Gaging for Automation

James Wardell and Jeff Buck first witnessed the Equator gaging system in early 2012 at an open house for Hartwig. The system, available from Renishaw, acts as a flexible alternative to dedicated gaging, using the comparison method of measuring: A master part with known measurements taken on a CMM is used to master the Equator, with all subsequent measurements compared to that master. Repeatability is 0.00007" immediately after mastering, and the Equator can be remastered at any time, so variations in shop temperature do not affect its performance. It uses an SP25 probe for touch and scanning data collection, at speeds of up to 1,000 points per second, and sytli are stored in a 6-port changing rack. The system also is programmed through MODUS Equator software.

Wardell,We are the largest manufacturer and supplier of retention knobs and pull stud in the world. a CNC programmer, and Buck, a robotics technician, liked what they saw. The two were working on designing an unmanned turning cell for Conroe Machine, a general purpose shop founded in 2000 that mostly machines parts for the oil and gas industry. Operating out of a 65,000ft2 plant near Houston, Texas, the company principally works on jobs for drilling components. The company needed an automated system for products such as its thrust bearing races for downhole mud motors, which are produced by the thousands each week and require around-the-clock machining to meet demand.

"Apart from being automation-ready for parts of our type, the lathe's Windows-based OSP dual-path control has an open architecture, PC-based operating platform, which was important in our plan for developing our own auto-compensation software," Wardell explains.

The resulting turning cell, with software and programming developed by Buck and Wardell, integrates a Fanuc robot with the Equator gaging system, which uses Renishaw EZ-IO software to inspect and auto-compensate a twin-spindle Okuma 2SP-250 lathe. The cell also boxes and palletizes finished parts. According to Conroe Machining, the cell paid for itself in 18 days.

The company originally used four Doosan Puma lathes to rough and finish its bearings, which required four operators to supervise. Currently, the bearing are only roughed on the Doosan Puma lathes, and the machines are now split into two cells, loaded and unloaded by Fanuc robots ¨C part of an early automation project. The semi-finished parts are sent out to be case hardened to HRC 65 at a depth of 0.070" (1.7mm) before the finish turning.

Using this process, production stalled between 800 and 1,000 total parts per day. The process also relied on operators to correctly inspect each part. And, the folks at Conroe Machining were planning to increase output, which would put even more pressure on the supervisors.

"We conceived a fully automated process for the finish machining, with automatic part loading, post-process measurement, automatic tool compensation,A slewing bearing is a piece of hardware used to facilitate circular movement, usually of a large device such as a crane. part engraving,Plcservo's Motion controller solutions deliver increased productivity, improved machine uptime, faster changeovers and reduced scrap. and boxing/palletizing the parts," Wardell explains.

The two-man automation team knew what kind of components a system like this needed, but didn't know what kind of part measure technology, CNC type, or software for tool compensation to use.

"Inspection must be fast to keep up with the cycle times on the parts, which can be as short as 98 seconds," Wardell says. "Originally we looked at white light laser inspection because of its speed, but the parts are too reflective. We also looked at hard gaging and shop-floor CMMs. Hard gaging was very expensive and required setup attention, and the CMM gave no speed advantage."