Advances in CNC machining, new composite materials, computer-aided design and even newer computer feedback have increased quality and speed and reduced waste. These are important factors in a competitive global economy, but every high-quality machining process has steps that rely on customer service and intelligent design. Here we review some basic steps for both manual and CNC operation to get the best results every time.
Machine processes, whether manual or computerized, are only as good as design input. Following the design and manufacturing process of each part is critical to a high-quality machine shop. While CNC machining is a technical business, people really come first. Your shop needs to follow a process for every project, especially as you grow, so new mechanics and software designers will provide the same level of quality. Start with customer service. Assessing customer needs using your equipment capabilities should be the first step in any project. Once contracted, each project goes through a design and approval process, modelling, tool selection and final machining.
Technical drawings created and approved collaboratively between the client and design engineer play a vital role before machining begins. Drawings must include various views, precise measurements and angles to ensure all criteria are entered correctly in the final execution. While the initial design concept comes from the client, quality engineers may be able to find design recommendations to reduce costs or use their expertise to improve the final product.
While CAD systems easily prepare drawings for trained operators, good technical designers are still able to draw parts by hand, demonstrating their skills as engineers. New AI (artificial intelligence) can enter designs and generate quotes in minutes, but this still lacks the experience engineers can communicate with clients to get the best results.
Detailed drawings include tolerances, threads, finishing instructions, and should include cross-sections and 3D views when required to aid the next stage of production. No work may be carried out without the client’s approval of the technical drawings.
While 3D CAD designs can be easily generated from 2D technical drawing input, it is strongly recommended that technical drawing files be accompanied by a 3D CAD file to ensure accuracy. The 3D CAD file itself can be used for modeling, or it may be necessary to run a prototype.
In manual machining, prototyping is often a necessary step beyond 2D drawing, but many applications still require prototyping to meet a range of quality and finish observations from customers and manufacturers. Prototypes can be made of composite materials different from the final product to expedite time and cost, such as wood or aluminum. And there are other prototyping options such as 3D plastic printing and injection molding. The complexity or application of the product design will determine whether a prototype is required to model in each project.
Choose the right tool
When you’re ready to start production, the number of production runs, the complexity and precision of the parts affect machine and tool selection. Hand shops can machine almost any part using lathes and mills, starting with the machine itself. In a CNC machining shop, there is often a wide variety of machines to choose from. Newer multi-spindle machines can often handle the entire production at once.
Technical drawings are usually made with the machine in mind, but in a busy workshop, machine availability may dictate production options. Tools are specially selected based on finish and workpiece material. Machinists must be well versed in the strength of composite materials to guide their selection of tools and fixtures.
Mechanic skills are now related to quality control and safety. Automated machining will begin production, enabling hands-free operation. Mechanics need to check quality through various tests and measurements. Tool wear and maintenance is an important function of CNC machine shops to ensure that tolerances for high quality production are met.
Having a standard operating system for each quality machining process ensures easy training of new employees, high-quality production and satisfied customers. Even as more technology emerges, you can still see how the human factor affects the production process.