LaserCutter Vector Cutting Basic Tutorial

Introduction

In order for the Laser Cutter to cut through materials, it needs a vector line to follow with the laser. Vector lines are created on the computer using various applications such as:

• Adobe Illustrator
• CorelDraw
• InkScape

A vector line in its simplist form is two points on the screen, which have a line connecting them. Images made in these applications might only consist of points and lines. These lines might have a colour and thickness. If these lines enclose an area, the area can be filled with a colour or gradient.

This is in contrast to the images you will be used to which are 'pixel' based. Pixel based images are made up of a large grid of dots, each with a colour value.

Overview

In this tutorial we will take a pixel based image and convert it to a vector image using Adobe Illustrator CS5. We will then edit this to enable the laser cutter to follow the lines we would like to cut. This involves editing the line thickness, deleting all the 'filled in areas' and lines we do not want the laser cutter to cut.

Finally we'll stick it in CorelDraw and laser cut it.

Finding an Image

To make your life easier, it is best to start with images that have only a few colours, and which are flat. i.e. no gradients or noise.

For demonstration purposes I have not made my life easier, I have picked this image:

Although this image has gradients, we can fix it in Photoshop to make it a flatter image

Fine-tuning the image before using Illustrator

I will open the image in Photoshop. To make the image have less colours (I count the gradient as many colours) we can do a few things:

1.  If it is just one shaded colour, you can use threshold
1. Click on the threshold button in the Adjustments panel on the leftIt's in the bottom row of icons in the middle
2. It will add an adjustment layer in photoshop and take you to editing it. This panel should now look like this

3. And your image should now be black and white:
   
4.  Underneath the graph there is a slider, if you slide it around you should be able to get a good black and white image:
   
5. Heres where I moved the slider to:
   
6. If you are happy with it, you can save as a JPEG image and move onto the next Chapter "Converting Pixel Image into Vector Image"
2. If these last few steps didn't bode well, then we will try a different 'filter'
1. We will use the 'Cutout' filter, accessed in the menu 'Filters > Artistic > Cutout...
   
   
2.  You will see these sliders:
   
3. Move them about until you have however many colours you need. Your image should look flat (no gradients) like this:
   
4. Save your file as a JPEG image and close Photoshop.

Converting Pixel image into Vector Image

Now we can open our image in Illustrator and convert it:

1. Open Illustrator
2. Open your file
1. Go to the menu "File > Open" and find your file
3.  It will place your image on a sheet of paper. Click on the image and you will see the top bar change and a "Live Trace" button will appear
   
4. Click "Live Trace" and your image should change to Black and White and the top bar will change once more:
   
5. You can change the "Threshold" and "Min Area" numbers to change how it converts your image
1. You will find that the flatter your image is, the better the results will be
6. To just get the outlines of the image, we need to click the "Tracing Options Dialogue" which is the small button at the top, next to the "Custom" dropdown box. The dialogue box should look like this:
   
1.  Uncheck the Fills box
2. Check the Strokes box
3. Check the Ignore white box
7.  When you click OK, your image should look like this:
   
8. When you are happy, click the "Expand" button at the top:
   
9. You will now be able to see the points and lines Illustrator has created. It naturally strokes the line with a thickness of 1pt. We want make the thickness 0.01pt as this is what the lasercutter likes.
1. Change the 'Stroke' number in the top bar to 0.01pt (it's not in the dropdown box, you have to manually type it in)
10. Now we must Save
1. Go to File > Save as
2.  Save it as an Illustrator Document (.ai)
3. Click save
4. On the dialogue box with more options on:
   
5. Uncheck "Use Compression"

Laser Cutting

Now we are ready to use CorelDraw to layout our artwork and send to the laser cutter

1. Login to the lasercutter computer
1. Username: .\lasercutter
2. Password: lasercutter
2.  Load up CorelDraw X4 (icon is at the bottom next to start menu)
3.  CorelDraw makes you a new document which is 40cm by 30cm
4. Import your image
1. go to File > Import
2. find your image and click import
3. Click OK if it asks you any questions
5. Its easier if you group you artwork lines together.
1. right click on your artwork and select Group
6. Position your artwork so it will line up with the material you put in the lasercutter
7. Now you're ready
8. Before we send the whole thing, we need to do test cuts.
9. Make a small square using the square tool.
10. In the bottom right corner, double click the black box and change the stroke to "Hairline"
11. Click OK
12. go to File > Print
13. Check the box which says "selection"
14. Click on Properties
15. Go to the Advanced tab and find a preset which most resembles your material.
16. Click it and click "Load"
17. Now it should have updated the setting on the previous tab. Go back to this one
18. Make sure the Vector check is marked
19. Have a look at the speed and power settings in the vector section (bottom right)
20. Click OK
21. This takes you back the print window. Click "Print" (make sure the lasercutter is on and connected)
22. Open the lasercutter and put in your material.
23. Click Focus button and use up and down arrows until measuring tool brushes the surface of the material
24. Click the Job button and you should see your file as JOB1:graphic1.cdr
25. Switch on Extractor fan (big green button)
26. Press GO!
27. When machine beeps it's finished.
28. Check whether it was a good cut
29. If not, readjust settings (12.) and retry.
30. When it is a good cut, select your work and go through the last steps to send it.

Cheers

Epilog examples and presets

Just got emailed a couple of links to some quick and easy samples and presets for the Epilog Laser Cutter. Here they are:

http://www.epiloglaser.co.uk/zing_16.htm

http://www.epiloglaser.co.uk/sample_club.htm

3D Eye Depth Map and Gradient Maps

Now we have a laser cutter I was intrigued to see what sort of 3D objects it could make. The way in which is works is when it is in 'Raster' mode, it works like a dot matrix printer, creating more and more sparse spots the lighter the area is. So the blacker an area, the more dense the dots and the further into the material the laser should go. I think they'll be a slight rough texture to it though.

My idea was to just have sections of the face imprinted into acrylic or some such transparent material. My main focus was on the eye section of a face. I thought of taking the already made 3D me but after many trials it wasn't good enough. Here's some pictures

Sooo, I got a picture of Anaïs' eye and made in mudbox (it's good practive anyway) and here's the result:

I was quite pleased with this, but perhaps I should say how I got the depth map. So, Mudmox doesn't do Depth Maps. I exported from Mudbox as an OBJ and imported into Maya. I had to create another sphere for the eye. I got a new camera and pointed it at the eye. It was quite hard working out how to do a depth pass, but I found it here. Particularly Emil3d - 03-26-2007, 03:31 PM.

So, go to the render properties, check the "Z-Depth" option, and also make sure it saves it as IFF format. Do a batch render and somewhere you'll find an .IFF file. Open this in FCheck and it'll list the channels that were rendered. Check the z-depth one (or something similar) and you'll see the Depth Map. Save this as a TIFF.

I then put this into Photoshop and re-adjusted to get the whites - white and the blacks - black. But I also thought that the lasercutter could only cut 8mm at a time, so I'd need to separate the picture into segments for each cut. I did this by having another curves layer and creating a straight line from bottom to top, for just 1/4 of the graph, 4 times. Images look like this:

 

 

So 8mm X 4 = 32mm = 3.2cm. I think this is about right for the depth of Anaïs' eye?

Another problem would be the 'dithering' that it need to do. To achieve different depths it doesn't vary the power of the laser, just the amount of dots. So this might make it look pretty weird. But it's something we'll need to trial and error.

Whilst looking into the gradients, I found 'Gradient Mask'. It looks at the gradients in the image, and applies whatever gradient over the top of it. Works nicely with depth maps. An example is a multiple black and white gradient based on this depth map. It could be used to make stuff look like terrain maps:

I also overlaid it to keep the depth.

I also thought about adding texture for the eye, but thought it'd look good with skin as well. So I took the original photo of Anaïs and overlaid it.

Using PVC in the Laser Cutter

So, Sue called and wanted some circles cutting for use with Jo. Set it all up and asked if it was PVC, she said no, probably not. I went on and started cutting and she asked "what is PVC", and I said it was like PVC windows and doors. She then said she got it from home after they'd done the conservatory! She had to go anyway, so I stopped the job.

So talking to Tom he said there was a test for PVC, so I looked it up. Found the "Beilstein Test" where you get some copper, put it in the flame so that there is no other material on it and touch the hot copper onto the suspected PVC (it should melt onto it). Then put it back in the flame. If the flame goes green then it contains PVC (poisonous and erodes metal). Found an example here:
http://jchemed.chem.wisc.edu/JCESoft/CCA/CCA5/MAIN/1ORGANIC/ORG16/TRAM16/E/0570301/THUMBS.HTM

Turns out Sue did the rest of it after she phoned the people to see whether it was PVC. It did stink out most of North Block 3.