Phrozen Sonic Mini 4k

[timwatson]

Just asking to make sure. Does it matter how tight I pinch down the backlash spring under here? I have it a little tighter than it came.

The nut can be pushed down but it’s just for anti backlash. It doesn’t make so much of a difference. You can collapse it some and it will get a tiny bit tighter but it will also introduce some play. Which you don’t want so it’s a compromise.

[Chris333]

I should have put the money towards an Elegoo Saturn instead!

Jeff

That thing still says "sold out".

[timwatson]

Put it all back together. For right now I did a perimeter of 9 layers of Kapton tape. My screen is up .016" plus their tape seal trim .004" so .020" total. Nine layers of tape is ~.018" so the FEP only has .002" of play instead of .020". We'll see what happens.

And my version is V4.3.19_LCDPs1/3840/F2.18  I said it does have manual lift controls, but that is not how you zero the build plate. On the Photon you level the build plate and then use the fine manual controls with a piece of paper to zero it till the paper is tight. With this Sonic Mini you level and zero all at one time with the 4 screws and don't use the fine controls at all. Hopefully this really doesn't mater since my Photon has stayed leveled and zeroed, the Sonic Mini should stay as well.

Now I need to make a file for this thing.

I wish I could grab your firmware somehow. Yours is newer than mine.

[Chris333]

I just searched and couldn't find any firmware for it     There is a whole page of Photon firmwares right on Anycubic's site.

[timwatson]

Sounds like you’re seeing the same thing I was @Chris333 glad I’m not all “tin foil hat” after all! Some newish findings. There is lots of play in that crummy little shiny bracket. In fact Phrozen seems to be the the only ones using this kind bracket. The rest are made of stamped steel at bare minimum and max cast aluminum. So that will likely need to get fixed.


I have another arm design that diminishes that some. Still iterating. The dual rail does help the z-axis banding but until we get the leaning to stop it won’t be gone. I see you got Jeff’s side brackets nice!


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[Chris333]

I like that your new bracket goes further forward where the print head screws on. Every time I unscrew mine I think it is just going to fall.

[timwatson]

I will say, before whatever broke loose, it was rock solid. So I am not sure what’s loose and will be disassembling it soon. Sadly my photon is acting up so I can only fdm print. Sounds like your screen is more parallel than mine as well.


The next arm iteration will latch the build plate at the front giving the silver flex guy lots of structural support. Here I was trying to print the printers own parts on the machine it was for. Sadly the main screw down area is too narrow (oops).


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[Lemosteam]

Has anyone tried stiffening the base to the guide riail at the bottom

[Chris333]

I will say, before whatever broke loose, it was rock solid.

I saw you glued rails under your base. I wonder if you would have screwed them in place.

John, Yeah Tim put 4 braces under the base of his machine along with the larger dual rails.

It is like the only good part of the machine is the 35 micron pixel screen. (I'm no longer calling it 4K because that is meaningless).

[JeffB]

It is like the only good part of the machine is the 35 micron pixel screen. (I'm no longer calling it 4K because that is meaningless).

Yeah...  Pretty much.  Tim and I were discussing swapping the internals of the Mini-4K into the Photon (in a PM), but that's just a bridge too far.

Has anyone tried stiffening the base to the guide rail at the bottom

Not yet, but I'm contemplating laser cutting a new base plate from 6mm aluminum.  This should stiffen things up and it'll allow me to inset the screen further and make it level to the top of the base plate.

But I may just reinforce the existing base plate instead and mill out the shelf that the 2mm thick glass plate (which is under the LCD screen) sits on.  The new stiffener plate would provide a new "shelf" for the glass and LCD to sit on.

Still far too much work for this thing...  I never used mine prior to these "upgrades" but based on all the issues others are having, this certainly isn't a very robust machine. 

Jeff

[JeffB]

That thing still says "sold out".

I know...  I usually check once or twice a week.  If Amazon ever stocks them at a slightly discounted price, I'll probably buy one.  Would like to be able to print full length (one piece) "Maine Two-Foot" cars for Sn2 at some point.  Just wish that unit had slightly better resolution, but I guess it doesn't matter if they're sold out!

Jeff

[peteski]

Interesting...  What happens if a stepper motor cannot move the load that is applied to it?

Jeff

Nothing happens.  Quoting https://robotics.stackexchange.com/questions/1270/how-to-detect-when-a-stepper-motor-has-stalled

it is difficult to tell if a stepper motor is stalled because the current through the coils of a stepper motor is roughly the same if it is stalled (can't step), holding position, or stepping normally. . . . Unlike a brushed DC motor, stalling a stepper motor is typically not bad for it.

Unless the stepper motor drive circuit has some sort of means of detecting the stall, it will not even be aware of the stall. No damage to the motor occurs either.  As I said, the stepper motor coils are always energized at full power (whether it is stepping or stopped.

[JeffB]

Nothing happens.  Quoting https://robotics.stackexchange.com/questions/1270/how-to-detect-when-a-stepper-motor-has-stalled

it is difficult to tell if a stepper motor is stalled because the current through the coils of a stepper motor is roughly the same if it is stalled (can't step), holding position, or stepping normally. . . . Unlike a brushed DC motor, stalling a stepper motor is typically not bad for it.

Unless the stepper motor drive circuit has some sort of means of detecting the stall, it will not even be aware of the stall. No damage to the motor occurs either.  As I said, the stepper motor coils are always energized at full power (whether it is stepping or stopped.

Thanks...

[Chris333]

Here is the result after changing the screw.


Not really banding, but I see lines that look like a whole layer offset by one pixel. This could be from the flexing. I don't think I'll print any more till I get the flexing fixed.

[SkipGear]

Is it a coincidence that the lines, both in this print and the last match up with the rivets/holes on ladder?