The Quality Control process and its implementation

The quality control process we have developed consists of dimensional verification and assembly control of manufactured products and can be applied in any area of the iron and steel industry for the manufacture and assembly of all types of parts in carbon steel, stainless steel, special steel alloys, aluminum and various types of plastics.
Our quality control process has the peculiarity of being implemented throughout the entire production process and its aim is to mitigate the probability of errors or defects in the production and assembly of parts, as well as to carry out a correct dimensional control of the assembly of the different components.
Its importance lies in the fact that although the assembly of the product is carried out manually, the dimensional control of the product is associated with the different stages in the manufacture of the parts, which are carried out in an automated way. This is the situation in most sheet metal cutting and forming companies that work for the manufacturing sector in which there are laser cutting machines, punching machines, bending machines or CNC panel benders, etc., as in our case.
The procedure defined is a self-monitoring system in which each operator involved in the production process can know whether what he is carrying out or manufacturing at that moment is completely in line with the parameters established in the design stage and/or required by the client or, on the contrary, an error or defect is occurring. If this is the case, he/she must act and notify the person responsible so that the fault can be investigated, corrected and its origin detected in order to adopt future measures.
The development and evolution of this control process involves the entire production system of the company from the first stages of design to the final assembly of the components, obliging all the people involved in it to make good the maxim that "quality is everybody's job" in order to achieve total quality as defined by K. Ishikawa, as a "philosophy, culture, strategy or management style of a company according to which all the people in it study, practice, participate and promote continuous improvement of quality" (Gómez González, 2002).
For a better understanding of this article, we will first describe the overall manufacturing process of the company and, subsequently, we will detail each stage of the production process, based on the application of our global quality control process in the manufacture of part of a car body with the explanatory figures in the accompanying text.

Metal manufacturing production process

In order to achieve the precepts of total quality, the manufacturing process begins with the design of the parts that make up the assembly and from this first stage of the production chain, the quality standards to be met at all stages of production will be set. The phases of the production process in our company are shown in the flow diagram in figure 1.

Diagrama de flujo
Figure 1. Flow chart of the operational process

The dimensional verification and assembly control process of our quality system begins at the first stage of the manufacture of the product, the body in the case of our example, i.e. at the design stage. It is at this stage that the guides or marks in the form of holes of various shapes and sizes are established in the sketch of the prototype and which will be made later in the next stage, during cutting, when the parts that make up the product are still in a flat sheet format.
Once each part has gone through each of the phases of the production process, shown in figure 1, and before being assembled with the rest of the parts that make up the assembly or final product (the bodywork), it is verified that each of the holes made occupies its specific place in the design of the part, adjusting to the parameters and tolerances defined in the first phase.

In the design of the different parts that make up an assembly, it shall be foreseen that the different holes drilled in each of the parts that will make up the body will have their corresponding hole in the part or parts to which it is to be attached, making their centres coincide on the different faces in contact.

In the assembly phase of the different parts that make up the final product (the bodywork), the total coincidence or not of these centres, within the tolerances imposed beforehand, would indicate the correct or incorrect dimensional situation of all the parts.

The complete flow diagram of the body manufacturing process (or product in general) is shown in figure 2.

Diagrama de flujo completo
Figure 2. Complete process flow diagram, assimilation of the dimensional verification and assembly control process.

You can continue reading about the full quality system in the pdf by clicking HERE.

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