# What Instrument Measures Flatness?

On the other hand, a coordinate measuring machine (CMM) measures the height, width, and depth of the part using coordinate processing technology. In addition, such machines can automatically measure the target, record the measured data, and obtain GD&T measurements.

## How can flatness be tested?

Flatness is can be measured using a height gauge run across the surface of the part if only the reference feature is held parallel. … This is a 3D measurement so points must be measured across the length and width of the part to ensure the entire surface is in tolerance.

## Can CMM measure angles?

Coordinate Measuring Machine (CMM)

are calculated from a set of detected coordinates, a coordinate measuring machine can precisely measure angles, positional relationships between elements, profile, and geometrical deviations, in addition to lengths of complex stereoscopic objects.

### How do you measure a chamfer angle?

If a chamfer is called out as a face width, then it is to be measured along the hypotenuse of the chamfer. To convert a leg length dimension to face width simply multiply the leg length value by 1.414. To convert from a face width dimension to a leg length dimension, reverse the process and divide by 1.414.

### How is flatness of steel plate measured?

Flatness is measured by placing a sheet on a horizontal flat surface and measuring the distance to the highest point of the sheet from the flat surface, then subtracting the material thickness.

### How do you manually measure flatness?

In application, one way to physically measure flatness is to use a height gage, as we can see in Figure 2. To use the height gage correctly, the part to be measured is first placed upon 3 columns with adjustable heights. Then, the height gage is run across the surface while looking at the amplitude of the needle.

### How is flatness and straightness measured?

Surface: Straightness can be considered the 2-Dimensional version of Flatness as both are measured without a datum and controls and refine the size of the feature. While flatness measures the variance across a 2D plane, Straightness only measures the variance on a straight line.

### How accurate is CMM?

For a CMM using a touch probe, this relates to the repeatability of the probe and the accuracy of the linear scales. Typical probe repeatability can result in measurements of within . 001mm or . 00005 inch (half a tenth) over the entire measurement volume.

### Can a CMM measure thickness?

Measurement of variation in thickness between inner ring raceway and bore . The thickness variation of large bearing elements can be measured using existing devices. Coordinate measurement machines (CMM) are able to determine the coordinates of any point reachable by the stylus of the machine.

### What precise movement does CMM?

What precise movement does CMM have? Explanation: Co-ordinate measuring machines are useful for three dimensional measurements. These machines have precise movements in x,y and z coordinates which can be easily measured and controlled. 2.

### How is flatness defined?

Flatness is a condition of a specified surface having all elements in one plane. Flatness tolerance provides a tolerance zone of specified and defined by two parallel planes in where the specified surface must lie. The flatness tolerance may be used to control the form of derived median plane. …

### How does an Autocollimator work?

An autocollimator works by projecting an image onto a target mirror and measuring the deflection of the returned image against a scale, either visually or by means of an electronic detector.

### How do you measure a flat surface?

There are a number of ways to measure the flatness of a surface. The most common method within the Flat Lapping sector is by using a Monochromatic Sodium light unit and an Optical Flat. This gives extremely precise measurements, more accurate than most CMM measurements, in an economical way.

### What is a reasonable flatness tolerance?

11/16″ 5/8″ FLATNESS TOLERANCE. The maximum deviation from a horizontal flat surface—the material is to be placed on a perfectly flat table. A ruler which does not flatten the material will give the degree of flatness.

### Does parallelism cover flatness?

Remember: Parallelism does not directly control the angle of the referenced surface; it controls the envelope (like flatness) where the surface needs to be. The goal is to ensure all points are within a specified tolerance distance away from their corresponding datum points.

### How do you measure flatness with optical flats?

The bands should be viewed from a distance at least 10 times the diameter of the optical flat and with the line of vision as nearly perpendicular to the flat as possible. If the bands are straight, parallel and evenly spaced, the surface is flat. If the bands are curved or are unevenly spaced, the surface is not flat.

### How is flat steel measured?

One way it is measured is by placing the sheet on a flat surface and determining the distance from the surface to the highest point of the sheet, then subtracting the thickness of the material. Some people may just measure from the flat surface to the point where the steel starts.

### What is the unit of flatness?

I-Units is an exacting quantitative flatness measurement. It is a dimensionless number that incorporates both the height (H) and peak to peak length (L, or P in the diagram below) of a repeating wave. For example: a sheet with a 1/16” high wave which repeats every 12” would have an I-Unit value of 6.7.

### How do you read a flatness gauge?

Place the gauge on the surface to be checked. Read the deviation from perfect flatness directly on the dial. The reading from the gauge can be used to predict the flatness of a part lapped on the plate by using the graph on the flatness gauge body.