How to Calibrate Ruida RD6445

I am finishing up a home built laser cutter based on the Further Fabrication build series. I am trying to calibrate the how far the X and Y axis travel. I have read the directions on this and other forums and I am still stuck. Can someone please explain this as if I am a 5 year old? The formulas I have found are not working. Thank you

The easiest way is to run RDworks to get things set up. RDworks will calculate things for you.

I do it by using a piece of paper with just enough power to mark the paper but not burn through it.

Start by etching a 25x25mm square ( really all depends on how far things are off, but one would hope this will show up on the paper ). In RDWorks where you set the steps it will ask you for the graphics size ( 25x25mm ) and what you actually measure.

Once you have it close, you can go for a much bigger square to dial it in better.

no math needed.

Go back to LB when done

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Thank you for the input. However, I downloaded RDworks to get the steps calibrated but now I cant get it to talk to my laser. First I tried an ethernet cable and it failed, then I plugged in a USB cable to a USB C port on my computer and that failed as well. Any tips on that?

I used math. It is in my opinion a better way of calibrating. You get a correct theoretical starting point and whilst checking you can immediately spots mechanical problems like loose belts.

Consider the following: (I believe this is correct for your laser build, but please verify)

Belt pitch: 2mm
Pulley number of teeth: 30
Stepper steps per rotation: 200
Microstepping: 1/32

This results in the following:
Belt travel for one rotation of the pulley: (Belt pitch) * (Pulley number of teeth) = (2) * (30) = 60mm
Steps to rotate motor one time: (Stepper steps per rotation) * (Microstepping) = (200) * (32) = 6400 steps
Millimeter per step: (Belt travel for one rotation of the pulley) / (Steps to rotate motor one time) = (60) / (6400) = 0.009375
Micrometer per step: (Millimeter per step) * 1000 = (0.009375) * (1000) = 9.375

Now just fill in the micrometers per step in your axis setting and double check positioning using digital calipers or any other digital depth measurement tool(s).

Edit: here is a google spreadsheet to make life easier:

The simplest way is to tell the laser to move 100mm, then measure how far is actually went. For example, if I draw a 100mm line, and measure it at 101.2 mm long, then my step size is too small - the controller thinks it has to take more steps than it needs to in order to make that 100mm line.

If my current step size is 6.25 micrometers, to get the step size I need, I multiply by 101.2 (what I got) and divide by 100 (what I asked for). My new step size would be 6.325 micrometers.

You don’t have to use 100 for this - you can use any number, and the math is always:

NewSize = CurrentStepSize * Measured / Requested

Watch this helped me a lot.
https://www.youtube.com/watch?v=PipeAxhWbzE&t=189s

You can also do it in the 6445 menu setting I believe it says calculate same as the rd works.

I’ve only ever used lLAN, no problem going back and forth between LB and RDworks. From the Ruida panel, go back and make sure your LAN setting are still correct.