File Prep

Good Files Make the Magic Happen - Unite Pathfinder Tool

The Pathfinder tool in Illustrator is a great tool for preparing files for laser cutting. To view the pathfinder window (pictured below, go to window - pathfinder)

Using adobe illustrator pathfinder tool for prepping/preparing files for laser cutting.

The Pathfinder tool includes several different shape modes. Today we’ll cover the unite tool, which is the very first box in the pathfinder menu. We’ll cover the other shape modes over the next couple weeks.

SHAPE MODES:

UNITE /// MINUS FRONT /// INTERSECT /// EXCLUDE

UNITE TOOL

The unite tool is a great tool for connecting vector shapes in Illustrator. Make the vector shapes that you want to connect, select them and then select the unite tool. This will eliminate any overlapping lines, allowing you to create desired shapes without any unnecessary lines. If overlapping lines are left in your design file, the laser will cut each line!

We use the unite tool frequently when creating files for the laser! For example, if we’re create a custom drink stirrer, we would create the text and outline it. (You can learn more about outlining text in Illustrator here!) We also offset the text slightly in this situation to thicken it. A good rule of thumb is that you want your cutting area to be at least as thick as the material thickness. Our drink stirrers are cut out of 1/8” acrylic, so our text needs to be at least .125” thick. Once we outline the text and offset it, we create the base for the drink stirrer. This one is .18” x 6” tall. We then select everything and click unite. Now we have a clean file that’s ready for the laser!

 
 

Laser Cutting Kerf

When the laser cuts through material it burns away a small amount of that material - this is called the laser cutting kerf. The amount of kerf is dependent on the material type and thickness, along with a couple other variables (including the lens on that particular laser cutter, air pressure, etc). Typically the kerf ranges from about .15mm to .2mm.

 
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To account for the laser cutting kerf, we offset the cut paths by the amount of the cutting kerf. Most of the time, we do this in our laser cutting software, but this can also be done in other CAD based programs (Illustrator, Sketchup, etc.)

It isn’t always necessary to offset cut paths to account for the kerf if something doesn’t need to be an exact fit. For example, if we’re cutting out a wooden 5” x 7” menu card, accounting for the offset isn’t necessary, as the piece will be just barely smaller than 5”x7” - measuring .49940” x .699040”.

One example of a project where accounting for the kerf IS NECESSARY is when we’re doing inlay. If we’re cutting an acrylic piece that a wooden letter will fit into, we need to account for the kerf to ensure that everything is a tight fit. If the kerf isn’t accounted for, the two pieces will not fit together.

 
Laser Cut Wood and Acrylic Inlay
 

Good Files Make the Magic Happen - Adding Tabs to Text to Avoid Dropbox

Sometimes when you’re making projects, you’ll have text that’s cut out from another shape. If your project includes this, you’ll want to add tabs to avoid having the inside of your letters drop out.

To get started, you’ll want to create your text and outline it. If you’re not sure how to do that, you can check out our blog post about outlining text here. Ungroup your text. To do this, select your text and then go to object - ungroup [command, shift, G].

The size of your tabs is dependent on the size of your piece. I wouldn’t recommend going much smaller than .125” for your tabs, as anything much smaller than this is too weak to support most materials (however, this might work for paper or chipboard, as the tab doesn’t have to hold much weight).

My tabs are .125” tall and .3” wide. The width of your tabs isn’t too important, you’ll just want to make sure that it’s longer than the section of the letter that you’re adding the tab to.

To add a rectangle shape to your artboard, select the rectangle tool. Then left click anywhere on your artboard and a rectangle menu will pop up. Here you can add the dimensions of your tab, then select OK.

Adding tabs to a laser cut file to avoid having letters drop out or fall out.
Changing the size of your rectangle tab in Adobe Illustrator to prepare your file for laser cutting.

You’ll want to switch back over to the black selection arrow and then select your new rectangle and copy it. Then move your rectangle to your first letter that needs a tab. Letters that don’t have an interior area, such as an C or an E, don’t need tabs. Letters that do have an interior area, such as an A, B or O, do need tabs to avoid dropout. You might decide you like the way your text will look without the interior of your letters, like the example below.

Example of text without tabs being laser cut, there will be drop outs for the interior of letters.

I place all of my tabs first. You’ll just want to paste your rectangle and place, until you’ve added tabs for every letter that has an interior. I then select all tabs for letters that just have 1 tab -for example, in my top row of text, I’ve selected the tabs for ADD and A (I did NOT select the tabs for the B because it has two tabs) and then open the align window. You might have the align window already open in your workspace. If you don’t, click on window - align, and the align tool bar will pop up. With all of the single tabs selected, click on the vertical align center tool. Do this for all tabs that you want to line up.

Adding Tabs to Outlined Text in Adobe Illustrator to prepare or prep file for laser cutting or to be laser cut.
How to open the align window in Adobe Illustrator to line up tabs equally.
How to align tabs using the vertical align center tool to prepare file for laser cutting.

Next, open the pathfinder tool. You might already have this open in your workspace. Otherwise select window - pathfinder. Then select your first letter, as well as the tab. You’ll use the minus front pathfinder tool to “subtract” the tab from the letter. Repeat this for each letter. If your letter has two tabs, like the B, you can select both tabs and the letter at the same time.

How to use the pathfinder tool in Adobe Illustrator to create a tab for the interior of a letter to prepare for laser cutting.

You’ve now added tabs to your letters! Your final piece will now cut and include the interior of the letter, like the example below. I’ve inverted the colors on the example to portray how it will look when the letter are cut out.

Adding tabs in Adobe Illustrator to avoid having the interior of the letters drop out when you laser cut.
Adding tabs to avoid letter drop out or dropout during laser cutting