Slate coasters are a staple of laser engraving. They're cheap, they look premium when they're done, and they make a great gift or something to sell. They're also one of the easiest things to get right once you know the setup.
This guide covers two of my videos: a logo on a round coaster with the xTool F2 Ultra UV (above), and a family photo on a square coaster with the xTool F2, including a little outline trick that makes it pop. The process is the same on any F Series laser. Only the settings change.
Jump to: Coasters · Placement · Focus · F2 Ultra UV: logo · F2 Ultra UV settings · F2: photo prep · F2 settings · The outline trick
Choosing your coasters
You can buy slate coasters cheaply from most shops, and even cheaper in bulk. They usually come round or square, about 100 mm (4 inches) across, with little rubber pads on the bottom for grip. Engrave the top face.
Placing the coaster
You don't really need a jig for slate. You can put the coaster in the middle of the bed and you're fine.
On the F2 Ultra UV I used my self-centering jig, simply because I like a guaranteed, repeatable position. If you have an F1 Ultra, F2 Ultra or F2 Ultra UV, that's the XL Self-Centering Jig, and the 4-Inch Coaster Jig holds round and square coasters in the same spot every time. For the F1, F2 and F1 Lite there's the Self-Centering Jig.
Focus
It's good practice to focus by hand first. You want the two dots to join into one.
- xTool F2: turn the knob on the side. Right moves the head up and the dots apart. Left brings it down and joins them.
- xTool F2 Ultra UV: press the down arrow on the touch screen until the dots join.
Then in xTool Studio, click New project in the top right. You'll hear a beep when it connects, and it refreshes the camera image. You can also click Auto measure on the right. The machine's lights go off while it measures, then it updates the picture with the height. My square coaster measured 8.8 mm thick. On my F2 Ultra UV, the image sometimes comes back dark after auto measure. Click the camera icon again and it refreshes with a lighter one.
xTool F2 Ultra UV: a logo on a round coaster
- Click the plus (Import) icon on the left and choose your design. An SVG vector file is ideal, and text works with these settings too.
- Coasters have a little beveled edge. I keep the design inside it, which usually means sizing it to about 90 mm.
- With the coaster in a self-centering jig, select the design and use Align center, and it's centered on the coaster without any fiddling.
I get a lot of my designs from Creative Fabrica, which I pay a subscription for because its files are sold as commercially usable. Whatever site you use, always read the license on the file you download before you sell anything made with it.
Always frame by hand, even with the camera, because the camera isn't 100% accurate. Click the three dots next to Framing on the right, pick Outline (so you see the round shape rather than a square box), then click Framing and check it on the coaster.
xTool F2 Ultra UV slate settings
xTool's own material library has slate coaster settings, but I found them a bit dull. These came out best in my own material testing, for SVG designs and text:
| Setting | Value |
|---|---|
| Power | 100% |
| Speed | 300 mm/s |
| Lines per cm | 550 |
| Frequency | 128 kHz |
| Passes | 1 |
The high lines per cm makes it slower, but you get a better, more contrasting result with the fine detail the UV laser is capable of. My coaster took 11 minutes 55 seconds. You could speed it up by lowering the lines per cm, but I'd stick with these.
I engraved with the lid up so you could see it on camera, wearing UV laser safety glasses. Either close the lid or wear UV-rated glasses, and have extraction running, because it makes fine particles.
xTool F2: preparing a family photo
For this one I did everything inside xTool Studio, no other software, apart from removing the background first.
- Remove the background before you import. Search for a free background remover, or use Adobe Express. A background washes the photo out. With just the people on it, you get far better contrast.
- Import the photo and size it to cover most of the coaster.
- Select it and click Edit. Crop the bounding box tight to the people, right down to the top of the hairline, so a frame shows the true size of the photo.
- Open Adjustments. If it's a color photo, tick Grayscale. Black and white is easier to judge and comes out better.
- Click Auto adjust. It might look a bit odd at this point, but trust it.
- Tick Invert. On slate, anything dark in the photo comes out white and anything white comes out dark, so without this it looks like a negative.
- Set Sharpness to about 10.
- Lower the Contrast a little. I was wearing a black T-shirt, and this makes it slightly cloudier so there's some definition between my shirt and the black slate.
Then add your text with the Text tool. I typed the family name, picked a script font I like, and centered it under the photo. A quick copy and paste (Ctrl+C, Ctrl+V) gave me a second text box for the year. For a festive touch I added a couple of Christmas icons from Elements.
xTool F2 slate settings
Set the material first. I saved my own Slate material, so applying it loads my text settings straight away. The text and the photo need different settings, so set each one separately.
Text and vector designs (select all your text):
| Setting | Value |
|---|---|
| Laser type | Infrared light |
| Power | 60% |
| Speed | 600 mm/s |
| Lines per cm | 200 |
| Passes | 1 |
Photos (select the image):
| Setting | Value |
|---|---|
| Laser type | Infrared light |
| Dot duration | 225 µs |
| Power | 100% |
| DPI | 350 |
| Bitmap mode | Jarvis |
| Passes | 1 |
Use Jarvis, it's important. I spent a lot of time refining these and they should work with most photos.
To frame, click the arrow next to the frame icon and choose Outline, because the design is an unusual shape. Turn the light power up, as it's hard to see on a dark surface. Once you're happy, click Process. These settings are quick for a photo: everything took 4 minutes 28 seconds. As with the UV, only run it with the lid up if you're wearing safety glasses.
The outline trick
This is a nice little extra that makes the photo stand out from the slate even more: a thin white line drawn right around everything.
- Don't move the coaster after the first engraving.
- Select the photo and click Offset in the top toolbar (the box with dotted lines). It defaults to 2 mm. Drag it all the way down to 0 and click OK. You now have a vector line exactly around the photo.
- Do the same for your text and icons if you want them outlined too, then select all the outlines and switch them to Score.
- Turn off the photo's output, so its toggle goes from green to red.
- Click Process. Mine took 3 seconds.
| Setting | Value |
|---|---|
| Mode | Score |
| Laser type | Infrared light |
| Power | 70% |
| Speed | 600 mm/s |
| Passes | 1 |
It draws a faint white line around everything, and that bit of extra contrast really lifts it.
More slate settings
All my tested slate settings are in the free Laser Settings Library. There are pages for the xTool F2 and the xTool F2 Ultra UV. If you've got an xTool M2, I tested all three of its modules on slate photos in this guide.
What's going on your coaster?
Let me know in the comments on the video what you engrave, and how the settings work on your slate.
