Nadcap announces new Task Group for Conventional Machining

[Sorin]

Email received yesterday...everyone should be ready for customer requests in regards to Nadcap approved suppliers for conventional machining.

In response to feedback from customers including Avio, Eurocopter, GE Aviation, Goodrich Corp., Honeywell Aerospace, Israel Aerospace Industries, Lockheed Martin, Messier-Dowty, Pratt & Whitney, Raytheon Co., Rockwell Collins, Rolls-Royce Corp., Rolls-Royce plc, Snecma, Spirit AeroSystems, Volvo Aero and 309th Maintenance Wing-Hill AFB, Nadcap has launched a new Task Group for Conventional Machining.

The audits will cover a variety of hole making processes, broaching, turning, milling, grinding and edge treatment (such as hand benching, mass finishing and automated processes).

John Pfeiffer of GE Aviation is the Chair of this new Task Group and explains: "Many major aerospace companies, including GE, have internal systems to qualify and audit suppliers performing critical conventional machining processes. It makes sense to utilize the infrastructure of PRI - which already administers many process accreditations through Nadcap - to identify common industry requirements that can be audited through one series of checklists, assuring compliance while saving both the Primes and Suppliers time and money."

Following more than a year spent in checklist development and four pilot audits to validate the checklists, the Conventional Machining Task Group was approved by the Nadcap Management Council at the February 2010 Nadcap meeting in Rome, Italy.

Arshad Hafeez, Executive Director of Global Business Operations at PRI welcomes this development: "By adding a new Task Group to the fourteen already in operation, aerospace quality experts are further demonstrating their trust in the Nadcap program to delivery timely, accurate and cost-effective accreditations throughout the global industry as part of PRI's Customer Solutions & Support (CS&S) mandate."

 

[alspread]

I heard that this was in the works a couple of years ago. Expanding on GE's controlled holemaking and controlled broaching/splining specifications.

It will be interesting to see how this plays out. These processes are typically reserved for high stress parts and/or rotating parts (shafts, rotating seals, spools, etc.).
The processes will be invoked at a part number level, they are not optional, and like other special processes, require strict adherence to the manufacturing parameter sheet requirements and practices.

It will be particularly difficult to practically control many of the hand benching processes now employed on many of these parts.

It will be interesting to see this mature and I'd like to be a part of it if I can.

Good luck

 

[bobdoering]

It would be a good start if they used correct SPC for precision machining - X hi/lo-R charting - until then they are never really going to reach their goal of understanding and controlling the machining processes. It would make the whole process a lot easier, too.

 

[alspread]

i don't know if you are familair with their interpretation of controlled holemaking and that the concern is for high stress being inflicted on the parts during machining.

The concern is about how much stress the part sees during machining and not the physical size or shape of the feature. The size and shape can be measured for conformance, but the amount of stress exerted on the surface of the part due to a dull tool, or a process designed to take too much stock in a particular material type cannot be measured for conformance. It can only be controlled by analyzing the effects on a sample and applying those parameters to the process.

I apologize if you were already aware of these requirements.

 

[bobdoering]

I was not aware of these requirements, however, utilizing X hi/lo-R charting methodology provides the most direct feedback on tool pressure and dullness by the R chart data analysis (ID or OD). It is the most meaningful predictor for the need for change from tool wear. The technique is ideal for circular characteristics, although also suitable for lengths. X-bar -R, I-MR or X trend-R -most commonly and incorrectly used for machining will not provide that information. So, being the most commonly used, SPC is dismissed as a resource of information - but it should only be incorrect SPC should be dismissed!

It is not just about the size or shape....it is process control.