Best posts made by Eumldeuml

Hello all!

In the process of rewiring my printer (getting rid of the pasta in the back) I did some sanity checks with a multimeter and I was shocked (not literally lol) to see that the ground connection to the printbed does not ground the entire frame (most likely due to the anodising of the extrusions).
If the anodising is non-conductive is there even a need to ground the entire frame? Or does a stray current penetrate the anodising and trigger the main fuse anyway?
If not: How can I ground the entire frame without dissassembling the whole printer and sanding away the anodisation at every contact point between two extrusions?

Thank you all for your answers and your tips, even though I couldn't find a solution after hours of tinkering. That's why I admitted defeat and ordered new, better suited stepper motors. The old ones were 0.9° motors with sub-optimal parameters (according to the EMF calculator) which gave me a lot of reliability issues, mainly random unpredictable step losses. For this reason I wanted to upgrade to the JMC servos that I had lying around anyway, just to open another can of worms
Live and learn I guess... Thanky anyway!

Just a question out of curiosity
Where and what for do you use machining (milling, turning) for your 3D printers or in conjunction with your 3D printed projects?

I will start with a few parts that I did:

This is an extruder drive wheel made from brass:

I also made my own heater blocks ('cause I'm cheap and milling is fun). The left one is one from china in comparison:

Here is a custom cooling block for a tilting extruder (which was later replaced with a watercooled one):

For the cooling blocks I also had to make an M7 tap...

And finally some brackets for an absurdly overpowered 32 mm ball screw that I got from eBay for next to nothing. To be fair, my printer is quite sturdy and heavy (about 25 to 30 kg for the whole thing) but that ball screw still is completely overkill. That's why I'm also using it as a 'guide rod' for the print bed (which in theory isn't very good practice but since it came from a CNC milling center it couldn't care less about the side load). On the other side of the print bed there's a puny 16 mm rod to keep it from rotating.

I'm looking forward to see what you guys do in metal for your hobby!

Obviously it isn't clear...
The feature isn't something that helps during a print, just during setup and troubleshooting.

I'll try to make up an example:
Let's say you command your z-axis to move 10 mm. You look at your printer and you'll see the motors running and the bed moving.
But unless you put a dial indicator or calipers against the bed you'll never know how much it actually moved.
If your steps/mm are calibrated right then one could assume that your axis moved the right distance and most of the times that is true.
But let's say you're tuning in your accelerations or maximum speeds (or maybe even the anti-backlash but on your leadscrew which could produce too much friction if too tight): Unless the motor loses a lot of steps and makes horrible noises of you see the print bed stuttering there is no way of knowing if your motors can handle this speed.

So what you would do now (with my proposed feature):

1. Press the button "check for lost steps" (or however it will be called)
2. the axis (in this case the z-axis) will go to its homing switch
3. If the motor didn't lose any steps the distance to the homing switch is exactly the distance that you can read in your UI (-> the real position and the assumed position did match).
   But if any steps were lost the firmware would read the endstop as triggered before or after the distance that was displayed. The difference in mm times the steps/mm will give you a value for how many steps weren't performed.

I hope this makes it clear since I don't know how to make it clearer