EquipmentGauging system measures motor bearing & parts

Conroe Machine is doing what most machine shops only dream of – hard turning a family of parts around the clock in an unmanned cell that operates a ‘self controlled' process. It integrates a FANUC robot with the Equator? gauging system, using Renishaw EZ-IO software to provide simple comprehensive communication functions, for 100% part inspection and auto-compensation of a twin-spindle Okuma 2SP-250 lathe. The cell also boxes and palletises finished parts. The company states that the turning cell paid for itself in 18 days.

The programmable Equator, with software and programming was developed by CNC Programmer James Wardell and Robotics Technician Jeff Buck.

The same automation team have gone on to create an unmanned part measurement/sorting cell for a customer, this time combining two Equators, a FANUC robot, a vision system and multiple lanes of low-profile conveyor. In both applications, the Equator demonstrates the value of programmable comparative inspection by quickly measuring a family of bearing races, doing it cost effectively, and without fixturing, or problems from a shop floor environment.

Conroe Machine is a relatively young company, founded by Murray ‘Tippy' Touchette in 2000, with the objective of producing parts with the best manufacturing technology available. The company grew rapidly to about 150 employees operating in a climate-controlled 65,000-square-foot (6000 square metres) plant. While it is a general-purpose shop, Conroe's location near Houston results in a high percentage of business from the oil and gas industry, principally for drilling components. One of the company's continuously running jobs for the industry is manufacture of thrust bearing races for downhole mud motors. These parts are produced by the thousands each week, around the clock.

Moving up the automation ladder
The bearings are currently roughed out on four Doosan Puma lathes that originally did both roughing and finishing, and were served by four operators. These machines are now split into two cells, loaded/unloaded by FANUC robots, doing only the roughing operation – these cells were among the shop's earlier automation projects. 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.

“Our production plateaued at 800-1000 parts per day with these two cells, so 400-500 per cell,” explains James Wardell. “We had a single operator loading the machines and inspecting the parts. However, you can rely on an operator to correctly inspect only so many parts with this kind of volume, and we needed even more output.”

Inspection methods
“For our next step up, we conceived a fully automated process for the finish machining, with automatic part loading, post-process measurement, automatic tool compensation, part engraving, and boxing/palletising the parts,” he adds. “We had pretty good ideas for the components of such a system, except for the part measurement technology, CNC type and software for tool compensation. Inspection must be fast to keep up with the cycle times on the parts, which can be as short as 98 seconds. Originally, we looked at white light laser inspection because of its speed, but the parts are too reflective. We also looked at hard gauging and shop-floor CMMs. Hard gauging was very expensive and required setup attention, and the CMM gave no speed advantage. While working with Renishaw on other projects, the regional manager, Sheila Schermerhorn, introduced us to the Equator as a possible solution.”

Process-control tools and software
Equator is a low-cost, flexible alternative to dedicated gauging. It uses the comparison method of measuring. A master part with known measurements taken on a CΠΑΙΔΙΚΑ ΠΑΠΟΥΤΣΙΑ