The faucet has been opened a little, and you've just received a long-awaited contract to produce 10,000 large trunnion caps for a manufacturer of earth moving equipment. Despite the joy, you realize that you have a problem: The machines will be in place and ready to run the part shortly, but you haven't given much thought to the gaging.
Manual gaging is not going to cut it, because the process is too slow. An operator-introduced variation may be too large for the tolerance, and there are too many parts to inspect over a relatively short period of time. On the other hand, the size of the job just won't justify the expense of a fully automatic gage.
There is something in between that can solve the problem: a semi-automatic gage—one that makes multiple checks, classifies the part, and can mark or stamp it for identification. These are frequently manually loaded and unloaded, but they can also incorporate a disposal system.
In certain applications, these features offer the user a number of distinct advantages. Since part of the gaging cycle is automatic, semi-automatic gages are much faster than completely manual, individual gages. And, when manually loaded, they can handle workpieces that may be difficult and costly to feed or orient manually. Manual loading of the part also permits visual inspection for scratches, discoloration and unclean finishes prior to the gaging process.
Semi-automatic gages will check a relatively large volume of parts quickly and accurately, enabling the inspector to keep up with production by taking over the gaging function. Many manually loaded gages can be operated at speeds close to one part per second. Disposal is automatic, eliminating operator interpretation or sorting errors. Most semi-automatic gages are controlled by a small gaging computer that takes over the complete gaging function-positioning gage heads, moving the part, collecting data, marking the part, and disposing of it in the correct class. Operator fatigue and misclassification can be a big problem when handling many parts. Since the semi-automatic gage is tireless and consistent in its decision-making, many of the operator-influenced problems go away.
Today there are many choices in semi-automatic gages, and design time is not as long as is sometimes perceived. A semi-automatic, built with off-the-shelf gaging components and supplemented with motion control and gaging computers, can be designed quickly and delivered ready to meet its gaging challenge.
Now if we could only get it to put the parts in boxes and deliver them to . . . .
Editor PickNon-Contact Vision Probe for Multi-Sensor System
RVP, Renishaw's vision measurement probe, is designed for use with the Revo five-axis measurement system on coordinate measuring machines (CMMs).