Phrozen Sonic Mini 4k

[timwatson]

Thanks for posting the video.

Just spit balling: Are there loose bolts from the factory? My Photon was pretty loose when I bought it.

I saw a few days back on FB that Phozen released a new g-code for the printer. Did you try that? I suspect this is what Phozen will have you try.

Another modeler I know had a Phrozen before I got my Photon and he said they were about the same, but no Anycubic quality issues.

I have been reticent to try the gcode "fix" because it seemed many users that commented wanted to roll it back.


The crazy thing is if you try to push the arm (up or down) you will maybe get .1mm of deflection. The fact that it goes to 3 times that is definitely odd and it does affect vertical surfaces. So far it's printing much worse than my Photon. LIKE MUCH worse.

[timwatson]

That is crazy that you cannot manually move the Z rail. I use that all the time on the Photon. But as far as leveling the plate, I've only had to do that 2-3 times in 2 years with the Photon. Once it is set you should be good.

Yeh that's why I mentioned the software fix with the GCode. Bare minimum we should be able to do that and set it whatever we want.
That is if they get the z tower to reliably start at the same spot.

[JeffB]

I don't have a dog in this hunt but just looking at the build plate attachment, bent steel relatively light weight brackets as well as attaching hole placements, I suspect that the rigidity desired to make parts holding extreme tolerance just isn't there, especially vertically.  A dial indicator and finger tip loading of the build plate would afford some sense if this is true.  Additionally, if only to make adjusting the squareness of the plate easier, add at least some washers to those bolts on the slotted adjusting holes and better yet, a drilled bridge plate that joins those holes, with the idea that they will resist the propensity of the turning bolt to cause the slotted bracket to shift position while torqueing those bolts. 

I've also heard reference to the "Z" axis nut allowing some angular shifting of the build plate while running but without seeing the latch-up I'm not sure what that's all about.  If the axis isn't rigidly guided then it's a problem, maybe bigger than the suspicion that I outlined above.  It's also possible that any one of those things might not be a huge issue by itself but they are cumulative so...     If the rigidity isn't there, all of the wonderful screen resolution and light brightness becomes moot.

If all this were a problem, do you think that the prints you see in the various YouTube reviews would be as good as they are??  Even the one negative review I've watched, where the reviewer shows the head flexing during the retract between layers, the prints (once he had a successful one) were exquisite.

I have one of the Mini-4K's.  I purchased it just before Thanksgiving, got it just before Christmas.   I haven't used it yet, but I did, on the recommendation of the negative review I referenced above, installed some build plate bracket supports.  They're laser cut from 1/8" (3mm) thick aluminum and bolted in place (I work with industrial laser cutters).  With the supports installed, the build plate support bracket is rock solid.

Watched the video showing the the deflection...  The important thing I took away from that, is that the indicator on the Z-axis appears to be consistently resetting to specific positions for each operation (up/down, peel, etc...) within an indicator tick or two (can't see what the graduations on the indicator are...  0.01mm??  0.001"??)

I also have a Photon I with many hours of prints on it...  I'll admit it is rock solid, especially considering I installed a Jackson Z-axis dual rail upgrade on it.  Like Chris333, the build plate on my Photon can be flexed a little when you grab hold of it.  But I've never seen any negative effects from this in the prints.

My recommendation would be to do a few prints on your Mini-4K...  If you're not happy with the results, return it.

Jeff

[timwatson]

Chris mentioned this briefly in this thread but the answer is an apple and an orange. They aren't printing on the build plate and they aren't printing anything with tight geometries. Everyone is printing miniatures. They're these big organic blobs that would be impossible to get any kind of dimensions from. Very different use case from what we are doing. We have rectangles on cylinders on sphreres.

[timwatson]

I have one of the Mini-4K's.  I purchased it just before Thanksgiving, got it just before Christmas.   I haven't used it yet, but I did, on the recommendation of the negative review I referenced above, installed some build plate bracket supports.  They're laser cut from 1/8" (3mm) thick aluminum and bolted in place (I work with industrial laser cutters).  With the supports installed, the build plate support bracket is rock solid.

Watched the video showing the the deflection...  The important thing I took away from that, is that the indicator on the Z-axis appears to be consistently resetting to specific positions for each operation (up/down, peel, etc...) within an indicator tick or two (can't see what the graduations on the indicator are...  0.01mm??  0.001"??)
Jeff

I would buy a set from you Jeff - you know if you offered to sell me some


Also as the build plate gets higher the deflection decreases. So it certainly is only doing this on the lower layers and then clears up. I think this is why no mini guys have had any issues because the deflection occurs in the bottom 30 or so layers.

[Chris333]

Well as of right now I'm just a keyboard warrior without a Mini 4K.

[rodsup9000]

 I got this from the video that Chris posted. You could print a set up and try it.

 
 

[Chris333]

Rodney,

Did you get a Sonic Mini 4K as well?

[JeffB]

Here's the brackets I added to my machine...  They're attached with 4mm screws and are the same on both sides to avoid any asymmetric twisting forces.  I also sanded the build plate where the attachment bracket slides on so that the bracket is more loose.  I also de-burred the slots in the attachment bracket so the bracket would slide freely over the build plate.  The washers on the bracket were added to mitigate any twisting moment from tightening the screws.  I added washers under the screws that attach the Z-axis homing flag to prevent the screw heads from biting into the plastic flag.

Untitled by jeffB, on Flickr

Untitled by jeffB, on Flickr

Jeff

[rodsup9000]

Rodney,

Did you get a Sonic Mini 4K as well?

No, not yet. I'm going to wait till you get yours and see what you think of it. It sounds like there is some software problems and the "Z" axis problem.

[timwatson]

This is impressive. You did all of this before printing anything? I’d love to see how your 20mm cube prints!

Here's the brackets I added to my machine...  They're attached with 4mm screws and are the same on both sides to avoid any asymmetric twisting forces.  I also sanded the build plate where the attachment bracket slides on so that the bracket is more loose.  I also de-burred the slots in the attachment bracket so the bracket would slide freely over the build plate.  The washers on the bracket were added to mitigate any twisting moment from tightening the screws.  I added washers under the screws that attach the Z-axis homing flag to prevent the screw heads from biting into the plastic flag.

Untitled by jeffB, on Flickr

Untitled by jeffB, on Flickr

Jeff

[JeffB]

This is impressive. You did all of this before printing anything? I’d love to see how your 20mm cube prints!

Yes...  I did something similar with my Photon when I purchased the Jackson Z-axis upgrade after only two prints.

I was going off the one review I watched where the reviewer listed all the weak points on the Mini-4K and some solutions.  I chose to preemptively apply all the fixes to my machine as they all made sense to me and I figured "why wait".  None of the fixes were all that involved, though removing the black screen seal and replacing it with thinner Klapton tape was a pain in the backside!

Jeff

[timwatson]

See I think drilling and taping those holes for the bracket would be much more difficult.

[Lemosteam]

You could probably design that support and reinforcement plates as integral and have it printed in aluminum or steel at Shapeways, depending on how that lead screw bushing attaches. 

[Chris333]

I just saw another PSM4K brace on FB that was 3D printed and slides into place.

EDIT: here it is https://www.thingiverse.com/thing:4719928?fbclid=IwAR1Im_eAxw-_H3kuj0y7HHIf18mQ6aSXpoVODUiMKzA7QgFUKcQXLMsIauo


Tim,  Have you tried a regular print yet like your tie strips?