LaserUser.com Forum (formerly RDWorksLab)

Going through my Laser today and I have reached the conclusion that the angled sides on my cuts are not fixable without adding a vertical slot system to the head to drop it down 3mm+. As soon as I tried to adjust the path the result is the beam started hitting the nozzle

It seems the Laser manufacturer had tried to mask this by screwing the final mirror hard to the body of the head then fudging the beam path back from the head. When the mirror to body gap is increased to say 1.5mm to allow some adjustment either the Laser needs to be lifted by 3mm or the head needs to be dropped by 3mm (actually just over 3mm for a 1.5mm gap). Smaller offset of the mirror would mean smaller drop needed.

Clearly the final mirror holder should have been inset into the body by the adjustment gap and the small mirror flange (maybe 2mm) so the beam could hit center then pass at 90 degrees out of the nozzle correctly.

Is this a known design flaw and if so is the normal fix to drop the head 3mm and live with it? Has anyone been back to Cloudray and clones to try and get this error fixed?

This will apply to all similar heads.

I hacked together the drawing partly for my interest but I also may look at making a modified head with the correct mirror placement.

Thoughts?

I guess I don't understand the connection with Cloudray- did they supply the laser head? Russ did a video about the actual path of the properly aligned laser not being in the center of the horizontal hole in the head mirror housing as you might expect. Mine was also not in the center. It looks like the mirror holder has more than 1.5mm gap to me- I believe keeping that to a minimum would help? If you did the alignment from the height of the laser path from the 3rd mirror [laser head] backwards you would end up raising the 1st and second mirrors by the amount necessary [also the tube]. That might be a way to correct your problem?

Nice drawing!

Are you saying that when you close the gap from 1.5mm down to (almost) 0mm (by turning all three adjustment screws), the beam is still not centered?

Regards,

-Jeff

Call this a minor rant to stupid Engineering design or lack thereof. I was told the head on mine was a Cloudray but like other things Chinese that could actually mean that or 'clone'.

The gap was set with feeler gauges to 1.5mm plus the small (not measured accurately) 0.5mm? offset to the mirror. So even if shutdown to say 0.5mm the beam would still need to run nearly 1.5mm high.

On my 12mm Lens based head the nozzle opening is only 2.5mm and in the order of 6-10mm from the focal point so alignment needs to be very square or you bounce off the sides.

It just seems crazy to my Engineering brain that the Mirror plate was not set into the head to allow for a gap plus mirror offset to maintain the beam using the center of the mirror.

I am not sure that I have ever heard of a 12mm lens- the entire laser head must be very small? I have a 20mm lens and my head is about 7" tall.

Both the 12mm and the 18/20mm versions are here Cloudray Aliexpress

The Hiwin rails on my Laser are not very heavy or I would consider going to the larger head to get the better Lenses. I see Russ did make an Acrylic head might be a good way to keep the weight down (more watching to do ). Making a 3D printed one might work in my case too as I don't own a Lathe.

Not a beautiful job, just a short term bodge until I design and make an adjustable mount. Everything much straighter and room to adjust the third mirror and final beam position and where it hits the lens using the screws.

Tested on a tiny logo and a reasonable result (4x5.5mm). The horrid packing 8mm crate ply was the deepest ready to hand material and the cut edges are now even. 7mm/sec @ 70% cuts and a range of engrave speeds and powers (will finish up in quality 5mm ply for a friend).

So... is it fixed? What did you do?

Put a 4mm kink in the mounting plate to lower the head with a large hammer and a cold chisel So the optics are not 'fixed' just the path is now correct square and adjustable for even sided cuts.

I had a look at a couple of Russ's iterations of his Acrylic Head so I will look at doing something in a hybrid Acrylic/3D printed 20mm Lense providing I can keep the weight down.

Tim Mellor wrote: Fri May 31, 2019 Put a 4mm kink in the mounting plate to lower the head with a large hammer and a cold chisel

This prompted me to back and re-examine the photo you posted. You put a very precise kink in the mounting plate - you're obviously a very good metalworker!

Just out of curiosity, where is the Y-axis rail in this photo? It seems to be missing.