Cura 4 generates a mirror image

[CharlieWorton 0]

I've encountered the strangest problem ever.  I generated a small cap for an accessory lens I own, and I labelled the cap with the phrase '2X Barlow Lens' using the text function in 123Design (Yeah, I know.  I haven't switched over yet.)  The cap printed fine, but the text was completely reversed - a mirror image.  I found the option to generate a mirror image of the .STL file in Cura (4th screen button down on the left hand side) and when I clicked that, I was able to duplicate on screen what had actually printed.  I now have a print of that reversed image coming off the printer.

 

But... what the heck?  Is there some setting in the printer setup file I might have messed up?  Has anyone else had this problem?  It just seems so bizarre, that the printer will spring to life, and generate a perfect, exact mirror image of what I asked it to print.  Thanks for any help you can provide... >Charlie

[gr5 2,333]

What kind of printer is it?

 

Cura expects 0,0 to be in the front left corner.  If either your Y or your X axis is backwards then it will print a mirror image.

[CharlieWorton 0]

Hi, GR5!  The printer is a Chinese Zonestar printer, essentially a stainless steel frame Prusa design.  Software is (I believe) Marlin, running on a Melzi board.  Here's a link: https://www.aliexpress.com/item/Upgraded-Quality-High-Precision-Reprap-Prusa-i3-3d-Printer-DIY-kit-with-2-Rolls-Filament-free/32342171432.html 

This link shows the current model; mine is about 2 years old, and has the older Melzi board.

 

The strange thing is, it worked fine for quite a while, and has only started to print backwards in the last 6 months or so.  (I don't use it a lot.)  So, in the beginning, it did work well, which leads me to believe that I've inadvertently set a switch to the wrong setting.  I can't imagine a hardware failure causing this.

 

BTW, the reversed print printed properly.  So, somewhere in the slicer or the printer, a horizontal mirror image is being asked for and created.  I just have no clue how this might have happened.  Thanks for your help!  >Charlie

[buddybu 0]

I know this is old, but my 0,0 is the left rear of the bed.  My printer is a rebuild of an old 3DSystems printer that had it's home in the same place.  I am having the exact same issue.  How do I tell Cura that 0,0 is the left rear, not the left front?

[gr5 2,333]

WTF?  I've never heard of that.  I don't think there is such an option in cura (only front left or center).

 

This is so bizarre - there are thousands of printer makers out there and I've never heard of this.  Oh - 3d systems.  That's... ancient.

 

One hack would be to mirror image the Y axis in the part - you can uncheck the lock in the scale menu and then set the Y scale to -100% (negative 100%).  That will do it - the view in cura will be mirror image still but at least the part will come out correct.

 

[CharlieWorton 0]

I'm the originator of this thread, and I did solve the problem.

 

I'm using a Chinese Prusa clone printer, and it has been incredibly troublesome.  I have replaced or modified virtually everything on the machine.  During one of these repair episodes, I inadvertently swapped the X and Y motor actuator leads.  This resulted in the mirroring activity I originally described.  Signals intended for the X stepper motor were being sent to the Y stepper motor, and vice versa.  When I discovered and rectified my mistake, the issue went away.  My advice would be to check your wiring, and make sure that you haven't made the same mistake I did.

 

When I win the lottery, I will purchase an Ultimaker.  Until then, I'm stuck in 3D hell with a printer that spends most of its life broken.  As it currently is, with issues unrelated to this thread.

 

Hope this helps - Charlie

[Rumoldus 0]

Hi Charlie,

thanks for posting your solution, it helped me. I had the same problem here, solved thanks to you.