Find the right tool in 3 steps
As a production planner, you know that while you know exactly which cutting tools you can purchase, you certainly lack this experience when it comes to rolling tools. Which tool is right for your application? Which is the most cost-effective rolling tool for the application? These 3 steps will help you find the right burnishing tool or deep rolling tool – and save you time and money when selecting the right rolling tool.
Rolling, also known as roller burnishing or deep rolling, involves plastically deforming and mechanically finishing surfaces with a rolling body. Rolling is therefore a surface treatment process in which a roller is pressed onto the surface of a component with a defined force. Due to the relative speed between the roller and the component’s surface, the roller moves over the entire surface. High contact pressures between tool and workpiece result in a significant smoothing of the roughness peaks (improvement of up to 95%) and a hardening of the subsurface area.
Rolling tools for roller burnishing and deep rolling
A basic distinction can be made between mechanical and hydrostatic rolling tools. With mechanical tools, the roller is pressed onto the surface by a mechanical force. The roller is either self-supported or held in place by a support element (support cone or support roller).
In hydrostatic tools, a ball is pressed onto the surface at high pressure via a hydraulic medium (oil or cooling lubricant). The ball is hydrostatically surrounded and supported by the medium. These tools are very wear-resistant and, thanks to the stroke of the ball, are able to compensate for inaccuracies in a force-controlled manner.
But how does a production planner find the right tool for a specific application?
3 steps to finding the right tool
Of course, boundary conditions must be considered when selecting a tool. Here, the machine, the component, and the process itself play a decisive role. These boundary conditions must be known. Of course, not all boundary conditions can be covered below. In addition, the number of available tools is very large. Once the basic tool principle is known, it can usually be easily adapted to the specific situation.
The following section therefore describes three steps that can be used to select a tool concept efficiently and easily. Experience shows that not many questions need to be answered to do this.
Step 1: Define the goal – burnish or harden surfaces or create precision holes
Do you want to reduce surface roughness, consolidate the subsurface, or optimize a borehole? Each goal requires a different tool and a different process control.
- Smoothing surfaces
If the process is to be used to reduce existing surface roughness after turning, milling, or drilling, this is referred to as roller burnishing. - Hardening the subsurface layer
If the goal of the process is to improve dynamic strength or achieve a specific surface hardness, this is referred to as deep rolling. This induces compressive stresses and achieves cold work hardening, which increases the hardness in the subsurface area. - Improving bore properties
Special tools are available for machining bores. If a bore with minimal roughness is required, special rolling tools can be used. These can be combined with the peeling process. Peeling and roller burnishing can be used to produce precise bores and, above all, long pipes.
Rolling is also referred to as roller burnishing or deep rolling. Both processes are basically identical. However, with roller burnishing, results can easily be measured afterwards. This means that the process can be controlled retrospectively.
It’s different with deep rolling. Especially when it comes to introducing compressive stresses into the edge zone, the result cannot be measured non-destructively. Here, the process must be monitored much more closely.
For this reason, there are some tools that are well suited for such processes and others that are ideal for deep rolling.
Step 2: Checking material hardness – Why 45 HRC is the limit
The second step concerns the most important material property when selecting tools: material hardness. Hardness is the measure of resistance to penetration by a counter body. In hardened materials (>45 HRC), the loads on the rolling bodies are significantly higher.
There are special types of tools whose rolling bodies are suitable for processing hard materials. These tools can be used to process materials with a hardness of up to 65 HRC.
Furthermore, hard materials also require significantly higher force to achieve the desired deformation. This also limits the use of some tools.
Step 3: Analyze the geometry – Which tool is the right one for your application?
The third and final step is to select the actual geometry. Due to the geometry of the rolling bodies, their arrangement, and the rolling direction in the tool, certain tools can only be used for a specific component geometry.
Of course, there is more than one possible tool for many of the geometries shown in Fig. 2. However, by selecting the geometry, the list of suitable tools can be reduced to a minimum.
The tools themselves have different sizes and rolling forces. The tool that is suitable for the boundary conditions must then be selected from the list of possible tools. This can be illustrated using the example of a cylindrical geometry. There are basically four tool types here, which are very similar in design but are each suitable for either small or large components and machines.
It is important to note that the selection of the tool always depends on the basic principle of roller bearing and force application. The orientation of the rolling element or the clamping of the tool can often be freely selected. Whether the tool is equipped with a clamping bar, a VDI or Capto mount are also details that need to be defined in consultation with ECOROLL. Our trained technical sales staff will be happy to assist you with this.
Find the right tool with the Toolfinder
On the ECOROLL homepage, the Toolfinder guides you through the tool selection process by asking precisely these three questions. The result is a list of possible tools that are suitable for your application.
After starting the Toolfinder, all you have to do is answer the three questions and you will be taken directly to a selection of suitable tools.
Would you like to find the optimal rolling tool for your application? Use our free Toolfinder now or contact our experts for individual advice.
