aag
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Posts posted by aag
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OK thanks, I will move back to the UHU sticks which I had abandoned earlier. Has anybody tried to make "diluted UHU"? I was thinking of something like a 1:1 UHU in water, which could be easier and faster to homogeneously apply to the glass, perhaps with a large brush...
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I am printing Tough PLA models with a VERY large base, sometimes occupying the entire buildplate. And they adhere extremely strongly to the plate. Adhesion is a good thing, but this is clearly too much. What is the best practice for getting a Tough PLA model off the plate without resorting to ice picks etc.?
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the sensor wire seems to be connected with a kind of ceramic plate on the back of the printhead. I am guessing that its impedance or capacitance changes when the filament touches the plate, and that this is what's being measured.
BTW I find it annoying that it doesn't say which of the two extruders has stopped flowing. It wouldn't even need a hardware change: it could be implemented in firmware/software by simply annotating the printhead in use when the problem occurs. -
I have played around with adhesion sheets. The good news is that they are very practical indeed. Not only is adhesion better during print, but models with a large footprint are easier to remove from the plate without damaging the model. The bad news are:
- The sheets are not cut to match the glass plate. They are wider and their depth is less than that of the plate.
- The reason for that is obvious. These are simply repackaged Avery sheets. The Avery code is L7567. In fact, most Ultimaker sheet do not have any imprint, but some are labelled "Avery L7567". How embarassing!
- Ultimaker states that the sheets can be re-used, but I haven't yet be able to salvage a single sheet from damage by removing the model.
- The sheets add to the overall printing costs, particularly if they can only be used once. They cost more than the original Avery.
In summary, adhesion sheets are a good thing. The advantages prevail over the drawbacks, and I am no longer printing without them. However, I find it a bit rich of Ultimaker that they do not even bother to ask Avery to produce sheets that are at least cut to size.
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On 3/13/2019 at 2:06 AM, Shadowman said:
I have read many comments about PVA only wishing that I truly understood its characteristics. Some say it’s brittle when wet, others just the opposite.
When I have had the PVA brittle to the point that a slight bend will cause it to snap then I have experienced it breaking in the Bowden tube when loading and I am unable to straighten it to insert it into the feeder.
So using your comments as shared and my shared experiences how do you successful load and use PVA if it will break with only slight bending?
Takes care
I know! It's difficult to insert ultra-dry PVA into the tube, and I also occasionally experienced PVA breakage within the Bowden. Still, ever since I maximally dry the PVA, I never again had any flow-sensor issues. Ultra-dry PVA is a pain, but I think that it's the price to pay for peace-of-mind during long prints.
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Also, I am not sure if it has anything to do with the water. I submerged it immediately together with the glass plate. Maybe it is just the temperature shock.
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thanks - but wasn't CPE supposed to be more thermoresistant than PLA?
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Something horrible happened. I made a large Ultimaker CPE+ print, and it came out of the printer beautifully (build plate: 110°C, UMS5 with plexiglass cover to retain heat). Then I put the model into warm water (45°C, thermostat + pump) to dissolve the PVA. And now the model warped horribly! It seems that the surface that was against the build plate has contracted and is now all bent. However, the upper surface (opposite to the build plate) is still in shape. What could have happened? How can I prevent that? Any help would be very gratefully accepted!
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It doesn't happen very frequently, but it does happen. Tightening the clips helps, but not always. I consider it a design flaw: Ultimaker could have completely prevented the issue by raising the side borders of the build plate.
Maybe two little angles could like these be hooked to the adjustment screws. However, I do not know if it is possible to print them, as they would have to be very thin and should withstand the build plate heating over a long time. Sheet metal would be ideal, but such custom pieces may be expensive. Any opinions?
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I have experimented with "oozing shields", since I read somewhere that they can substitute prime towers. The shields are fine, except that they sometimes melt with the corners of the model, and then some postprocessing is needed to remove them (and the result may not be optimal).
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I head a major filament jam that destroyed my S5 printhead. Ultimaker very kindly accepted that this was a warranty issue, and sent me a replacement printhead with its electrical connector and cable. Since the cable is also damaged, I would like to replace it as well. However, I do not know how to get to the connector between the motherboard and the cable. What do I need to disassemble in order to expose the motherboard-cable connector?
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In this particular case the silicon cover was ripped off and torn into two pieces. How that exactly happened is unclear. But talking about the silicon cover, I find that the mechanism that should keep it in place is very clumsy and unsafe. I do not understand why UM couldn't engineer a more stable and more easily serviceable cover.
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After an overnight print, the head is now completely filled with toughPLA and Breakaway. I doubt that it can be rescued, but maybe somebody has a suggestion. It kind of printed everything upwards into the printhead. Also, is this to be considered a warranty replacement issue?
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The title says it all. Since upgrade to 5.2.8, I have lost the camera stream (it's black). I reset the Cura Connect, to no avail. Any advice?
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I'd like to try Ninjaflex as well. Might you be able to give me advice on what kind of profile to use for Ninjaflex (temperatures etc.) as well as recommended printhead speed etc. Also, I have read that AA0.8 printcores are recommended with Ninjaflex. I have an AA0.8, and would be happy to try.
Many thanks in advance! -
What is the best workflow for printing two materials with Cura? I need to print a cover with ToughPLA, and a flexible gasket with Hytrel. In theory I could print these separately and assemble them with glue, but since I do not need the second extruder for support, I thought I could try using two AA-0.4 cores for the two materials. I use Fusion360 for design. How would you do that? Print two model and align them? The black contour is the hytrel (which is white in reality, but the black symbolizes "rubber".
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I cautiously suggest that you could do more to dry the PVA. It may be already bad when it comes from the shop, and a dry box will not correct that. I suggest a simple test. Try to bend the PVA. It should have the Young modulus of a uncooked (raw) Barilla spaghetti: it should be rigid, and break without even bending. If it bends before breaking, or it does not even break, it's not sufficiently dry.
For details: https://arxiv.org/pdf/1810.07069.pdf 🙂 -
I had the same problems at the beginning. I then started to dry the PVA tremendously. I always keep it in a heated dry box, it hardly has a molecule of H2O left inside. Lo and behold, all the issues are gone! You really need to seriously dry your PVA, it will work miracles. Since you say that the problems are always with the PVA, it seems clear that the issue is not the mechanics of the printer, but rather the filament. Dry your PVA, I tell you, you will be surprised. But you need to dry it actively and continuously with heat and forced ventilation, anything else will not be enough.
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You know what would be extremely useful? If Cura would provide a way to instruct the printer to stall and pause at a defined layer. This way one could truly implement multi-material composite printing. As an example, I have a complex print that requires Tough PLA and a Hytrel gasket. However, it also requires PVA as a support. With a dual extrusor, this cannot be accomplished. However, if I could pause the printer in a controlled manner (say, at layer 124 or something), I could print the lower piece with Hytrel and the upper with PLA by replacing the material in Extruser #1, and leave the PVA in Extrusor #2.
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maybe not the most pressing issue, but garbled text when printing from Fusion (long file names).
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maybe not the most pressing issue, but the text of the queue gets garbled when printed from Fusion (long file name).
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humans needs to set goals for themselves! No, seriously, I have found that when printing tall objects the printhead sometimes gets entangled with the object and this pushed the plate around. If the plate were fixed with a proper kinematic mount, the tallest piece may still get knocked-off, but at least the lower models could still get printed properly. Or maybe not, I don't know. Maybe not such a great idea after all... 🙂
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weeell, I was thinking of giving 2-3 glass plates (which are not very expensive) to a glass-working shop, and have them drill a few holes through the glass...
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what about drilling two 2mm holes at the corners of the glass plate and of the heatbed, then use thin set screws to secure things? Bad idea?
tough PLA: too strong buildplate adhesion
in Improve your 3D prints
Posted
Might a printed single-layer PVA raft be equally effective in getting easier release from the plate?