W3 | Computer-Controlled Cutting

📝 Group Assignment:

1. Do your lab's safety training.
2. Characterize your lasercutter's focus, power, speed, rate, kerf, joint clearance and types.

What We Did

This week, as part of the group assignment, we covered two main topics: lab safety training and laser cutter characterization. During the safety session, we reviewed the essential procedures and good practices required before operating any laser cutting equipment in the lab. For the characterization, we evaluated the TROTEC Speedy 400 CO₂ laser cutter.

What I Learned

To see the full process in detail — you can visit the folowing page here.

📝 Individual Assignment:

1. Design, lasercut, and document a parametric construction kit, accounting for the lasercutter kerf, which can be assembled in multiple ways.
2. Cut something on the vinyl cutter.

Parametric Construction Kit

TROTEC Speedy 400

What is a Parametric Construction Kit?

A parametric construction kit is a set of pieces designed with variable parameters that control their dimensions and geometry. When a value is modified, every part of the design that depends on that parameter updates automatically — making it possible to scale, adapt, or adjust the pieces without redrawing them from scratch.

Kit Overview

For this assignment, I designed a press-fit construction kit in Autodesk Fusion. The kit consists of four pieces, all derived from a shared parameter set. Each piece has rectangular and triangular slots that allow them to connect and stay together without adhesives, and can be assembled in multiple configurations.

The design process started by defining a set of user parameters directly in Fusion's parameter manager. Instead of entering fixed dimensions into the sketch, each measurement is linked to a named parameter — so adjusting a single value is automatically updated through the entire geometry. This approach makes it straightforward to test different slot sizes, tolerances, or proportions without modifying the sketch manually.

Base Parameters

All pieces share a common set of user parameters defined in Fusion 360. These parameters control the overall dimensions of each piece as well as the size and position of the slots:

The Four Pieces

The kit includes four pieces, each sharing the same base parameters but differing in their shape and slot configuration:

Piece 01

Is the base piece — rectangular in outline, with four slots along its center.

Piece 02

Shares the same slot structure but features one curved side, giving it a different silhouette that adds variety to possible assemblies.

Piece 03

Is also rectangular but includes only two slots along its center, making it a shorter connector between pieces.

Piece 04

Is the most distinctive piece of the kit. Instead of a solid body, it features a repeating cut pattern along its length that gives the piece flexibility — the more repetitions, the more flexible the piece becomes.

Piece 04 — Flexibility

Pre-Cut Setup

1 Kerf Test

Before cutting, I used a kerf test available in the lab — fabricated from the same 3mm MDF material I would be using for my kit. This comb-style tool has slots at incremental widths, and by sliding the pieces together I was able to identify which slot produced a snug, accurate fit. The result confirmed a kerf value of 0.2mm for this material and machine combination.

4 Design Settings in CorelDraw

With the DXF file open in CorelDraw, I assigned the correct line properties to each path: cut lines were set to red hairline, and engraving lines to black. This color convention is what Job Control — the software linked to the TROTEC Speedy 400 — uses to distinguish between operations. Since the lab maintains pre-configured profiles for each material, there is no need to manually adjust power or speed values. Once the file is ready, you simply select the material type — in this case, 3mm MDF — and the machine applies the corresponding settings automatically. It is worth noting that these pre-configured profiles are not fixed — they can be modified or expanded if you want to test different speed or power settings, or experiment with engraving depth and quality.

Line	Operation
Red hairline	Cut
Black	Engrave

Cutting

1 Turning On the Machine

To power on the TROTEC Speedy 400, a key is used to turn the machine on. Once activated, the platform begins to descend and an alarm sounds to indicate the machine is ready to use.

2 Loading the Material

With the cover open, the 3mm MDF sheet is placed in the upper left corner of the cutting bed, which serves as the origin point of the work area (0,0).

3 Calibration

Once the material is in place, the calibration tool is used to set the correct distance between the laser head and the material surface. The tool is inserted into its designated slot on the laser head, and the platform is raised slowly until the tool drops — this is the point at which the correct focal height has been reached. After calibration, the laser pointer is positioned at the upper left corner, establishing the 0,0 origin, and the cover is closed.

4 Sending the File

From the computer connected to the machine, the CorelDraw file is sent using Ctrl+P. The TROTEC cutter is selected as the output device, and in the print settings the material type and sheet dimensions are configured before clicking accept. Job Control opens automatically, where the machine is connected so the job appears in the software. The design is then dragged to the correct position on the virtual cutting bed. Job Control also displays an estimated time for both engraving and cutting, as well as the power and speed settings for each operation.

Operation	Power	Speed	Frequency
Engrave	25	7.00	1000 PPI
Cut	80	0.50	5000 Hz

Power: laser intensity (0–100%) · Speed: head movement velocity · Frequency: laser pulse rate (PPI for engraving, Hz for cutting)

Layout 1 — Piece 04 sheet. Engraving: 1:49 min · Cutting: 19:20 min · Total: 21:09 min.

Layout 2 — Pieces 01, 02, and 03 sheet. Engraving: 2:16 min · Cutting: 6:04 min · Total: 8:20 min.

6 Removing the Cut Pieces

Once the smoke has cleared, the cover is opened and the pieces are carefully removed from the cutting bed. This same process was repeated for both MDF sheets.

🥳 Hero Shot

With both sheets cut and all pieces removed, the kit was ready to be assembled. The press-fit joints held the pieces together without adhesives, and the flexibility of Piece 04 allowed for curved configurations that added a new dimension to the assembly possibilities. Below, the pieces assembled — showing some of the configurations the kit can achieve.

Vinyl Cutting

Roland GX-24 CAMM-1 Servo

During Week 3, I worked with the Roland GX-24 CAMM-1 Servo, a desktop vinyl cutter used to cut shapes and designs on adhesive materials. With this machine, I cut adhesive vinyl to create custom stickers.

I also explored another application: using the cutter to prepare vinyl masks for sandblasting. This makes it possible to transfer designs onto surfaces such as glass and create engraved patterns.

⚙️ Design Process
Before starting the vinyl cutting, I first prepared the design. I wanted to try a small sandblasting experiment on a glass coaster, so I measured it to define the area where the vinyl would be placed. While designing, I considered that the uncovered areas would be exposed during the sandblasting process and become engraved.

With this in mind, I developed the design. I chose Cinnamoroll, one of Hello Kitty's characters, and personalized the coaster with my sister's name. I arranged the figures around the border and added the text to fit within the defined area.

For this, I used CorelDRAW, a 2D software that allowed me to vectorize an image, clean unnecessary elements, and prepare the shapes for cutting. Once the design was ready, I exported it in SVG format.

⚙️ Setting Up the Vinyl Cutter Software

1. To set up the vinyl cutter, I first connected the Roland GX-24 to the laptop using a serial cable. Once connected, I opened the terminal to launch ModsProject — the program used to generate the toolpaths that the cutter follows — by running the following commands:

   
   $ cd Documentos/mods
   $ bash mods-local-server
                   

   After pressing Enter, the ModsProject interface opened automatically in the browser. To send the file to the cutter, ModsProject offers two communication modules:

   WebUSB

   Communicates directly from the browser to the machine via USB, without needing a local server. Works natively in Chrome, which supports WebUSB/WebSerial and can pass through directly to the serial port.

   WebSocket pyserial ✓ used

   Uses a local server (mods-local-server) running in the background to bridge the browser with the serial port via a WebSocket connection. This requires the terminal setup shown above.

   📝 Note: While WebUSB would have worked directly from Chrome without any terminal setup, the lab's Roland GX-24 connects via serial cable — making WebSocket pyserial the appropriate module for this machine's configuration.

   • Here are the examples:
   

   

2. In ModsProject, the first step is to select the correct machine. In this case, I chose the vinyl cutter module, which allows the program to recognize the Roland GX-24 and generate the appropriate toolpaths for cutting. The workflow of this module is shown in the next image (2).

3. Once the machine is selected, the next step is to add the module that connects the vinyl cutter through the serial port. This enables communication between the computer and the Roland GX-24, allowing the cutting job to be sent once the file is loaded. The complete workflow is shown in image (3).



Select the machine (2)



Add the module (3)

4. This module must be linked to the workflow generated when the machine is selected. In this step, I also adjusted key cutting parameters such as force and speed. The force controls how much pressure the blade applies, while the speed defines how fast the cutter moves during operation.

   🖰 Force: 120 g   🖰 Speed: 2 cm/s

   
   For this test, I used a force of 120 g and a speed of 2 cm/s, which provided a clean cut while maintaining good control, especially for smaller details in the design.

   

5. Then, I loaded the SVG file into the workflow and checked both the size and DPI settings. The size is automatically detected once the file is uploaded, but the DPI needs to be adjusted manually so that all cutting paths are correctly displayed in the preview. This step is important to ensure that every line of the design is recognized and ready for cutting.

   • Here are the examples:

   📝 Note: For this example, I used 150 DPI. When testing other values, the preview did not show the complete toolpaths. This seems to be related to the scale of the design, so the DPI needs to be adjusted according to the file dimensions. This is something I plan to explore further.

   🖰 DPI: 150
   

   

6. Once I confirmed that all the toolpaths were correct and the machine was properly connected to the new module, I sent the file to the vinyl cutter.

   

⚙️ Setting Up the Vinyl Cutter Machine

1. First, I placed the material, in this case, blue vinyl. It is loaded from the back of the cutter, where a tray supports it, and inserted from back to front (a), leaving it at the correct height as shown in the image. Then, the material is secured using the lever located on the left side of the machine (b).

   📝 Note: The cutter has white alignment marks, and the vinyl must be positioned between them to avoid issues during the cutting process (c).
   

   • Here are the examples:

   Once the material was properly fixed, I turned on the machine. After powering it on, the cutter automatically measures the length of the material to detect the available working area. This ensures the machine recognizes the limits of the vinyl before starting the cut.

   

   a. Inserting the vinyl into the machine

   

   b. Adjusting and securing the material

   
   
   

   c. Verifying the vinyl position



2. 
   
   

   After that, I followed the steps described in the previous section on setting up the vinyl cutter software. Once the file was sent, the machine began the cutting process. The following videos show how the Roland GX-24 performs the cut:

   • Watch the video:
   📝 Note: In some areas, the vinyl started to slightly lift off the surface during cutting. The exact cause is hard to pinpoint — it could be related to the design itself (broken vector lines or the DPI and size settings used when preparing the file), but it may also be due to the vinyl being old or dried out, or the blade being dull. In practice, it is often a combination of these factors.

   • Watch the video:
   
   

3. After finishing the cut, I needed to remove the material from the machine. For this, I used a cutter knife to trim it off. The vinyl cutter has a small built-in cutting section that makes this step easier, as shown in the image. And with that, the cutting process was complete — the design was ready for the next steps!
   

   • Here are the examples:
   

   
   
   

   Removing the cut-out area

Applying the Vinyl Transfer

1. Once I had the piece of vinyl that was already cut, I placed a transfer sheet (also called transfer sticker) on top of it. This layer helps lift the entire design from the vinyl backing and makes it easier to position it on the desired surface.

   • Here are the examples:
   

   

   

   
   Process of applying the transfer paper

2. After applying the transfer sheet, I carefully placed the vinyl onto the glass surface, pressing it firmly to make sure it adhered well. Then, I started removing the areas that would be sandblasted, leaving only the parts covered with vinyl to protect them during the process.

   • Here are the examples:
   

   

   

   
   Process of removing the transfer paper

   • If the design is intended to be used only as a sticker and not for sandblasting, the same transfer process applies — you can place it on any smooth surface and simply remove the vinyl parts you don't need. For this step, I used a pair of tweezers to help peel off the small pieces of vinyl. It took a bit more time because of the complexity of the design, but the result came out just as planned. Here is the result:
   

   Removing the parts that will be sandblasted

   

   Vinyl mask ready for sandblasting

Sandblasting Process

Once the sandblasting was finished, we put everything back in its place and turned off the machines. It was time to clean the exposed surface and remove the remaining vinyl sticker. After wiping away the dust and checking the engraved areas, the design was finally complete — and this was the result.

Final result: personalized Cinnamoroll glass coaster

Final Thought

As part of the 2025 cycle, I focused on the vinyl cutter, learning the complete workflow from design to cutting and application. In 2026, I expanded on this week's content by exploring the laser cutter, focusing on the design of parametric parts and their fabrication using the laser cutting process.

Files