CNC Machines Improve Quality and Efficiency

Contract aerospace manufacturing is a very competitive business. Being and remaining competitive requires investments in state-of-the-art machine tools, continuous system software upgrades, ongoing staff training and improvement initiatives. Combining modern CNC machines that improve product quality and increase efficiency, with focused strategic planning, addresses two critical elements necessary for sustaining and growing a successful CNC contract machining business.

Other considerations in a strategic plan are having a thorough  knowledge and understanding of accuracy requirements, process repeatability, production volumes,  scheduling stability, quality control and documentation support, all vital to a successful contract manufacturing business.

CNC Machine Basic Applications

Computer Numerical Control (CNC) machines are offered in many different configurations and work envelope sizes. There are various machine types, the most common are lathes for turning round parts, mills (both horizontal & vertical) for milling prismatic parts, and combination machines (turn/mills), that can do both. The most recent machine type, can machine up to 5 axis simultaneous on a single spindle, and up to 7-9-11-13 axes depending on the number of spindles and turrets.

As computer and servo technology has advanced so have the accuracies and repeatability of CNC machines. The early versions of CNC machines performed basic machining two and three axis operations (turning, milling, drilling tapping, etc.). The most recent generations of CNC machines have  expanded control and axes capability functions and added in-process gaging, post process gaging and automation, resulting in fewer setups, higher throughput, less operator intervention, and greater overall efficiencies.

Relationship of CNC to CAD/CAM

CNC part programs are often generated offline in a CAD (Computer Aided Design) program. The CAD information is then translated for machine useage into CAM (Computer Aided Machine) language. The program is then loaded into the machine CNC controller. This CAM generated program contains machining  instructions using a machine G code & M code format.  Machine movements (slide and spindle speeds) are achieved through sending G&M code instructions to the spindle motors and slide servos, which control spindle speeds and slide movements. All instructions are looped back to the controller, for confirmation. This programming loop confirms  instructions are received and confirmed to the correct slide position and spindle feeds and speeds. The latest generations of CNC machines with advanced servo and software feedback technology can control movements to a very finite measurement. The smaller the finite movement, the greater the accuracies achieved.

Because of the advancements made in CNC controller and servo technology, CNC machine are able to repeat movements to a higher degree of accuracy than previous generations. The newer technology can define more program points, which enable the cutting tools to generate complex shapes, with less deviation and better finishes. The machine not only produces accurate, consistent parts, with less operator intervention.

Flexibility

One of the defining attributes of a successful contract manufacturer is flexibility. Quantity order size from OEM”S is shrinking. Inventory carrying costs are a major driving force. The overall amount of parts required does not necessarily shrink, just the order size, to minimize inventory carrying costs.

In aerospace, this is a common occurrence. Schedules are in a constant state of flux. They get moved in and out on short or no notice, but “on-time” deliveries are still expected to be met. To compensate for the smaller lot sizes, the contract manufacturer has to be very flexible. This flexibility includes having CNC multi-purpose machines equipped with more tools, tool holding positions, variable work holding, capable of handling different levels of complexity, with shorter setup times. Part of this solution is having a robust, flexible ERP/MRP system to manage the production process.

Quality Control

In the aerospace world quality is everything. At Intrex Aerospace, all our production revolves around our quality system. We utilize a TQM (total quality management) a process improvement methodology system. We are ISO 9001 and AS 9100 certified, both audited systems. By utilizing these systems, we are constantly utilizing continuous improvement practices. Intrex has qualified management professionals trained and knowledgeable in total quality management. Intrex also utilizes CNC coordinate measuring machines (CMM), both on our shop floor and in our quality lab. This utilization of CMM technology guarantees higher levels of part accuracy and process efficiency.

Conclusion

At Intrex Aerospace, keeping up-to-date with CNC  technology, coupled with staff education and training is ongoing. It is our commitment to our customers. We welcome the challenge.

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