2D design for this week assignment i decided to design a mdf case for the electronics that i will use to control the motor of the rotational molding machine i will use the press fit technique to join the case
1.- after we click on the autocad shortcut and it run, we have to click on the new file button (here is where we find the new file button, i installed autocad in my native language but the icons and the place where they are is the same) 2.- then we have the option to choose the template, i always choose the acadiso.dwt template 3.- this is how it looks the autocad screen, i will describe you the different toolbars and buttons that it have.  1.- here we find the tools to draw lines, circles, arcs, insert text, rotate the draw, do arrays, manage the layers change the color of the line, measure etc.  2.- this is the origin its marked with the "x" and "y" axis it is useful when we draw based in coordinates and commands.  3.- we use this box to write the commands, every tool have a command to call it. Using commands is helpful when we don´t find a tool in the toolbar but we must memorize the commands. Drawing a line with commands example. to draw a line we write "line" in the box follow by the enter key, then we white the coordinates of the first and second point of the line, we must write the coordinates separate by a comma example: "10,20" this first point of the line will be placed 10 units in the x axis and 20 in the y axis, if we want to draw a 20 units horizontal line we must write "20,0"for the second point, autocad will take the last point as origin so we put "0" for the "y" axis. we want a horizontal line so we rest at the same "y"axis distance. this example will work if we have autocad configured with relative coordinates, relative coordinates will take the last point as origin if we want that autocad always take "0,0,0" as origin we must change the configuration to absolute coordinates
to design the sides of the case i first draw a square, then i use the offset tool to draw parallel lines with 3 mm of distance, we have to write the distance, press enter key, click on the line and then click on the direction to create the second line. 3mm is the width of the mdf board. so i made the rectangles with 3mm of width then the tabs will fit in the rectangles. also the tabs must have 3mm long so the tabs don´t pass through and it rest at the edge. i used the offset tool to repeat the lines and mark the tabs and rectangles distance. for the tabs i made only one line and for the rectangles two lines. i used the rectangular array to divide the lines in 7 equal parts. i repeat the last step in all the four sides of the square, i copied the square two more times and i start cutting the left over lines as it follows. after i finish one face of the cube i start cutting the left over lines in the other squares to have the complementary side that will fit in the first face. thats how i design the 3 principal faces of the cube. in the future weeks i will design the circuit board that will be in the case so i will modify the sizes, i will add engraved signs to help the user operate the machine and i will add some cuts to add buttons and a screen. 3D design to do the design i will use the solidworks software this is the final result of the design
in solidworks i click on new file and then i choose part because we want to design a single part of the system (in the future we could make all the machine and we could run tests to see if all is well designed and any parts crash with anything) then we choose draw and we click on the line tool, to select the side of the part where we are going to draw we click on the plane view in the tree placed in the left side of the screen we draw the shape of the gears as we will see in the next image
as we did in the previous step to draw the shape of the gear we are going to draw the teeth in each side of the revolved gear
when we have the two gears drawed we can now use the coat tool
if we pick the wrong point the coat tool will make bad teeth as shown in the image on the right
ABOUT ME
Model (raster, vector, 2D, 3D, render, animate, simulate, ...) a possible final project, and post it on your class page For 2D modeling i decided to take advantage of the autodesk license that fab academy gave us. now i´m going to describe how i did the design of the case in autocad
 4.- this compass will help us to see all the sides of a 3d model when we do 3d design in auto cad. clicking on the corners of the cube will change the view to that side of the model. (i personally prefer use autocad only to do 2D modeling and catia or solid works to do 3d modeling) to draw with references i only have to put the mouse in the direction of the line, a green line will appear showing the direction of the line, i just have to write the size of the line or just click in the green mark to fiish the line. For the 3D modeling i will design a 45 degree conical gear or pinion. this gear will be 3D printed two times to do the mechanical system that will transmit the turn of one axle to other placed in 90 degrees. (in the sketch we can find the pinions shown in green and how are they supposed to work)
now i´m going to show you how i did the 3D model of the pinion

 

if we did all the steps correct we will have our gear finished and ready to be 3D printed and tested again i didn´t have the right measures of the axle so this design is only to test and know how to draw the pinion, when i get all the material i would do the design with the right measures and sizes
ASSIGNMENTS
week two Computer-Aided Design
after we did the shape we use the revolve tool we click on the drawing of the shape and we choose the reference line that will work as an axle that will show a preview and then we have to click on the green check mark. to draw the teeth of the gear we are going to draw one tooth and then we are going to use the circular array tool to repeat the tooth the 18 times needed, the circular array will ask us to select the center of the array and the tooth. we will reduce the size of the tooth in the top face to fit all the teeth in the circular shape of the top face, we will keep the same 18 theets in both faces and as we see in the image we will draw the gear outside the face
this tool will ask us to select two faces and two points, the points that we will select must have the same coincidence.
FINAL PROJECT
this is how look the final file, here i mark how it can be assembled. there are 3 different pieces that must be cut two times to have the 6 sides of the cube. i must have the electronic board to know the real size of the case and the place for buttons, screen and bolts tho do the cuts for every space needed. you can download the mdf case autocad file by clicking here or download a .rar file with the .dxf file inside by clicking here
5.- in this toolbar we could change the references, grid and snapping that will help us to draw with the mouse. this is how i have the references configured. i found it easier drawing with references than with commands.
you can download the solidworks part file clicking here or download the part with .stl extension clicking here
CONTACT

 

Carlos Pérez Ramírez