Laser Rotary Engravers: Has this ever happened to you?

You’ve created the perfect design in your graphics software, set up your cup on the laser rotary attachment (hopefully a PiBurn!), and sent the job to your laser. But when you check the cup you realize that the image is distorted. Frustrating. It doesn’t look like the original design because it is either stretched, warped, or is oval when it was meant to be circular. You’re thinking: What could I be doing wrong?! Well, in this blog post we will try to help with the most common cure for the stretched (or squished) or distorted images on your cup. Here are some of the most common reasons why your image looks wrong and the steps you should take to make sure the image is perfect. In order of most common problems (assuming you have a roller rotary):

1. Setup on the laser rotary: Check your tumbler’s neck and body diameter – are they different?

This is the most common cause of distorted images – especially if your designs appear stretched on the tumbler. Here is something people don’t always realize. If your flask or water bottle has a narrow neck, AND the neck is placed on the motorized wheels, then the body of the flask is rotating further distance than the neck and the image will be stretched. Your settings are accounting for the wheel diameter, not the object diameter but the laser thinks the bottle is moving the same as the motorized wheels, not further. But in fact, the body is moving more than the neck! To solve this do one of the following:

• Take off the clamp from your PiBurn and flip the bottle around on the rotary so that the narrow neck is on the smaller wheels (back wheels). This is the most common solution and works most of the time when you do not need the clamp. If you need more friction get the Mega Clamp for the PiBurn.
• Adjust your image. Given your image will appear stretched, adjust down your image to compensate. Use masking tape and lower power to get it just right and not mess up any cups. Takes a little tweaking.
• Change your steps per rotation. You will need to reduce your steps. We almost never recommend this method for a number of reasons, one of which is people sometimes forget to change their steps back!

 

2. Foiled by an Optical Illusion: Measure your image

That was supposed to be a circle but the image looks quite oval!

This is the second most common problem we hear and it’s caused by an optical illusion of a circular image superimposed on a cylindrical object. It will appear oval to the eye! If you think about it, the parts closer to the edges are further away from the observer, hence they look smaller. The difference is tiny but with a circle engraved on a smaller diameter tumbler, it’s very visible. Check the image and engrave it on a flat surface. Now, take your tumbler and measure the height and width of the image. They are probably the same! The best way to adjust for this is to manipulate the image and compensate for the illusion. Some people have got this down to a science and created a handy calculator that helps you with the dimensions based on your image. Check it out in the files section of the group PiBurn Labs (our official support group) Direct link to file.

3. Steps per rotation are off: Dial in your laser rotary

Check your steps per rotation and perform a 100mm test to make sure you have dialed in your laser rotary correctly! Pulses (or Steps) per rotation settings are a very common source of headaches but can be avoided by performing a simple test and dialing in your rotary. With a PiBurn, you only need to do that once! Perform the test described in Chapter IV (Page 18) of the PiBurn manual If you are a visual learner, watch this video instead.

4. Can the cup be slipping on your rotary? (Does it have a heavy handle?)

This is the one clear drawback of using a roller as opposed to a chuck as discussed here at length. By the way! Check out our new chuck rotary, the PiBurn Grip. This is hands-down the best chuck rotary for laser engraving – and the Grip don’t slip! [button et_class=”” target=”_blank” style=”medium” url=”https://www.lensdigital.com/product/piburn-grip/” icon=”” title=”Get a Grip”]   A roller rotary relies on friction between the object you are engraving and the wheels it is resting on. An unbalanced object or a cup with a large, heavy handle will test the tension between the object and the wheel and it will increase the chances your cup will slip. Now, the PiBurn does an amazing job at reducing this slippage: Enter the new metal clamp.

If you have the latest metal clamp for the PiBurn 4.0, you are lucky! This is the only clamp on the market that has adjustable tension. Go ahead and give that thumbscrew a spin to increase tension and reduce slipping even on the most stubborn cups with handles. If you still see some slipping, you can add a counterweight like a magnet to opposite where to handle is.  

5. Adjust the belt tension on your PiBurn Laser Rotary Attachment

After doing thousands of orders on the PiBurn, our customers find that it can use some TLC. If your images have problems at the very edges (start or end of engraving) most likely, a loose belt or pulley is to blame. Here is how you check to make sure you are up and running smoothly again:

6. Thanks, but nothing you mentioned helped!

If this still does not help, post your image with as much detail as possible (which laser do you have? What settings are you using?) on our support group PiBurn Labs. We have amazing people who selflessly help other makers on our forum. They are true PiBurners and they might be able to help you as well! Hope this helps the many of you struggling with getting your image to perfection on your tumblers. We are here to help! Happy PiBurning! Len and Stan