Oddwick Industries

This is the first time that I have ever worked with aluminum dibond, so it was a bit of an adventerous learning curve. One thing that I did learn the hard way is that when using my dust collector, that it was a lifesaver for all of the small chips that came off of it, but it creates lots of long strings of plastic that got caught up in the intake of it and caused a huge rats nest. It took a couple of days to realize that I had lost alot of suction and when I was cleaning out my bag, that is when I noticed that my intake was clogged!

When cutting into it, overall it cuts much like hdpe maybe a little firmer. The aluminum cladding really didnt affect my cuts or speeds too much. For most things like this, I use a spiral ramp with a single cleanup pass at the bottom and I overcut the depth by about 0.25mm just to make sure that all is cut through and clean. Sometimes the aluminum will leave rougher edges because of how fast I was feeding, but that was easily cleaned up with a deburing tool. But if using one of these (which are one of the greatest tools I ever bought), just make sure that you use a light touch because once you debur the aluminum it is super easy to dig right into the composite center!

One of the other things is always make sure that your spindle is off and retracted before you make a jog! I went to jog after cutting one of the side panels and it had came up because I was just using its weight and a few screws to hold it in place and one of the corners came up and totally got ate by the bit! That was a huge let down because I had measured and only bought exactly what I needed at least for the big panels, so after much cursing and kicking things, decided that while it was still fastened down that I would cut out the corner and make an access panel right there so that I could get in and adjust the first mirror alignment without taking off the entire side panel. Not an ideal situation, but a nice recovery. Nobody saw that right?

So on my original version, I really failed with this part. I wish I had pictures but the humiliation wouldn’t be worth it! Anyway, it was nothing if not a pain to keep adjusted. So my design goals with this were to make a mount that was accessable, adjustable, robust and relatively inexpensive using materials that I had lying around.

Because I wanted to keep it simple, I decided to make a two part clamp that used zip ties, 3/4 HDPE, and silicone tubing to protect the tube. When thick enough, HDPE is surprisingly stout and super easy to machine. I also desided to only make it adjustable vertically seeing as that there is only around 20mm between the laser output and the first mirror.

Centering of the beam is achieved by using the vertical adjustments on the tube mounts and the horizontal adjustment on the first mirror. This actually seemed to work out pretty well, aside from the fact that I violated the “No hidden screws” mantra that is now my life goal. But really it looked better in my mind; it always does.

Another thing that I was focused on was cable management. The last version was a spaghetti nightmare with wires so I decided to incorporate holes in the bottom mount for keeping the cooling lines and cables organized.

To keep the springs in place, I used a M6 threaded insert that was countersunk in a few mm to capture the ends of the springs around the screws. For the adjustment screws, I went with M6 nylon thumb screws. They work great and are non conductive, but I really did not leave much room on the inside for using them, so that would be something that I would change if I were to rebuild it in the future.

In the original engraver, the optics were from Lightobject, and worked great, but they were 23mm and I needed new mirrors and lens which is a very odd size to find. So for the price of what I was going to pay to get off sized optics, I decided to just order a complete 25mm mirror and mount set from Cloudray. The one thing that I really did not like was the way that the first mirror was mounted, which was on a long post. Although I never used it as such, it just did not seem like it was that stable and since I designed this machine to seriously haul when engraving, I thought that the vibrations would be amplified to the mirror on such a long mount. Therefore I opted to invert the first mirror so that it could be mounted from the top of the frame. This involved fabricating a new mount with adjustments and a few modifications to the actual mirror holder itself, namely drilling and tapping the other side of it for the shield. I think I should also point out that side drilling plates has always been my nemisis. So as aprehensive as I was, I went for it and surprisingly it worked!

One of the main features that I wanted to include with this laser was the ability to focus with software and/or to be able to autofocus. In the previous version, I had to use a use a distance block to focus and for different types of engraving or etching I would just sometimes have to eyeball it. That was not really great in the repeatabiliy department. Now with a z lift table I can just put a piece of material in and just press start.

I did alot of research when it came to laser z axes, and there are a few different designs out there which had pros and cons about each one. I am not a huge fan of the scissor lift type, because I feel that the lift height to complexity ratio is not there for me. In the end I settled on just a simple screw lift with bearing rod stabilizers. Some of the factors that went into my decision was that i sometimes engrave heavy objects (granite tiles etc) so I needed a robust solution. I also wanted to be able to have a fair amount of travel so that I could etch larger objects or use things like pin stands for laser origami or whatever.

I had alot of t8 leadscrew lying around as well as some 8mm hardened rods and supports. By using four leadscrews, I was able to independently level each of the corners. Each screw it supported top and bottom with 8mm flanged bearings and kept in place with a 8mm cuff on the top and a 32t gt2 pulley on the bottom. They are all ran from a single belt through a pair of idlers to the motor with a 16t gt2 pulley. This gives me a 2:1 advantage for torque lifting heavy objects. Because the motor is in a small area in the front used for venting, I suppose that I could have gone with a nema 23, but that seemed like a bit of overkill and besides I had a pile of 17s lying around, so that seemed like the obvious choice. Waste not, want not, make cheap laser or something like that…

So this will begin to detail the process of rebuilding my laser engraver. The original incantation started off being more of a proof of concept and was only the second machine that i ever designed, so it was at best both unfinished and flawed. It was 40w and based heavily on the 2.x Laser from Bart Dring at buildlog.net. It worked well and introduced me into the world of laser engraving and cutting.

But, some of the obvious flaws were that it was controlled by LinuxCNC, which while amazing for cnc machines, it lacks in the laser department. Vector engraving was easy enough, but raster engraving was next to impossible with any degree of accuracy. I was using an extension from Ben Jackson and Jeremy Van Grinsven that allowed laser rastering using a “magic z” approach. Late last year i started upgrading all of my machines to Mesa control cards, specifically a 7i96, and because of the speed reqiured to fire the laser vs the transfer rate over ethernet, it ended up breaking the whole system. Then end the middle of reworking the laser, it ended up getting -15º and for the first time it froze inside of my garage and cracked the water jacket on the laser tube.

So that cemented my decision to go with an DSP controller and at the same time, do away with makerslide/openV configuration. While OpenV is pretty awesome for quickly cobbling together machines, I have found that there are some pretty glaring flaws with it, namely its weakness when dealing with lateral forces. Also it is super easy to deform the rails when tightening insertion nuts. This has caused many a bumpy road when trying to adjust an endstop!

While surfing around looking for design inspirations, i stumbled across this one on instructables called the R-Laser 6020 and i was amazed at the attention to detail and clean engineering that went into it. I also learned what aluminum dibond was and there is a plastics supplier in Denver that sells sheets of it pretty reasonably. But there were also a few things about it that i thought that i could improve upon. I wanted to design something that was entirely self contained because i was not a huge fan of the 2 part machine / electronics cabinet. My space is limited and i could build one that would fit entirely on a workbench, albiet a wide one. The other thing i wanted to change was the lid. Something that opens both top and front would be easier to place objects inside of it and get them situated. And of course the z table would have to me much more stout because i do engrave on granite tiles which can be quite heavy.

so after a waiting for my Misumi order, here is the frame. The rails are MGN15 rails which are bigger than i wanted to go, but they were what i had and i really did not feel like waiting weeks for to order them from RobotDigg and i was trying to stay within a budget as well.

The overall design is an internal frame with a external cage to give it stability. The z axis was really designed around a handful of parts i had lying around, and mostly a long belt that would be able to turn 4 T8 threaded rods at the same time and used 8mm smooth rods for the guides.