Reflection on Group Work and Safety Training

This week, our group engaged in several activities starting with a comprehensive safety training session led by our teammate Evelyn from Peru. She provided clear guidelines about essential safety standards within Fab Labs, including general procedures, PPE, and common risks. This was especially useful for us at the ENA University FabLab, since our space is relatively new and still improving its internal processes.

Thanks to that session, I was able to identify areas where we could improve our own lab’s safety protocols. I even arranged a meeting with our university team to begin implementing new safety measures and awareness strategies.

As part of our group exploration, we worked with a large-format CNC machine. Due to its size and power, I initially found it intimidating, but after several days of practice I became more comfortable. We learned how to power it on safely, run basic calibration, and identify crucial steps like origin setting, material Z-height, tool types, and machine tolerances. We also explored different types of cuts and operations it allows — including roughing, pocketing, and contouring — as part of our group task.

Introduction

For my individual assignment, I didn’t want to make a large object “just for the sake of size.” Instead, I began by analyzing which item in our FabLab could benefit from a better workspace.

I identified a common issue: our small vinyl cutter had no fixed station and was frequently moved around. This inspired me to design a custom table with integrated storage that could safely house the cutter, provide workspace, and support proper cable management.

The following sections describe the full development process — from defining goals and design criteria, to preparing toolpaths and executing the job on the CNC machine, and finally assembling and testing the final piece.

1️⃣ Project Idea & Objectives

At the beginning of this assignment, I didn’t want to build a large object just to meet the size requirement. Instead, I reflected on what could be useful in our lab. We have a Cricut Maker 3 vinyl cutting machine, but no dedicated station or workspace for it — it's often moved around without a stable setup.

After searching for inspiration, I found a design on Pinterest that finally caught my attention. It was simple, functional, and included storage — exactly what I envisioned.

Of course, I couldn’t copy that exact design. CNC routing has different constraints compared to traditional furniture making. That’s why I started by considering how each part would be assembled using tabbed joints and pockets, and how material thickness would influence the fit.

I then made a rough sketch to structure the idea and later used an AI tool to generate a more polished visual that better represents the final intention for the CNC-friendly design.

2️⃣ Design Process

For this furniture project, I chose to work directly in 3D modeling using Fusion 360, and later unfold and flatten the parts for CNC machining. This is a workflow I commonly use — even in laser cutting — because it allows me to confirm dimensions, ensure all parts align properly, and anticipate the physical fit before generating toolpaths. In this case, my goal was to create a custom table for a machine that didn’t yet have a fixed location.

I started by defining the physical constraints of the space where the furniture would be placed. After measuring the available area, I determined the structure should be no more than 92 cm tall, 65 cm deep, and 100 cm wide. These values would become my fixed design limits.

Before jumping into CAD software, I always begin with traditional methods. I made a hand-drawn sketch of the full structure, including proportions and notes about the function and location of each piece. This helped me visualize the overall form and pre-plan where joints and connections would be placed.

Then I moved into Fusion 360. I began with 2D sketches of the most important elements. First, I drew the side panels. These define the height and shape of the piece. I added curves for aesthetics and included holes for horizontal pieces.

I extruded this 2D profile to 18 mm, matching the real thickness of the plywood, and turned it into a solid body. Using the mirror tool, I duplicated it across the center plane, creating a symmetric structure that would define the furniture's width.

The next step was to add horizontal braces. These would connect the two lateral panels and provide support. I started with a single 2D sketch of one brace and extruded it to the correct thickness.

After validating its fit, I placed three copies into the design: one at the base, one near the middle, and one towards the top, forming the internal shelf structure and reinforcing the rigidity of the piece.

With the base complete, I moved on to the top surface. I drew it in 2D, then added cutouts to ensure it would fit snugly on the tabs of the side panels. These cutouts were dimensioned precisely based on the real material thickness.

To ensure proper fitting during CNC cutting, I added dogbone fillets to all internal square corners of the joints. These small arcs are necessary because the CNC uses a round endmill and cannot make perfect right-angle internal corners.

After assembling all components virtually, I placed the top panel and confirmed alignment and fit with the rest of the structure. This step helped me identify any potential interference or adjustment before moving to fabrication.

As part of the testing process, I validated my tab design by physically assembling test pieces. I discovered that with my chosen tool and material, using 0 mm tolerance (no offset) was enough to produce tight-fitting joints. The parts locked together with pressure and didn’t require glue, which improves both simplicity and strength.

The material selected for this build is 18mm plywood (triplex). I chose it because the final furniture will be placed in an operational area of the lab, where it will undergo frequent use and may need to support heavy loads. I’ve also worked with this material in past projects, so I’m familiar with its behavior under CNC conditions.

Once I finalized the 3D model, I exploded and arranged the parts within Fusion 360 to prepare them for the CAM workflow. This allows a direct transition from design to toolpath generation, while maintaining dimension accuracy and nesting efficiency.

3️⃣ CAM Setup & Toolpaths

I started by defining my material in Fusion 360. In the Setup tab, I chose Fixed Size Box and entered the real dimensions of my plywood: 1130 mm width (X), 2300 mm depth (Y), and 18 mm thickness (Z). I set an 8 mm offset on X and Y, and 0 mm on Z so the tool will cut exactly through the sheet.
This tells the CAM engine the exact size and position of my stock before creating any toolpaths.

Image S – Stock Setup panel: size 1130×2300×18 mm with 8 mm X/Y offsets

Next, I arranged all the parts on the stock inside the same Setup tab. I dragged each shape into position to optimize material use and avoid waste.
This ensures the CNC only cuts where I want and maximizes wood yield.

Image 7 – Parts positioned on the defined stock

For clean-through cutting of 18 mm plywood, I chose a 6.35 mm (1/4") carbide compression end mill with 2 flutes. This tool pushes fibers downward on entry and upward on exit, leaving smooth edges on both faces and minimizing tear-out.
Compression bits are ideal for through-cuts where edge quality matters on both sides.

Image 8 – 6.35 mm carbide compression bit for dual-face finish

Attribute	Value	Purpose
Diameter	6.35 mm (1/4")	Matches material thickness for stability
Flutes	2	Good chip evacuation + finish
Type	Compression	Clean edges on both faces
Material	Carbide	High hardness, long tool life
Flute length	31.75 mm	Complete engagement through stock

I selected the 2D Contour operation in Fusion 360 to follow each part’s outline. Contour keeps the bit at a constant Z-height along the profile.
Ideal for clean profile cuts around shapes.

Image O – 2D Contour operation selected

To prevent wood tear-out when plunging, I enabled Ramp Entry under Linking > Ramp. I set a 4° ramp angle, 4.5 mm max ramp step, and 1.6 mm clearance height, allowing the bit to enter gradually.
Gradual entry reduces tool stress and material damage.

Image P – Parameters panel: feed, speeds, ramp settings, heights, tolerance

Below is a preview of the actual toolpaths in Fusion 360, showing the contour lines and ramp entries. The yellow lines represent rapid moves, and the red lines show the cutting passes.
This gives a clear view of how the machine will move.

Image T – Toolpath preview: yellow rapids and red cutting passes

🔎 Detailed Toolpath Parameters

These settings were fine-tuned from group tests to balance speed, finish, and tool life:

Parameter	Value
Spindle speed	18 000 rpm
Cutting feed rate	1 500 mm/min
Plunge feed rate	600 mm/min
Depth per pass	18 mm (full thickness)
Ramp angle	4°
Max ramp step	4.5 mm
Ramp clearance height	1.6 mm
Retract height	15 mm above stock top
Feed height	15 mm above stock top
Top height	0 mm (stock top)
Bottom height	-0.7 mm (below stock bottom)
Tolerance	0.01 mm
Sideways compensation	Left
Feed optimization	Preserve order
Tab size & spacing	10 mm × 3.5 mm every 80 mm

I carefully added tabs (10 × 3.5 mm) every 80 mm along each contour to hold parts securely until completion.
Tabs prevent premature part release and potential damage.

Image 10 – Tabs placed at 80 mm intervals

Finally, I ran a full simulation to verify there were no collisions and the tool followed the intended path cleanly within material boundaries.

Image 11 – Final simulation shows clean toolpath with no collisions

Video – CNC toolpath simulation demonstrating full operation

4️⃣ Machining Process

Before operating our CNC machine, we follow a precise startup protocol to ensure safety and proper machine performance:

• 1️⃣ Open the air valve to activate the pneumatic system (kept off to preserve the compressor).
• 2️⃣ Press the oil pump button to automatically lubricate the system before any movement.
• 3️⃣ Power on the control module.
• 4️⃣ Unlock the emergency stop, which remains engaged by default after shutdown.
• 5️⃣ Turn the energy key to enable power to the drivers.
• 6️⃣ Switch on the stepper drivers.

With the machine initialized, the first step is performing a homing sequence so that the machine locates the zero point for all axes (X, Y, Z).

Next, we prepare the sacrificial layer — in this case, a 4 mm MDF board — placed under the workpiece to allow clean-through cuts without risking damage to the machine’s bed.

The actual workpiece is then mounted on top. Due to its size and weight, this step is done carefully, using gloves and with at least two or three people.

With the material fixed, we use the handheld control to gently move the machine and define the XY origin point (usually at the lower-left corner). After that, we lower the tool to set the Z height using the touch probe — even if using a single tool, this step is critical to ensure accurate depth.

Once everything is set, we transfer the prepared CAM file to the machine and begin the cutting process. The ramp entry, feedrates, and tab configuration ensure a smooth and safe operation.

After all the pieces are cut, we wait for the machine to finish, then proceed with careful removal and tab cutting. At this point, the parts are ready for sanding and final assembly.

5️⃣ Assembly & Finishing

After machining all the parts, the first step was to remove the tabs cleanly. For this, I used a compact handheld multi-tool that acts as a fine jigsaw. It allowed me to cut the tabs precisely without damaging the surrounding surface.

Once the tabs were removed, I lightly sanded the tab areas to remove sharp edges. Fortunately, the compression bit I used left very clean cuts — with no burning and almost no burrs.

The next step was the assembly process. Using a rubber mallet, I started by joining one of the side panels with the base, carefully aligning all joints. Then I inserted the internal shelves and continued with the second side panel. Finally, I added the top surface which locks all the parts in place with a strong press-fit.

Once fully assembled, I checked for fit and structural rigidity. There were no loose joints, and the piece felt very stable. All components aligned properly, and the joints held firmly without the need for screws or glue.

Conclusions

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Personal Reflections and Lessons Learned

Designing and building furniture may seem simple at first, but it actually involves many critical factors — the machine, the tool, the material, the tolerances, and especially the assembly logic. It’s essential to think carefully about how the parts will come together before cutting, otherwise the process can quickly become overwhelming.

Thanks to previous experiences building a similar structure, I already had an idea of how to visualize this project in 3D and anticipate potential issues. This time, I didn’t face any incidents during the cutting or assembly process, but in the past I have — including breaking tools due to mistakes in CAM setup or stock calibration.

I believe those past mistakes helped me approach this project with greater awareness and precision. Especially when working on something as large and structural as a piece of furniture, experience and attention to detail really matter.

I also appreciate how this task challenged me to leave my comfort zone. The CNC machine used here is one I tend to avoid due to its size, noise, and power — and because of the fear of breaking expensive tools. But this week helped me overcome those fears and gain more confidence in handling complex jobs.

Downloads

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Project Files – CNC Furniture for Vinyl Cutter

• 🔗 3D Model – Fusion 360 file (.f3d)
• 🔗 CNC G-code – Part 1 (.nc)
• 🔗 CNC G-code – Part 2 (.nc)