GalvoMATIC Development June Update

It's been a little over two months since the GalvoMATIC pre-order launch in New Orleans with the one and only Louisiana Hobby Guy, and we are overdue for an update. In this blog post we'll go over some changes that we're making to the production version of the GalvoMATIC, and how the delivery timeline has been affected. The quick takeaway - We are baking two new capabilities into the GalvoMATIC, namely 1) the ability to engrave curved surfaces, and 2) the ability to engrave large images in sections, making that process go even faster. As a result of the time needed for this effort, delivery will be pushed back into the fall, to around early November.

When the GalvoMATIC was first introduced at the end of March, many of our customers and many in the laser engraving community at large expressed excitement for the new level of performance and novel technology it brought as an accessible desktop laser. As the laser engraver market continues to evolve, we want to make sure that our GalvoMATIC continues to stay at the head of the pack in terms of performance, versatility, and bang for the buck for our customers. While the delay in delivery is a large one, we feel it's the right decision to include these new capabilities now, instead of rolling them into a future "Pro" version, or a GalvoMATIC Mk2. Let's get into the details of these two new features.

Large Image Tiling & A Better Auto-focus

As you may recall, the galvo scanner mounted on the GalvoMATIC toolhead has a 100 x 100mm scanning field. For any engraving job that fits within this scanning field, it's able to take full advantage of the extremely high acceleration (up to 800,000mm/s²) of the galvo. However, for images that are larger than 100 x 100mm, the galvo has to call upon the X/Y gantry for help, with the scanning motion split between the two. The combined result looks like a "paint brush" motion:

A faster way to complete these large photo engraves is to break them up into strips or "tile", and engrave each tile separately. With a typical horizontal scan, using this new tiling approach means the laser dot is always traveling left and right using the full galvo acceleration, instead of potentially being slowed down by the X axis.

Consider the following Log Cabin image, sized 200 x 200mm, the March GalvoMATIC prototype cuts engraving time roughly in half with its "paint brush" approach. The new tiling method would cut that time down in half again, to a quarter of the time that it takes the LaserMATIC Mk2.

The biggest challenge we've encountered with tiling is making sure adjacent strips join together seamlessly. The launch prototype is not able to accomplish this consistently. We find that any gap greater than 0.1mm will be visible. Overlaps are a bit more forgiving, but of course ideally we want the seam to be as precise as possible. The below images show a comparison between near-perfect tiling, and a more typical result from the launch prototype.

These visible seams come from variability in the distance between the galvo and the engraving surface. This variability is in turn caused by two factors: 1) Error in distance measurements from the auto-focus camera/lidar; and 2) Unevenness in the engraving surface. The diagram below shows how height differences will create gaps or overlaps.

Given that most workpieces are warped to some degree, improvements must be made to the autofocus camera to achieve perfect tiling. It not only has to be more accurate, but also must have the ability to measure multiple points, in order to capture any curvature in the workpiece. To accomplish this, a second camera is being added to the toolhead. This camera will be tailored for making rapid height measurements, using a telephoto lens higher accuracy and a global shutter for moving capture.

3D Engraving & Dynamic Focus Module

By popular request, we are adding curved surface engraving to the GalvoMATIC. This will open up a lot of new possibilities in terms of items that can be personalized with a laser. Off the top of my head, I can think of sporting goods like balls of various shapes and sizes, helmets, golf clubs, kitchenware like bowls, spoons and a few other examples, but I'm sure once our users get a hold of this new capability, there will be many, many more use cases. Being able to engrave curved surfaces will also speed up certain tumbler jobs without the need to use a rotary. 

To make curved engraving possible, the focus of the laser beam needs to be changed dynamically, and ideally at a faster rate than what's possible with raising and lowering the honeycomb bed. To do this, a dynamic focus module is being added to the GalvoMATIC toolhead. Specifically, a pair of expander and collimating lenses are introduced, and by changing the distance between them with a stepper motor, the focus length of the laser beam can be rapidly adjusted.

A proof of concept was put together in May and tested. The design is being refined to improve focus resolution and repeatability. A design with a post-objective galvo and no F-Theta lens was also considered but not adopted.

In order to engrave on 3D surfaces, the GalvoMATIC will have to build a topography of the workpiece. Luckily for us, this requirement overlaps with what is already required for reliable tiling. As discussed above, a second camera will be added to the toolhead for accurate and fast height measurements. This is exactly what we need for building topographies.

Besides dynamic focus and topography capture, there is a third piece to curve-engraving puzzle. The input G-Code from LightBurn will need to be adjusted and warped, so that the artwork does not look distorted when projected onto a curved surface, similar to what is done in LightBurn with Cylinder Correction. This means our G-Code translator "LightBurn Buddy" program will not only need to group rearrange and group G-Code and account for galvo/F-theta distortion, but also needs to cancel out distortion from arbitrary workpiece curvature as well.

Design targets for the dynamic focus module are as follows. Also, limitations in focal depth and warp compensation means there will be limits as to what curved surfaces can be engraved. Engraving more aggressive curves, like trying to cover a full half sphere, likely will not be possible.

• Focus depth: 30mm
• Max focus adjustment speed, or Z-axis speed: 400mm/s
• Z-axis acceleration: 20,000mm/s2

Impact to Delivery Timeline

Besides adding a second camera and a dynamic focus module to the toolhead, many smaller tweaks are being made to accommodate these two changes. Many more tweaks are also being implemented to improve the overall reliability, ease of manufacture, and fit and finish of the final product. As a result, we've had to push back kicking off certain tooling and scrap and redo some others.

In addition, the dynamic focus module is new to us and carries significant technical risks. We don't expect to be able to jump straight from the prototype shown above to a pre-production or beta state, and likely will need at least one more iteration in between. Not to mention that both vision-related code on the GalvoMATIC, and the LightBurn Buddy program will need to be heavily modified and tested.

All this means that our delivery to pre-order customers will need to pushed back into the fall. A simplified Gantt chart of our development schedule is shown below:

Beta Test Units & Pricing

As part of the updated schedule, delivery of beta test units will be pushed back as well. They will be divided between internal testing, customers who have expressed interest, our launch livestream winners 😃, and several of our social media partners. We expect to ship beta units some time in August.

Pricing for the GalvoMATIC will remain unchanged.

Thank you for giving this update a read. If you are a pre-order customer, we sincerely hope you agree with the choices we made to push back the delivery schedule in order to make the GalvoMATIC, simply put, the best desktop laser engraver possible. Going forward, we'll continue to provide updates on our development progress, though hopefully those will be shorter and serve more as showcases of project progress instead of explaining design changes!

As with all orders on our website, the pre-order can be cancelled at any time before the final product is shipped. I should also mention that come fall when pre-orders need to be completed, customers can select a different size or laser source configuration from their original pre-order choice. If you have any questions or suggestions, please feel free to leave a comment below, or reach out to us at support@rolyautomation.com. Till next time!