Revista de Ciencias Tecnológicas (RECIT). Volumen 3 (1): 10-22

Revista de Ciencias Tecnológicas (RECIT). Universidad Autónoma de Baja California ISSN 2594-1925

Volumen 5 (1): e216. Enero-Marzo. https://doi.org/10.37636/recit.v5n1e216.

ISSN: 2594-1925

Research article

Methodology to implement CAE validation in repair &

redesign parts process of plastic injection molds

Metodología para implementar la validación CAE en el proceso de

reparación y rediseño de piezas de moldes de inyección de plástico

Natanael González-Bautista , Victor Hugo Mercado-Lemus , Maricruz Hernández-Hernández ,

Isaias Emmanuel Garduño-Olvera , Hugo Arcos-Gutierrez

Plásticos y Materiales Avanzados, CIATEQ-CONACyT, Circuito de la Industria Poniente No. 11 Lote

11 Mz 3, Parque Industrial Ex Hacienda, 52004 Lerma de Villada, Estado de México, México

Corresponding author: Natanael Gonzalez Bautista, Plásticos y Materiales Avanzados, CIATEQ-

CONACyT, Circuito de la Industria Poniente No. 11 Lote 11 Mz 3, Parque Industrial Ex Hacienda, 52004

Lerma de Villada, Estado de México, México. Email: nata_1594@hotmail.com. ORCID: 0000-0001-

7871-3017.

Received: November 26, 2021 Accepted: February 22, 2022 Published: February 25, 2022

Abstract. - Repairs and redesigns for plastic injection molding parts generally is a short and

straightforward process consisting of inspection, modeling, and evaluation. The present paper implements

a methodology for redesigning and repairing injection molding parts based on the frontal process for

developing concepts. The proposed methodology helps in the validation through Computer-Aided

Engineering (CAE) in the designing stage using CAD software, ensuring the quality of the repair.

Furthermore, the redesigned development has been carried out in the best way to obtain a better cooling,

robustness, or plastic flow. In this research is implemented the proposed methodology in a Hot Runner

System. Furthermore, a numerical simulation for three cases to evaluate the heat transfer and cooling

times performed, finding the main differences in heat transfer due to drilled or milled rectangular

channels, minimizing the time to reach ejection temperature and mold/part temperatures.

Keywords: CAE validation; Injection molding; Redesign & repair inserts.

Resumen. - Las reparaciones y rediseños de piezas de moldeo por inyección de plástico generalmente

son un proceso corto y directo que consiste en inspección, modelado y evaluación. El presente trabajo

implementa una metodología para el rediseño y reparación de piezas moldeadas por inyección basada

en el proceso frontal de desarrollo de conceptos. La metodología propuesta ayuda en la validación

mediante Ingeniería Asistida por Computador (CAE) en la etapa de diseño mediante software CAD,

asegurando la calidad de la reparación. Además, el desarrollo rediseñado se ha realizado de la mejor

manera para obtener una mejor refrigeración, robustez o fluidez plástica. En esta investigación se

implementa la metodología propuesta en un Sistema Hot Runner. Además, se realizó una simulación

numérica para tres casos para evaluar la transferencia de calor y los tiempos de enfriamiento,

encontrando las principales diferencias en la transferencia de calor debido a los canales rectangulares

perforados o fresados, minimizando el tiempo para alcanzar la temperatura de eyección y las

temperaturas del molde/pieza.

Palabras clave: Validación CAE; Moldeo por inyección; Rediseño y reparación de inserciones.

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1. Introduction

Packaging and containers industries widely use

polymers due to their excellent mechanical

properties, thermal properties, and chemical

resistance [1]. For the fabrication of polymeric

parts, the injection molding process is one of the

most important, and it is used to process more than

1/3 of all plastic pieces [2, 3]. This manufacturing

process is widely used in civil and mechanical

construction, automotive components, aerospace,

aeronautical industries, transportation equipment,

and household products [4]. Product and part

design are essential areas related to plastic

injection molding design, all of which contribute

to the quality of the molded product and

production efficiency [5 ]. This process involves

many process parameters such as melt

temperature, gate design, filling, and cooling times

strongly affect both part quality and cycle time [6].

The injection molding process comprises four

essential stages: mold cavity filling, melt packing,

solidification (cooling), and ejection [7]. Although

one of the most critical stages in the cycle is the

cooling time, it plays a crucial role in injection

molding by taking more than half of the molding

cycle time and affecting the plastic part's final

quality and mold productivity [8].

The general mold design has two parts: the

creation of the part and the design of the mold [9].

The mold design includes the mold base, designing

the core and cavity, components, coolant channels,

creating returning pin, adding ejector pin, creating

gate and runner, adding locating ring and sprue

bushing in sequence [10].

A two-plate mold with some of the essential

components and parts is shown in Figure 1 [11].

Figure 1. Cross-section view of a two-plate mold [ 11]

Generally, the cooling mold pars are

manufactured by standard processes that

consist of a pattern of drilled holes to pass

coolant through the mold plates and connected

by hoses to form a continuous pathway [10].

Many different cooling systems designs are

used in practice. While many molds use straight

lines, such designs are often not optimal [11].

The layout of the cooling channels is currently

carried out by experienced designers who

usually take as a reference set of geometric

criteria based on their experience and related to

dimensional values of depth and separation

between channels [12]. When the injection

process is completed, the filling time is only

20%, while the proportion for cooling is about

80%, so the cooling system is essential amongst

the injection mold design factors [13].

Computers have aided the plastic injection

mold design for an extended life cycle. Various

authors have developed program systems that

help engineers design part, mold, and selection

injection molding parameters. [14]. In many

times the process to repair or redesign is not

documented, and it depends on the experience

and judgment of the designer [12] or the mold

tooling room. Frequently, the repair or redesign

of mold pieces inferred the development of new

geometries, the manufacture of the same

components but longer dimensions, or the

exploration of new manufacturing processes

and materials [15]. In the case of redesigning

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applying additive manufacturing, there are plenty

of opportunities, benefits, and freedoms,

especially at the design part level [16].

The development of new mold pieces without the

theoretical basis is complicated, mainly due to the

lack of knowledge of the correct gain of efficiency

or improved qualities. Therefore, the latest are

fundamental reasons to implement a methodology

to validate the Computer-Aided-Design (CAD)

stage and ensure the efficiency of the repair or

redesign process.

Mold reparations take a long time, especially the

parts in contact with high wear due to closing

pressures, wrong operation, or poor maintenance.

When mold has worn out, the mold shut off areas

show signs like dragging, compaction, rounded

edges, or analyzing the injected part, where the

presence of quality defects like a difference in

thickness, heat marks, gas marks, scratches is

evident or surface finishes. The reparation

complexity and scope will depend on the size and

construction of the mold. Generally, molds are

tools designed and planned for a long-life cycle to

facilitate the maintenance, repair, and replace

components like spare parts. For example, a plastic

part quality generates defects due to a wear insert

at the cavity that needs to be repaired. In this case,

it is easier to manufacture and adjust it rather than

manufacture the entire cavity and adjust with

components.

Repair workshops worldwide are scarce; hence

when injection molds are simple with two or three

plates, it is easier and cheaper to manufacture a

new mold due to the complexity involved in

repairing molds. On the contrary, it is easier to

repair damaged parts by cutting molds to continue

producing plastic parts due to complexity. Some of

the main objectives and activities as a mold tooling

room are repair molds, improving efficiency or

product quality by a mold modification that can

include the manufacture or redesign of new pieces,

product updates, or injection runner system

improvements. Getting better efficiency is an

objective to follow in our mold reparations and

redesigns. One of the most common workflows

that consist of repairing or redesigning mold

parts is shown in Figure 2. The process is short

and effective when the reparation is easy, but

the current approach is insufficient when

considerable reparations or redesigns are

needed.

Some methodologies have been successfully

applied in additive manufacturing, as

mentioned in [15]. In the reference, the authors

introduce a study case to create a Design for

Additive Manufacture (DfAM) from a

conventional manufacturing piece or an

automated process to redesign mold cooling

pieces [12]. Generally, the implemented and

documented methods are applied to the design

and manufacture of molds and mold pieces, but

no processes help in the redesign and repair of

molds [15].

Figure 2. Current workflow to repair or redesign mold

parts.

CAD software is helpful to design mold pieces

and perform modifications that help model a

correct mold part. However, CAD software and

experience are not enough when it comes to

new parts design. From this point, it is

necessary to look for new engineering tools that

give certainty that the redesigned part will

behave as expected and improve in aspects such

as the efficiency of the mold reflected in the

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quality of the final plastic product. After extensive

research, commercial Computer Aided-

Engineering (CAE) packages such as Moldex3D

[17] or MOLDFLOW [18] are now widely used in

practice to analyze a given part design o mold

design [19]. The CAE methods can predict

temperature, pressures, times to improve the CAD

stage and mold efficiency by simulating the

injection plastic process [20]. For example, Figure

3 shows an injection process simulation in

Moldex3D.

Figure 3. Moldex3D, plastic injection molding simulation

[21].

A typical redesign process at the tooling workshop

is implementing Hot Runner Systems (HRS) to old

molds with Cold Runner Systems (CRS). HRS

provides better parameters for injection molding

and makes the most efficient process, an excellent

reason to implement in almost all new molds [22].

In the implementation of HRS, the engineering

design have to consider a temperature increase,

flow rate, turbulences by corners, injection point

profiles, overheating in some pieces, into others

[23]. In practice, the implementation of HRS is

necessary to redesign the cooling system, gate

profile, and sprue bushings to avoid heating

problems and make the most efficient injection

process. CAE packages are widely used in the new

cooling system design in HRS implementation

[24].

In filling imbalance problems, CAE Software is

widely used. The flows of molten polymers in

injection molds are unsteady, non-Newtonian,

and non-isothermal flows occur at very high

deformation rates. Such complex flows can

only be modeled numerically, e.g., using FEM

(Finite element method) computations [25]. It is

necessary to remember that some factors like

injection polymer melt pressure, temperature,

shear rate, and others during the mold filling

process will affect the melt rheological

properties [26]. In this context, a CAE tool can

help predict the behavior to avoid quality

problems.

The CAD-CAE integration system does not

lead to modifying the analyzed model as an

analysis result but predicts the behavior of the

piece simulated [27]. The following section

presents the structured methodology proposed

for redesigning and repairing mold parts

implementing the CAE Validation.

2. Methodology to implement CAE

Validation

Computational technologies are a widely used

and essential tool for the engineering field, such

as plastic mold design. Without a doubt, every

facet of design, analysis, simulation, and

manufacturing improves with the help of CAE

techniques [28]. However, the current repair

and redesign plastic mold parts process rarely

has a validation stage because sometimes new

mold concepts are copied and applied to molds

with old ideas, or repair is done based on the

judgment and experience of the designer.

Generally speaking, this practice can improve

or worsen the mold's performance, so validating

the CAD models through a Computer-Aided

Engineering (CAE) stage is necessary to

improve cooling parts, plastic flow, robustness,

and others.

As is mentioned in [29], each mold designed

has its process and specific knowledge. The

initial stage design defines costs, delivery time,

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and mold manufacturability [30]. In the process of

redesigning and repairing plastic mold pieces, it is

similar; the first step consists of analyzing the

scope to set general objectives to achieve by the

designer.

As an essential process of production and because

of mold and product design, in [31], the authors

perform a study about Taguchi's design of

experiments to determine the optimal process

parameters for injection molding to determinate

mainly melt temperature, injection pressures,

packing pressures, packing time, and cooling time.

The last examples are some of many

methodologies to implement in the design of

plastic products, plastic injection mold, or

injection process, but now, applying these

processes to the daily repair tasks may not work in

the same way and provide good results. Therefore,

the latest is a reason to develop an especial

methodology to implement in our current redesign

and repair process.

2.1 Redesign process methodology

The proposed methodology is based on the front-

end process for concept development. For

example, see Figure 4, containing numerous

interrelated activities, roughly ordered [32] and the

already existing process (mentioned in the flow

diagram in Figure 2) taking the essential stages,

such as inspection and CAD modeling. Then to

strengthen and improve the process, different

locations were added.

The base of the current repair process is to define

the scope, objectives, and specifications firstly

achieved with the modeling and experience. The

following steps correspond to implementing the

validation stage through a CAE application, which

should guide the way forward; it means adding

extra steps for the prototyping and selection before

CAE simulations. Based on the general lineal

process of the design shown in Figure 5 [33], the

different stages through product design from a

"Problem Identification" to "Result in

Documents" are followed.

Figure 5. General lineal Design Process [33].

Next is depicted the proposed methodology to

implement in the redesigning and repairing

process, Figure 6.

Figure 6. Proposed flow diagram to the methodology of

CAE validation.

The first step is the physical inspection of the

mold and plastic part, with the respective

documentation for the final stages. After mold

inspection, the second step is" Establish

specifications and objectives" that help define

the scope of the repair, considering the current

conditions of the mold, characteristics of the

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plastic part, and behavior of the tooling in

production. The final stage corresponds with why

repair or implement the redesign, focusing on one

or more problems.

The specifications and definitions of the CAD

problems are established under features related to

improvement and validation [12]. In addition, it is

necessary to define specific materials and

geometries as they are redesigned into new

parts.

Figure 4. The various initial activities comprise the concept development phase [32].

Once the proposal is defined, the next step,

"Prototypes selection," is used to choose the best

option (by a decision matrix method). That

allows identifying, analyzing, and evaluating the

different proposals raised [32] and selecting the

best one that sticks to the repairing program, cost,

machinability, and other aspects to consider.

The CAD model is defined with the CAE

system's necessary characteristics to make

decisions [5]. The fifth step consists of the

Prototypes debugging: "CAE Validation,"

which, by applying temperatures, pressures,

injection, or mold conditions, it is possible to

know if the CAD product concept will behave

according to the proposed stage two. This stage

helps know if the specified materials and

geometries are adequate to meet the objectives

and specifications previously set up or achieve a

theoretical gain in cooling efficiency or part

robustness.

The sixth step is crucial for the process: "Result

from the analysis." This step is based on the

analysis, and the decision to continue must be

taken towards the final stage or return to step two

and redefine the problem. Although this may not

always be the case, if the analysis of results is not

consistent, it is possible to return to the previous

step and validate that the boundary conditions

were correctly applied, in this way, ensuring the

integrity of the results.

Once a CAE stage has validated the results, the

methodology finishes in the seventh step, "Detail

design," which includes the complete

specification of the geometry, materials, and

tolerances of all unique parts of the product. This

stage provides product control documents, that

is, the drawings or files that describe the

geometry of the pieces [32]; in the operation of

redesign or repair, the assessment is an important

file.

3. A repair case study

In this case, a base cavity insert redesign is

achieved through two objectives: update the hot

runner injection system and improve the cooling

at this piece. From the literature, it is very well

known that changing the injection system from

cold runner to hot runner will increase the heat

transfer. Hence it is necessary to redesign the

cooling system. The proposed methodology in

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Figure 6 is used in this case study to prove the

new stages. Due to that, the first stage, "Mold

Inspection," must be a physical activity and has

no changes in process (see Figure 2); this case

study will start in step two, "Definition of

specifications and objectives." The plastic

product to analyze is a 30 liters capacity

rectangular container, see Figure 7.

Figure 7. 30 The rectangular container.

3.1 Definition of specifications and

objectives

After "Mold Inspection," it is possible to start the

establishment of the Objectives and

Specifications:

1. Keep original sizes of the piece; it must

consider a refurbish to assembly.

2. The surface molding finishes must be the

same.

3. Apply the newest design standards.

Objectives:

1. Make three independent flow water-

cooling circuits.

2. Keep an almost equal heat transfer on

molding surfaces.

3. Know the gain heat transfer.

4. Make the CAE validation with two

different materials in sprue bushing.

The specifications and objectives were

established by mold repair and redesign pieces

experience; the designer can add more during the

process.

3.2 Develop of proposals

The original design (the original cavity, made in

1989, is shown in Figure 8.) offers a piece with a

"grid" of holes and copper plugs to create a flow

water circuit; in this design, the sprue bushing

does not have a water-cooling.

Figure 8. View of original cavity base cooling design.

The cooling circuit shown in Figure 9, once

implemented in a similar plastic product of 20

liters of capacity, produced the cycle time was

improved in 8 seconds, with the advantage of an

evident reduction of the quality defects.

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Figure 9. Cross-section of implemented cooling.

Uniform flow distribution helps improve the

thermal conductivity of coolant, cooler parts, and

heat transfer applications in medical, fuel cells,

solar panels [34]. However, having a

maldistribution in high heat flux cooler parts will

be a reason to decrease efficiency systems [35].

Although circular cross-sections are the most

common profiles [10], additive manufacturing

explores other non-circular section cooling

profiles such as square, rectangular, diamond

elliptical, trapezoidal, and other polygons [36].

Notwithstanding, this manufacturing technique is

expensive. This research considers two cross-

section cooling profiles: circular and half-

circular (see Figure 10). In the first case, Figure

10a has a non-constant distance between the

molding surface and the CC (cooling channel)

surface; this problem could be solved by a

parallel section CC to the molding surface as

shown in Figure 10b, further, to enhance the

uniformity of heat dissipation [37].

Figure 10. (a) circular cooling channel and (b) parallel

profile cooling channel [37].

The proposals consider keeping the original sizes

but manufactured in two pieces to make an

internal continuous water channel. In general, the

fabrication of old parts corresponded to one steel

piece.

As a sub-step, sketches were developed to

analyze different ways to improve the system

cooling in configurations and cross-section

profiles. Finally, the CAD models are defined the

coolant inlet and outlet.

The parts' manufacturing dimensions are 420.0 x

380.0 x 85.0 mm; it is then expensive to use

additive manufacturing to create an internal

cooling system. The solution to this

inconvenience is to divide the mold part into two

pieces: base cavity and insert Figure 18. This

manufacturing method helps to design a

particular channel configuration, as shown in the

following proposal sketches.

The first proposal consists of two parts and two

milled channels. It is necessary to think about the

simplest way to refresh the cavity base, with two

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inlet/outlet and sprue cooling circuits. The

inconvenience of this configuration could be the

distance route; probably at a medium distance,

the water is hot, see Figure 11. Finally, the

proposed channel profile is rectangular.

Figure 11. Sketch proposal 1: two parts, two milled

channels.

Regarding proposal two: it considers four circuit

drilled channels. Here, the main idea is due to a

similar product geometry in its container and

good cooling results obtained to implement these

drilled hole configurations (see Figure 12).

Figure 12. Sketch proposal 2: implemented cooling circuit.

Proposal 3 comes from various equal

distributions [35]; the main problem is the space

between the inlet/outlet water; in this case, there

is no way to the coolant, see Figure 13.

Figure 13. Sketch proposal 3: two parts, manifold equal

distribution.

Fourth proposal: considers two parts and the

circular milled channels taking advantage of the

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plastic distribution inside the cavity. It is needed

to remark that the cooling configuration is made

by a radius from the center to edges to get a better

heat distribution by the rectangular profile

channel to the injected plastic flow, as shown in

Figure 14.

Figure 14. Two parts: circular milled channels.

3.3 Decision Method

Concept selection is an extensive process that can

include sub-iterative stages associated with

concept generation and testing. A design team

can refine and improve concepts by ways such as

concepts screening and scoring [32].

Once the general concept of the scheme has been

developed, it is necessary to carry out the process

of selecting one or two proposals to perform the

numerical simulation for the new mold part.

The process of "Concept Screening" aims to

narrow the number of concepts quickly and

improve them. Table 1 shows the scoring.

Table 1. The concept screening matrix.

The selection process in the screening matrix is

based on general information to delete or

improve the proposals. The characteristics to

evaluate the "Scoring process" are more specific

and help a team choose one or two options for the

following product development stage. Because

the variables involved are economical,

manufacturing, fitting, and design, it is

impossible to place an Equitable evaluation

scale. Generally, it is easiest to focus a discussion

by rating all the concepts concerning one

criterion at a time, as shown in Table 2.

Table 2. Rate the concepts

Table 3 presents the final scoring selection

matrix.

Table 3. The scoring matrix.

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According to the scoring selection matrix, the

best proposal to simulate is the fourth concept

which considers two parts and circular milled

channels. However, as mentioned previously, the

implemented idea in proposal two is similar to a

previous product. Therefore, a numerical

simulation of the current cooling system will be

performed as a reference.

3.4 Develop 3D models

The geometries considered in the following

proposals were developed in the CAD software

of the company Siemens, denominated NX 12

[38].

Proposal 1

Here the consideration goes to the original design

(see Figure 8); in this way, the correct heat

distribution could be known and give another

reason to redesign the current cooling system

knowing the zones with bad heat transfer, to

implement the new HR system.

Proposal 2

In this proposal, drilled holes are made through

the steel piece to create a continuous water

circuit, manufacturing in one steel piece; see

Figure 15a to Top view and Figure 15b for cross-

section view.

Figure 15. 3D model of proposal 2, a) top view and b)

section view.

Proposal 3

The cooling circuit set designed in this

consideration needs to have a correct fix

configuration and a balanced inlet/outlet water;

Top view and a cross-section view are shown in

Figure 16a and Figure 16b as corresponding.

Figure 16. Proposal 3 a) top view and b) section view.

3.5 CAE validation

The objective of the simulation is to know the

temperatures of plastic, flow, and cooling

behavior to analyze if a new cooling system will

be good or bad. The numerical simulations were

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performed in Moldex3D, software for injection

plastic simulation. First, the cooling and product

were modeled to a case setting. Second, the

proposed cooling cases, current cavity, and core

cooling had to be modeled according to original

specifications. Next, Figure 17a presents the

current circuit cooling modeled in green; then,

Figure 17b shows the final cooling proposal 2

with sprue bushing cooling and four inlet/outlet.

Finally, Figure 17c shows the milled circular

cooling circuit of proposal 3.

Figure 17. Final 3D cooling model a) current design, b)

proposal 2, and c) proposal 3.

The numerical simulation mesh was performed,

as shown in Table 4.

Table 4. Characteristics of the numerical simulation

meshes.

The used polymer was a Polypropylene (PP),

Braskem manufactured with the grade name

Braskem PP CP 442 XP, with a viscosity

behavior shown in Figure 18.

Figure 18. Braskem PP Viscosity-shear rate plot at three

temperatures 200 °C, 240 °C, and 280 °C

The injection process was performed with

parameters shown in Table 5.

Table 5. Process condition parameters.

Once the process is OK and saved, continue to

analysis type. To this simulation, a "F P C W"

(Filling, Packing, Cooling, and Warpage) was

selected to get Injection results. Now, the

numerical simulation can be performed for the

data analysis.

3.5 Result Analysis

The interpretation of the results is crucial for

repairing or redesigning the mold or molding

parts. It is derived from comparing the two

results vs. the original cooling concept.

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The cooling temperatures show the distribution

of the current plastic product. In Proposal 2,

Figure 19b, a difference in cooling temperature

is visible due to variable distance from molding

area to drilled hole; this is a cause of defects like

warpage and deformation or different shrinkage.

In proposal 1, the difference is minor according

to cold runner injection, Figure 19a. Proposal 3,

Figure 19c, has a good temperature distribution

due to equal distance from molding surface to

cooling channel; this helps to reduce quality

defects like deformation.

Figure 19. Cooling temperatures in a) current, b) proposal

2, and c) proposal 3.

According to the polymer maker, the safe time to

reach ejection temperature (TTRET) is when the

plastic part is at the temperature of 108°C or

lower. Therefore, due to a cold runner injection

and minor injection temperature, the best option

is proposal 1, with a TTRET average of 4.4 secs

with 65% of total volume, Figure 20. Proposals 2

and 3 have a similar behavior due to injection

setup, but the injection parameters are different

to make the injection process better and increase

the temperature. The result is a better response in

the cooling system, see figure 20.

Figure 20. Histogram TTRET.

With the current cooling system, Figure 17a, the

maximum cooling temperature in thickness is

110°C in 81% of total volume. Therefore, the

best option is proposal 3; according to figure 21,

41% of the volume is at 110°C, and 42% is at

115°C; instead, proposal 2 the 42% is 127°C,

heater that proposal 3 and current condition.

Figure 21. Maximum cooling temperatures.

The mold temperature differences (figure 22)

show the final cavity and core at the end of

cooling time; even proposals 1 and 3 have good

heat conductivity. Proposal 3 is the best due to a

higher injection temperature, Figure 22c.

Proposal 1, Figure 22a, has a good mold

temperatures distribution with an average of

10°C. Proposal 3, Figure 22b, shows the heat

transfer pattern due to the profile cooling

channel; its design has cooler lines caused by the

circular drilled channel.

1.5 3.2 5.7 9.7 13.7 17.6

Volume [%]

Time [sec]

Current Prop 2 Prop 3

100

110 115 127

Volume [%]

Temperature [°C]

Current Prop 2 Prop 3

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Figure 22. The mold temperature difference in a) current

system, b) proposal 2, and c) proposal 3.

Even proposals two and three have similar

behavior. Therefore, the best option is proposal

three due proposal two has a different heat

difference. However, this will cause problems

like deformation, heat zones, and a higher cycle

time.

3.5 Detail design

Once the analysis of the results, it is necessary to

work on the final dimensions of the 3D models,

create the 2D drawings (with GD&T

specifications) and finalize the assessment

format to indicate processes and sub-processes

involved in the parts modified. Finally, it is

necessary to detail the critical aspects in the 3D

models, the 2D drawings (exploded and

assembled), BOM (for large assemblies), and

assessment.

4. Conclusions

The proposed methodology can be used for

repairs and redesign. In this research, the results

were essential to making the right decisions

about CAD Models to simulate, what kind of

results to calculate and analyze, and finally,

define the proper way to take in repair or redesign

with a CAE-Theoretical base.

The validation by Computer-Aided Engineering

is a stage that reinforces the designer's experience

and facilitates decision-making for

inexperienced engineers in the repair and

redesign of molded parts.

In this study, the results are significant for

choosing an accurate cooling system to reduce

cooling cycle time, improve the quality of plastic

products, and avoid different temperatures

during the cooling stage. Otherwise, the mold

modification could be implemented in a cooling

system like Figure 15, causing cooling problems

and quality issues like deformation.

The numerical simulation helped avoid the mold

repair, rework and carry out a successful repair in

a single intervention, avoiding production delays,

reprogramming the production of molds, and

wasting time due to a machine without a mold.

The methodology to implement CAE validation

is a tool that modifies the process of redesigning

and reparation of molded parts. At first glance, it

seems to lengthen the process, but the reward of

that extra time of analysis and validation consists

of avoiding the rework of a failed repair.

5. Authorship acknowledgements

Natanael González: Conceptualización;

metodología; validación; escritura; revisión;

administración de proyecto; software;

investigación; visualización; escritura borrador;

escritura revisión y edición. Victor Hugo

Mercado-Lemus: Conceptualización;

metodología; validación; escritura; revisión;

administración de proyecto; software;

visualización. Maricruz Hernández-

Hernádez: Conceptualización; metodología;

validación; escritura; revisión; administración de

proyecto. Hugo Arcos-

Gutierréz: Conceptualización, metodología,

validación, escritura, revisión, administración de

proyecto, análisis formal. Isaías E.

Garduño: Conceptualización; metodología;

validación; escritura; revisión; administración de

15 ISSN: 2594-1925

Revista de Ciencias Tecnológicas (RECIT). Volumen 5 (1): e216.

proyecto; escritura borrador: escritura revisión y

edición.

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