Robot-Loaded Breakaway Pedestal Gage For Machining Cells
The Challenge
With manufacturing cells serviced by a central robot becoming more common in factories, many of our customers have approached us with the following measurement challenge: develop a gaging system that will inspect the parts for a critical feature or two after the machining operation and keep the machining process under control at the same time.
The Solution
To address both issues of measurement and process control, we developed a robotically-loaded, post-process breakaway pedestal gage at Harley-Davidson which can be loaded by a robot or gantry. This gage can sustain the increased volumes that cells provide. The time it takes to measure a part is generally significantly faster than the machining process, allowing the robot to load the gage, measure the part, unload the part from the gage and deposit it accordingly, before the next part is cut in the machine tool. Further, the gage can provide compensation offsets to the machine to control the process as long as the machine can accept compensation inputs from a gage. We have designed and built breakaway pedestal gages in turning, grinding, and assembly cells, and in other processes where a robot or overhead gantry is used to handle parts. The parts produced have been gear blanks, transmission hubs, brake rotors and drums, and other parts that have an ID or OD as critical features.
The Sequence
In operation, the robot or gantry loads a part onto the pedestal gage. The robot controller provides an electronic signal that the grippers are free of the part. The gage controller checks that the breakaway feature of the gage has not collapsed (it collapses if it detects a part has an unmachined ID or OD), and then initiates the gage amplifier, a CAGQCM, to measure the part. The measurement status is displayed and the results provided to the robot controller. This signal triggers the robot to remove the part from the gage and sort it accordingly. If compensation is necessary, the CAGQCM sends the offset signals to the machine tool. This all takes place in a matter of seconds. If by chance the breakaway feature is triggered and collapses, the gage sends an immediate signal to the robot to stop the loading process immediately and retract, indicating an un-machined part or some other event requires operator attention.
The Result
This entire sequence is very fast. Measuring 600 gear blanks an hour, for example, is typical. The gaging results are displayed as bar graphs, digital values, histograms or with control charts, such as X-bar and range or scatter charts. A part counter and time clock organize the results of the measurement cycles with a “Gage Data File” for a time date stamped recording of the results. Retrieval of the measurement data is easy with the Ethernet port, LPT port, or RS-232 ports. We also include a remote “zip” drive for retrieval and transportation of the data to remote locations.
Most importantly, our customers who have incorporated this gage into their operations experience increased production volume, less scrap, increased tool life, and increased labor efficiency, which are all significant benefits to the production process.
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