Eccentric components are used in mechanisms where one axis is intentionally offset relative to another. This type of solution is applied, among other things, where rotary motion needs to be converted into linear or oscillating motion, or where the position of a cooperating component needs to be adjusted.
Producing such parts requires not only maintaining the correct dimensions, but also ensuring the precise position of the axes and surfaces in relation to one another. For this reason, CNC machining of eccentric components requires proper referencing, stable clamping, and the correct sequence of operations.
Table of Contents
What Are Eccentric Components and How Do They Differ from Axial Parts?
In a typical axial component, the rotational surfaces share a common axis. In an eccentric component, at least one of them has an axis that is offset from the main axis of the part.
The size of this offset is defined in the technical documentation and has a direct impact on how the component operates later.
This type of geometry can be found, among other things, in eccentric shafts and journals, adjustment components, and parts of drive mechanisms.
From a production perspective, it is important not only to achieve the required diameters, but also to maintain the specified axis offset and the correct relationship between the axes. These relationships are what distinguish machining eccentric components from standard axial parts.
How Is CNC Machining of Eccentric Components Carried Out?
The manufacturing method depends on the geometry, dimensions, material, and requirements specified in the documentation. The process may include turning, CNC milling, or a combination of several operations.
Before production begins, the process engineer analyzes the position of individual surfaces, the referencing method, and the sequence in which they should be machined. The aim is to prepare the process so that each subsequent operation maintains the correct relationship to the previously machined features of the part.
Part Setup and Determining the Machining Axis
In the case of an eccentric surface, the axis of the machined section is located outside the main axis of the component. Therefore, the clamping method must take the required offset into account.
In our work, we pay particular attention to establishing the correct reference surfaces during the first stages of CNC machining.
A setup error can affect the position of subsequent surfaces, even if their individual dimensions are machined correctly.
Turning and Milling Eccentric Surfaces
Eccentric surfaces can be produced using different machining methods.
For rotational components, offset-axis turning can be used, while CNC milling makes it possible to produce more complex geometries.
The choice of CNC machining method also depends on the required tolerances, production quantity, tool access, and the ability to clamp the component securely.
In more complex projects, it may be necessary to combine several machining operations.
What Affects the Accuracy of CNC Machining of Eccentric Components?
In eccentric components, not only the accuracy of individual dimensions matters, but also the position of the axes and surfaces relative to the defined references.
The final result is influenced by the clamping method, component rigidity, operation sequence, and dimensional inspection after CNC machining.
In serial production, it is equally important to maintain the same machining conditions for every component.
Clamping, Rigidity and Process Stability
The component must be clamped in a way that ensures a clearly defined position and sufficient rigidity during cutting.
Insufficient stability can lead to vibration, poorer surface quality, and problems maintaining the required dimensions.
From our experience, in the case of more demanding components, preparing the CNC program alone is not enough.
An earlier analysis of the entire process and potential sources of error is equally important.
Inspection of Axis Position and Dimensions
Inspection should cover both the basic dimensions and the relative position of the machined surfaces.
Depending on the technical documentation, this may include checking diameters, distances between axes, runout, and geometric tolerances.
A component may have the correct diameter while still failing to meet the requirements for its position relative to the rest of the geometry.
You can read more about component inspection in the article: “Quality control in CNC machining – how do we ensure precision at SIM Gdynia?”.
The Most Common Challenges in CNC Machining of Eccentric Components
One of the main challenges is maintaining the correct relationship between surfaces produced during different machining operations.
Each new setup may introduce an additional deviation, which is why the machining sequence and referencing method are so important.
The geometry of the component also matters. An offset center of gravity, limited rigidity of certain sections, or restricted tool access may require changes to the clamping method or cutting parameters.
For larger production runs, an additional challenge is maintaining the same accuracy across all components.
You can read more about preparing a stable production process in the article: “From documentation to stable production – the work of a technologist at SIM Gdynia”.
Where Are Eccentric Components Used?
Eccentric components are used where an axis offset is required to generate a specific motion or adjust the position of other parts of a mechanism.
CNC machining makes it possible to produce such components both as individual parts and as part of repeatable serial production.
Typical applications include:
- Eccentric shafts and journals,
- adjustment and tensioning mechanisms,
- systems that convert rotary motion into linear or oscillating motion,
- components of machines and production equipment,
- parts of drive and positioning mechanisms.
In each of these applications, the eccentric geometry performs a specific function, so the accuracy requirements should result from the actual operating conditions of the component.
Summary
CNC machining of eccentric components requires not only maintaining the correct dimensions, but above all ensuring the proper position of the axes and surfaces relative to one another.
Proper referencing, stable clamping, the correct operation sequence, and final inspection of the component are all essential.
A well-prepared process helps reduce the risk of errors and maintain the required repeatability both for individual components and for larger production batches.
Do you need components with demanding geometry? Contact us. We will analyze your documentation and select the appropriate CNC machining method.