Edward Octavio Muñoz Sandoval                                                                                                                   Contact: edw_ard0@hotmail.com

Week 3 Assignment: Computer-Controlled Cutting

 

Design, make, and document a parametric press-fit construction kit

For this Assignment I used Autocad for the design of a lap top base, and a vinyl cut of a molar, also used Solidworks for design the pieces and assembly of a pressfit kit.

In general I experimented with 3 kind of designs in laser cutting for the construction of:

Go to  final product of laser cut

1.-Live hinge

2.-Normal press fit

3.-Circular press fit

1.- Live Hinge

For this design i downloaded a catalog from the page: http://www.instructables.com/id/Curved-laser-bent-wood/

 

As you can see in the images, i had to adapt the live hinge to my model because it have a press fit. the results were surpresily good in the first attempt.

2.- Normal Press fit

For this design I estimate a Kerft of 0.1 mm, after the laser cutting I realized that it fit correctly in the larger side, but in the thickness measurement the material have a small variation, so i had to adjust my design for a tight fit.

 

The letters were just for engrave, in order to do that, I had to vary the max/ min power and the velocity of the machine.

 

3.-Circular Press fit

I experimented the laser cut with the circular mechanism and try to do a press fit on the four columns of the lap top base.

 

The first step was try to rectify the cilinder to 1 inch, it was made by hand with the wood torno.

The idea was to made a design like press fit, but instead of leave the holes empty, I filled them with lines as a shadow in a normal engraving, with the same power of a cut of an MDF 3mm in order to do a "hole" in the wood.

This image show a close up of the fill, in the software you can determinate how many lines are going to be in the filled area,

Once the laser cut ended, the next step was cut the pieces in the band saw as shown in the images.

A problem i have to face is the inexactitude of this kind of cutting, so I had to fix the border with a rasp in order to fit in the acrylic piece.

4.-Final product

I can conclude the circular press fit is no recommendable because of the irregularities you can have, and you´ll end fixing up them by hand.

Also In my experience you can´t control the deepness of this kind of cut.

 

Vinyl cut

Go to  Beginning

In this part of the assignment I wanted to do something for a dentist friend, the first step was processing the image to obtain vectors with Inkscape up software.

First you have to open sketch up and import the image you want to process

Then open in the menu:

Trazo/Vectorizar mapa de Bits

 As shown in the image:

I made nine tests until one image like me to cut it in vinyl:

This is the winer:

In this window you can configure 3 kinds of methods to obtain vector from the image is being processed, also you can set parameters in order to have better results.

I obtained the best results with "Corte de luminosidad" and the "Umbral" in 0.7

when I agreed with the result in Inkscape, I exported the image as a DWG file, and opened in Autocad for the cleaning of the vectors.

The next step is import the vectors into the vinyl cutter, I have some problems with the extension of the file, because the .dxf is not compatible, it have to be .eps, With Adobe Illustrator you can make this change.

In this images you can see that my design was not the best because of the little parts it have, like the star, the eyes or the eyebrows.

If you have this little pieces may take off while the cutting or "depilation" wich is the next step:

In the depilation you remove all the useless vinyl, as you can see some molars don´t have eyes nor eyebrows because this pieces are too small, so it´s not recomendable in a vinyl cut design.

To pass the design from the vinyl to the surface you want, I used a "transfer paper" wich is a paper with glue in one side.

First paste the transfer paper on vinyl.

Then paste it in the surface you want and take it off

This is the final product:

Pressfit Kit

For this part of the assignment I thought in a organizer that can be builded as the user need, first I used Solidworks for the 3D design, one advantage of use this software is the possibility of the assembly visualization and the facility of make change on the pieces.

For make easy to understand and use, I only design 3 pieces, the base plate, lateral wall and separator.

Once the pressfitkit looks fine in solidworks, I exported the pieces to .DWG (Autocad extension file) by choosing the "drawing" option in solidworks and place the pieces in the sheet, then just click on "save as" button and choose .DWG extension.

 

NOTE: Make sure that the scale in the sheet for all the pieces is 1:1, otherwise the dimensions will be wrong.

 

When the files were in .DWG I had to make bigger the size of the tabs by 0.2 mm and compensate the kerf. In Autocad is easy to do this with the command "offset" and erase the undesired line extensions with the command "trim".

The next step is cut the pieces with in the laser cut with the next parameters:

The next images show the laser cut working:

Just left assembly the organizer as you want.

Here is a example to use:

Go to  Beginning