Industrial Engineering Department Islamic University of Gaza Faculty of Engineering Industrial Engineering Department Coordinate Measuring Machine Prepared by Shaima'a A. EL Najjar Juleat S. EL shami Jumana J. Aldaghma Jehad R. Abu reda 23, May, 2010

What IS CMM?!

CMM . A coordinate measuring machine (CMM): is a device for measuring the physical geometrical -such as point, line, plane, circle, arc, ellipse, cylinder, cone and sphere- characteristics of an object. Coordinate measuring machines (CMMs) are mechanical systems designed to move a measuring probe to determine the coordinates of points on a work piece surface. This machine may be manually controlled by an operator or it may be computer controlled. Probes may be mechanical, optical, laser, or white light, among others.

CMM Development

The first CMM was developed by the Ferranti Company of Scotland in the 1950s as the result of a direct need to measure precision components in their military products. although this machine only had 2 axes.

The first 3-axis models began appearing in the 1960s (DEA of Italy) and computer control debuted in the early 1970s.

Description To CMM The typical "bridge" CMM is composed of three axes, an X, Y and Z. These axes are orthogonal to each other in a typical three dimensional coordinate system. The machine will read the input from the touch probe, as directed by the operator or programmer. The machine then uses the X,Y,Z coordinates of each of these points to determine size and position.

Parts Of CMM

Coordinate-measuring machines include three main components: The main structure which include three axes of motion. Data collection and Reduction system - typically includes a machine controller, desktop computer and application software.

3.Probing system. Probes may be mechanical, optical, laser, or white light, among others. Precision sensors for fast, accurate acquisition of component dimensions and surface data.

Applications

Common applications for coordinate measuring machines include: Dimensional measurement, Profile measurement, Orientation, Depth mapping, Digitizing or Imaging, Shaft measurement.

How to use it? It uses the probe to indicate the first point of the dimension then by moving the arm of machine to put probe on the other point it calculates the coordinates’ shifting which known by actuators and scale, and that calculated by computer system inside. By knowing all dimensions it can calculated the size, shaft .. etc.

Finally ..

A Coordinate Measuring Machine (CMM) is an instrument that locates point coordinates on three dimensional structures mainly used for quality control applications. The highly sensitive machine measures parts down to the fraction of an inch and must be properly maintained and protected to ensure accurate measurements. Specifically, a CMM contains many highly sensitive air bearings on which the measuring arm floats.