Computer Controlled Cutting NWZC¶
for this assignment, we were tasked to find how the laser cutter behaved with different focus, speeds, powers, frequency, and the kerf, joint clearance, and joint types applicable to for cutter.
Group Members & Work Distribution¶
Noah
Kerf, Focus
Cooper
Power, Speed, Rate/Frequency
Wilson
Joint Clearance
Zaina
Joint Types
Kerf¶
In order to test the kerf, we made 5 cardboard strips that were supposed to be exactly 5 inches. By comparing their real sizes to the size they were supposed to be, we could find the kerf. The caliper that we used could go to 3 decimal places, so accuracy in measurement was not a worry. After checking all 5 strips, we found that the kerf of our laser cutter to be 0.0144 inches. Of course, this is on cardboard, which is known for having a higher kerf than other materials, and A group from last year found that be as low as 0.012 inches for a wooden piece. 
Focus¶
In order to test focus, we first manually homed into the perfect focus, then offset by different amounts to see its effects. We kept all other settings at their defaults, which were probably found by students of fabacademy past. We found that as we got closer to the material, it started producing more flames but the line was thinner. As we got farther from the material, it started cutting more at once and producing more flames. We therefore devices that when the machine was focused right was best, except for when kerf was such a problem that focusing closer would be a better option. For engraving colors, we found that at around .2 inches farther away the black was much more visible. 
Speed, Power, Frequency¶
To test the different settings on the laser cutter I chose to cut through a piece of cardboard 30 times. 3 rows for each modified setting and 10 columns for intervals going up 10. How it would go is that the other two values would remain the same that they were when usually cutting through cardboard while the 3rd setting would be modified by a percentage in between 10 and 100 in jumps of 10. This is all inspired by the group work from last years fab academy but instead of stars I chose to do rectangles so it could be seen if the cut went all the way through since to do all 3 settings the file needed to be a vector one.
In CorelDRAW I set up a row of 3 boxes in a column, from their I copied and pasted it 10 times across the file. From their I labeled each row with the setting and each column with the interval by 10. To distinguish the different boxes on the lasercutting software I switched the color value of the boxes to RGB and then gave each setting one of the colors. For instance power was blue so the values when the speed was modified to 30 would be R: 0, G: 0, B: 30. This was very tedious but the only way that all 30 boxes could be differentiated since the only way the settings could be changed on the different parts of the file on the laser cutter was by line point and then the color. Since all of the boxes already had to be hairline the next thing available was the color.
Once that was done I was able to go over to the lasercutter and start entering values. A slight issue I ran into was that when I grouped the hairline setting by color was that the RGB values while all different were all very off. For instance the example blue setting would have become R: 16, G; 31, B: 51. The one good thing is that all of the values were different so all it took was looking at the small image on the setting modifier and comparing it to the file in CorrelDRAW. It took a while but it worked out in the end.
After cutting the cardboard, it was clear how the settings effect the cut. For instance as the power got higher the cut was able to go through. In the case of frequency, while its hard to tell, the size of the cut got thicker. Finally in the case of the speed, the higher it got, the less time the laser had to cut through the material entirely.
Joint Types¶
Snap-fit joint¶
Snap-fit joints are mechanical connections where parts flex and lock together without glue, screws, or additional fasteners. These joints rely on elastic deformation to temporarily bend and then snap into place. A con that can be associated with the use of snap-fit joints is that they are not ideal for high-stress applications.
Chamfer joint¶
Chamfer joints are edges of the two joined that are beveled before joining. Instead of straight 90-degree edges, chamfered edges are cut at angles is cut at an angle typically 45 degrees. This makes assembly smoother and improves the joint’s strength and improves assembly and strength. The cons of using chamfer joints are that they require accurate cuts for tight fits and thinner edges may reduce load capacity.
Flexure Joints¶
Flexure joints are hinge-like connections that allow movement through the elastic bending of material, rather than mechanical parts. It allows for controlled bending and movement by using thin, flexible, sections in a rigid material, instead of traditional hinges Some detriments that can come with using flexure joints are they can weaken or crack over time, they cannot support heavy forces, and can only bend within a set limit before failure.
Press-fit Joint¶
A press fit joint is where two parts are fitted together by friction, The parts hold together due to the slots being slightly smaller than the inserted pieces, creating a compression friction that keeps the joint secure. Some detriments associated with using Pressfit are that it requires precise tolerances, It may weaken over time, and it may be difficult to adjust after assembly.
Pinned Joint¶
A pinned joint is a connection where two parts rotate around a fixed pin or hinge. This allows controlled movements while restricting other directions. This type of joint is ideal for hinges and moving parts and can handle loads if it is designed properly. However, it requires precise fits. If pieces are too tight, then they might not move and if it’s too loose they may wobble.
Wedge Joint¶
Wedge Joints are angled pieces that are driven into slots to create a tight, secure fit between two parts. The friction from the wedge allowed pieces to be held together without glue and screws. This joint is effective in wood, metal, and plastic. But it is not ideal for thin materials, because it requires thick materials for the wedge to hold.
Snap Joint¶
A snap joint is a connection where parts snap together using flexible features like hooks, clips, or tabs, creating a secure hold. They provide fast and tool-free assembly, they work well with plastics, wood, and metal.
Finger Joint¶
Finger joints are interlocking rectangular tabs that are cut into two pieces that fit together almost link fingers. This increases the surface area, allowing for strong precise connections. However, Improper kerf adjustments can lead to loose or tight joints.
Joint Clearance¶
Using inspiration from Richard Shan, Angelina Yang, and Alana Duffy’s group project, we designed a cardboard design with slots of different widths in order to test the optimal width for joints.
After testing all the widths from 3.5mm to 4.0mm, we decided that the best fit for the cardboard was the 3.6mm or 3.7mm(for a looser fit) slot. The 3.5mm slot was too small and needed to be wiggled for it to fit. The 3.8mm slot was a little too loose, and 3.9mm and 4.0mm weren’t able to stay stuck.
