane without any bubbles. Read the six Ra values in the longitudinal and transverse directions of the three specimens.

 

5. Result

 

The surface roughness is expressed as the arithmetic mean of six Ra of three specimens.

 

Ergonomics

 

From an ergonomic point of view, graphic overlay is a control component. The design should not only conform to the user's physiological characteristics in terms of shape, size, position, and control force, but also meet his habits, aesthetics, and other psychological needs.

 

Membrane switches are display devices for most instruments, so they must have an effective combination of control and display functions, clear and unambiguous markings, and buttons that are very easy to operate. No one wants complex and troublesome things.

 

In general, there are a few points of the interface design and requirements of graphic overlay.

 

1. Interface aesthetics

 

The interface design is coordinated with the whole style of the entire graphic overlay. It conforms to people's aesthetic habits, reflects the industry characteristics and brand image.

 

2. Easy to learn

 

It conforms to our cognitive habits and cognitive characteristics, and can be quickly accepted when first used. It can adapt to the learning cognitive abilities of different ages, occupations, and educational levels.

 

3. Interface efficiency

 

In the process of interface operation, the operation steps can be reduced, and operation time can be saved, thereby improving the overall efficiency.

 

4. Fault tolerance

 

It prevents the user from making operational errors, that is, reminders and remediation after the error, thus effectively preventing the occurrence of some wrong messages and accidents.

 

The size of graphic overlay is not limited, but it should be too large. The number of keys is not limited. The more keys there are, the greater the advantage of it. The key body, key position, display window, indicator window and other positions should be arranged to facilitate operation, and comply with ergonomic relationships.

 

Function-intensive buttons should be divided into two or more control areas according to their functions. If you want to prevent accidental physical contact, you can put that special one out of the group. If some need to be mixed with discrete components, the hybrid arrangement is available.

 

For the color design, we must consider visual effects from the aspects of aesthetics and industrial hygiene. The color areas (color blocks), function keys or discrete components on the graphic overlay should be marked with words familiar to the user. The patterns you design by yourself should be concise and easy to remember.

 

Buttons and keys can be available in square, round, rectangular, oval, etc.. Considering the versatility of the mold, try to use flat (embossed keys for special ones), square and round keys. The round buttons should not be too small, nor should it exceed 40mm in diameter.