week 07

Computer-Controlled Machining

Class with Neil

During Week 07 – Computer-Controlled Machining of the Fab Academy, we learned about the fundamentals of manufacturing large parts using CNC machines. The class focused on the workflow from CAD design to CAM toolpath generation, as well as key machining parameters such as feed rate, spindle speed, tool selection, and safety considerations when operating CNC routers.

This week we also had guest presentations from Tom Bodett and Tony Schmitz. Tom Bodett shared insights about creativity and communication in the development of ideas and projects. Tony Schmitz, a professor at the University of Tennessee and an expert in advanced manufacturing, spoke about machining dynamics and how research helps improve precision and efficiency in CNC machining processes.

Overall, this week helped me understand how computer-controlled machining allows the fabrication of large and precise components, which is essential for building structural parts and prototypes in digital fabrication projects.

Group Assignment:

°Complete your lab's safety training

° Test runout, alignment, fixturing, speeds, feeds, materials and toolpaths for your machine

° Document your work to the group work page and reflect on your individual page what you learned

Have you answered these questions?

I. Linked to the group assignment page. ✅
II.Documented how you designed your object and made your CAM-toolpath✅
III.Checked your board can be fabricated ✅
IV. Documented how you milled and assembled your final product (including setting up the machine, fixturing, feeds, speeds etc.). ✅
V. Described problems and how you fixed them ✅
VI.Included your design files and 'hero shot' of your final product✅

Group Assignment Sumary

Before starting the individual work for Week 07 – Computer-Controlled Machining of the Fab Academy, our group organized a virtual meeting the day after the theoretical class to attend the Lab’s Safety Training. During this session, we learned about the essential safety measures required when working in the laboratory, including proper behavior, risk awareness, and the importance of maintaining a safe and organized workspace. We were also introduced to the meaning of different safety signs used in laboratories and workshops: red indicates danger or emergency situations such as machine shutdown systems, blue represents mandatory actions like the use of personal protective equipment (PPE), yellow signals warnings or potentially hazardous areas, and green identifies safe conditions or locations of first aid equipment. This training helped us better understand how to work safely when using digital fabrication machines.

Group Assignment Sumary

Later, we met in person at the FabLab UNI to carry out the group assignment. At the beginning of the session, we received an additional safety briefing before operating the ShopBot PRSalpha 96-48 CNC router, where we reviewed the proper procedures and precautions needed to safely work with large computer-controlled machines in the lab.

1.Router Tools Used

During the Electronics Design week, we worked with different measurement and programming tools to evaluate and confirm the performance of our electronic board. These tools allowed us to generate and analyze electronic signals to verify that the circuit was functioning properly. Throughout the process, we observed signal waveforms, checked voltage levels, ensured there were no short circuits, and confirmed that the generated signal remained stable.

🔫 Cordless Drill / Screwdriver

For the first step of the fabrication process, I used a cordless drill/screwdriver. This tool allowed me to easily drive screws into the wood and securely assemble the structure. Cordless drills are portable power tools powered by rechargeable batteries and are commonly used for drilling holes and driving screws in construction and carpentry tasks. :contentReference[oaicite:0]{index=0}

The drill provided enough torque to quickly fasten the screws and ensure a firm connection between the wooden parts.

🔩 Wood Screws

Wood screws were used to join the structural components of the project. These screws penetrate the wood and create strong mechanical joints that hold the material firmly together.

In woodworking, screws are commonly used together with drills or drivers to assemble wooden parts efficiently and securely. They provide a strong and reliable fastening method for structural assemblies. 🔩

🚪 Phenolic Plywood (18 mm)

The material used for this step was an 18 mm phenolic plywood board. This type of plywood is widely used in digital fabrication and construction due to its strength, durability, and resistance to deformation.

The screws were used together with the drill to securely fix the plywood pieces, ensuring a stable base for the next stages of the project. 📏

2.Router Tools Used

🔧 Wrenches for Spindle Adjustment

These wrenches are used to tighten or loosen the spindle nut in order to install or remove the milling bits. Using the correct wrench ensures that the tool holder is properly secured.

Tool type: Open-end wrench
Function: Tightening the spindle nut
Use: CNC tool installation

⚙️ Collet / Tool Holder

The collet (tool holder) is the component that holds the milling bit inside the spindle. It ensures that the bit remains centered and stable during the machining process.

Component: CNC collet
Function: Holding the milling bit
Importance: Precision and stability

🪚 Milling Bits (3mm / 6mm)

Milling bits are the cutting tools used by the CNC machine to remove material. In this process, 3 mm and 6 mm drill bits were used depending on the type of cut and machining requirements.

Sizes: 3 mm and 6 mm
Use: Cutting and drilling
Application: CNC machining

🔍 1. Refletions

During this assignment, I understood the importance of following safety procedures when working with fabrication tools and CNC machines. Applying safety measures and paying attention to warning signs is essential to prevent accidents and maintain a safe working environment. The proper use of personal protective equipment (PPE) and careful handling of tools such as drills, wrenches, and CNC components helps ensure safe and efficient work in the lab.

Later, I learned how to prepare the CNC machine by installing the milling tools correctly. Using the wrenches, I adjusted the spindle nut and mounted the collet holder, where the milling bits of 3 mm and 6 mm were placed. This setup was important to guarantee stability and precision during the cutting process.

individual Assignment:

° Make (design+mill+assemble) something big

1. Introduction

During this week, I learned the process of computer-controlled machining by designing, milling, and assembling a small shelf using a CNC router. The project was made with 18 mm phenolic plywood, starting from the digital design, followed by the milling process, and finally assembling the pieces.

This assignment helped me understand how a digital design can be transformed into a physical object, as well as the importance of proper material preparation, tool selection, and accurate assembly to create a stable and functional structure. 🪵⚙️

📊 2. Furniture Sketch

Before starting the machining process, I created a sketch to define the structure and dimensions of the wall shelf made from 18 mm phenolic plywood (triplay). The sketch helped me visualize how the different parts would fit together and plan the joints and screws needed for the assembly.

This initial drawing served as a guide for the digital design and ensured that the pieces were suitable for CNC milling and final assembly. 🪵📐

📈3. 3D Modeling:

The 3D model of the shelf was designed using Fusion 360, where I created the digital structure of the furniture based on the initial sketch. In this stage, I defined the dimensions of each component considering the 18 mm thickness of the phenolic plywood (triplay) that would be used for fabrication.

Using Fusion 360, I modeled the different parts of the shelf, including the slots and joints that allow the pieces to fit together during assembly. This step was important to verify that all components aligned correctly and that the design was suitable for CNC milling.📐🪵⚙️

⚙️🪵4. 2D Drawings

After completing the 3D model in Fusion 360, I created the 2D drawings of each component of the shelf. In this step, the pieces were flattened and arranged to prepare them for the CNC machining process.

The 2D drawings included the outlines of the parts, slots, and joints that allow the pieces to fit together during assembly. This step was important to ensure that all the dimensions were correct and compatible with the 18 mm phenolic plywood (triplay) used in the project.

These 2D files were later used to generate the toolpaths required for the CNC router to cut the pieces accurately. 📐⚙️🪵

⚙️🪵5. Import 2D Plans into PartWorks

After generating the toolpaths, I saved the G-code file and transferred it to the CNC machine. The file was then loaded into the ShopBot3 Router control software, which is used to operate the CNC router.

Through this program, I prepared the machine to start the fabrication process. Once the file was loaded, the CNC machine followed the programmed toolpaths to cut the parts from the phenolic plywood (triplay) accurately, allowing the components of the shelf to be produced for the assembly stage. ⚙️🪵

⚙️🪵6. Material Selection:

For this project, I selected 18 mm plywood as the main material for the fabrication of the shelf. This material was chosen because it provides good strength, durability, and stability, making it suitable for furniture structures.

The thickness of 18 mm also allows the pieces to fit properly using slot joints and ensures that the shelf can support weight once assembled. Additionally, plywood is a material that works well with CNC machining, allowing clean and precise cuts during the milling process. 🪵⚙️

⚙️🪵7.Fixing the Material on the CNC Router:

⚙️🪵8. Cutting the Pieces:

During the cutting stage, the CNC machine followed the toolpaths to mill the parts of the shelf from the 18 mm plywood board. Before starting the machining process, I prepared the file in RDWorks, where I added tabs to the design.

These tabs were important because they help keep the pieces attached to the board while the CNC is cutting. This prevents the parts from moving or jumping when the milling bit follows the cutting path, ensuring that the pieces remain stable and the cuts follow the original design accurately. This step helped achieve cleaner and safer machining results. ⚙️🪵

⚙️🪵9. Sanding and Assembly:

After the CNC machining process was completed, I removed the pieces from the plywood board and cleaned the edges where the tabs were located. Then, I sanded the surfaces and edges to eliminate small imperfections and obtain a smoother finish.

Once the sanding process was finished, I proceeded with the assembly of the shelf, fitting the pieces together according to the design. To reinforce the structure and ensure stability, I used wood screws and a drill/driver to securely fix the components. This final step allowed me to complete the wall shelf (repisero) and verify that all the parts fit correctly. 🪵🔧⚙️

⚙️🪵10. Experimenting with news materials:

As part of the experimentation process, I tested a different material to observe how it behaves during machining. The material I used was a 10 mm board made from pressed recycled plastic bottle caps.

This material allowed me to explore how alternative and recycled materials react to CNC cutting. By machining this board, I could compare its behavior with plywood, observing differences in cutting quality, material resistance, and finishing. This experiment helped me better understand how different materials respond to CNC fabrication processes. ♻️⚙️

⚙️🪵10. Experimenting with news materials:

📟Difficulties (Individual)

During the development of this assignment, I faced some difficulties related to the current situation in my country. Due to government decisions requiring public institutions to maintain remote work, access to some university facilities was limited. Since the Fab Lab UNI is located inside the Universidad Nacional de Ingeniería, this situation affected the time and availability I had to work in the laboratory.

Because of these restrictions, I was not able to fully complete the assembly of all the pieces of the shelf. Some components could not be assembled as planned since I did not have continuous access to the equipment and workspace needed to finish the final structure. However, I was still able to complete the design, machining, and most of the fabrication process.

📟Group Challenges

During the group work, one of the main challenges was coordinating the use of the CNC machine and organizing the workflow among team members. Since several people needed to use the equipment, we had to carefully plan the machining times and preparation steps to avoid delays.

Another challenge was ensuring that everyone correctly understood the CNC preparation process, including setting the X, Y, and Z axes, fixing the material properly on the machine bed, and verifying the toolpaths before starting the cutting process. Small mistakes in these steps could affect the machining results.

Through collaboration and discussion, we were able to solve these issues by helping each other review the machine setup, checking the files before cutting, and sharing our observations during the fabrication process. This teamwork helped us achieve more accurate and safer results when using the CNC router. ⚙️🪵

📟7. What We Learned (Group)

As a team, we learned how to safely test an electronic board before measuring signals by first checking the power connections and possible short circuits using a multimeter. After confirming that the board was working correctly, we used the oscilloscope to analyze the signal generated by the Raspberry Pi Pico, connecting the probe ground to GND and the tip to the corresponding GPIO pin.

We also learned how oscilloscope settings such as VOLTS/DIV, TIME/DIV, and the trigger configuration affect signal visualization. Through troubleshooting issues like incorrect pin selection or unstable trigger settings, we were able to obtain a clear and stable signal and understand the difference between a multimeter reading and an oscilloscope waveform.

Files

Here are the project files available for download:

Peineta: Download .dxf
Practice design: Download .dwg
Design en Fusion 3D and 2D model: Download .f3d