Samrudhi Rovalekar - Fab Academy

Assignment Brief:

As a group assignment: Complete your lab's safety training.
Test machine parameters: Runout, alignment, fixturing, speeds, feeds, materials, and toolpaths.
Design a large (~meter-scale) object. Mill the designed object using the tested machine settings. Assemble the milled parts into a final product.

Computer-controlled cutting

A computer-controlled machine is a machine that operates using pre-programmed instructions from a computer rather than manual control. These machines follow precise digital commands to perform tasks like cutting, milling, engraving, 3D printing, or assembling.

CNC (Computer Numerical Control) Machines

A CNC machine is an automated manufacturing tool controlled by a computer using numerical commands. It eliminates the need for manual operation by following pre-programmed instructions, allowing for high precision, repeatability, and efficiency in shaping various materials like metal, wood, plastic, and composites.

Types of CNC Machines

CNC Milling Machine: Uses rotating cutting tools to remove material, available in 3-axis, 4-axis, and 5-axis models.

CNC Lathe: Spins the material while a cutting tool removes excess material, ideal for cylindrical objects.
CNC Router: Similar to a milling machine but mainly used for wood, plastics, and soft metals. This is the CNC router that we use in the Riidl Fab lab.
CNC Laser Cutter: Uses a laser beam to cut or engrave materials like wood, acrylic, and metal.
CNC Plasma Cutter: Uses a plasma torch to cut electrically conductive materials.
CNC Waterjet Cutter: Uses high-pressure water with abrasives to cut through hard materials like stone and glass.

How CNC Machines Work

CAD (Computer-Aided Design): The design is created in software like AutoCAD, Fusion 360, or SolidWorks.
CAM (Computer-Aided Manufacturing): The design is converted into G-code for machine execution.
Machine Setup: The material is fixed, and tools are prepared.
Execution: The machine follows the G-code to cut, drill, or shape the material.
Finishing: The product is removed, inspected, and polished.

Advantages of CNC Machines

High Precision: Ensures accuracy up to microns.
Repeatability: Produces identical parts consistently.
Efficiency: Faster production compared to manual machining.
Flexibility: Can produce complex designs with multiple tools.
Reduced Waste: Optimized cutting paths minimize material loss.

Riidl Fablab CNC Machine: Numac Hitech CNC machine

The Numac Hitech CNC machine is a high-precision, large-format CNC router designed for cutting, engraving, and milling various materials. Given its 8' x 4' (2400 mm x 1200 mm) bed size, it is ideal for working with full-size sheets commonly used in fabrication and industrial design.

Key Features

Large Work Area: Supports full-size 8' x 4' sheets, making it ideal for furniture-making and industrial projects.
High-Precision Cutting & Milling: Supports 2D and 3D cutting with accurate toolpath execution.
Optimized for Large-Scale Production: Batch processing and material optimization reduce wastage.

Group work

Safety instructions for using the CNC router:

Wear PPE: Use safety goggles, ear protection, and a dust mask.
Check the Work Area: Ensure the machine bed is clean and free of obstructions.
Secure Material: Properly clamp the workpiece to prevent movement.
Inspect the Machine: Check tool tightness, spindle alignment, and emergency stop function.
Set Correct Parameters: Use appropriate feeds, speeds, and depth for the material.
Stay Clear: Keep hands and loose clothing away from moving parts.
Monitor Operations: Never leave the machine unattended while running.
Use Proper Ventilation: Ensure adequate airflow to remove dust and fumes.
Emergency Preparedness: Know the location of the emergency stop and fire extinguisher.
Power Down After Use: Turn off the CNC machine and clean the work area.

Testing machine parameters: Runout, alignment, fixturing, speeds, feeds, materials, and toolpaths.

Recent Projects:

Fabricating 3D letters: TOSS

I, along with the help of my friends Sharvari Akerkar and Kanika Kadam. have recently built, designed and fabricating large 3D letters for TOSS, the annual sports event at Somaiya Vidyavihar University. Learn more about TOSS at the attatched link here. The event took place recently, and the goal was to create a bold and striking installation that serves as a visual centerpiece on the grounds of Somaiya Cricket Ground, Sion.

Find the complete documentation video at @abstract_s16.

Process: Design and Fabrication of 3D Letters, TOSS

1. Conceptualization & Design Development

The process began with designing the letters, ensuring they were visually impactful and aligned with the official TOSS event branding. The TOSS logo is as below

Logo Tracing in Adobe Illustrator: The first step involved tracing the official TOSS logo in Adobe Illustrator. This process required precision to ensure that the curves and typography matched the original branding. The traced version was then converted into scalable vector outlines, allowing for high-resolution resizing without distortion.
Exporting to Fusion 360 for CNC Manufacturing: Once the tracing was complete, the vector file was imported into Fusion 360 in DXF format. Here, exact dimensions were defined for each letter, ensuring proper proportions and alignment. Fusion 360 allowed for precise parameter-based modeling, which was crucial for ensuring that the design translated seamlessly into the CNC manufacturing process.

CNC Machining Setup The Numac Hitech CNC router (8' x 4' bed) is calibrated for precision. Key machine parameters set include: Toolpaths: Contour cuts for letters Fixturing: Clamping the plywood securely Speeds & Feeds: Adjusting spindle speed and feed rate for optimal cutting A test cut is performed on scrap material to confirm alignment and depth settings.

Cutting & Fabrication: The CNC machine mills out the letters while ensuring smooth edges. Post-cut, the edges are hand-finished using sanding tools to remove rough fibers. Structural reinforcements are added for stability if required, ensuring the letters stand upright when placed outdoors.

Assembly & Installation: The finished letters are assembled on-site at Somaiya Cricket Ground. If necessary, a base support system is added to withstand outdoor conditions like wind. The final installation serves as a visual centerpiece for the TOSS event, making a bold and striking statement.

Final Outcome:

Find the complete documentation video at my Instagram Page reel @abstract_s16.

My learnings

Working with flexible plywood introduced unique challenges that needed to be addressed throughout the fabrication process.

Designing with manufacturing constraints in mind was a crucial step to ensure efficiency and sustainability in production.

Optimizing Letter Sizes: One of the key considerations was optimizing the size of each letter to fit within a single standard plywood sheet measuring 8' x 4' (2400 mm x 1200 mm). This approach significantly reduced material wastage, minimized cost, and simplified the assembly process. Layout nesting techniques were used in Fusion 360 to arrange the letters efficiently on the sheet.

Parametric Book shelf

My learnings

Precise slot dimensions are crucial. If the slots are too loose, the structure may wobble or collapse. If too tight, assembly becomes difficult and may require force, potentially damaging the material. While i build this structure I realized that my slot joinery was a loose fit, which made the structure stand on straight as well as slanted angles. The slanted angular structure was very firm, but it's base wasn't to the ground. On the other hand, If I placed the structure on with straight lines, it was parellel to the base but the stability was a little low. Thought the model was functional, I realised that a kerf test was required before building the model.

The interlocking nature of the slots provides structural integrity without requiring screws or adhesives. Slot positioning and orientation affect weight distribution. A crisscross or staggered slot pattern increases balance and load-bearing capacity.

My assignment

A previous work on CNC had made me well acquainted with the processes and outcomes the machine could give. Thus, for this week I thought of building someething out of the box. I was suggested to go with something with ease of production, but that would limit my limit of reach. Further, I explored the intesity and exception of production of the CNC machine.

So I recalled that I aspired to build a wall mount interactive structure. This was my initial idea for final project of making an interactive wall mounted frame. Find the description about it in my final project documentation here.

I thought ways of interactivity, to which a musical emitting caught my mind. Using Human powered mechanisms, I thought of a design idea for a musical wall mount that serves as both a functional interactive unit and a decorative piece

One the sketch was ready, I Imported the image on Illustrator and traced each of the elements as different layers. gimp1

This is the prototype of my musical wall mount, created using layered cardboard to represent different structural elements. The blue pins indicate anchor points for strings, which will be stretched between them. Once attached, these strings can be plucked or strummed, producing sound, making the design not just a visual installation but also an interactive musical piece. This prototype helps visualize form, function, and material connections before developing the final version. The attatchment between each of the models will be with dowels.