Week 1
Principles & Cutting · HTMAA 2025
CAD/CAM, Laser, Vinyl
This week focuses on the fundamentals of digital fabrication: computer-aided design (CAD), computer-aided manufacturing (CAM), laser cutting, and vinyl cutting. We'll learn the complete workflow from design to finished parts.
This Week's Goals
- Master CAD fundamentals
Parametric design, constraints, and best practices - Laser cutting workflow
Design → CAM → cut → test → iterate - Vinyl cutting techniques
Vector graphics, weeding, application
Assignments
- Parametric construction kit
Design and fabricate a modular construction kit - Vinyl cutting project
Create a vinyl sticker or decal - Documentation
Document the complete design and fabrication process - Safety training
Complete laser cutter and vinyl cutter training
Tools & Materials
- CAD software — Fusion 360, Onshape, or similar
- Laser cutter — Epilog or similar CO2 laser
- Vinyl cutter — Roland or similar plotter
- Materials — Cardboard, acrylic, vinyl sheets
Training Documentation
Comprehensive training notes and media from laser cutter and vinyl cutter sessions.
Laser Cutter Training
Focusing Process
- Focus view follows the laser beam
- Use zoom in/zoom out to get better view
- Press Z, the number with checkmark shows how much to move
- Use focusing stick until it just hits the edge of the material
- Bed moves during focusing process
Cutting Process
- Control P to print, use max power with fast speed
- Go to universal program for cutting
- Turn on power for air compressor
- Press green button to start cutting
Vinyl Cutter Training
Software Setup
- Use Chrome browser
- Go to modsproject.org
- Select Program → Open Program
- Choose Roland vinyl cutter: cut program
- Load image (SVG or PNG format)
- Change dimensions with DPI settings
- For PNG: be careful with curves as it changes pixels
- Can invert to change where black areas are cut
- Set origin (defaults are usually fine)
- Blue lines = cut, red lines = rapids (knife lifts up)
Machine Setup
- Lever sets tension on drive wheels
- Clamp down at the end
- Wheel needs to be in white sections
- Press power (if just turned on)
- Select sheet and press enter
- Use arrow keys to move around
- Hold origin for new origin point
Connection & Starting
- Get device and connect properly
- Can change cut force but probably not necessary
- Send file to cutter
Weeding Process
- Weed early - pick out pieces you don't want
- Fold vinyl over itself, don't go straight up
- Use tweezers for precision
- Use transfer paper to lay front of vinyl on transfer paper
- Peel backing of vinyl off carefully
- Don't just plop things down to avoid air bubbles
- Use squeegee as you lay down to prevent air bubbles
- Consider sticker vs stencil applications
Useful Documentation
Additional resources and guides from Anthony Pennes for laser cutting, vinyl cutting, and image compression workflows.
Anthony's HTMA Guides
Comprehensive guides covering essential digital fabrication techniques, parameter optimization, and workflow best practices.
Image Compression Guide
Essential techniques for optimizing image file sizes, setting up batch processing tools, and maintaining repository efficiency.
📖 View GuideLaser Cutting Guide
Complete laser cutting workflow including safety, parameter optimization, joint design, and troubleshooting techniques.
📖 View GuideVinyl Cutting Guide
Detailed vinyl cutting techniques, software setup, machine operation, and weeding processes for professional results.
📖 View GuideNote: These guides were created by Anthony Pennes and are maintained as supplementary resources for the HTMAA course. View original Slack message for context.
Laser Cutter Characterization Group Assignment
Systematic testing and documentation of laser cutter parameters for optimal cutting performance. Assignment started: September 11, 2025 Assignment completed: MM DD, YYYY
Machine Specifications
Available Lasers
- CO₂ Laser: 75W (large machine)
- CO₂ Laser: 60W (small machine)
- Fiber Laser: Back of lab
Test Parameters
- Rate: 500 pulses per inch (PPI)
- Power: 100%
- Speed: 30% (increased by 2.5% each test)
Focus & Positioning
- Focus Point: Cut at the focal length (white part of the focusing stick)
- Kerf Measurement: Measure deltas between intended and actual cut dimensions
- Focus Accuracy: Critical for achieving clean, precise cuts
Joint Design & Clearance
Joint Type
Finger joint - interlocking design for structural connections
Clearance Definition
Size of the slot that provides tight enough fit for assembly
Material Considerations
Material choice significantly impacts joint quality and assembly precision
Key Learnings
- Speed increment of 2.5% provides systematic testing progression
- Focus accuracy is critical for dimensional precision
- Kerf measurement essential for compensating cut width in designs
- Material selection directly impacts joint quality and assembly success
- Systematic parameter testing reveals optimal settings for different materials
Parametric Construction Kit Individual Assignment
Design and fabricate a modular construction kit using laser cutting and vinyl cutting techniques. Assignment started: September 10, 2025
Preparation & Planning
Initial research and clarification discussions with instructors and classmates to understand assignment requirements and technical constraints.
Key Clarifications
Technical Insights
Acknowledgments
Special thanks to Erik Demaine for guidance on vinyl cutting crease patterns and fold differentiation techniques, and Anthony Pennes for clarifying assignment requirements, file formats, and material options. Their expertise was invaluable in understanding the technical constraints and design possibilities for this project.
Design Process
- Research and ideation for construction kit design
- Create parametric CAD model with adjustable parameters in Fusion 360
- Generate CAM toolpaths for laser cutting
- Test cut on cardboard to verify fit and function
- Iterate design based on test results
- Final cut on appropriate material
- Design and cut vinyl project (separate from construction kit)
Hand‑folded Prototype Assembly
I hand‑folded the crease pattern to validate the assembly. The parts do come together when the folds are reasonably close to the intended lines. A second, refolded gadget produced a noticeably cleaner assembly.
Single Gadget
Double Gadget
Assembly Detail
Full Pattern Failure
We tried cutting the full crease pattern on one side. It failed when layers with opposite cuts overlapped and had to be push‑folded through during the final folding step — the piece broke.
First Success Folded Single Gadget
First assembly of two gadgets. Folds were smooth after separating mountain and valley cuts onto opposite sides to avoid breaking during push‑folds over multiple layers. The shop cardboard was tight in the assembly pocket; thinner Amazon box cardboard folded by hand fit better. Next step: make the laser‑cut pattern more exact.
Cut Strategy Videos
Left to right: clear mountain cut, flip and cut the opposite side, clear valley cut.
Mountain vs Valley Sides
Measurements confirming mountain vs valley sides.
First Gadget Assembly
Side profile and insertion step demonstrating clean folds without tearing.
Double Gadget Cut Variations
Exploring double‑part strategies: sequential cuts, flips between sides, and opposite‑side cuts.
Double Gadget — Rubber Band Assist
Temporary rubber band used to hold alignment while completing final folds.
First Success Assembly
Switched to thinner Amazon cardboard because the shop cardboard was too thick for the assembly pocket. The Amazon box folded by hand fit perfectly and assembled smoothly. Three gadgets worked with the thinner material. Rubber bands are just for compression — they assemble without them, though the bands make it easier to keep them as one unit during insertion into the next gadget.
Quadruple Cut Strategy
Scaling up to quadruple cuts: sequential cuts, flips between sides, and opposite-side cutting strategies.
Double Gadget — Amazon Cardboard (No Support)
Three views of the double gadget assembled with Amazon cardboard, showing clean folds and proper fit.
Assembly Process with Support
Assembly sequence showing compression, support positioning, and insertion process for stable construction.
Triple Gadget — Final Assembly
The culmination: triple gadget assembly demonstrating successful scaling with Amazon cardboard and support techniques.
Further Refinements: Thick Origami
Applying thick‑origami concepts to avoid layer collisions and enable folding with real material thickness.
Guidance from Erik Demaine
From a discussion with Erik Demaine: double each crease into parallel offsets and open vertex regions as polygons to prevent collisions. A uniform spacing works for a first pass, but for correctness the spacing between the doubled creases should depend on how many layers lie between faces in the final folded state. I plan to estimate per‑crease layer counts from an unfolded model and adjust offsets accordingly.
Citation: Jason S. Ku and Erik D. Demaine, “Folding Flat Crease Patterns With Thick Materials”, Journal of Mechanisms and Robotics, 8(3), June 2016, pp. 031003‑1–6. View paper
Thickened Crease Patterns
- Estimate: double each crease with a uniform offset and add regular polygons at intersections.
- Exact: compute sector‑aware offset polygons at vertices using incident crease angles.
How the Estimate Works
Input: crease segments with mountain/valley labels; sheet size S; target thickness t
offset = t / S (or a chosen fraction)
for each crease c:
draw two lines parallel to c at ±offset
for each vertex (intersection of original creases):
place a small regular polygon (e.g., octagon) centered at the vertex
Output: doubled creases + vertex holes
How the Exact Method Works
Input: crease lines; sheet size S; target thickness t
offset = t / S
for each crease c:
compute unit direction v and normals n1,n2
define two infinite offset lines at ±offset along n1/n2
for each vertex:
collect incident creases; sort by angle into cyclic order
for each adjacent pair (i, j):
pick the offset side that lies inside the angular sector
intersect those two offset lines → one polygon vertex
connect all vertices in order → convex vertex polygon
trim faces/creases by polygons as needed
Output: doubled creases + exact vertex polygons
Next Step — Layer‑Aware Offsets
Following Erik's advice, offsets should scale with the number of layers between faces in the folded state. Plan: estimate per‑crease layer counts and set per‑crease offset = k × thickness × layers(c), while keeping vertex polygons valid to avoid collisions.
Vinyl Cutter Individual Assignment
Design and cut vinyl stickers and stencils using the vinyl cutter. Assignment started: September 15, 2025 Assignment completed: September 15, 2025
Project Overview
Successfully completed vinyl cutting project creating lab logo stickers. The process involved designing vector graphics, setting up the vinyl cutter, and executing the complete workflow from cutting to final application. The project demonstrated both successful execution and troubleshooting when equipment issues arose.
Lab Logo Designs
Gladyshev Lab Logo
Abugoot Logo Design
Successful Cut and Transfer
Complete workflow from vinyl cutting through final sticker application, demonstrating the full process from design to finished product.
Vinyl Cutting Process
Vinyl cutter in action, cutting the Gladyshev Lab logo design with precise blade control and proper tension settings.
Completed Vinyl Cut
Clean vinyl cut showing precise cuts with proper registration and no tearing or incomplete cuts.
Weeding Process
Systematic weeding process: starting from center, progressing through unwanted sections, and finishing with clean weeded vinyl ready for transfer.
Transfer Paper Application
Transfer paper application process: carefully applying transfer paper to hold vinyl design, then removing it to prepare for final application.
Vinyl Application Process
Final application steps: positioning vinyl on target surface, using tweezers for precise removal of backing, and achieving clean final application.
Completed Takehome Sticker
Final result: professional-quality vinyl sticker ready for use, demonstrating successful completion of the vinyl cutting workflow.
Motor Failure
Encountered and resolved a motor failure during the vinyl cutting process, demonstrating troubleshooting skills and equipment maintenance knowledge.
Motor Error Display
Vinyl cutter displaying motor error, indicating a mechanical issue that prevented normal operation.
Roll Failure Analysis
Side-by-side comparison showing the vinyl roll before and after the failure. The roll ran out of material and then fell, causing the vinyl to kink under the cutting wheel.
Troubleshooting Solution
Simple fix process:
- Turn off the vinyl cutter
- Remove tape from the fallen roll to get the weight off
- Readjust vinyl in between the wheels to ensure proper tension
- Start again (or load a new roll if needed)
This common issue occurs when the vinyl roll runs out or becomes misaligned, causing the cutting mechanism to fail. The solution involves proper material handling and machine setup.
Reflections & Learnings
Key insights and challenges encountered during this week.
Reflections will be added here as the week progresses...
Contributions
Acknowledgements for the help I received this week from my classmates and instructors.
Katrina Li - Training Documentation
This week's training was well-documented by Katrina Li, thank you!
Mariam Fitaihi - Photos and Videos
Photos and videos of this week's training were taken by Mariam Fitaihi, thank you!
Erik Demaine - Thick Origami Guidance
Erik reviewed my approach to folding thick materials and suggested using the Ku & Demaine thick‑origami method. He pointed me to the paper and emphasized that doubled creases should be spaced according to the number of layers between faces in the final fold. This feedback led me to implement two variants (estimate and exact) of thickened crease patterns and to plan a next step for layer‑aware offsets.
Personal Notes - Laser Cutter Characterization
I took notes on the individual group assignment for characterizaing the laser cutter. :-)
Ethical AI Use
Transparent documentation of AI assistance used in this week's work, following course guidelines for ethical AI usage.
AI-Assisted Web Development in Cursor IDE
This week's webpage development, training documentation, and assignment preparation were assisted by Cursor AI. The AI helped with HTML/CSS implementation, content organization, and structuring technical documentation.
AI-Assisted Section Organization and Content Updates
Cursor AI assisted with organizing webpage sections, cleaning up HTML structure, and updating content for both week 0 and week 1 pages. The AI helped with code refactoring, section reorganization, and maintaining consistent styling across pages.
AI-Assisted Documentation and Link Integration
Cursor AI assisted with adding Anthony's HTMA guides to the Week 1 page, creating a new "Useful Documentation" section, and integrating external resource links with proper styling and organization.
AI-Assisted Thick Origami Conversion
A separate chat was used to convert a flat crease pattern into a thick‑origami version following Ku & Demaine.
The AI doubled each crease into parallel offsets and generated vertex polygons (estimate = regular polygons; exact = sector‑aware polygons) and explained how to map desired thickness by setting OFFSET_FRAC = thickness / sheet_size.
AI-Assisted Repository Management and Content Organization
Cursor AI assisted with repository size management by breaking down large commits into smaller, manageable chunks under 10MB each. The AI helped organize media files into logical commits, added the Vinyl Cutter Individual Assignment section with proper styling and image sizing, and provided guidance on git workflow optimization to work within platform size limits.
