Complex Parts CNC Machining Guidelines

CNC Machining, product development

Technology developments in CNC milling, turning, and wire EDM have changed the simplicity of machining extremely complex geometries in the manufacturing sector. We explore the world of complex parts that may be created using CNC technology in this conversation, showcasing our ability to create unique CNC complex parts as required.

It’s important to understand how CNC machining works before starting your projects. The capabilities of CNC machining equipment must be thoroughly understood in order to effectively design for manufacturing (DFM). We encourage you to check out our DFM Analysis resource, where you may find helpful hints and ideas for improving your designs, to gain a more thorough understanding.

Complex parts can be machined using modern production processes like CNC milling and CNC turning. However, best practices must always be taken into account to keep the project under budget. Then, we’ll describe these procedures and show how cutting-edge machining methods enable us to create even the most intricate pieces.

complex parts CNC machining

Complex Parts

Complexity plays a pivotal role in the CNC part manufacturing process, as it significantly impacts costs and lead times; complex parts inherently demand more skill and time. But what defines complexity? Perhaps you’ve endeavored to simplify your part design, or you’re grappling with assessing its level of complexity. In essence, complexity hinges on factors such as part dimensions, weight, unique features, tolerances, wall thickness, surface contours, and finishing requirements. Grasping the intricacies of your part’s complexity can be a challenging task. To facilitate this assessment, we’ve developed a user-friendly quiz that helps gauge the complexity of your part, offering insights into the ease or difficulty of its manufacturing. Discover your part’s complexity by discussing with our experts!

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Why Opt for CNC Machining for the Production of Complex Parts?

To comprehend the “why” behind the suitability of CNC machining for crafting intricate components, one must first grasp the capabilities of contemporary manufacturing technologies. Most CNC machines have a longstanding presence, and their enhanced efficiency and performance have significantly expanded the realm of CNC machining for complex parts. There are several compelling reasons why CNC machines excel at creating complex parts, encompassing their operational characteristics, tolerance management, and surface finishing capabilities.

Machine Cutting Axes

The capabilities of your CNC machine dictate the extent of complexity achievable in CNC machining. Modern CNC technology enables the manipulation of multiple axes, facilitating the machining of highly intricate features. For instance, a 5-axis machine possesses the capacity to cut angles that a 3-axis machine cannot accommodate. Traditional part manufacturing often requires numerous setups to machine all features, but a higher axis capability minimizes the need for multiple setups, thereby enhancing the potential to manufacture CNC complex parts. Various iterations of CNC milling techniques ensure consistent adherence to design specifications.

Cutting Tools and Part Features

The design of a part defines the requisite level of complexity for its fabrication. While multi-axis machines can handle complex parts, cost-effective manufacturing practices must also be observed. Employing standard-sized cutting tools whenever feasible is a prudent approach for cost management. For CNC machining of Complex parts, even those with intricate features, carbide and ceramic-coated cutters stand as the preferred options. These tools are capable of machining hardened materials and are suitable for high-speed machining applications. Nevertheless, their employment comes with a premium cost, prompting product development teams to deliberate whether the incorporation of high-complexity features is truly essential, considering the associated manufacturing demands and expenses.

Tolerancing and Surface Finishing

Stringent tolerances and refined surface finishes represent pivotal attributes of custom-machined parts, elements that significantly contribute to complexity. The complexity of complex parts is contingent on geometry, dimensions, and the degree of precision and accuracy attainable through machining.

Work Holding

The complexity of a CNC-machined part is often influenced by the quality and capacity of available fixtures and jigs. The principles of stack-up analysis further elucidate how fixture quality governs machining capability. Design engineers must also take into account how the part will be secured within the machine, a consideration of particular significance for highly intricate designs. Effective work holding in CNC machining hinges on the firm attachment of all fixtures and machining tooling to the CNC machine. The rigidity of the CNC machining setup is paramount in ensuring the precision and accuracy of the final product.

CNC Milling: Unveiling Precision and Efficiency

CNC milling is a sophisticated process that employs computerized controls and rotating cutting tools to selectively remove material from a workpiece. The realm of CNC milling technology encompasses a spectrum, ranging from the conventional 3-axis machining to the remarkable precision of 12-axis cutting capabilities.

A remarkable facet of CNC milling is that achieving a complete part within a single set-up is a rare feat. The inherent challenges posed by intricate angles and complex profiles render it nearly unattainable on a 3 or 4-axis mill. As the complexity of a custom part escalates, so does the cost of its production. For instance, when working with a 3-axis mill, the need for four or more setups to finalize complex parts drives up the overall manufacturing costs. However, the ever-evolving landscape of CNC milling has yielded machines with a substantial number of axes, thereby diminishing the number of setups required for the most intricate components.

Designing for Manufacturability

Even in the age of advanced CNC milling, adhering to best machining practices remains a cornerstone of effective design. A 12-axis CNC mill may make the machining of highly complex parts appear straightforward, yet there are always avenues to optimize manufacturing costs.

Maximizing the dimensions of internal features, pockets, and profiles is a critical aspect of designing cost-effective complex parts. Larger internal features permit the utilization of more sizable cutters, resulting in the removal of more material along the tool’s path. This, in turn, reduces machining time and mitigates the risk of tool breakage.

Moreover, substantial internal profiles and features create more extensive clearance areas for tools to navigate. When tools must navigate around features with limited clearances, machining time progressively increases with each pass. Even incremental time increments as slight as a tenth of a second contribute to elevated aggregate costs.

Another pivotal consideration in CNC milling is the management of internal corner radii. For instance, using a 0.250″ end mill to machine an internal pocket yields a 0.125″ inside corner radius. Employing this consistent radius across all applicable areas simplifies the machining process by eliminating the need for tool changes, thereby reducing both machining time and associated costs. Conversely, necessitating a shift between a 0.250″ end mill and a 0.1875″ end mill for two distinct corners introduces interruptions in the machining process, resulting in increased processing time and elevated part costs.

Furthermore, the depth of pockets plays a significant role in CNC milling complexity. A straightforward formula dictates the minimum internal corner radii of a feature to be one-quarter of the feature’s depth. Adhering to this formula ensures adequate tool clearance within an internal feature and accommodates the usage of standard-sized cutters, such as end mills. Exceeding this depth risks an inability to attain the requisite feature depth without tool breakage, due to the standard lengths based on cutter diameters.

Tolerance and Surface Finish Mastery

CNC milling boasts the capacity to produce parts with precise tolerances. For example, a CNC machine typically maintains tolerances of +/- 0.004″ alongside a surface finish as refined as 125 microinches. These specifications satisfy the requisites of numerous applications and uphold the integrity of assembly stack-ups.

CNC Turning: Precision in Rotation

CNC turning is a meticulous process that involves spinning a workpiece at high speeds while advancing a cutting tool along its surface to sculpt it. This method of turning, which has its origins dating back to 1940 when the inaugural numerical turning machine was conceived, is a time-honored approach for creating CNC machined parts. Another nomenclature for this apparatus is a “CNC lathe.” Within the confines of a CNC lathe, cutting tools are affixed to a numerically controlled turret, affording the capacity for intricate operations. For instance, a hexagonal turret facilitates the simultaneous use of six distinct cutting tools within a single setup, empowering the machine to execute six different types of cuts in one comprehensive operation.

Live Tooling versus Non-Live Tooling

The advent of live tooling has significantly enhanced the cost-effectiveness of shaping intricate parts on a stationary CNC lathe. Live tooling empowers a CNC-controlled lathe, along with the turret’s diverse spindle and sub-spindle configurations, to execute a spectrum of operations while the workpiece remains immobile in orientation to the primary spindle.

Conversely, operating a CNC lathe without live tooling constrains the range of cuts and tooling applications. In the conventional turning operation, the tool resides in a fixed turret, and the sole feasible movement is a linear motion along the z-axis of the workpiece. This restriction limits the variety of cuts that can be achieved within one machine setup. Additionally, owing to the sole z-axis translation, more intricate machined features necessitate a secondary operation on a CNC mill.

Live tooling transcends these limitations, accommodating both axial and radial cuts in addition to standard turning operations. The introduction of live tooling lathes has not only curtailed lead times but also driven down machining costs. This, coupled with the capacity to fashion features in both radial and axial directions, has paved the way for the design and prototyping of highly intricate CNC machined parts within a more modest budget.

Tolerance and Surface Finish Mastery

An essential objective when designing intricate CNC machined parts is achieving surface finish standards without resorting to post-processing. Present-day CNC lathes are equipped to deliver machined finishes with a precision of up to 32 micro-inches—an outstanding finish that once necessitated post-CNC-machining procedures like surface grinding and polishing.

The standard tolerance for a lathe typically rests at +/- 0.005″, but with the right tooling and appropriate machinery, even greater precision can be achieved. While CNC grinding can produce custom CNC parts with remarkable precision, finish, and accuracy, it is not always a cost-effective choice for complex parts design. With the strides made in CNC turning, engineers can now design complex parts that meet the same standards of finish and tolerance as CNC grinding, all without the need for post-processing.

Therefore, when formulating designs for manufacturing, the initial step should involve an examination of the system’s fit and functionality. A profound understanding of how the complex parts will integrate into the parent assembly simplifies the targeting of specific tolerances and finishes. By appropriately applying CNC lathe tolerances, the necessity for grinding can be obviated.

Moreover, CNC grinding not only adds to the expense but also can create bottlenecks in many workshops due to lengthy setup and processing times, stringent quality inspection requisites, and elevated rates of rework and fallout. The objective for designs should be to attain a surface finish and tolerance that demands minimal manual intervention to fulfill the part’s intended fit and function.

EDM: Shaping Precision through Electrical Discharge

Electrical Discharge Machining (EDM) stands as a distinctive non-traditional method, deviating from the conventional employment of sharp tooling found in CNC mills and lathes. Rather than relying on traditional cutting tools, EDM leverages the power of electricity and thermal energy for material removal, making it an electro-mechanical process.

In the classic EDM technique, an electrode (cathode) emits an electrical current that traverses a workpiece (acting as an anode) immersed within a dielectric fluid. This closed electrical circuit generates intense heat and sparks, effectively vaporizing the material. To execute this cutting process successfully, it is imperative for the workpiece material to exhibit electrical conductivity. Sungplastic offers a variety of non-ferrous metals, whether normalized or hardened, which represent excellent choices for cutting intricate part profiles.

The primary advantage of EDM machining lies in its adeptness at efficiently machining hardened metals. EDM machining surpasses traditional CNC methods due to a considerable reduction in tooling expenses. Conventional tooling quickly wears down when employed on hard materials. Additionally, CNC EDM expands the horizons of machining, enabling the creation of intricate mechanical parts such as gears, splines, internal gears, keyways, and other complex internal profiles that typically necessitate the use of CNC mills or broaching machines. EDM simplifies these processes, offering high efficiency and minimal setup requirements.

One of the remarkable facets of EDM machining is its capacity to handle multiple complex parts simultaneously. Thus, it is not confined to the creation of a single rack gear profile; multiple racks can be arranged linearly and processed concurrently. This capability streamlines lead times, reduces part costs, and slashes machine cycle processing times.

Tolerance and Surface Finish Mastery

EDM excels in delivering precision cuts with exceptionally tight tolerances, reaching as high as +/- 0.0001″. This feature empowers the design and manufacture of exceptionally intricate and customized CNC parts. In the realm of wire EDM, materials as thin as 0.0004″ can be processed, while thicknesses of up to 16″ pose no challenge. Moreover, EDM provides surface finishes as fine as 32 micro-inches, a level of refinement akin to CNC grinding, all achieved without the need for post-processing. Achieving this level of finish entails multiple tool passes, yet the associated cost remains a fraction of the expense incurred through traditional machine grinding.

Complex Parts CNC Machining at Sungplastic

Our complex parts manufacturing solutions include:
Complex Parts CNC Machining: CNC Milling, CNC Turning, EDM, CNC Grinding, Laser Cutting, Waterjet Cutting and so on.
Complex Parts Injection Molding
Complex Prototypes manufacturing
Small Parts Manufacturing and Large Parts Manufacturing
Batch Manufacturing
Complex Parts Design and Mold Design Guide
Competitive Pricing And Controllable Costs
Advanced Automation Equipment: 3-axis/4-axis/5-axis CNC machines
Highly Experienced Designers and Engineers

If your projects refer to complex parts manufacturing, directly contact us for the best advice.

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