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In 1988, a small company began developing and supplying electronic instruments that automatically and in real time compensate for temperature induced errors in industrial gauges that are used to make precision dimensional measurements. Today, its products are in use world-wide, benefitting factories and workshops that machine metal parts to tight tolerances.

ISO 1, the first standard issued by International Organization for Standardization (ISO), specifies the standard reference temperature for geometrical product specification and verification, which is fixed at 20 °C, (68 °F). This temperature can be difficult to maintain in a manufacturing environment and all the "elements" of a measuring system (workpiece, master and gauge fixture) can be affected by thermal influences.

When certain parts are measured after precision machining or cleaning operations, or after otherwise being exposed to temperatures other than the reference temperature, 20 °C/68 °F, their dimensions can be significantly altered by thermal expansion or contraction. Gauge fixtures and masters may also not be at reference temperature. The result will be that erroneous measurements will be taken unless this is taken into consideration. Normalization to 20 °C/68 °F before measurement can take precious time. The quickest and most economic option is to compensate for those errors in real time while taking measurements.

Albion Devices, Inc. has successfully delivered and maintained literally thousands of "3 element" temperature compensation systems. They are used in gauges to determine true size at reference temperature of machined components, such as automotive pistons and pins, crank shaft journals, engine and transmission bores, railroad axle journals, bearing rings, differential carrier parts, large forged parts such as marine gears and shafts, turbine journals, etc.

Obtaining the best results from an electronic temperature compensation system requires several inputs. Coefficients of Expansion (COE) of workpiece, master and gauge fixture or frame (elements) are user-programmed into the controller, along with relevant dimensional data relating to the workpiece. Live temperatures of each of the elements are collected from purpose-designed industrial sensors and transmitted to a micro-controller during operation.

The controller computes a net correction for thermal errors in real time. This solution is then added to or subtracted from the gauged dimension so as to arrive at the temperature corrected size of the workpiece.

The COE of master and workpiece can be reasonably estimated from published materials. For any given part, subject to its geometry, net effect COEs may not always be empirically identical to the referenced publication and can be modified if necessary by testing in the gauging system. It can be more difficult to estimate the effective net COE of gauge fixtures or frames because they are often made of several components involving different materials, and/or each piece may adversely interact mechanically with its neighbor and fasteners as temperatures change. Again, testing in the gauge can result in determining an acceptable COE value.

"By simultaneously compensating for thermal effects in the elements of a measuring system in real time, it has been possible to eliminate 95% or more of thermal error in dimensional measuring systems on the shop floor," said a company spokesperson. "The result is that displayed measurements reflect the predicted dimension of a measured part at 20 °C/68 °F to within a few percentage points. The benefits of this in mass and precision production are experienced in improved quality control, reduced scrap and rework, improved process control, reduced warranty costs and increased customer satisfaction. Invariably, users have become repeat buyers and have experienced rapid pay-back of their investment."

For more information contact:

Albion Devices, Inc.

5320 Lena Road

Bradenton, FL 34211

760-814-0511