Adventures with the Photon Mono 4K printer
This model was bought as ideal, from my point of view, in terms of price/pixel size ratio. This is one of the most budget printers with a grain size of 33 microns.
At the same time, its main task should be to print engineering, you need to print different parts that correctly match each other.
Well, at the same time, a fairly small pixel size allows you to provide a very clean surface
When starting the printer out of the box and the first printing, a whole bunch of defects were revealed: a shift of the layers relative to each other, unstable height of the layers - blurring of the layers after reducing the area of the printed layer, different printing heights of the layers depending on the location of the part - in the center of the table or along the edge, and so on and so on and so on …
When I was printing another RERF file on stock settings, I accidentally noticed how the column swings during printing, the bracket bends and the table moves. He hiccuped. An unforgettable sight.
They say the only doctor who is not mistaken is a pathologist. Well, then. The printer was neatly disassembled into its component parts. To the last bolt. We are watching. Cubature…
The autopsy revealed the following:
Column:
The place of support of the column on the table is not ideal - there is pressed metal around the edges of the mounting holes of the column, and since they are located in the middle of the section, the column is like ... Well, in general, you understand. Sanded, tightened with a retainer.
The screws for attaching the intermediate boss to the table were not fully tightened, therefore, with some load, the table had the opportunity to fidget along the Y axis, and they themselves were too short and soft. I put kosher ones, tightened them with a thread lock.
Printing table:
The factory-made printing table was not flat - the deviations along the probe reached 0.4 mm (!). The table was sent to visit the milling machine, a magnetic plate was mounted on it, well, the probe of the Home sensor was naturally displaced on the printer.
Printer screen and table:
The very design of the duralumin table and the LCD shutter looks like this: first there is a protective film glued to the screen, the screen itself lies in a milled table base and rests on a supporting glass, which in turn lies in its base. All this is also not ideal – there is a gap between the glass and the screen, and why should the screen be put in its cradle, if it is supposed to be unloaded on the bottom glass at all, well, okay, the authors know better. Yes, and here's another thing - the whole sandwich is flooded down from 0.0 by about 0.5 mm. The stock table is larger than the screen and, when moved to 0, rests on the duralumin table field that surrounds the screen. Probably so as not to crush the screen? But in this case, a fortune teller is needed: which piece will fall off from the part – 0.3 or 0.4 and if 0.45? And the screen rests on a pedestal and it still bends to the glass…
Bath:
If you attach a ruler to the bath, it turns out that the film is raised from the base by 0.3 mm, the plastic bath itself is generally beyond praise - it changes the geometry depending on the tension of the film. That's actually all.
Print:
That is, when printing, something like the following happens - the table, dropping to 0.3, drags the film down to 0.1 (this is the height of the calibration on a piece of paper), naturally it cannot go lower, because that's all. Having descended, it creates a lens of about 0.5 mm of viscous resin under itself, which is gradually squeezed out from under it solely due to the tension force of the film. All these charms, of course, are a little less later, when printing the details, but they are there anyway. Like that gopher from the DMB…
Results:
To understand what was happening to the column, there was a separate dance: a socket for a micrometer was mounted in the upper part of the printer cover, and with the help of this traditional tool and an exchange, a full-scale experiment was conducted to see: what kind of load leads to the same deviation of the column as when printing?
Then all this was modeled, loaded and analyzed. After lighting a pair of pipes, it turned out the following:
It turned out that the weakest creature in this whole story is, of course, the table. There is a motor hanging on it, there is a column on it, there are brackets on it that transfer the load from the film when it is detached, in general, everything is put on it. And he is poor - firstly, duralumin, secondly, flat, and even weakened by a hefty hole under the shutter (which we remember requires a separate socket) and glass, and as a result, he simply lacks rigidity. The main deformation zones are the side flaps along the short walls of the bath and the motor attachment point.
The classic question is "What has been done?":
There were options: to reframe the table, strengthen the existing one, but in the end the simplest solution was left - it was to put a duralumin bath and tighten the screws tighter. With high-quality tightening of the side screws, this whole pie from the table and bath acquires sufficient rigidity. If you continue to bother with rigidity, then it seems to me that you can just put another clamp on the bathtub near the motor, but it was enough for me
The supporting glass, along with the shutter, was raised to zero on rigid gaskets. The shutter naturally shifted completely to the glass. The printing table was milled to fit the size of the printing area and now fits inside the mask, and so that it does not hang on the bracket, with the help of a stop, the backlashes of its positioning are removed. (... or maybe they compensated for the size of the table with its confusion and wobbles? )) The printing table now sits slightly on the printing area. And why more? There are no gaps under it.
By the way, during the printing process, pieces of parts fell off. Well, where would you go without it? And nothing. Everything is normal. Everyone is alive.
The installed indicator in conjunction with the measuring limb (up to 0.01 mm!), which remained after experiments on animals, allows you to VISUALLY adjust the time of the lower exposure, see and adjust the break point on the fly, as well as the speed before the part is detached from the film. All these processes are very clearly visible on the analog and such a cute dial. In general, this hinged pair turned the printer into a very boring and allowing thing to grow above itself, which adds understanding to the brain - what is going on there in the unknown darkness of thick sludge...,
As a result of all the upgrades, the printer consistently prints at all print heights.
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