<topbar style="display:none;"> <item><a href="../index.html">Home</a></item> <item><a href="../about_me/about_me.html">About</a></item> </topbar> <!-- This is a comment, it is ignored by the compiler/interpreter --> <style> h0 { font-family:; font-size: 30px; color: #414040; margin-top: 50px; margin-bottom: 6px; word-spacing: 5px; } </style> ##week2: computer-aided cutting <br> ###Group assignment: Kerf experiment <br> ####Objective <br> To understand the effect of variables in laser cutting on kerf. ####Metrics <br> * Laser cutter: Thunder Laser’s Nova 24 (60W). *Based on my web research. The name and watt might be incorrect. * Material: cardboard, with the thickness of 4mm (approx.) * Protocol: we crafted the following method. 1. Cut a set of identical rectangles with various laser-head speed (i.e., 30, 40, 50, …, 90, 100 mm/sec), fixing the laser power to be 60% of its capacity. 2. Same operation but with 80% of its laser power capacity. 3. Measure the widths of (1) exterior: i.e., what was left after removing the cut rectangle and (2) interior: i.e., simply the width of the cut material. 4. Obtain the kerf value by subtracting (2) from (1) and then dividing that value by 2. <br><img src="./Kerf_1.png" alt="laser_module" width="500"/> <br><img src="./Kerf_2.png" alt="laser_parts" width="500"/> ####Results <br> We obtained the following results. | # | Power | Speed | exterior | interior | kerf | | --- | ----- | ----- | ----------- | -------- | ----- | | | % | mm/s | mm | mm | mm | | 1 | 80 | 30 | 30.48 | 29.65 | 0.514 | | 2 | 80 | 40 | 30.22 | 29.61 | 0.510 | | 3 | 80 | 50 | 30.00 | 29.60 | 0.507 | | 4 | 80 | 60 | 29.96 | 29.80 | 0.503 | | 5 | 80 | 70 | did not cut | n/a | n/a | | 6 | 80 | 80 | did not cut | n/a | n/a | | 7 | 60 | 30 | 30.65 | 29.71 | 0.516 | | 8 | 60 | 40 | 30.47 | 29.50 | 0.516 | | 9 | 60 | 50 | did not cut | n/a | n/a | | 10 | 60 | 60 | did not cut | n/a | n/a | <br><img src="./Kerf_Graph.png" alt="laser_parts" width="800"/> Key findings are summarized in bullets below. * Beyond certain points, either the strength or the residence time of laser was not enough to cut through the 4mm-thick cardboard. * When the power was fixed to 80%, we could see the strong negative correlation between the speed of laser head and the kerf. The relationship was linear with R2 = 0.9992, which makes sense as the duration of energy deposition is likely to determine how much microstructure of cardboard could be decoupled by laser. * When the power was fixed to 60%, there was no clear decrease of kerf in response to the increase of the laser-head speed, although there were only two data points we could collect. While we have not managed to develop our hypothesis about this phenomenon, one thing we confirmed was that less power (60%) resulted in the failure of cutting cardboard more quickly than the other condition (80%) did.