Question for those familiar with laser engraving...

[Tom Albrecht]

Is it possible to use a laser engraver on the outside of a bowl, in other words, on a curved surface?

 

[Rob Gabel]

Yes, but you would typically want a rotary attachment to have it work well (this is what they use for engraving tumblers). You would be limited in diameter with the rotary attachment depending on the style and also the laser setup itself. You could also checkout https://transpirationturning.com/ for doing this at the lathe. Paul Paukstelis has some posts on this.

 

[William Rogers]

I think it depends on the size of the engraving and maybe the laser. I have the Xtool d1 pro 20w and engraved some hearts on the outside. Each was done individually. My laser focal point is somewhat forgiving, If you are going to try to go around the bowl you would need a rotary suggested by Rob. You can get distortion if it is a large engraving. Here is a picture of the hearts I engraved.

 

[Doug Rasmussen]

Yes, laser engraving can be done on most any surface, flat, round, highly contoured surfaces, etc. It does depend heavily on your equipment though. I do it on a CNC machine so any place the cutter can go so can the laser beam with some rare limitations.

My recommendation is to buy a CNC router rather than a machine specifically made for laser engraving. To be really effective the machine needs to move the laser head up/down to follow surface contours to maintain focal distance. Woodcraft frequently has their small CNC's on sale with a free laser head included. A rotary head attachment is a nice addition to the CNC for round objects. All told a CNC machine to do laser'ing plus much more can be purchased for a fraction of the cost of a high end lathe.

 

[Paul Paukstelis]

Yes, but you would typically want a rotary attachment to have it work well (this is what they use for engraving tumblers). You would be limited in diameter with the rotary attachment depending on the style and also the laser setup itself. You could also checkout https://transpirationturning.com/ for doing this at the lathe. Paul Paukstelis has some posts on this.

The big advantage of the LatheEngraver for doing laser or router work around the rim of the bowl is that you can rotate your tool to be normal to the surface of the workpiece. Additionally, the way I have written the control software you can use any 3-axis gcode from your favorite CAM package (Vectric, LightBurn, etc.). You input the diameter of the workpiece where your design will be centered and it will do all the necessary coordinate modifications (and it is free).

 

[Richard Coers]

To directly answer your question, yes it’s possible. There is a certain amount of tolerance on how out of focus the laser can get before you loose clarity in the work.

 

[Tom Albrecht]

Thank you all.
You have answered my question completely and helpfully.

 

[Doug Rasmussen]

o directly answer your question, yes it’s possible. There is a certain amount of tolerance on how out of focus the laser can get before you loose clarity in the work.

Again, this depends on machine you're using. With a CNC router the laser head moves vertically (Z axis) to maintain the focal distance.

Here's a random image I found online. Think of this as a surface you might want to laser engrave. The highs and lows might exceed the focal length of your laser so the laser head has to move up/down to compensate for surface irregularity.

 

[Paul Paukstelis]

Again, this depends on machine you're using. With a CNC router the laser head moves vertically (Z axis) to maintain the focal distance.

Here's a random image I found online. Think of this as a surface you might want to laser engrave. The highs and lows might exceed the focal length of your laser so the laser head has to move up/down to compensate for surface irregularity.

Most basic CAM packages aren't going to have the necessary tools to generate this gcode. Those that are designed for generating laser gcode almost certainly aren't (they might have basic rotary at best).
The other problem you run into is that the Z travel on a hobby machine is likely to be fairly limited. Assuming you are on a rotary setup (which itself takes up some Z travel unless you are build a drop table) you may not be able to reach either the rim or the base of the bowl.

 

[Doug Rasmussen]

Most basic CAM packages aren't going to have the necessary tools to generate this gcode. Those that are designed for generating laser gcode almost certainly aren't (they might have basic rotary at best).
The other problem you run into is that the Z travel on a hobby machine is likely to be fairly limited. Assuming you are on a rotary setup (which itself takes up some Z travel unless you are build a drop table) you may not be able to reach either the rim or the base of the bowl.

Vectric's Desktop at $349 will do it. Some CNC routers sold at Woodcraft include Desktop. Desktop also supports a rotary 4th axis. Vectric software is very widely supported, hundreds of Youtube videos.

Here's how I would do it using Desktop. Desktop includes quite a collection of free clipart. That clipart can be manipulated (stretched, resized, distorted, etc, etc) to create a 3D surface or wrapped on a circular work piece. Design your laser path as a 2D file using the design tools in Desktop. Then using the project cutter path option onto the 3D surface. The Gcode generated will be a cutter path. The cutter path is easy to modified to a laser path by using search and replace in free Notepad++. Then use another free software to modify the Gcode to raise the laser head in Z axis to the correct focal length off the 3D surface.

This isn't speculation on my part. I've had my 4 watt laser head at least 20 years and used dozes of times..

I recommend CNC's because they're so versatile. They can even cut your complete bowls to a finish that hardly needs any sanding.

The CNC skeptics will say CNC is not woodturning, but then neither is laser engraving.

 

[Paul Paukstelis]

Here's how I would do it using Desktop. Desktop includes quite a collection of free clipart. That clipart can be manipulated (stretched, resized, distorted, etc, etc) to create a 3D surface or wrapped on a circular work piece. Design your laser path as a 2D file using the design tools in Desktop. Then using the project cutter path option onto the 3D surface. The Gcode generated will be a cutter path. The cutter path is easy to modified to a laser path by using search and replace in free Notepad++. Then use another free software to modify the Gcode to raise the laser head in Z axis to the correct focal length off the 3D surface.

That's all it takes? It is baffling that thousands of turners aren't using these simple steps to embellish their bowls. You only need to use three pieces of software and a deep understanding of gcode to make it work.

 

[Bill Blasic]

I have a CNC or 2 and they are not wood turning, but they can aid you with your wood turning as can 3D printing, Lasers, Rose Engines for a start. Now I know that you can make a laser work with anything. I have the 4th axis for my CNC but the laser for my machine is just way to expensive. But the LP series of lasers are very versatile especially the LP1. You can easily build a stand so that you can position the LP1 over the piece and burn the outside or as shown on this site you can position it on the lathe to do the bottom or the inside. Then there is the Lathe Engraver (I'm getting there with the build). Now I can argue with Doug till we're both blue in the face but I'm good with him thinking a CNC is a lathe as I hope he thinks my thought that they are not is ok By the way Doug if you know a way to adapt a laser to the Shark 510 HD I'd be grateful.

 

[Bill Blasic]

I don't believe Vetrics desktop will not allow you to do laser work. I have Vetric Aspire and you need to purchase the laser package to use a laser in Vetric. NOTE!!! I was wrong the laser package is available and works for all 3. Vetric Desktop, Vetric Pro and Aspire.

 

[Ed Davidson]

A relatively low costs diode laser with 5 to 20 watts of power output (small laser spot) is fairly forgiving on curved surfaces (not using a rotary setup). I can get sharp results on my 10/20w machine when lasing concave or convex curved surfaces that are about 1/2" deep or high over a 2" yo-yo surface. Putting a 1" logo on a 6" bowl's curved side for example, using this method, shouldn't be a problem.

 

[Ed Davidson]

If you are wanting a large lased coverage that goes completely around the bowl for example, then you'd need a $100 to $ 250 rotary attachment.

 

[Ed Davidson]

One last thought from me on laser engraving woodturnings. Many engravers are set up to use a commercial software called Lightburn. You can get a free copy off the net to try out for 30 days. A lifetime license cost $99, but you'll have to re-up for an annual subscription if you want updates, which are frequent. Lightburn provides comprehensive controls for running your laser as well as tools to both design things from scratch and/or modify (clean up or customize) artwork you find on the net. Here's some things recently designed from scratch with Lightburn.

 

[Richard Coers]

Again, this depends on machine you're using. With a CNC router the laser head moves vertically (Z axis) to maintain the focal distance.

Here's a random image I found online. Think of this as a surface you might want to laser engrave. The highs and lows might exceed the focal length of your laser so the laser head has to move up/down to compensate for surface irregularity.

View attachment 85768

No it doesn’t depend on the laser you are using. Every laser can accept a certain amount of out of focus work. Some laser engraving users actually set the focus in the center of the material for a cleaner cut in thick stock and some only focus on the top surface. You don’t have to explain the differences in the machines to me, I’ve had a laser engraver for over 25 years and ran a CNC for my day job for 15 years. (I retired 12 years ago). That CNC router had a 5’x10’ bed with a Z axis of 3’ It was a 5 axis machine, so I do know what I am talking about.

 

[Paul Paukstelis]

Many engravers are set up to use a commercial software called Lightburn. You can get a free copy off the net to try out for 30 days.

They also just recently released MillMage for CNC machines.

 

[Doug Rasmussen]

No it doesn’t depend on the laser you are using. Every laser can accept a certain amount of out of focus work. Some laser engraving users actually set the focus in the center of the material for a cleaner cut in thick stock and some only focus on the top surface. You don’t have to explain the differences in the machines to me, I’ve had a laser engraver for over 25 years and ran a CNC for my day job for 15 years. (I retired 12 years ago). That CNC router had a 5’x10’ bed with a Z axis of 3’ It was a 5 axis machine, so I do know what I am talking about.

I said it depends on machine not the laser head itself. A flat bed laser might not work so well on a highly contoured surface. My laser head is only 4 watt so it doesn't do so well unless it can maintain a precise distance above the work. The moveable Z axis provides that positioning. It'll barely cut paper without a couple passes. It marks plastics and wood though.

 

[Doug Rasmussen]

That's all it takes? It is baffling that thousands of turners aren't using these simple steps to embellish their bowls. You only need to use three pieces of software and a deep understanding of gcode to make it work.

When I first starting doing laser-type work I didn't have a laser. I used a digital temperature controlled soldering iron with a sharp tip. One easy to use piece of software, Vectric Desktop. The soldering iron became the tool. The problem with using a wood burning tool was the tip's heat recovery time from a burn.

I eventually went to a low power laser with instant on time, no waiting for heat recovery. I'm a cheapskate and developed the 3 software system which is certainly not rocket science. I suppose I could have bought dedicated laser software but why spend the money when my way is so simple.

Ultimately the reason for recommending a CNC is it can make bowls or any number of other turning-type objects without a lathe plus do flat and rotary laser work. Being able to do oval bowls is almost reason enough to buy a CNC without spending $4K on a Vicmark oval turning attachment.

Anyone doing CNC work without at least the minimum of Vectric Desktop is missing out. Thousands of users all over the world, unlimited support with user forums and Youtube, etc, etc.