3. Computer controlled cutting

For this assignment, I worked on trying something new with the Cricut Maker 3 cutting machine and learning how to use the XTool F1 laser cutter/engraver.

Vinyl Cutting

The Cricut Maker 3 is a cutting machine that can cut vinyl as well as other materials. It also has print then cut capabilities.

To use the machine, you first need to download and install their software, Cricut Design Space. To use the software, you need to log in with a Cricut account. That is the one downside to using a Cricut machine in a shared environment, the makerspace would need to create a general use Cricut account or each user would need to create their own account. Cricut's target market is towards people who buy the machine to use at home as a personal machine.

Then you need to pair your machine with your computer via Bluetooth. Since I've used this Cricut machine before, the machine already shows up in my profile in Cricut Design Space.

Print Then Cut Sticker

Usually I use an online sticker service to make name stickers for my kid's clothing. However, you can also make your own stickers using Cricut's Print Then Cut feature. I am working on setting up a studio space in my local makerspace, so I want to label the items I put in the space with my studio number in case anything "walks", so that it can be returned to the right space.

To start, I open up Cricut Design Space and put together a simple design with text and an oval background for the sticker shape.

Then, I flatten the image by selecting the layers and hitting the Flatten button at the bottom of the screen. This merges the layers and turns it into a "Print Then Cut" project, where Cricut Design Space will prompt you to print the file on your printer and then feed it into the Cricut machine to be cut. Cricut Design Space will generate registration marks.

I have used the Print Then Cut feature in the past and saw that in the new version of Cricut Design Space, there is now a Create Sticker button, so I thought I would try it out for this project. It turns out, you need a Cricut Access subscription to use this feature. I didn't have a subscription, but was offered a free 30-day trial, so I joined that in order to try out this feature.

When you click on the button, it asks whether you want a Die Cut sticker or a Kiss Cut sticker. I selected Kiss Cut, and then was presented with some options to configure.

Once that was set up, it was time to hit the Make button in the top right corner.

On the first screen you set what size material you are using and how many copies of the sticker you want. I had some 8.5x11 inch holographic sticker paper that I wanted to try out, so I set the material size to "8.5 in x 11 in". Then I incremented the number of Project Copies to the maximum number allowed for one sheet of paper. In order to see the layout for the number of copies, you have to hit the ""Apply" button. I learned that for this particular sticker, I could make 20 per sheet. With a more narrow sticker, I could have a third column of stickers. Something to keep in mind for next time.

Then Cricut Design Space gave the option of printing the design or saying that you already had the design printed. Since I hadn't printed the design yet, I asked to print the design, so the program brought up a print dialog. In it, there was the option to add a bleed to the design, where the background color would be printed a bit more around the image so that the cut would be entirely through the background color. Since there isn't a background color in this design, I turned off the bleed option.

When I went to load the paper in the printer, I noticed that the paper packaging stated that white paper should be used for the registration marks as sensors may have trouble reading them on the glossy surface of the paper. So, I actually printed the design twice, once on the holographic paper and once on white paper, and then assembled them on the Cricut mat. During the cutting stage, I learned that I didn't have enough white paper around the registration marks, so I had to add a bit more in two corners to make it work. The assembled setup on the Cricut mat is shown below.

The next step in the process is to pick a material. Since this was a new material for me, what I should have done was a number of test cuts first, to dial in the proper cut pressure setting. Instead, I just selected what I thought was a similar type of material and tried it out. My first pick did not cut deeply enough. My second pick was too deep, scoring the mat a bit. Then, I decided to search the internet for settings for this type of material and found this video which recommended a Cricut pressure setting of 221 and showed how to edit material properties. The video recommended to start from the Premium Vinyl-Shimmer material. However, when you use the new Cricut Create Sticker feature, it turns out, you are limited to a small set of acceptable materials, as shown below.

I clicked on the Material Settings option to customize one of the available options before selecting it. It turns out, the reason there is a limited number of material options for the Create Sticker feature is that Cricut has calculated Kiss-Cut and Die-Cut Pressures for that set of materials. Most materials only have a general cut pressure setting, but these materials have 3 cut pressure settings. So the Create Sticker feature is intended to work with Cricut specific materials. However, we can just edit the material settings to get it to work with other materials. I changed the Kiss-Cut pressure to 221 for the Printable Waterproof Sticker Set - Transparent material and then selected that as the material I was using.

It's good to know that even if you customize a material setting, when you go back to edit it again, there is a Reset option to set that material's options back to its default values.

From the video referenced earlier, I learned that the Cricut might be able to read the registration marks without the white paper and that you could adjust the lighting in the room or cover the registration marks with matte Scotch tape if the Cricut has a problem, so I decided to try without the white paper.

In my environment, the Cricut did not have problems with the registration marks on the holographic paper. The cuts were clean. Some were kiss-cut, but some were close to being die cut. When I use the same material again, I would experiment with lighter pressure settings. I also needed to let the ink on the sticker dry a bit more, as I smudged it a little when I applied it on the Cricut machine.

Overall, the Create Sticker option would benefit people who use Cricket sticker supplies or don't know how to add outline borders to their designs. You can design your images with borders in a graphic design program (e.g., InkScape or Illustrator) and import them into Cricket Design Space. So, having the Cricket Access subscription to access the feature is not required for making stickers in general.

Matless Cutting

Typically, when you cut materials on the Cricut, you use a cutting mat. Cricut sells various cutting mats for different materials. I also tried out their matless "Smart Materials" to make a number sticker for my house. According to guidelines in my area, house numbers need to be a minimum of 4 inches tall. I tried cutting a few different sizes, re-feeding in the same material each time.

From this set of experiments, I learned the following:

• The material must be the full-width and have extra length to feed through the machine. If you have smaller scraps, you will need to put them on a mat.
• The material can bunch up and jam the machine if it is not fed in carefully (pushed against the left rail) and kept flat. Since the material is stored in a roll, keeping your hand on the material as it feeds in helps to keep it flat.
• The back of the smart vinyl material has a grid on it so that it is easy to trim it straight using scissors.

Overall, while I can see that matless cutting could save time, I'm not sure that the premium for the material is worth it unless you want to do projects that are bigger than the size of the mat (and that can't be split up into smaller chunks) or need to make many copies of a design in a short amount of time. It's mostly a time versus money tradeoff. Also, there's a much smaller selection of materials available in the matless format.

Laser Cutter

While my local makerspace has Black Cat CO2 laser cutters, I wanted to try out the xTool F1. I downloaded and installed the xTool Creative Space software.

Connecting to the laser cutter

While the F1 can run over a WiFi network, it needs to be connected to a computer via USB to be configured for WiFi. When I hit the "Connect device" button, I received a "Can't find device connected through USB" message. I followed the troubleshooting steps on the F1 help page for Mac OS, restarted the computer, and it still didn't connect. Then I tried my son's Windows 11 machine and had the same problem. I reached out to xTool tech support and got referred to the same page above. Searching for solutions on the internet didn't seem to help, either.

I reviewed the xTool setup instructions in the user guide and thought I had it set up properly. One of the common mistakes is plugging the USB-C cable in the wrong place on the machine (it goes on the bottom slot on the side of the machine, not in the back of the machine), and that was correct.

Eventually, I decided to watch the xTool unboxing video, and when it mentioned the emergency stop button, I decided to double-check that it was released. That turned out to be my problem! I thought I had released the emergency stop button, but it wasn't fully released. In the fully released position, the orange section is about 3/8" wide. Ideally the software should have been able to tell me that was the issue! When the emergency stop button is engaged (i.e., pushed in), no power is delivered to the machine. Being new to the machine, I hadn't realized that it wasn't powered on when I flipped the power switch. When there is power delivered to the machine, the xTool logo on the front is lit up. The xTool F1 First Use Guide video also goes over these points.

Safety first

For laser safety training, I read over two documents provided by xTool: their 10 Tips to Ensure a Safe and Clean Lasering Experience and their xTool F1 LSO Training (LSO stands for Laser Safety Officer).

Since this xTool F1 is in a house, it is hooked up to the xTool Desktop Air Purifier for the F1.

Characterizing the laser cutter

The F1 has two lasers, a 10W 455nm diode blue laser and a 2W 1065nm infrared laser. It has 3 modes: score, engrave and cut. It can go up to 4000mm/s in engraving mode. The diode laser is used for cutting and can be used to cut wood and acrylic. It can also be used for engraving the same materials. The IR laser is used for engraving only (no cutting) and can be used to engrave on metal in addition to wood and acrylic.

For my project, I wanted to use 2mm EVA foam. xTool has a library of material settings, but this isn't a material that is supported off-the-shelf, so some experimentation was needed to get the right settings. Because I wanted to cut instead of engrave, I put the triangular prism working panel on the baseplate. According to xTool, this serves to protect the baseplate and also reduce burnt areas.

To focus the laser, I tried both manual and auto-focusing. xTool recommends that if you want to cut the material that you focus the laser on the middle of the cutting depth for best results. So, I measured out about 1mm of a sticky note pad and placed that in the F1 to focus on. First, I tried out the manual focus, which involved turning a knob until the red and blue lights overlapped on the surface of the material. Then I tried auto-focus. This is triggered when you input a thickness into the machine. The first time you try to auto-focus, the machine will prompt you to run the init sequence. I input 1 mm, but after the machine auto-focused, the blue and red lights were no longer overlapping. It turns out, the height of the material that the program wants doesn't take into account that the material is sitting on top of the triangular prism working panel, which is approximately 19mm thick. When I entered 21mm, the F1 focused on the top of the foam. So, I set it to 20mm in order to focus in the middle of the foam.

For my first test, I put some lines and circles in xTool Creative Space. I tried out the blue laser for cutting at 20, 40, 60, and 80% power and the IR laser for engraving at 10, 20, 30, and 40% power. The engraving wasn't visible at 10 or 20% power. While it was visible at 30% power, it was much more clear at 40%. For the cutting, at 20%, it cut through but the piece stayed in place and had to be punched out. At all higher levels, the piece was cut through and dropped out. The straight lines were wavy at 20% and a little bit wavy at 40%. The straight lines were pretty good at 60% and very good at 80%. You could also tell that the kerf was bigger with increases in power.

Before each cut, I made sure to use the framing feature (blue rectangle on material) to check that the cuts would be within the boundary of the material.

There was also a slight lingering smell after the cut, so I increased the time the air purifier works after the job is finished from the default 10 seconds to 45 seconds. I also made sure that the air purifier was set on "max" in the back (it was in the default middle position), which is recommended for cuts. For everything, the default speed of 16mm/s was used. There wasn't a problem with smell after this change of settings.

For my second test, I made a series of 10mm by 40mm rectangles and tested cutting at the maximum cutting speed of 20mm/s at different power levels, 60%, 70% and 80%. I also ran a rectangle at the default cutting speed of 16mm/s at 80%. The 60% rectangle had wavy sides. 70% was a better, but 80% was best. I couldn't tell a difference between the 80% at 16mm/s vs 20mm/s. I also tested different engraving speeds at 80% IR. This was a mistake, as I meant to test at 40% IR. However, the test was interesting. At the higher power, the default speed of 80mm/s and also the 100mm/s speed cut through the material entirely in places. The engraving was better at the higher speed, like 150mm/s.

For my third test, I tested cutting rectangles at 85% and 90% power. To me, there wasn't a noticeable difference between the higher powers and the 80% power rectangle. I also tested engraving at 40% and 60% power and different speeds. 60% at 100mm/s seemed to work well. It was interesting to see the engraving get more faded with the increase in speed at 40% power, whereas an increase in power initially made the 80% engraving more clear (when the slower speed was too much and cut all the way through).

I tried to measure the kerf using digital calipers. The kerf is going to depend on the material and the settings used for the cut. Measuring foam is difficult because it is compliant. The values I got were all over the place, anywhere from .5 to 1.5mm over the width or length of the rectangle, so the kerf could be anywhere from .25 to .75mm.

Joint experiments

For my first test, I drew up 3 1-inch squares and did 0.25 inch slots that were .25mm, .5mm and .75mm wide in Inkscape. To create the slot in the square, I used a rectangle for the slot, set its dimensions, centered and aligned it with the square, and then used the ShapeBuilder tool to remove the slot from the overall shape. Although I added text to engrave and exported separate .svg files for the square and text layers, the text could not be imported into XCS since it needed to be converted first (according to the message). I proceeded with the test. I missed asking xTool to cut the last square, but assembled the test pieces anyways. The .25mm slot was a bit too tight. The .75mm slot was a bit loose.

For my second test, I changed the units to mm since Inkscape was rounding the inches measurement. I tried out 8mm length slots and widths of .4mm, .45mm, .5mm and .55mm. For the first run, the foam was flapping due to the suction of the air cleaner, so I hit the emergency stop button and put in a new piece and taped it down. For the resulting pieces, the .4mm and .45mm felt a bit tight. .55mm width seemed the best of the lot.

Parametric Construction Kit

Take 1: Dogs and Cats

So, my initial idea was to do dog and cat pieces and assemble them together. I need to practice drawing more. I did an initial sketch on paper, then tried to sketch it in InkScape and then cut it out. I wasn't too keen on it, so I changed the theme.

Take 2: Clouds and Stars

I decided to try a clouds and stars theme, since it could be made in a straightforward manner in Fusion 360. InkScape could also be used to draw the overall shapes, but it doesn't support parameters. First, I drew the pieces, 2 clouds, a star and a disc. For the clouds, I used overlapping ellipses and then used the Trim function to get rid of the internal lines. For the star, I used the strategy in this video. I created two user parameters to define the slot and created a sample slot that used those parameters.

I then duplicated the template slot multiple times and placed it around the different shapes. Next, I used the extend and trim tools to create the slots. I didn't realized until the end that I had actually trimmed away too much of the slot rectangle for most of the slots. Only 4 of the remaining slots (the ones that still have the slot dimensions) were still parametric after I finished. In the future, I'll be more careful about that and understand how to recognize that right away.

After saving the sketch, I tried to export it, but nothing appeared on the .dxf. It turns out, in order to export the sketch, you have to first extrude it. So, I extruded each of the four shapes to be a thickness of 2mm (the thickness of the foam), though the exact thickness doesn't matter in this case.

When I exported the sketch after extruding the shapes, I did get the shapes, but I also got the construction lines in the .dxf file. I went through and deleted the construction lines, but would really prefer to figure out a way to keep them and not export them in the .dxf. Without the construction lines, the .dxf file was cleanly imported into xTool Creative Space. I set each of the shapes to Cut at 80% power, and ran the job multiple times on different color foam pieces.

Most of the pieces turned out well, but sometimes the pieces fell through before the cutting was done. This happened most frequently on the disc shape. The laser cutting would continue even though the disc had fallen through, resulting in extra cuts or extra wide cuts in the pieces. The lesson is to make foam pieces really big, or use additional support under the material. Typical laser cutters have a metal grid to support the material. Having that here would have prevented the problem observed. Will be sending that suggestion to the manufacturer that they should have a metal grid support accessory for the F1.

The other observation made was that in the initial sets, the foam pieces would fly around a bit after being cut out due to the strong suction of the air purifier. This would result in extra cuts being made in the pieces. I ended up putting the air purifier on minimum strength (even though maximum is recommended for cutting) to reduce that issue.

The pieces of the construction kit are shown below, in the order that they were cut (starting from orange and ending in yellow). I had watched this video, which had said that different colored foams would need different cut settings. Even though I used the same cut settings for all the different colors, it did look like some colors had a bit of burning on the edges, so the power could have been turned down a bit for those.

The pieces can be put together in different ways. Below is one way to do that (shown from different angles).

Reflection

The vinyl cutter and laser cutter can both be used for many creative projects. However, due to the variety of materials that can be used with them, experimentation will always be needed to get the best settings to use for each use case. One should prepare by having extra materials on hand for tests and time to do thorough testing before making final cuts.

I was also aware that Adobe Illustrator is a favorite for creating designs for laser cutting, but did not realize that it, like Inkscape, doesn't support parametric modeling, so using a parametric CAD tool would be a better option when designing parts that need to fit together.