Testing of Machines
Testing of Machines
the experimental determination of design and operational properties of machines either to ascertain whether they meet technical requirements or to study the actual processes that take place in machines.
The testing of machines differs considerably in procedure, purpose, nature, and even terminology in different branches of machine building. Tests are made in laboratories or factories and while the machine is in operation (industrial, military), on the road, in water, or in flight. The purpose of the trial determines whether acceptance tests, check tests, or research tests are made. All branches of machine building test models or full-scale machines of new designs and random samples from assembly lines; they also test machines to continue research.
New designs are tested to determine the basic qualities of machines before they are put in production. Tests are done both in laboratories and under operating conditions. Laboratory (or factory) trials of machines, including the testing of individual units and assemblies, are done in plants with specially equipped facilities. The operational or industrial testing of new designs can be done on special areas, roads, or test grounds that duplicate production conditions or directly at a work site.
Industrial testing determines the productivity of machines under various working conditions and their efficiency, acting forces, speed, and acceleration; establishes the reliability and durability of a machine and its components; studies the starting properties, maneuverability, and thermal regimen; and rates the economic feasibility of introducing the machine. In some cases machines are tested under emergency conditions—for example, by clogging the working mechanism of a mining cutter-loader. The laboratory reports of the results are used to decide whether a machine can be put into production or whether it needs further development.
Machines produced on an assembly line are spot-checked for quality and correct assembly and to see whether they meet technical specifications.
Research testing of machines makes it possible to study the influence of various factors that were difficult to foresee, to confirm theoretical hypotheses by experiment, and to gather experimental data for further improvements.
The volume and duration of various machine tests, the number of measured parameters, and the methods of determining and checking proper parameters are set forth in advance. Special methods for resolving specific problems are employed in testing various types of machines. In motor vehicles, for example, tests are made of dynamic and traction properties (the time and distance for acceleration, maximum speed, traction, and braking efforts), fuel consumption, performance on rough roads, ease of operation, and stability. Transmission mechanisms, axles, suspensions, frames, bodies, controls, and brakes are tested for durability and sturdiness.
Electrical equipment is tested for electromagnetic, thermal, aerodynamic, mechanical, and dielectric properties. Metal-cutting machine tools are tested for precision of working parts, ease of control, smoothness, and stress in the feed mechanisms and in reverse. The power of the tool spindle and the productivity of mechanical components are measured. Special attention is given to tests for reliability.
An integral part of design and research to create new machinery, the testing of machines gains ever-increasing importance as a means of improving the quality of new machines and reducing the time needed to make them operational.
A. A. PARKHOMENKO