First off - new to the forums, so hello all.
I bought a Moai 130 some time back, and have had numerous excellent prints from it. However a problem arose after a couple of months of it sitting idle.
As background: I initially carefully calibrated the printer using the advanced calibration guide (I’m an electronic/optical engineer by profession, so familiar with the technology in use) and have had excellent dimensional accuracy even on quite large prints.
The problem that arose however manifested in a print that came out unexpectedly large on the Front->Back dimension (X axis, I believe, but can’t recall for sure without taking the side off the printer again!). When I replaced the calibration circle in a PDMS vat and ran the associated circle scan test, I found that the X axis was now substantially larger than it should be.
Surprised at how far out it was, I opened up the printer again to repeat the calibration process and dial back the X amplitude pot on the galvo PCB, but I found I had to turn the pot 2 or more full revolutions to return the scale close to what it should be - this is a substantial adjustment for a 10 turn pot (> 20%).
I suspect an electrical fault in the system somewhere, but I don’t have enough detail on the galvo control PCBs to troubleshoot the problem. I have however measured the +/- 24 V supply and found them to be +23.8 V and -24 V (and stable while scanning the circle) which suggests at least the power supply seems to be ok.
Following recalibration of the X amplitude, I’ve found that the X deflection in the positive axis doesn’t seem to mirror that in the negative axis any more - If I align to the centre using the cross scan, then I can’t align the circle scan to follow the circle(s).
As a stop gap (I really need to get a print out ASAP) I have aligned the galvos by hand to follow the circle, and have ignored the slightly off-centre cross that results. I’m now in the process of printing out a calibration cross again to generate another calibration file for Asura.
Any input on what might have caused the problem, and any troubleshooting advice would be greatly appreciated.
Just to clarify - I have not touched any of the sealed pots on the galvo PCBs, and internally the printer seems sound. It was bought pre-built and the only adjustments I’ve ever made was to tweak according to the advanced calibration guide.
Cheers for any help.