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# Surface pressure

The difference between pressure, load, and linear pressure, how to calculate, and how to make them uniform

## What is surface pressure?

### What is surface pressure?

Surface pressure is the load per unit area.

For example, in the automotive industry, the contact of brake pads on disc brakes can be checked by measuring the surface pressure.

In the semiconductor industry, the contact distribution of the polishing head can be checked by measuring the surface pressure to maintain polishing quality.

### How to calculate surface pressure and its formula

Surface pressure is calculated by force divided by area, expressed in [MPa] or [N/m2].
To measure surface pressure, [force] and [area] are required.
Force is expressed in various elements such as weight (kgf), weight (kg), and load (N).
Area refers to the area of the part in contact.

#### Formula

Weight (kgf) / Area (cm2) = Pressure (MPa)

### Difference between surface pressure and pressure

Pressure is a force acting perpendicularly to a unit area.
There are various types of pressure, such as surface pressure, water pressure, and atmospheric pressure.

Surface pressure is one of the pressures, and the pressure calculated by the area receiving the load (pressure-sensitive area) is the surface pressure.

### Difference between surface pressure and load or force

Surface pressure refers to the force per unit area, while load simply refers to the force itself.

### Difference between load, linear pressure, and surface pressure

Magnitude of force applied to an object (regardless of contact area or shape)

Linear pressure

The magnitude of the linear force applied to the object (the contact area is the total load applied to the contacting cylinder times the effective axial length of the cylinder)

Surface pressure

Magnitude of force or pressure on a surface applied to an object (varies with contact area and shape)

## How to keep the surface pressure uniform?

### Surface Pressure and Prescale

Surface pressure must be checked to ensure that a uniform pressure is being applied to a surface.
If pressure values are not controlled at the surface, it is impossible to determine the inclination of the equipment or the overall trend, which may lead to product defects.

This is where the pressure measurement film "Prescale" comes in.

### What is pressure measurement film “Prescale”

Prescale, sometimes called as “pressure indicating film”, “pressure inspecting film” or “pressure paper”, is a film that enables visualization and quantification of pressure on a surface.
Surface pressure can be easily measured simply by inserting the film between the desired areas.