Leetro to Ruida Settings

The first step towards upgrading a leetro based machine is to acquire a replacement controller. I opted for the Ruida 6442G to make it the same as my other machine. I bought my controller through ali express from Cloudray, it's currently $266 USD for delivery to the UK it took 3 weeks to arrive and cost around £250 GBP once customs and duty had been paid on it. I would probably recommend buying it through cloudray ebay instead, it's £260 but it'll arrive within a few days. Cloudray is my current part supplier, they've been pretty good so far. A delay suited me nicely with the Christmas rush on fractal puzzles and other products.

The kit of parts as it arrived was very complete. The controller and the screen were protected with bubble wrap and anti-static bags. Other parts include two USB cables to go from the controller to the edge of the laser, one for USB sticks, one for the laptop connection. An Ethernet extension to go the the edge of the laser and all the screw terminal connectors for the internal parts. Additionally there is an Ethernet cable to go from the edge of the laser to the network and a USB cable to go from the laser to the laptop.

The internal USB cable is Type B plug to Type A socket which means you need a Type A plug to Type A plug between the laser and the PC. This is a personal bug bear as A to A cables are not advisable in the USB standard and can be looped back into itself in a USB hub and cause electrical problems, but it appears to be a fairly common laser connection. My laser only has one USB hole currently cut into the case so I'll be using it for the USB storage connection and temporarily connecting straight from my laptop to the laser using a 3m A to B cable (the same as it currently does). I'll buy a B to B extension when I get round to cutting out more holes and ultimately I'll be using the Ethernet anyway.

As mentioned previously it's a busy time of year and I wanted to minimise disruption to my workhorse laser so I found a separate 24V power supply and connected the controller and display on my workbench. This allows me to communicate to the controller, through the USB, from my laptop so I can configure the system before I connect it to my laser. Because this is a machine upgrade I already have the machine settings in my Leetro configuration files, it's just a matter of matching the two things up. 

X and Y Axis Settings

The X axis settings are the easiest place to start. 

• The maximum travel of the axis is something you should already know, in this case 900mm. 
• The step length is the same as the pulse unit and it is the distance the axis travels in a single laser step.
• I prefer my laser cutter to 'home' to the zero position upon start up so I've ticked enable homing.
• The direction polarity should be true, to ensure that the laser moves to the right hand edge when it's trying to 'home'.

The other settings may not exactly have direct equivalents but the figures can at least be used for guidance. The Ruida controller splits into two sets of speeds and accelerations, these are for when the machine is doing work or for when it's being driven manually, in which case it can be a little faster and less accurate.

• The maximum speed would be equivalent to the quick speed and determines how fast the machine can move. On the leetro this was set to 200mm/s and this value refers to both axis, I've set it to 350mm/s on the Ruida because it only refers to the lighter and faster X axis.
• The maximum acceleration is set to 700mm/s^2, this would equate to the work-acc on the leetro machine which used to be 500mm/s^2. I'm keen to see how well the machine copes running slightly faster.
• The jump off speed is how fast the laser moves when it starts, if this is too high you get a big 'clonk' as the head tries to go from stationary to moving instantly. I've copied the start speed value, of 3mm/s from the Ruida controller.
• There is a second set of Jump off speed and acceleration values, these refer to the axis speeds when moving the laser manually using the keys on the keypad. I've kept them the same as the other values, the big difference between the Leetro and the Ruida is the slow speed control when moving the laser manually, the top speed is already fast enough for me.
• The E-Stop acceleration refers to how fast the laser slows down and stops in case of an emergency. I left this with the default value, I'm used to the Leetro coming to a dead stop, skipping steps and ruining your workpiece in an estop scenario, if the Ruida comes to a managed stop then it's already an improvement over the Leetro.

The Y axis settings are going to be very similar to the X axis, on the Leetro controller they share the same values. I've taken the liberty of setting up X and Y slightly different on the Ruida. The Y axis has more mass because it has to move the X axis around, I have set the maximum speed and acceleration to closer to the original values.

Z Axis Settings

The Z axis has similar settings to the other axis but much slower, the Z motors have to move the entire bed up and down so can't achieve the same top speeds. The Z axis on my old machine has always been quite clunky and jumpy so I'll take this opportunity to adjust the values. The acceleration values on the Leetro controller don't really add up anyway, if you hold the keypad down the laser moves into a fast speed

• The Z axis on my machine can drop down 400mm into the machine body.
• The Z axis start speed is much higher than the other axis, that's probably what makes it clunky. I've dropped this down to 1mm/s, I also reduced the top speed to 8mm/s.

Empirically these changes to the Z axis make it seem a little slow but if I use Lightburn to drive the Z axis I can specify a distance to go. I'll only be using the keys to go up and down short distances while I manually focus the laser and I can use the Lightburn controls to go down further if I want to engrave on the top of a box.

Cut and Engraving Parameters

Lasercut 5.3 has settings for cut and engrave parameters but they don't really match the Ruida settings. They refer to things like corner acceleration and ranges of engraving accelerations. The Ruida settings appear to be much simpler but I assume the controller works out the more complex values from these simple inputs. I took these settings from the previous X and Y settings and a combination of the default values.

That's as far as it goes for setting up the controller without attaching it to the machine. There were a few other changes that needed to be made once it was connected to the machine but at this stage the controller is ready to be attached to the laser cutter. In my next blog post I'll talk about wiring this thing up to the the machine and occupying the place of the Leetro controller.