Straight BAR
We can have different lengths of the bar by changing just 1 parameter (number of holes).
3. Computer-Controlled Cutting
This week assignement is to design a parametric kit using a CAD software, then cutting it in LASER. Also to create or cut something in the Vinyl machine.
Recap of the group assignement
(Click here)Fortunately this isn't my first time using the LASER MAchine so this helped me a lot in using it for the assignment.
LASER Machine
First of all, the most important thing when using the machine is its calibration. The LASER most important parts are:
- Unfocused LASER beam: the source LASER, not so powerful.
- Focus Lens: concentrate the beam.
- Focal length: distance between the lens and the focal point.
- Nozzle: gives direction.
- Focused beam: comes out of the nozzle, powerfull.
- Focal Spot: best to cut material.
- Depth of Focus: distance it remains focused.
Turning on
Steps for turning on the machine
- Turn on the ventilation, located on the bottom left of the machine.
- Turn on the machine, on the right side below the emergency STOP.
- Release the STOP button.
- Insert the Key at the top of the machine.
- Turn on the LASER and turn the knob on the power
- On the screen of the machine.
- Control arrows for moving on X/Y axis.
- Click on Z/U for moving in Z axis using left/right arrows, press Esc to return.
- When well positioned press Origin to save position.
Software
- Open SmartCave software
- Import files in DXF
- Change color if needed
- Modify cutting parameters on the right side
- Go Scale to verify it fits on the material
- Start to initialize cutting
Materials
- Cut: paper, cardboeard, foaming, felt, cotton, fiber, synthetic, leather, rubber, cork, MDF, wood, plywood, plastic, acrylic.
- Engrave: are the same from above plus glass, crystal, ceramic, marble, stones, tile, metal (apply special resin).
- Don't try: PVC, Polycarbonate, ABS, HDPE, Epoxy, Fiberglass, Carbon Fiber, Food.
All the complete test is on the FABLab Puebla.
From all the 3 test, we can retrieve that the best parameters to cut MDF 3mm is between 50% to 60% power and between 20mm/s and 30mm/s of speed. You can check the complete tables on the Puebla page where it compares different speed/power ratios. Also we calculated the kerf, this helps us on our designing beacuase is the material loss by the LASER. In MDF of 3mm is about 0.123 mm of kerf and in Acrylic is 0.252 mm.
Joints
Joints are aery usefull in LASER cutting and for creating Assembly parts without the use of glue or screws.
Types of joints:
- Snap Fit
- Finger
- Wedge
- Pinned
- Press Fit
- Flexure
For last, Hinge are pieces that can be flexible using formulas by Deffered Procastination.
After getting all the joints and hinge with parametric design in Solidworks, we can start designing our own kit.
Steps for parametric Design
All are more explained in My Assembly Kit below.
- Sketch: create a sketch of your own
- Variables: open equations and add variables
- Apply: add them into your sketch constraints
- Extrude: if needed extrude the sketch
Parts of my Kit
L BAR
Just as the straight bar, we can change the lenght of the X and Y axis (2 parameters).
SQUARE
It can go as far as a circle, triangle, hexagon, etc. it only changes the number of sides.
HINGE 2
A bar with 2 perforations that can bend 45°, don't worry it all can be change in the angle paramter.
HINGE 3
A three way bar with 45° every separation, 90° in total.
SNAP L1
For changing the construction axis it is necessary an L, in this case with snap joints.
SNAP L2
Counterpart of the snap L1, it can change its lenght.
JOINT
For last, joining all the parts together with a finger joint.
Straight bar
We start by drawing a bar with a circle, which has a horizontal linear matrix. In the figure we can see that the dimensions
have equations or dependent variables.
In the case of the horizontal bar, as important data, we placed the length of the perforations which is constant at 32mm; its internal diameter of perforation, in this case 10mm and, finally, the number of instances that the matrix (perforation) is going to be repeated. By changing these values in the equations part we can obtain different bar sizes.
Files
L bar
In the case of the L-bar it becomes relatively easy by having the straight bar, hedge because it is to perform the same procedure
for both X and Y axes. Each will have a length and number of holes that will change the distance of the links.
We can change N_perf_xL and N_perf_yL for changing the lenght of the bar.
Files
Square
The creation of the square and triangle becomes more tedious because it depends on only one variable, the desired number of sides.
First we have to create a circle and place it as a construction object, then we place two construction lines, a horizontal line from the
center of the circle to the right point (180°) and another line from the center to any other point between 90° and 180°. Finally, we connect
these lines with a line that is bounded by the length of the hole. If you want to make internal perforations, place half circles on the
construction lines. In my case, to give it a more aesthetic touch, I added arcs at the intersections of the construction lines with the line.
With its equation to always maintain a distance of 6mm.
Already having all the desired lines, we add a circular matrix around the center of the circle, here we dimension the angle to be an equation depending on the sides, remaining as =" Sides"/360. By changing this value we can obtain different figures, but for now we are only interested in the square and the circle.
Files
Hinge2
To make a flexible part we use the previous file with the flexibility formulas, by modifying the sketch adding the internal holes
and the final length we get something like this. Within the equations we can modify the material thickness, the kerf and the angle
we want to achieve with the part, in this case it is 45°. It is important not to extrude this part and keep it only as a sketch,
because if you give it a thickness, the partition lines for flexibility cause conflicts and it does not detect them.
Just remember to remove the unwanted sketch lines before cutting the part.
Files
Hinge3
Using the previous design I added a matrix of the bending and drilling lines at the same distance as the drilling length of the previous figures.
I want to clarify that I tried to merge both designs into one or to be able to create larger dies, but I did not succeed.
Files
Snap L1
In order to be able to make changes of direction in the axes it is necessary to have a part that can make 90 degrees, to make this possible two SnapL
parts L1 and L2 will be used. Where L1 has a square hole and L2 has a snap type joint that will enter the hole.For the L1 joint we will
use the test design of the group, adding a combination of the bar to the rectangular part of the snap, where we can modify the number
of perforations that will be present, as well as the material used.
Files
Snap L2
For Snap 2 the same thing happens in the same way, it will change its dimensions with respect to the material and the number of holes needed.
Files
Joints
This part will be used to press 2, 3 or more parts together by changing 2 values the number of parts to be joined and the inner
diameter of the hole. In the sketch we define the height of the square and its perforation of the material thickness and the
kerf.
Files
My Assembly Kit
Parametric Design
Time is the most important resource in all areas of work, which is why the use of parametric part design is of the most importance.
CAD software is built based on geometries, dimensions, and constraints that result in modifiable shapes and sizes. This type of design makes
it easy to modify and adapt models. In SolidWorks, you can create these constraints in the Equations part. When you open the window,
you can name a variable and a value (mm, m, angle, number, etc.) that will be stored in the system. When dimensioning a contour,
you can place this variable so that it always depends on it, it is placed with a =" Variable" or in the same way it can be used with
a mathematical equation, for example: =" Variable" * 0.5 + "Variable2". By having n variables depending on one, you can change the length,
perforation, position, etc. by changing a single value.
Test
So now I can cut all the parts for the assembly.
After getting all the pieces cutted it its time to asssemble some figures, is up to your imagination.
NOTE: I always created the equations and global variables one by one when I created a new part, but then I was told that you can link variables. If you want to use this function in your designs so that you don't have to waste time copying variables, at the bottom of the equations there is a linking part, clicking on it will ask you to select a file, it must be a .txt file, if you link the file with several parts you will always have the same dimensions and parameters (if you change one you change them all).
Vinyl
The Vinyl cutter use a small knife to cut the outline of a picture or DXF (vector) into a sheet of different material.
- Materials:
- Glitter
- Printing
- Basic
- Patterned
- Copper tape
- Steps:
- Find/create an image
- Save it like JPEG/PNG
- Open the software, in my case is Silhouette
- Open the image
- Modify the parameters
- Load the vinyl
- Start cutting
For the vinyl cutting I will use the software Silhouette America and ft the Logo, like I'm fan of the F1 I will print the logo from their Webpage.
First we have the main page of the software:
In there you can upload a PNG file and in Enviar on the top right corner you can convert the file contour, select the cutting material and start cutting. On the center image you can change the paramters of depth of the blade and number of pases.
