Week 13 - Molding and Casting

The group assignment was documented in detail on the lab page. In this personal page I include a short summary of the work: we reviewed the safety information for the molding and casting materials, made small test casts, and compared CNC milling, TPU printing, and resin printing as mold-making technologies.

Assignment Requirements

• Review the safety data sheets for each molding and casting material.
• Make and compare test casts with each material.
• Compare printing molds versus milling molds.

Safety Summary

Material	Safety Focus
Silicone rubber	Use gloves and clean containers, mix the two components correctly, avoid contamination, and respect curing time.
Photopolymer resin	Use nitrile gloves, eye protection, ventilation, careful cleaning, and UV post-curing before handling the final part.
Plaster and wax	Avoid plaster dust inhalation, control heat when using wax/paraffin, and clean spills before they harden.
MDF and 3D printing materials	Use dust extraction for CNC milling, avoid hot printer parts, and work in a ventilated area.

Process Comparison

Technology	Result
CNC milling	Best option for a rigid master mold; it requires dust extraction, machine setup, and PPE.
TPU printing	Useful for flexible molds and easier demolding; layer texture can transfer to the cast.
Resin printing	Best surface detail; it needs strict chemical handling, cleaning, drainage, and UV curing.

The conclusion was that the best technique depends on the priority of the part. CNC milling is more stable for master molds, TPU helps with flexible demolding, and resin gives better surface detail but demands stricter chemical safety.

View Full Group Assignment Page

Individual Assignment

Design a mold according to the selected manufacturing process, produce it with a smooth surface finish, and use it to cast parts.

Extra Credit

• Use more than two mold parts.
• Make or experiment with custom materials.

This project focuses on the complete process of molding and casting using a human face as the main model. The workflow starts with a digital scan of a person's face, followed by 3D model correction, mold design, 3D printing, and finally casting using wax and paraffin.

The objective was to understand how digital fabrication tools can be combined with traditional molding and casting techniques to create a physical reproduction of a scanned face.

As the first step, the face of a person was scanned using a program called Creality. This software allows the physical face to be converted into a digital 3D model.

The scan captured the general shape of the face, but like most 3D scans, the model presented some imperfections, rough areas, and small geometry errors that needed to be corrected before producing the mold.

After obtaining the scanned model, the file was imported into Blender. In this software, the imperfections of the scanned face were corrected. The main purpose of this step was to clean the geometry, improve the surface, and prepare the model for mold creation.

Blender was used to adjust the shape, repair irregular areas, and improve the final appearance of the face. This step was important because any error in the digital model could appear later in the printed mold or in the final cast.

Once the face model was corrected, the next step was to design the molds in the same software, Blender. The mold was created around the face model, considering the shape, parting line, and the way in which the cast material would be poured.

The mold design had to be strong enough to keep the shape of the face and also allow the material to be removed after casting. For this reason, the design considered the mold parts and the container that would later hold them firmly during the casting process.

After finishing the mold design, the files were exported in STL format in order to prepare them for 3D printing.

Once the TPU molds and PLA container were ready, the casting process was carried out using candle wax and paraffin. These materials were melted and poured into the mold to reproduce the shape of the person's face.

The container helped keep the molds stable during pouring. After the material cooled and solidified, the cast was removed carefully from the mold.

This process made it possible to obtain a physical reproduction of the scanned face using a combination of digital manufacturing and casting techniques.

The face model was also printed directly in resin using the ANYCUBIC resin printer. This allowed a more detailed physical version of the scanned face to be obtained.

Resin printing provides a smoother surface finish compared to FFF printing, which is useful when the project requires fine details and better visual quality.

A casting process using plaster was carried out to reproduce the facial mold obtained from the 3D printing stage. Plaster was selected because of its easy preparation, low cost, and ability to capture fine surface details after hardening.

During the process, the plaster mixture was prepared manually and poured carefully into the mold cavity. After the curing stage, the final piece was removed and inspected to verify the surface quality and dimensional accuracy of the cast.

As an additional molding technique, a silicone rubber mold was produced from the same scanned face model. Instead of printing the mold directly, the digital model was used to create a rigid base mold through CNC machining. This allowed the face geometry to be reproduced in a stronger master mold before pouring the silicone.

Materials Used for the Silicone Mold

• CNC-machined MDF base mold from the scanned face model.
• Silicone rubber for the flexible negative mold.
• Wood sealer and catalyst for surface sealing.
• Sandpaper and cutter for surface finishing and trimming.
• Mixing container, spatula, gloves, and clean working surface.

1. CNC Machining of the Base Mold

The base mold was generated from the same face scan used in the previous molding process. The geometry was prepared for CNC machining and milled into an MDF block. The objective was to create a positive face relief inside a rigid box that could later receive the silicone.

During machining, the CNC removed material around the face geometry and produced the cavity walls needed to contain the silicone. The photos show the machined surface after the operation.

Download CNC Face Base Mold STL

2. Sealing, Sanding and Surface Preparation

After machining, the MDF surface was cleaned and prepared. The surface was sanded to reduce rough machining marks, and the base was sealed to prevent the silicone from sticking strongly to the porous wood. This stage was important because an unsealed surface can absorb material, create bubbles, and make demolding difficult.

3. Silicone Mold Construction

Once the base was sealed and prepared, silicone rubber was poured into the CNC-machined mold. The silicone was selected because it is flexible, captures surface detail, and allows easier demolding than a rigid material. Care was taken to fill the cavity slowly and avoid trapping air around the face geometry.

After pouring, the mold was left to cure. The curing stage allowed the silicone to become stable and flexible enough to be removed without damaging the face shape.

4. Final Result

The final result was a flexible silicone negative mold and a rigid CNC-machined base mold. This workflow showed another way to combine digital fabrication and molding: first creating a precise rigid master with CNC machining, then using silicone to obtain a reusable flexible mold for future casting tests.

Material	Use	Reason for Selection
Candle wax	Casting material	Easy to melt and useful for testing the mold.
Paraffin	Casting material	Allows the face shape to be reproduced after cooling.
PLA	Mold container	Provides rigidity and structural support.
Plaster	Casting and mold material	Provides a rigid structure and allows detailed reproduction after hardening.
Resin	Resin molds and face print	Provides better detail and smooth surface finish.
TPU	Flexible mold	Allows easier demolding due to its flexibility.
MDF	CNC-machined base mold	Provides a rigid master mold for the silicone rubber casting process.
Silicone rubber	Flexible negative mold	Captures surface details and allows easier demolding after curing.
Wood sealer and catalyst	Surface sealing	Reduces material absorption and improves demolding from the MDF base.

Safety was an important part of the molding, casting, and resin printing process. Each machine and material had to be used carefully in order to avoid accidents, equipment damage, or failed prints.

• Use nitrile gloves when handling resin.
• Gloves for thermal support.
• Use a mask because resin has a strong odor.
• Work in a ventilated area.
• Avoid direct skin contact with uncured resin.
• Use the 3D printers carefully to prevent machine failures.
• Check the correct printer settings before starting each print.
• Handle melted wax and paraffin carefully to avoid burns.
• Keep the workspace clean to avoid contamination of the mold and materials.

1. The person's face was scanned using Creality software.
2. The scan was converted into a 3D model.
3. The 3D model was corrected in Blender.
4. The face molds were designed in Blender.
5. The mold files were exported in STL format.
6. The flexible molds were printed in TPU using the FLSUN printer.
7. The mold container was printed in PLA using the FLSUN printer.
8. The molds were assembled inside the PLA container.
9. Candle wax and paraffin were used to cast the face.
10. The molds were also prepared in Chitubox Basic for resin printing.
11. The resin molds were printed vertically using an ANYCUBIC resin printer.
12. The face was also printed directly in resin.

The project successfully combined 3D scanning, digital modeling, mold design, 3D printing, and casting. The use of TPU allowed the creation of flexible molds, while PLA provided a rigid structure to hold the molds during casting.

The resin printing process also made it possible to obtain molds and a face model with better surface detail. The casting with candle wax and paraffin demonstrated that the mold could reproduce the shape of the scanned face.

In this final casting test, I used a transparent epoxy resin to reproduce the scanned face using the mold system. The objective was to test a material with a different behavior from plaster, wax, and paraffin. Epoxy resin was useful because it flows into the mold cavity, cures as a rigid solid, and creates a translucent result where small bubbles, surface marks, and mold details can be clearly observed.

Before mixing the resin, the workspace was prepared with a silicone mat, disposable cups, spatulas, gloves, safety glasses, and the two epoxy components. The mold was cleaned and placed on a flat surface so the resin could settle evenly during curing. The resin used was Wesco EPOX-21, composed of Component A and Component B.

Exclusive Product Technical Datasheet: Wesco EPOX-21 Dura Quarz

The casting material used in this section was the Wesco EPOX-21 Dura Quarz epoxy resin kit. I documented it as an independent technical subsection because the final quality of a casting depends directly on the correct resin selection, mixing ratio, working time, curing time, thickness limit, and safety handling. The information below combines the data observed on the product label used in the lab, the attached technical datasheet, and the commercial reference from Pintulac for the 2:1 Dura Quarz kit.

This resin was selected because it produces a rigid and transparent casting, which made it suitable for reproducing the face geometry and inspecting the internal quality of the result. Since the material is a two-component system, the process required measuring both components carefully before mixing. An incorrect ratio can cause incomplete curing, excessive softness, sticky surfaces, or loss of transparency.

Technical Item	Product Information	Application in this Casting Test
Commercial product	Kit Resina Epoxica 2:1 Dura Quarz de 1 kg - Wesco	Used as the transparent casting material for the face reproduction.
Brand / line	Wesco EPOX-21, Dura Quarz epoxy system	The resin was handled as a two-component casting system.
Supplier reference	Pintulac product page: EPOX-21 Dura Quarz 2:1 kit	The link was included to identify the exact commercial kit used for the experiment.
Components	Component A resin + Component B hardener	Both bottles were prepared before starting, so the mixing and pouring could be done within the working time.
Mixing ratio	2 parts A : 1 part B by weight	The ratio was followed to obtain a complete cure and avoid sticky or soft areas.
Working time / pot life	Approximately 60 minutes at 25 °C	The components were mixed and poured before the viscosity increased.
Curing time	Approximately 10 hours at 25 °C	The mold was kept level and undisturbed during curing.
Dry-to-handle time	Approximately 12 hours at 25 °C	The cast was handled carefully after the cure, allowing additional time for surface stabilization.
Maximum application thickness	4 cm	The face cavity was filled below this limit to reduce overheating, bubbles, and curing defects.
Expected appearance	Clear or translucent glossy solid after curing	The transparent finish allowed visual inspection of bubbles and surface marks.
Recommended PPE	Nitrile gloves, safety glasses, clean containers, spatula, and ventilated workspace	PPE was used during measuring, mixing, pouring, and demolding preparation.
Main process risks	Incorrect ratio, air bubbles, skin contact, contamination, and incomplete curing	The process was controlled by slow mixing, clean tools, careful pouring, and keeping the mold still.

The technical datasheet was stored with the assignment files so that the material selection can be reviewed later. This is important for reproducibility: anyone repeating the casting process can check the product version, ratio, curing behavior, and handling precautions before using the resin.

Download EPOX-21 Technical Datasheet PDF

Epoxy Resin Specifications Used in the Lab

Property	Specification Used	Observation
Material	Wesco EPOX-21 epoxy resin	Two-component transparent resin for casting applications.
Components	Component A + Component B	Both parts must be mixed before pouring.
Mixing ratio	2 parts A : 1 part B by weight	This ratio was taken from the product label.
Pot life	Approximately 60 minutes at 25 °C	Working time available after both components are mixed.
Curing time	Approximately 10 hours at 25 °C	The piece was left undisturbed while the resin hardened.
Drying time	Approximately 12 hours at 25 °C	Additional time helps the surface become more stable before handling.
Maximum application thickness	4 cm	The face mold was filled below this limit.

EPOX-21 Technical Sheet for Casting

The following technical sheet was prepared specifically for the EPOX-21 casting section. It summarizes the practical information needed before mixing and pouring the material into the face mold. The values were taken from the product label and were used as the reference for this casting experiment.

Technical Item	EPOX-21 Data	How it was applied in this project
Product name	Wesco EPOX-21	Used as the transparent casting material for the scanned face reproduction.
Material type	Two-component epoxy resin system	The resin cures through the reaction between Component A and Component B.
Components	Component A + Component B	Both components were prepared before starting the mixture to avoid delays during the working time.
Mixing ratio	2 parts A : 1 part B by weight	The ratio was respected to avoid incomplete curing, sticky areas or a soft final piece.
Working time / pot life	Approximately 60 minutes at 25 °C	The resin was mixed and poured within this time window before viscosity increased.
Curing time	Approximately 10 hours at 25 °C	The mold was kept level and undisturbed while the resin hardened.
Dry-to-handle time	Approximately 12 hours at 25 °C	Extra waiting time was considered before handling the piece more firmly.
Maximum application thickness	4 cm	The face cavity was filled below the maximum thickness recommended on the label.
Expected finish	Transparent or translucent glossy solid	The final casting made it possible to inspect bubbles, surface marks and mold detail reproduction.
Recommended mixing method	Slow and continuous manual mixing	The spatula was moved slowly while scraping the cup walls and bottom to reduce unmixed zones.
Pouring method	Controlled pour from one side of the mold	The resin was poured gradually so it could flow through the cavity and reduce trapped air.
Personal protective equipment	Nitrile gloves, safety glasses and ventilated workspace	PPE was used during component handling, mixing, pouring and demolding preparation.
Main process risks	Incorrect ratio, bubbles, skin contact, contamination and incomplete curing	The process was controlled by measuring components, using clean cups and keeping the mold still during curing.
Storage and handling	Keep containers closed and avoid cross-contamination	Separate tools and disposable cups were used to prevent premature reaction between components.

Mixing Process

The first step was to estimate the amount of resin needed to fill the face cavity. After that, Component A was poured into a disposable cup and Component B was added following the 2:1 ratio by weight. This proportion was important because an incorrect mixture can leave the piece soft, sticky, or incompletely cured.

The two components were mixed slowly with a spatula. I scraped the sides and bottom of the cup to make sure both liquids were fully combined. The movement was kept slow and continuous because fast stirring introduces many air bubbles. Once the mixture looked uniform, it was poured carefully into the mold from one side, allowing the resin to flow across the cavity instead of trapping air inside the face details.

After pouring, the mold was kept level and was not moved during curing. The resin was left to cure for approximately 10 hours at 25 °C. After this curing period, the piece was demolded carefully from the flexible mold. A longer resting time was useful before final handling because the surface continued stabilizing after the first cure.

Final Finish

The final cast had a translucent and glossy appearance. The face profile was reproduced correctly, and the transparent material made it easy to inspect the internal volume of the casting. Some small bubbles and surface marks were visible, especially in the curved areas of the head and near the facial profile. These marks show how sensitive epoxy casting is to mixing speed, pouring direction, and mold surface quality.

For a future iteration, the finish could be improved by mixing more slowly, letting the resin rest briefly before pouring, vibrating the mold gently to release trapped air, or using a vacuum chamber if available. Even with these imperfections, the result was useful because it confirmed that the mold can reproduce the scanned geometry using a rigid, transparent casting material.

This molding and casting project demonstrated how digital fabrication tools can be used to transform a real human face into a physical object. The process started with face scanning, continued with model correction and mold design in Blender, and ended with 3D printing and casting.

The use of different materials such as TPU, PLA, resin, candle wax, and paraffin allowed comparison between flexible molds, rigid containers, resin molds, and casting materials. This experience helped to understand the importance of material selection, mold design, surface finish, printer configuration, and safety protocols.