In today's competitive manufacturing environment, producing high-quality sheet metal parts and CNC (Computer Numerical Control) machined components is a top priority. This article takes a close look at these two operations to determine what makes them tick in terms of achieving the goal of superior quality. In doing so, it explores many of the key aspects associated with both technologies, from basic process parameters to advanced strategies that are sometimes employed to solve quality problems.
High-quality CNC machining begins with precision. This is, however, the default condition. Microscopic accuracy is not something one achieves; it is something one attempts to achieve and one’s machines that are attempting to achieve it. That can mean, motors, encoders, and devices all attempting to reach and maintain high standards of quality consistently along with a neat, tidy set of maintenance and calibration services that run to an internal timetable.
Selecting top-notch materials is the essential first step of the pursuit of superior quality. Choosing them requires an unerring eye for not just the individual next-best alternatives but also the nuances of how well each part of a composite assembly works with its neighbors. Quality selection informs the production and assembly of the parts that make up a sheet metal assembly.
Innovative tools and advanced cutting techniques ensure metal workers obtain precise, clean cuts when working with sheet metal. Improvements in everything from tool design and coatings to cutting-edge coatings have enhanced efficiency and minimized material waste. But what else do facility managers need to know about precision metal cutting?
Integrated sensor technologies in sheet metal fabrication and CNC processes allow manufacturers to monitor operations in real-time. These sensors can pick up divergences, irregularities, and even the slightest changes in cutting and other machining parameters. The immediate feedback that these sensors provide to the operators and the systems in which they are embedded allows for real-time corrections. That is a big reason why these technologies—along with vision systems—are part of any discussion about “elevating the overall quality of produced components.”
Technological advancements have made it possible for manufacturers to achieve the unprecedented inspection speed and accuracy required in today's fast-paced production environment. Where humans once performed the tedious work of inspecting parts, machines now do the job—but with human-like versatility and unfailing precision. Today's optical and laser-based automated systems can assess the quality of finished components with breathtaking speed. And when components of complex geometries are involved, these systems can accomplish the task with unfailing ease and accuracy.
An in-process quality control system allows for a nearly continuous feedback loop during manufacturing. It is not just the final product that is inspected; in-process checks allow for inspection at timed intervals when it is easiest to correct a problem. This protects the system from "going defective" in between the final checks. If a defect is found, work can be stopped and the root cause identified; then corrections can be made. "In-process controls are a great way to protect against the 'surprise factor,'" as it is sometimes called.
The assurance of high-quality CNC machining and sheet metal working still requires the old-fashioned method of human know-how. The expertise that workers have today is what allows for the continued precision and quality of these two processes. Employees who learn the trades have a direct hand in keeping the processes exact. And since the quality of the end product also hinges on the assembly process, that too requires a quality workforce.
Quality control benefits from diligent documentation and traceability measures. Detailed records of the materials and processes used in manufacturing—and of the inspection results obtained at various stages—make it possible to trace the production history of each component in a product. When a quality problem arises, this documentation serves as the basis for investigations aimed at finding the root cause and fixing the problem so it doesn't happen again.
It is not a happenstance that sheet metal working and CNC processing are of superior quality; it is the result of careful planning, a few technological innovations, and the age-old commitment to excellence in manufacturing. The strategies employed by these shops—real-time monitoring, automated inspection, and (not least) meticulous documentation—might make them seem like the friendly folks who inhabit a secret quality control dungeon. But these strategies, and the ones I will discuss in this chapter, serve a single purpose: to impress upon the customer that the product is of exceptional quality.