TURNING: DEFINITION, PROCESS AND TYPES - TECHNOLOGY - 2024

The cilindrado is a cutting process to reduce the diameter of a metal part to make it smooth, compact or thin removing excess material in a controlled manner.

In industrial processes, the production of metallic elements has evolved in search of methods to improve aspects such as shape and finish; in order to achieve the ideal dimensions and surfaces of the required products with the minimum of failures / errors.

Figure 1. Turning turning. Source: Pixabay.com

This geometric finish has generated a great impact since its inception, since it is applied to metal parts and serves to improve the structural support and the aerodynamic appearance of vehicles and their architectural form.

Some applications of turning are oriented towards the manufacture of circular containers (silos) to store products or in the manufacture of mechanical parts for vehicles and pipes, among others.

This article presents the most essential aspects of the turning process, starting from its definition to the different types, as well as a general description of the process.

Definition

From an academic point of view, turning is defined as a process carried out on the lathe in order to reduce the bar diameters of the material worked.

In another order of ideas, the turning process is the operation with which a cylinder of revolution is shaped (according to measurements). In addition, some authors refer that when it is carried out in the internal part of the piece, the process is called internal turning, boring or perforation.

Turning is also defined as a process that is carried out by means of rollers, to give concavity to plates of a certain thickness and whose capacity depends on the diameter of the rollers.

In summary, the rolling process consists of a mechanical operation whose purpose is to give cylindrical shape and concavity to plates until they form a circle by joining at the ends and / or cutting materials into circular figures.

Process

The work of a bending machine consists of a mechanism capable of generating rotational movements between bending rollers or displacement elements for cutting and reducing material. This enables the manufacture of cylinders or cylindrical finishes with different diameters and radial angles.

Rolling machines have a motor that operates through electricity that is commonly coupled to a mechanical transmission system that allows the speed to be decreased or increased depending on the type of element to be manufactured, molded and / or cut.

The turning process is basically carried out on the lathe and depends on the finish to be carried out, whether at constant or variable diameter (profiling, conical, rounding or chamfering, among others). Also the process depends on the area (exterior or interior).

To carry out these turning operations on the lathe, the cutting tool and the part are positioned in such a way that they both form an angle of 90º, as can be seen in figure 1, while the carriage moves parallel to the part throughout the entire feed movement.

In the sheet rolling process, a set of rollers is used that will flex a small portion of the sheet causing controlled deformations along it until a curved section is achieved. It is used to generate large diameters.

Beginning of the process

In its beginnings, the different types of turning were carried out manually, since the machinery had limitations to generate products with quality finishes, requiring large investments and the loss of raw material.

But since the automation process evolved, these mechanisms have been extended to different areas of industrial production, which allowed a higher production performance, thus optimizing the use of raw material.

Through automated turning processes, products that meet quality standards are also offered and their applicability extends to the manufacture of machinery and medical elements, not only using metal as a base, but also other raw materials.

Turning types

The types of turning are directly related to the equipment that is being used and the mechanics of the process, forming the four most recognized types of turning: round turning, plate turning, sheet turning and profile turning.

Turning around

It consists of the use of cutting tools attached to a support that moves longitudinally to give a circular shape to a piece of material that, to a great extent, is metallic.

To carry out this type of turning, the tool and the transverse carriage must be positioned at an angle of 90º (perpendicular), moving parallel along the part as it advances.

Generally, the turning processes are also oriented towards the formation of internal holes (boring), using the lathe tool to achieve greater quality and precision in terms of the desired internal diameter for the piece.

Plate rolling

It is used to concave plates of a certain thickness by introducing them between the rollers of the bending machine to give it the desired diameter.

As the plate passes between the rollers, the rollers are aligned in such a way that they generate the radius of curvature required in the specifications. In cases of exceeding the capacity of the machine, the turning is carried out in parts.

Sheet roll

This process is generally carried out automatically and continuously, so it requires little labor. It consists of two phases: hot rolling and cold rolling.

Initially, very long and wide hot rolling tracks are used on which rolling mills, machines and reverberatory furnaces have been arranged to reheat, as well as a guillotine for cutting irregularities.

Then it undergoes a cooling process where tools are used to improve the final finish, depending on the requested specifications.

In the different types of turning, the estimation of errors is also taken into consideration, which have been minimized as the equipment and procedures are perfected.

References

1. Altintas, Y. (2012). Manufacturing Automation: Metal cutting mechanics, machine tool vibrations, and CNC Desing. University of British Columbia. Second Edition: p.4.
2. Hernández, L. (2019). Influence of feed rate and lubrication on the surface finish in a turning process. Innovation and Development Area, SL, p.10
3. Pujadas, A. and Torre, F. (2005). Execution of Machining, Forming and Assembly Processes. Ediciones Paraninfo, SA2da. Edition: pp. 266-267
4. Zamorano, S. (2013). "Steel Processing Production Line". Thesis. Faculty of Engineering Sciences. Austral University of Chile
5. Balcaza Chair Industrial Design-FADO-UNA. Transformation by Conformed- Primary Transformation.
6. Leyensetter, A. and Würtemberger, G. (1987). Metallurgical Process Technology. Editorial Reverte. Reprint, April 2006. p.73.