Assignment 3 8.2.2017

Topic: Computer-Controlled Cutting

1. Laser

make laser cutter test part(s), varying slot dimensions using parametric functions, testing your laser kerf & cutting settings (group project)
design, make, and document a parametric press-fit construction kit, accounting for the laser cutter kerf, which can be assembled in multiple ways.

Learning outcomes

demonstrate and describe parametric 2D modeling processes
identify and explain processes
develop, evaluate and construct the final project.

2. Vinyl Cutter

cut something on the vinyl cutter.

Learning outcomes

identify and explain processes
design and create the final project

Include your design files and photos of your finished project

Picture note: At first, I increased the picture size. I will use about 900 dots width and 72 or 96 dpi resolution.

Lecture note: The Laser MicroJet combines water jet and laser, and makes hot laser cold (http://www.synova.ch/technology/laser-microjet.html, http://www.itw-chemnitz.de).

Vinyl cutter

I use Roland GS-24 desktop cutter here. It is located right in following picture. The control computer locates left, where the cutter is connected by USB cable.

vinyl cutter

I lifted a black roll of paper to the back of cutter. It has stand there. And, I loaded the paper in. Important thing is the lever in left side of cutter, which locks the paper in place.
panel

Then, I switched on the cutter. I selected sheet as roll and
control panel shows cutting area as in following picture.

The control panel is very easy to use. You can test cutting, set origin and pause cutting.

Pen force setting controls the cutting depth. Blue button switch cutter on and off.

I used cutStudio program for my first cutting. My idea was big numbers 1 to 9. I used text tool to write numbers 1 2 3 4 5 6 7 8 9 to the bottom of the sheet. Then, I selected them and changed the text height to 100 mm as my plan. I selected font as Arial CE. Other parameters were as default.

vinyl 1

Then, I set cutting area by reading dimensions from machine.
vinyl 4

Then, I selected cut command from menu, checked parameters, selected OK and cutter started to work.
vinyl 3

Cutting

gone too deep in sheet. Therefore, I tuned the pen force to set the cut depth correctly.

Following picture shows correct test results.

After all, my cuttings went well. I needed these numbers in our laboratory as showed in the picture.
ready

Also, I made the second cutting study using data from NX11 program. I created new file, selected xy plain view as my work view, selected curve and text from menus. And, I inserted numbers 1 2 3 4 5 6 7 8 9 in place with height of 100 mm and length of 150 mm. Other parameters were as defaults.
nx vinyl 1

Then, I exported my drawing as PDF file.
nx vinyl 2

However, I must hide coordinate icon before exporting.
hide

Here, I do export. Line thickness is same for all geometry and it's value is 0.25 mm. It is not critical for vinyl cutting. Only vector graphics is needed.
nx vinyl 4

I opened the PDF file in control computer, selected print and again the printer as Roland GS-24. I must change cutting length to 200 mm in printer properties to ensure cutting to the bottom of the sheet.

Finally, I checked the size of my numbers. They are in order.
nine in scale

Laser cutting

I used Epilog Fusion laser with 75 Watts of power.

At first, I drew a sketch, what I would like to do. And, I decided to cut a chain of bars which are connected together by snap-on connectors. Also, I do them parametric by length series and connection details.
lasernsketch

Here, I have a first computer sketch. I want draw all as one assembly and develop my idea ready first. I want use 3 or 4 mm PMMA sheet as my material.
nx laser

Then, I mirrored my geometry, but I needed two reference lines to do it. Horizontal line mirrors the upper details down.
laser 3

Vertical line mirrors the geometry right to left. Several mirror operations got the geometry almost ready.
laser 6

I tested the parametric features after mirroring. The middle and left circles are mirrors of right circle and the size follows each others.
laser 8

Now, my first laser cut drawing is ready Only, I must hide unwanted details, such as dimensions, dots and reference lines.
laser 9

At first, I want test the snap feature, which are correct dimensions there. Then, I made final drawings for my chain of bars. Therefore, I made PDF file as earlier, but defined the line width as 0.02 mm. I opened the file in laser control computer and selected printer as Epilog Engraver WinX64 fusion.

laser with pdf

Then, I selected properties and from advanced tab I selected the ready set parameters for 4 mm PMMA (Acrylic) material.
laser param 1

General tab shows all cutting and engraving parameters as following. I can also tune them. I pressed ok here and print in next window.
final param

Then, I used laser control panel. I done final selections from right menu by pressing up and down arrows. I used jog to move laser beam there I want it to start. Jog confirmed by pressing the joystick.I used focus to focus beam to the correct level as triangle tool guided. And finally, I pressed GO.

laser panel

My first laser cutting is ready. I measured the snap joint details. The hole diameter was 7.1 mm and the head diameter 6.9 mm. The original (nominal) diameter was 7 mm in my drawings. Therefore, snap nominal diameters must be 7 mm for the hole and 7.25 mm for the head for tight connection. I can parametrize them and also bar lengths as presented is following picture, diameter p1 = p0, length p2'0 = p2+20 and length p2'1 = p2-10.
ready

The final parts were drown as separate parts to the same sketch. They was cut of green 3 mm PMMA material. The snap feature was working well.
green

Group work

I made also a kerf study as group work with Eino. We used 3 mm transparent PMMA. The most left parts were cut together. Others separately. Numbers in parts mean nominal dimensions in drawings. The best fitting pair was 5/4.8 mm. Kerf diameter should be then 0.1 mm. This confirm also my earlier studies. However, we found some tracks were not in right angle (90°) as supposed and this may cause errors. Reason for that is unknown. Maybe material had some defects. Eikka has documented also our results in his page (http://archive.fabacademy.org/archives/2017/fablaboulu/students/73/FabAcademy_Eikka/Assignment_3.html).

keref

Final project

In this case, I can not do any enhancements to my final project. However, this study was useful. I seldom needed these parametric features earlier. Now I can do them with NX.

My NX CAD files are here: vinyl cut and laser cut.
These also in DXF format are here: vinyl cut.dxf and laser cut.dxf.
CutStudio file is here: numbers_cut.cst.