Although "depth per pass" and overall “cut depth” may seem insignificant for some carves, taking a moment to adjust these two settings can save you a lot of time when carving your project. These two settings impact how many passes your machine must take to complete a carve, and thus how much time it takes to complete a project. First, let's walk through the difference between these settings.
Overall depth is how deep the machine carves your project, or different elements of your project. The overall depth is set using the depth slider in the "Cut" menu. Some projects will only carve partway into the material, whereas other projects may require you to carve all the way through your material.
Note: Keep in mind that you can only carve as deep as the thickness of your material, which you can set in the “Material Dimensions” section in the upper right corner. Easel will not allow you to cut deeper than your z-axis dimension (material height). Likewise, if you try to change your material to a smaller size but parts of your project are set to carve deeper than your new material thickness, you will get an error asking you to change the cut depth before adjusting the material to a shorter thicknesses.
The darker your design is in the 2D design preview pane (the left side of the Easel program), the deeper it will cut into your material. You can use the slider to adjust your cut depth, or you can enter in an exact depth in the space below the slider.
If your shape is set to "outline" and goes all the way through your material, Easel will automatically add tabs for that shape (tabs are small bits that extend from the shape and hold it in place). You can choose not to use tabs if you prefer, but you’ll want to make sure you secure your material to the waste board some other way. We’ve found that double-sided tape works well.
Depth per pass dictates how deeply your machine carves down into your material on each pass. Unless you are cutting a very, very thin piece of material with a large bit, your project will likely require multiple passes to get the desired depth. You can change this setting under "Cut Settings" in the right part of the Easel toolbar.
The number of passes your machine makes can be seen by hitting the "Simulate" button in the upper right corner of the Easel toolbar. By minimizing the number of passes your machine needs to finish a project, you can finish your project quicker.
The way these two settings work in conjunction with one another is important for optimizing the efficiency of your machine.
Let's take this project for a beach house sign as an example. We are using a 1/8" bit on soft maple. The recommended settings are already pre-loaded into Easel for feed rate (how many inches your machine carves per minute) and depth per pass. Right now, the project is set to carve .4" deep across all elements of the project. By clicking the "Simulate" button, we can see that this project will take around 3 hours to complete.
While we suggest using Easel's recommended settings when you are first starting to use your machine, you may feel comfortable adjusting your Cut Settings over time. As a general rule, your depth per pass should never exceed half the diameter of your bit. For example, the depth per pass for a 1/4" (.25") bit should not exceed .125" per pass, the depth per pass for a 1/8" bit (.125") should not exceed .0625" per pass, etc.
** Please keep in mind that adjusting the depth per pass settings may require some trial and error. We recommend using Easel's predetermined settings when carving hard materials like aluminum, PCB, Corian, etc. If you are using an engraving bit or a bit smaller than 1/16", using a more aggressive depth per pass than what Easel recommends for your material may result in breaking your bit. If possible, do a test run of your project in a piece of scrap material to see how your machine responds to different settings. ***
Since we are going to use a 1/8" bit for this project, we can adjust our depth per pass to be up to .0625" deep. Let's err on the side of caution in case our bit breaks. We'll set the depth per pass to be .05" and see how this affects our overall carve time.
Wow! Just adjusting the depth per pass a little has saved us 40 minutes on carving this project!
There are other ways to shorten the overall carve time on this project, though. Remember that depth per pass and overall cut depth work in conjunction with one another: changing one setting will impact the other.
Right now, all the elements in this project are set to carve .7" into the wood. However, for this sign, the depth is sort of arbitrary: we want the words to be visible, but it isn't vital that the carve be a certain depth. Let's see what happens when we change the overall depth for the entire project to .6" deep instead of .7" deep.
This change has saved us over 30 minutes of overall project time. Why is this? By changing the overall cut depth from .4" to .3", we have eliminated the number of passes required to complete this design.
Since our depth per pass is set to .05" deep, lessening our overall cut depth by .1 means we are saving two passes of the machine (.05 depth per pass x 2 passes = .1" depth). By clicking the "Simulate" button, you can see that there are fewer toolpaths with the .6" cut depth than the .7" cut depth.
This means that, on average, it takes almost 20 minutes to complete an entire pass of this project's design. Let's test this theory by seeing what happens when we change the overall cut depth to .5" instead of .6":
That's almost a third of the initial three hour time estimate we saw at the start of the project!
We encourage you to play around with improving your depth per pass and overall cut settings to improve the efficiency of your projects. However, please keep in mind that working outside Easel's recommend settings may result in broken bits, burning of wood, or other less-than-desirable outcomes for your project.
Take the time to practice on various materials with different bits and settings to find what works best for your machine. When in doubt, always err on the side of caution and don't overexert your machine's capabilities. You can also check out this great resource on feeds and speeds or visit the forum to learn more about feed rates. The forum also provides great insight into what other makers use for different applications.