Laser Rotary Engraving Glossary with all the Terms DEFINED!

Before getting creative with your laser engraver, you need to learn the lingo!

This glossary was made for you to quickly learn the most important and commonly used terms when using your laser engraver with your laser rotary attachment.  Not only will this glossary help you get familiar and master your equipment, if will also allow to short circuit the learning curve and jump into a sea of profits faster! Let’s get right into it.

Glossary of Laser Engraving Terms

• Steps Per Rotation (a.k.a. Pulses per Rotation): This setting determines how many steps or pulses the motor needs to rotate the object 360 degrees. It’s crucial for ensuring that your engravings are not squished or stretched. The exact value depends on your laser machine’s setup and can be found by checking your stepper driver’s DIP switch settings​​. To dial in the settings even further, you will need to perform the 100mm Test. Getting these settings right will enable you to engrave precisely what you see in your design software and will also help you master full wraps

• Object Diameter: The actual diameter of the cylindrical object you are engraving. This is different from the roller diameter used in other rotary types and is essential for calculating the correct movement during engraving​. You will need to measure the diameter of your object when working with a chuck rotary such as the PiBurn Grip. We recommend a good caliper!

• Roller Diameter: The diameter of the rollers on the rotary device that hold and rotate the object. This is usually fixed and used in software settings to calculate the object’s rotation​. If you are using the PiBurn roller rotaries the diameter is 66mm

• Y-Axis: In laser engraving, the Y-axis refers to the movement of the laser head along the depth axis of the machine (towards and away from you). When using a rotary attachment, the Y-axis is typically replaced by the rotation of the object​.

• Z-Axis: This is the vertical axis in a laser machine and moves the laser head up and down. On smaller machines this can be a limiting factor to the range of items you can engrave on a rotary. Check your machines documentation and get a lower profile rotary such as the PiBurn Grip2 for smaller machines.

• Gantry: A laser gantry refers to the metal structure in a laser machine that moves the laser head across the work area. It is typically composed of a framework with rails or beams, along which the laser head travels, allowing it to position itself precisely above the material to be cut or engraved. The movement of the gantry, usually in the X and Y directions, is controlled by motors, enabling the laser to reach different parts of the workpiece as the laser fires at exactly the right time. In the context of using a rotary attachment, the laser gantry is important because it must be positioned and aligned correctly over the rotary device to ensure accurate engraving on cylindrical objects. When setting up the PiBurn, you may need to move the rotary manually and run the red laser beam between the alignment indicators on the rotary until they are aligned.

• Rotary Attachment: A device that replaces the Y-axis movement with rotation, allowing for engraving on cylindrical objects like mugs, bottles, and tumblers. The PiBurn is an example of a high-end rotary attachment. There are many other rotaries and they all have different features to suit varying needs and budgets. They mostly fall into two buckets: Roller and Chuck rotaries.

• Roller Rotary: A roller is a rotary attachment for your laser engraver that uses either rollers (sometimes called hot-dog rollers) or a system of wheels to turn your object. PiBurn V is a roller style rotary. They are simple to use and quick to swap items. However they rely on friction and are not as precise as chuck rotaries for full wraps. A full comparison can be found here.

• Chuck-Style Rotary: A type of rotary attachment, like the PiBurn Grip, that uses jaws to hold the object securely in place while it rotates. This is different from roller-style rotaries, which rely on friction to rotate the object​. A full comparison can be found here.

• Focal Distance: The distance from the laser lens to the surface of the material being engraved. Proper focal distance ensures that the laser beam is at its most focused and powerful point, resulting in a clean, precise engraving​.

• Defocusing: The practice of slightly altering the focal distance from the ideal focus point to achieve specific effects, such as softer engravings or broader lines. In some cases, defocusing is used intentionally to create a desired visual effect, especially on curved surfaces where perfect focus might produce a more jagged look on the tumbler​.
• Full Wrap: A Full wrap is a popular style of engraving on a tumbler where the design wraps around the whole circumference of the tumbler. This could be a repeating pattern or not. They can be tricky to get perfect or “seamless” but are highly desired by customers. A high-end rotary is recommended for full wraps where you cannot see the seam. Here is a step by step video tutorial.

• Acceleration and Speed Settings: These settings control how fast the laser head moves between engraving points and how quickly it accelerates. Lowering these settings when using a rotary attachment prevents the object from slipping or flying off during rotation​.

• Homing: The process by which the laser engraver establishes its starting position. When using a rotary attachment, you may need to manually home the Y-axis since it is disabled or replaced by the rotary​​.

• DIP Switches: Small switches on the stepper motor driver that set the motor’s operation parameters, including the number of steps per rotation. These need to be checked to determine the correct steps per rotation for your machine​​. You may still need to dial in your steps using the 100mm test.

• V-Slot Rail: A structural component on which parts of the rotary attachment, like the PiBurn, slide to adjust the position and alignment of the object being engraved​.

• Linear Guide Rail: Some rotaries use a linear guide rail in addition to the V-Slot rail to ensure even more precise movement and reduce the need for alignment. PiBurn V and Grip 2 are high-end rotaries that use this dual-rail system.

• Back Wheels/Rollers: Components at the rear of the rotary attachment that support and help in leveling the object. Proper alignment of the back wheels is crucial for consistent rotation and engraving accuracy​.

• Clamp: A mechanism used to hold objects securely on the rotary attachment, especially for objects with handles or those that are not perfectly cylindrical​. The clamp is used on roller rotaries but is not needed on chuck rotaries.

• Laser Head: The part of the laser engraver that emits the laser beam used for cutting or engraving materials. Proper alignment and focusing of the laser head are crucial for achieving the desired engraving quality​.

• Slipping/Jumping Off: A situation where the object being engraved moves out of position during rotation, often due to inadequate weight or improper clamping. Adding weight or adjusting the clamp can prevent this​. Slowing down your frame speeds helps. Chuck rotaries can also help avoid jumping. 

• Y-Slop Error: This error occurs when the Y-axis of the laser machine reaches its maximum or minimum coordinate limit, causing the machine to stop and display an error. This error can have different names on different machines and is common when using a rotary attachment, as the machine doesn’t account for the infinite rotation of the object and tries to move beyond the physical limits of the laser bed. It is also called SLOP error, limit error, and simply SLOP. To fix it, move the Y-axis to a position closer to 0mm using the control panel’s arrow keys. Reset the starting position by pressing the “Origin” button. Here is our video explaining how to do this in LightBurn.
• Walking: “Walking” refers to the unwanted movement of an object (like a tumbler) back and forth during engraving due to insufficient clamping, irregularities on the object or poor alignment. This typically happens when engraving cylindrical objects with uneven weight distribution or objects that are not properly secured on the rotary attachment. To avoid this, you can use the front and back end-stops on the rotary to prevent the object from moving forward or backward.

• Beam Alignment: The process of aligning the laser beam with the center of the rotary attachment to ensure even engraving across the entire surface of the object​.

• Framing: A function in the laser software that allows you to trace the outline of your design on the object before actually engraving, helping to ensure proper positioning​.

• 100mm test:  The 100 millimeter test is a process to determine the right steps per rotation for your machine. You must perform this test once, when you first dial in your rotary. The process is simple and takes only a few minutes but it is very important to get this right! It involves drawing a 100mm line on masking tape, wrapping it around a cylindrical object, and then running a test engraving of a 100mm line on the object. If the engraved line matches the length of the drawn line, the settings are correct. If not, adjustments to the steps per rotation or object diameter need to be made​. Here is a step by step video.

• LightBurn: This is a popular design software that communicates with your laser and lets you engrave different designs.