Rotary Glass Engraving on the xTool F2 Ultra UV

After my flat glass photo video, so many of you asked how to do the same thing on an actual glass. So here it is: a photo and text on a tapered pint glass, using the xTool F2 Ultra UV and the RA3 rotary in chuck mode.

I'll go through measuring and mounting the glass, leveling it, focusing on clear glass, a trick for finding the top of the glass in xTool Studio, positioning your design, and the settings I use. There's one tip at the end that makes or breaks these.

Jump to: What you need · Measure and clean · Mount the glass · Level it · Connect and focus · Find the top · Set up Studio · Position the design · Settings · The big tip

What you need

• The xTool RA3 rotary. The RA2 works too, but the setup is slightly different.
• A glass. I used a tapered pint glass to show how to deal with the angle.
• Isopropyl alcohol and a cleaning swab.
• The level that comes with the RA3 (or your own).
• The tape measure that comes with the RA3.
• A sheet of plain letter or A4 paper for focusing.

Measure and clean the glass

Measure the perimeter of the glass right where you plan to put the design, because on a tapered glass it changes as you go up. Wrap the tape around that spot and read where it overlaps. Mine was 24.5 cm (245 mm).

Spray the glass all the way round with alcohol and wipe it with the swab. Hold it by the base so you don't touch the area you're engraving. Rotate it and wipe once more so you know you've covered the whole thing. Clean the inside too if there are fingerprints.

Mount the glass in the chuck

On the RA3, turn the knob on the side to the left to loosen it, and you can tilt the chuck. There's an angle scale on it, so note the number for each glass you do and you can repeat it every time.

Everything on the RA3 is magnetic and quick to remove. The chuck comes off with a bayonet fitting, and I take it off to load the glass first.

1. Set the claws to suit your glass. Mine face outwards, but there are lots of combinations. Use whatever works for your glass.
2. With the chuck loosened to roughly the right size, stand the glass upright and lower the chuck onto it. This way the flat edges of the claws sit evenly against the glass.
3. Turn the gold knurled ring clockwise until it won't go any more. The glass should now be held firmly.
4. Line up the bayonet openings on the end of the chuck and push it onto the rotary. You'll know it's in when it doesn't fall out as you let go.

The RA3 has lines along its base you can line up with, but it's hard to place it the same way every time. I use an alignment guide I designed, so the rotary slides into the same central position every time. That's the RA3 Alignment Guide for the F2 Ultra and F2 Ultra UV.

If your glass is too thick to focus on because the laser won't go high enough, you can mount the rotary underneath the bed instead and it will still be central.

Level it

If your glass has straight sides, you can skip this. With a tapered glass, the top surface won't be level to start with.

1. Put the level on top of the glass.
2. Loosen the tilt knob and lift the far end of the glass by hand, keeping your fingers off the cleaned area, until the bubble is in the middle.
3. Tighten the knob again.

Connect the cable and focus

The rotary cable only goes in one way. On the first connector, the two little notches face up. For the other end, pull off the small cover to reveal the two ports, and plug in with the curved edge at the top. It's a bit tight but it will go in. Tuck the cable out of the way so nothing catches it.

Focusing on clear glass is hard because the dots go straight through it. Lay your sheet of paper directly on top of the glass and use the arrows on the touch screen to join the two dots. Remember the paper is about 0.1 mm thick. You'll take that off the height in a minute.

Find the top of the glass

This is the trick that saves a lot of hassle. Look at the vertical arms of the chuck and turn it by hand until one of them is straight up and in line with the center. You're just eyeballing it. Now, when Studio takes its photo, that arm marks the very top of your glass. You'll see why next.

Set up xTool Studio for the rotary

1. Click New project. Studio connects to the F2 Ultra UV and takes a picture.
2. In the top right, change the mode from Process on flat surface to the chuck rotary mode. The canvas gets longer, with a green line across it.
3. Left-click and drag the green line down until it runs through the middle of that vertical chuck arm. That line now marks the top center of your glass.

The camera image of a cylinder looks a bit distorted, so it may not look lined up. Trust the line.

4. Choose RA3 manual mode from the drop-down. If your engraving ever comes out back to front, you probably had RA2 selected.
5. Enter your measurement. I chose perimeter and typed 245 mm. This tells Studio how far to rotate the glass.
6. The thickness (focus height) box doesn't always update after you focus by hand. Tap the up arrow on the touch screen once and the down arrow once, and the number appears. Mine read 136.2. Subtract the 0.1 mm of paper, type in 136.1 and press Enter.
7. Click Material in the top right, choose Clear Soda-Lime Glass and click Apply. This is important for the photo step.

Import and position the design

1. Click the plus (Import) button and bring in your photo. Remove the background first if it has one.
2. Crop the bounding box down to the edges of the photo and click Save.
3. Rotate it. Hold Shift while you drag the rotate handle and it turns in 15° steps.
4. Line up the handle in the middle of the image with the green line, so it sits centrally down the face of the glass. I lined up my nose.
5. Resize it with the middle handle (the aspect ratio stays locked), or type a size in the top left. Mine was 32 mm high.
6. Keep the design clear of the chuck's grips where they wrap over the glass, so you don't engrave over them.

For text, click Text, click the canvas and type. It comes in as Score, so switch it to Engrave. Rotate it with Shift, line its center up with the green line, and set the size. I used Georgia for my name. A quick copy and paste gave me a second line for "L3D Accessories" in a different font, set to the same height.

Then select the photo, click Adjust and click Auto adjust. Because you picked Clear Soda-Lime Glass, it optimizes the photo for glass, including inverting it. It's not always perfect, but it's pretty good.

Rotary glass settings for the F2 Ultra UV

Text and vectors use power, speed and lines per cm. Photos use dot duration, power and DPI. These are my best settings for both.

To frame, click the three dots next to Framing, turn the light power up to 10, and click Framing. On a rotary it doesn't draw a simple box. It sweeps side to side and turns the glass to show you the area. Lay paper on it if you want to see it more clearly.

Click Process. Mine took 13 minutes 26 seconds. Click Preview processing path and drag the slider if you want to see the order it engraves in.

With the rotary in, the lid only comes down part of the way before it hits the rotary, so light leaks out of the bottom. Wear laser safety glasses. Use extraction too, whether that's an external fan, an air purifier or a pre-filter, to pull the glass dust away.

Want to engrave the back as well? Use the same trick in reverse. Turn the chuck by hand until the arm points straight down, and the face on top is now the opposite side. I put my L3D logo directly behind the photo this way.

The big tip: not all glass is equal

I had a glass that looked just like this one, and I ran test after test without ever getting a result I was happy with. The same settings on this glass came out amazing. So check your glass, run a few test engravings first, and dial your settings in before you risk a glass you care about.

For flat glass coasters and more tested settings, see the xTool F2 Ultra UV settings page in my free Laser Settings Library.

What are you putting on a glass?

Let me know in the comments on the video how you get on, and what you'd like to see on the rotary next.