Tweaks and Changes

The laser upgrade went remarkably smoothly and the laser cutter was functional but there were a few minor changes and improvements that needed to be done.

Fixing the screen image
Image flipped on the controller
The first and most noticeable tweak for my new Ruida system was to fix the screen display. Most of my cuts are symmetrical so it was a day or two before I noticed that the image on the screen was mirrored. The laser cutter was cutting the correct way so I knew this had to be a simple setting on the controller. In the menu system is an option called 'Screen Origin' we have to set this to 'Top Right' so that the controller knows it's cutting from the same corner as the laser.

Screen origin setting
Screen Origin should be set to top right
Image corrected on the controller
Wiring in the water protection
The additional wire patched into the WP line on the PSU
The lid switch and the water flow detection were already wired directly to the high voltage power supply, this ensured that the laser wasn't going to fire accidentally during any of the previous testing. The Ruida controller is actually capable of understanding these inputs and generating a warning when something is wrong. Patching this input into the controller is as simple as running a wire from the WP connection on the laser PSU into the WP1 input on CN4 of the ruida controller. When this is wired correctly LED #9 will flash on/off when the inputs are activated.

The Ruida controller is actually capable of understanding the difference between the lid switch input and the water flow input. It would be possible to split the two inputs before they go into the laser psu but this is a suitable compromise for the moment.

The WP line connected to pin4 CN5, led #9 is lit
Setting up the water protection from RDWorks
The controller needs to be configured to use the water protection inputs, this has to be done from within the RDworks software. File->Vendor settings (password RD8888) allows you to see the settings on the machine and you can read/write the water protection settings.

The error that occurs when you start a cut
Once configured this is the error message you get when you start a cut without the safety switches engaged.

Autofocusing hack
Z limit switch hiding in the darkness
Lightburn has some interesting features where it's able to automatically adjust the height of the bed if you tell it the material thickness. The controller needs to know where the zero point for the Z axis is before it can do that, some lasers have an autofocus probe mounted to the head to sense the thickness of the material. My laser cutter only has a limit switch mounted on the Z axis, when that white collar moves to the top of the rod then it triggers the switch. The trouble is that it doesn't take into account for the honeycomb or the knifebed sat onto of the bed. The switch doesn't trigger until after the metalwork crunches itself into the nozzle.

A well positioned saw blade triggers the Z switch
The solution was to make the bed trigger the sensor a lot lower down. I was thinking about mounting a bracket onto the side of the bed but it's all at a very tricky angle and I would probably have to dismantle the Z axis to get to it. As I looked at it I realised I could slide a thin strip of metal between the bed and it's own brackets that would stick out under the switch. I ended up using a saw blade wedged into the gap to trigger the Z switch at a suitable height. (Don't forget that the telescopic tube of the Z axis gives you a wide range of suitable heights)

Setting the Z focus manually for the last time
The Z axis is now capable of zeroing and limiting before it crashes into the nozzle, that doesn't mean it's actually in focus though. The focus is a few mm below the zero point but there is an easy way to calculate what the offset is. If you adjust the focus manually you can read the offset from RDWorks and you can use that value in the controller. Now when you use the autofocus button the laser bed will move all the way up to the zero position and then back down until the surface of the bed is on the focal point. I may adjust this to be 2.7mm lower because I most commonly use poplar plywood.

Current position and new focus depth

While you're under the beds give it a good cleaning
While you're playing around under the laser cutter you might as well give it all a good clean, this was the state of my metal bed after about 6 months of cutting. I used a bbq cleaning tool with a nice metal flat edge which was great for scraping all the build up residue that had clung to the bed.

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