Help

CNC Machining Tips

Posted by author-avatar
0
Design highly complex machined parts more quickly and efficiently with the following tips
The performance of CNC machine tools has been improving year by year. Turret lathes with live tools can mill various shapes and machine eccentric holes or radial holes, operations that previously required separate processing in a milling workshop. Machining centers equipped with index heads support 3+2 axis machining, enabling the completion of multi-surface part processing in a single setup. This is great news for designers and engineers—now it is not only possible to produce extremely complex parts but also achieve production goals of higher quality, lower cost, and shorter lead times.
However, this does not mean everything will go smoothly—certain machining rules must be followed. Violating these rules may lead to high rework costs and project delays. This design guide explores key considerations that all part designers should be aware of, including: Hole Position Design, Milling Depth Features, Threads and Inserts, Permanent Markings, and Part Fillets.
Zomwave equipment is equipped with 5-axis milling or 3+2 axis milling capabilities. This feature allows the machine tool to clamp the bottom of the workpiece and complete the processing of the top and side surfaces in a single setup. This type of milling method can produce more complex parts, such as brackets with undercuts on the sides or similar parts with deep irregular holes.
Similar to Zomwave machining centers, CNC turn-mill compound machining on high-speed lathes can complete the processing of many complex parts in a single operation. The live tool and Y-axis functions mean that operations such as bolt turning, wrench flat milling, and cross-hole drilling for safety wires can be completed. More complex examples include hydraulic pistons with locating grooves at one end, fittings with adjustable wrench holes on the surface, or shaft parts with external keyways. In some cases, it is even possible to “turn” non-circular orthogonal structural parts.
Against the background of milling and live tool machining, the following are five key factors to consider when designing complex parts:
1. Hole Position Design
The minimum size of coaxial holes and axial holes machined by Zomwave CNC lathes is 0.04 inches (1 mm), with a maximum depth of 6 times the diameter. The diameter of radial holes (drilled from the side of the part) should be at least 0.08 inches (2 mm). Through holes that penetrate turned or milled parts are usually feasible (especially for hollow or tubular parts), but depending on the part size, hole diameter, and material, the tool may not reach a sufficient machining range. If possible, Zomwave will process from both sides, but it is crucial to check for potential limitations in the design analysis.
2. Depth Features
The depth of external grooves for turned parts shall not exceed 0.95 inches (24.1 mm), and the width shall not be less than 0.047 inches (1.2 mm). The dimensions of all other milling groove features are usually the same as those for drilling, but an important rule of thumb is: the depth should be less than 6 times the width of the feature. In addition, at least 0.020 inches (0.5 mm) of wall thickness should be retained for adjacent materials. Large planes and other milled surfaces (milled or turned) depend entirely on the matching degree between the part geometry and the available tool size. However, deep ribs and deep grooves are challenging wherever they are machined. Heat sink-like structural features can be machined on turned or milled parts, but this depends on the actual part geometry and available tools. Again, please carefully check your Design for Manufacturability (DFM) analysis. If necessary, feel free to send the drawings to us for testing or contact an application engineer for consultation.
3. Thread Machining
There is considerable overlap in the thread machining capabilities of Zomwave turning centers and milling centers. In general, depending on the machine tool type and functional layout, Zomwave can machine threads from #4-40 (metric M3×0.5) to approximately 1/2-20 (metric M10×1.25), with some exceptions. Please refer to the thread guide for accurate dimensions and detailed information. At the same time, be sure to read the chapter on the correct method of thread modeling and its correlation with internal/external threads and milled/turned part features. You may also consider using inserts. Coil inserts and key inserts have a longer service life than ordinary threads, are especially suitable for soft materials such as aluminum or plastic, and are easy to install.
4. Permanent Markings
Complex aerospace and medical parts usually require permanent marking of part numbers and company names. Recessed text, although aesthetically pleasing, is also one of the most time-consuming machining operations, and its cost becomes completely unacceptable as production volume increases. It is usually best to use electrochemical etching or laser marking for part identification, but if text must be engraved, keep the text concise and use a simple and clear font. We recommend: Arial Rounded MT font, 14-point size, 0.3 mm depth for soft metals and plastics; Arial Rounded MT font, 22-point size, 0.3 mm depth for hard metals.
5. Fillets
A common mistake in all machined parts is the presence of sharp internal corners. For example, the nose radius of turning tools typically used by Zomwave for finishing is 0.016 inches (0.406 mm), so this factor should be considered when designing mating parts. The minimum diameter of end mills is 0.040 inches (1 mm), which means that the internal fillet radius of any cavity will be slightly larger than half the diameter of the end mill. This fillet is already very sharp, but it should be noted that milling with such a small tool is time-consuming and limited to cavities with a depth not exceeding 0.375 inches (9.52 mm). The best solution is to eliminate internal corners or use the largest possible internal fillet radius in the design of mating parts.
Final Tip: Failure to adopt good Design for Manufacturability specifications will make already challenging machining operations more difficult, thereby increasing costs. For prototypes, a little extra cost may not matter, but when demand grows and parts enter mass production, this will result in huge cost waste. As always, if you have any questions about any complex parts or part functions, please feel free to contact Zomwave via email at sales@zomwavemetal.com.
Newer
Protect Your Intellectual Property
Back to list
Older About Our Privacy Policy

Related Posts