Week 7: Computer Controlled Machining
CNC Router
CNC stands for Computer Numerical Control. It refers to machines that are controlled by code to automate tasks like cutting, drilling, and shaping as part of a digital manufacturing process. A CNC machine is essentially a computer that takes code and turns it into motion.
Types
Milling machines: Versatile CNC machine tools that carve 2D and 3D shapes out of metal, plastic, or wood, including milling in 3-, 4-, and 5-axis configurations for more complex geometry and fewer setups.
Additing manufacturing machines: Additive manufacturing (AM) machines, or 3D printers, create 3D objects from digital files by depositing materials in layers. For more datails you can go to my Week 5.
Laser Cutting Machines: Are Computer Numerical Control (CNC) tools that use a high-powered, focused laser beam to cut, engrave, or mark materials with high precision and speed. For more datails you can go to my Week 3.
CNCs use to types of code, G-CODE and M-CODE:
G-CODE is a programming language for CNC that instructs machines where and how to move. The G in G-CODE stands for "Geometric" because is the type of movement the code produces.
G-CODEN## G## X## Y## Z## F## S## T## M## N##: Line Number.G##: Motion.X##: Horizontal Position (X axis).Y##: Vertical Position (Y axis).Z##: Depth (Z axis).F##: Feed Rate.S##: Spindle Speed.T##: Tool selection.M##: Miscellaneous functions.M-CODE is a programming language for CNC that instructs machines on what to do. The M-CODE has miscellaneous functions, bit it doesn't instructs on where to go.
Miscellaneous functionsM00:Program stop. M01:Optional program stop. M02:End or program. M03:Spindle on clockwise. M04:Spindle on counterclockwise. M05:Spindle stop. M06:Tool change. M07:Flood coolant on. M08:Flood coolant off. M30:End of program / Return to start. M41:Spindle low gear range. M42:Spindle high gear range.
Design
Stress Analysis
My idea from the start was to build a piece of furniture with three specific functions: to serve as a bench press so I could do pec exercises at home, a place to store my dumbbells, and finally, a bench so more people could sit in my living room.
That is why it was important to calculate the structural strength so that it could support at least 100 kg. I used the next formula:
\frac{5\omega L^{4}}{384\varepsilon I}
Base
Equation.
mw (material width).1.2 cm.
Base
1. First, I changed the document units to CGS and created a center point rectange of 87X35 cmin the top plane.
Base
2. Then, using the sketch fillet in all the corners I made arcs of 5 cm.
Base
3.After that, I made large finger joint for the lateral faces. For that, I drew a rectangle at the border of 19.5 X mw(1.2 cm) at a distance of 12 cm from the side and center. Then I used the mirror tool to replicate it in both, the opposite side and opposite face. These joints are this thick because they will be joined to the side faces, which are mw thick.
Base
4. Then, I made a rectangle of 2mw X 12 cm at a distance of 2.5 cm from the top border and 5 cm from the side. After that, I used the mirror tool for the 3 columns I planned my box to have. Each wall will consist of two identical pieces of mw thick.
Base
5. Finally I extruded my piece and the cuts.
Lateral Face
Equation.
mw (material width).1.2 cm.
Lateral Face
1. First, I changed the document units to CGS and created a center point rectange of 87X33 cmin the front plane.
Lateral Face
2. Then, using the sketch fillet in all the corners I made arcs of 5 cm.
Lateral Face
3.After that, I followed a similar process to the one for the base. First I made the holes for the columns or interior walls at the same distance as I did in the base, because it was crucial for them to fit on both sides, the base and the sides.
Then, I made center point rectangle at a distance of 10 cm from the left side and 6 cm from the center. Subsequently, I used the sketch fillet tool and made arcs of 5 cm in all the corners of that rectangle. Finally, I used the mirror tool and duplicate it in the opposite side.
This gates will be used to store my dumbells.
Lateral Face
4. Then, I made a rectangle of 19.5 X mw at a distance of 12 cm from the side and center. After that, I used the mirror tool for duplicate it in the other side. These rectangles will be to join this side face to the base.
Lateral Face
5. Finally I extruded my piece and the cuts.
Wall - Column
Equation.
mw (material width).1.2 cm.
Wall - Column
1. First, I changed the document units to CGS and created a center point rectange of 33 X 35 cmin the front plane.
Wall - Column
2. Then, I made two rectangles at the top and left border and mirror them.
Wall - Column
3. All of the joints have a height of mw with the exception of the top ones, those have a height of 2 mw because in the top will be two layers, each of mw. Each finger joint has a width of 12 cm.
In the sides, the distance between the finger joints and the bottom is of 2 cm. In the top, the distance between the joints and the sides of the rectangle is of 2.5 cm.
Wall - Column
4. Then, I made a circle of 0.78 cm of diameter at a distance of 15 cm vertically and 13 cm horizontally from the center. After that, I used the mirror tool for duplicate it in the other side and down. These holes will be for M8 screws that will connect the two pieces I’ll have for each column.
Wall - Column
5. Finally I extruded my piece and the cuts.
Top cover
Equation.
mw (material width).1.2 cm.
Top cover
1. First, I changed the document units to CGS and created a center point rectange of 35 X 87 cmin the front plane.
Top cover
2. Then, using the sketch fillet in all the corners I made arcs of 5 cm.
Top cover
3. Then I made the same holes of 2mw width, I did in the base.
Top cover
4. Then, I made a circle of 0.78 cm of diameter at a distance of 12.5 cm vertically and 34 cm horizontally from the center. After that, I used the mirror tool for duplicate it in the other side and down. These holes will be for M8 screws that will connect the two pieces I’ll have for each column.
Top cover
5. Finally I extruded my piece and the cuts.
Exporting as DXF
1.I made an Assembly with all the pieces to make sure everything was correct.
Results
RESULTS.I made an Assembly with all the pieces to make sure everything was correct.
Fabrication
VCarve
VCarve, developed by Vectric, is a popular, user-friendly software solution designed for designing and cutting parts on CNC routers. It excels at 2D design, 2.5D machining (V-carving, pocketing, drilling), and importing 3D models. It is widely used for sign-making, woodworking, and engraving, allowing users to create complex, carved 3D effects from 2D vectors.When used alongside a CNC router, VCarve serves as the bridge between the design phase and the actual production process. While CAD programs like SolidWorks are utilized to create the part designs, VCarve focuses on setting up machining details such as toolpaths, cutting settings, tool choices, and strategies, ultimately generating the G-code that controls the CNC machine.
VCarve
1. First we have to open VCarve and create a new file. In the left menu is a list where we must select the first option.
VCarve
2. Then, a workspace will pop up and in the left side we can choose the characteristics of our board and where to set the origin point.
Configuration.
Work Type.Defines the machine type in one side mill, two sides mill, Rotating. In this case, I´ll choose the first option, because the machine I will be using is the Mach 2/3 Arcs router that only has 3 axis (x,y,z) so it can mill up to 2.5D pieces.
Work Size.Defines the board size. In my case, my material size is of 1.220 X 2440 X 120 mm.
Z origin position.Sets the initial position for Z. It can be either at the top of the material or at the top of the top of machine surface.
Reference Position for XY.Sets the reference origin position for XY. In my case, it will start a the bottom left corner.
Resolution.Defines the resolution for the simulation.
Material Configuration.Defines the material appearance for the simulation.
VCarve
3. We have to open NI Multisim and a board will open.
VCarve
4. We have to open NI Multisim and a board will open.
VCarve
5. We have to open NI Multisim and a board will open.
Schematic
1. We have to open NI Multisim and a board will open.
Schematic
2. Above is a bar with components to simulate. We have to click on the symbols to choose thwe type of component we want to use.
Component bar
Source. The source components are the ones that power the system. In the left side list we can choose a specific type of component, in the center top we can search for a specific component of the family and in the right side we can see the symbol and place the component in the board. This repeats in each section.
Basic. These are the basic components such as resistors, buttons, capacitors, etc. We can select the specific family in the left list.
Component bar
Diodes. A diode is an electronic component that allows current to flow in only one direction, making it essential for various applications in electronics. We can select LEDs, SCRs, FWBs.
Transistors. These are the basic components such as resistors, buttons, capacitors, etc. We can select the specific family in the left list.
Component bar
Diodes. The source components are the ones that power the system. In the left side list we can choose a specific type of component, in the center top we can search for a specific component of the family and in the right side we can see the symbol and place the component in the board. This repeats in each section.
Transistors. A transistor is a semiconductor that amplifies or switches electronic signals. Transistors serve as the basic building blocks of modern electronics.
Component bar
CMOS. Stands for Complementary Metal-Oxide-Semiconductor, a technology used to build low-power, high-efficiency integrated circuits and microchips.
Schematic
3. After understanding where the components can be selected and placed, we must begin with the schematic.
Components for this example:Red LED
220 Ohm resistor
220 Ohm resistor
First we have to select the components, then place them in the board and if we want to rotate them we have to click the component and press CTRL + R.
Schematic
4. Finally we have to press the green triangle to simulate the circuit.
Simulation
1. To simulate I'll use an ALTIUM Design I made a time ago.
ALTIUM is a comprehensive PCB and electronic design automation software package that allows engineers to design and customize their own circuit boards. It is similar to KiCad, but it isn't free and you can do a lot more things like simulate from there. But this time I'll use NI Multisim.
3D Printer
For printing my piece I used an ANYCUBIC PHOTON M5s.
Steps
1. First, I connected my USB adapter so I could load my document.
Steps
2. Then I removed the cover.
Steps
3. After that, I made sure that there was nothing that may obstruct the printing process.
4. Then I logged into the USB and uploaded my document.
Steps
5. After that, I started the printing.
Steps
5. When the printing was finished, I gently removed my head with a spatula. My print consisted of 640 layers.
Steps
6. Finally I used an Anycubic Wash & Cure 3 to cure my piece and cleaned it using a paper towel and Isopropyl alcohol.
Results
Learning outcomes
This week, I learned a lot about 3D printing and its different types. I was not aware that ISO had classified 3D printing technologies into seven categories. I also learned how complex resin printing can be. It was my first time using this type of printer, and one of my prints failed due to poor adhesion to the build plate. Additionally, the cleaning process is quite tedious, although the results are highly accurate.
I also believe that 3D scanning is a remarkable tool for accurately replicating real structures. Its application in museums could be extremely valuable for the preservation of statues and historical artifacts.
When comparing filament printing and resin printing, I think both technologies have their own strengths and weaknesses. However, resin printing offers superior surface quality and detail, while filament printing is better suited for producing stronger and more durable structures.