Figure 2 shows the methodology steps grouped by the different phases of the design process. The following explains the steps in Figure 2 grouped by each design phase.

Task clarification (TC). At the end of this phase, the lists of requirements, criteria, or specifications/properties of the product to be developed will be obtained. For this purpose, the following steps must be followed:

a)Search within the database (DB) for the general case to which the product to be designed belongs according to one of the eight cases described in Table 1.

b)Within the general case, the specific case is searched according to the products described in Figure 1.

c)If the specific or similar product is not found in the DB, it is possible to:

• Search in the specialized bibliography.
• Analyze the references that coincide with the product.
• Define the product requirements and specifications for each reference according to Figure 2.
• Feedback of the DB.

d)Once a DB case matching the desired product is found, the list of requirements is displayed with the specifications defined for the DB case, and based on these, the product is defined for its own product.

Conceptual Design (CD). At the end of this phase, several initial CD will be obtained, and the selection of one or more will be based on requirements or criteria. For this purpose, the following steps should be followed:

a)Search for a combination of materials and specific FFF process parameters to meet the initial specifications.

b)If a feasible FFF alternatives is found or not, considering:

• a FFF redesign strategy
• a combination of FFF materials and processes with conventional materials and processes
• an indirect FFF manufacturing method

Look for correspondence between the requirements and specifications of the alternatives to ensure compliance with requirements.

c)Define selection criteria based on the requirements and specifications set in the CT phase.

• To consider include cost and process times.
• To consider health, and environmental impact criteria according to SGH or NFPA.

d)Assign a weighting to the criteria obtained in this phase based on the objectives pursued, market statistics, and quantitative figures.

• for example, state-of-the-art and market research like Taborda, Maury and Pacheco (2021).

e) Establish quantitative characteristics of the alternative per criterion using the DB.

• To consider consequences of using additional materials and process like cost and process times, or health and environmental impacts according SGH or NFPA.

f) Evaluate and select the alternative using the weighted criteria matrix (WCM) method. In this phase, the consultation of the DB and specialized bibliography is used to quantify properties to evaluate and select the best alternative based on objective variables.

Basic Design (BD).   At the end of this phase, the BD of the product will be obtained, that is, the rules and process to modify the DC, the modified DC to a shape close to the final shape, and the specific manufacturing process to be used. To this end, the following steps must be followed:

a)Search for the most suitable design rules.

• for example, in the present work or DB for the specific product based on the requirements, specifications, selection criteria, and previous DC.

b)Analyze and study the rules or methods by consulting the original references (framework) and apply them to the CD to transform the concept to a basic form according to the requirements.

c)Verify the level of concordance between the primary forms and the requirements and use the DB.

• for example, the specialized bibliography to quantify properties and percentage of improvement and features as support.

d)If different basic processing and design forms were generated accordingly, based on properties and requirements, a WCM evaluation would be required to select the BD and its processing form.

Design in Detail (DD). At the end of this phase, the final digital model and the specifications and process parameters will be obtained. For this purpose, the following steps must be followed:

a)In the DB and specialized bibliography, search for the information, model, or program that helps to specify the product property.

b)Appropriate in the use of models or CAD (Computer Aided Design) /CAM (Computer Aided Manufacturing) programs to apply to DB and transform it into DD. Including:

• Costs and Process times
• Health and environmental impacts according to GHS scale or the NFPA

c)Use the data and models to simulate and modify the design performance until it conforms to the requirements through an iterative process. Use WCM in the most demanding cases.

d)Generate design specifications by exporting:

• CAD models.
• Drawings
• processing sheets.
• manufacturing parameters.

On the other hand, in case of redesigning parts manufactured with FFF, whose properties do not conform to the desired specifications, the steps in Figure 3 should be followed: