PLA & BVOH?

[Tinkerer]

Hi All,

after still no success with PVA I today tried to print something with Verbatim's BVOH.
What shall I tell you - this stuff bound quite nicely to the bondtech plate.
But - PLA (I used the Raise3D-PLA here) does not bind to the BVOH - not a bit.

I slowly get disappointed

How do all the people print these nice things with soluble support?

[Rogman]

Where you failing with PVA in adhesion to the buildtak? PVA will not stick to Buildtak. use a bare glass plate with a glue stick. https://www.amazon.com/Elmers-Disappearing-Purple-School-E562/dp/B00143SNPG/ref=pd_day0_229_6?_encoding=UTF8&psc=1&refRID=CKHYZMJX7D3G743F3ZNS

[Michael.P@Raise3D]

I think we will need to test BVOH. If you want please upload some pictures of the problems you have encountered so we can help a bit.

[Tinkerer]

Hello again!

I have run a print last night. PLA and BVOH.
The first trials where a little problematic due to the BVOH and the PLA not really sticking together too well.
So I increased temperature quite a bit to PLA@220°C, BVOH @210°C.
Which - after all - was a bit too hot as we can see later.
Layer height was 0,1mm.
Wipewall enabled.

The result is not really "usable" (after all it's useless anyway since it is a Pokemon;-).
But I thought this might be an interesting test object due to some small details.
Here are some pictures with some issues to talk about;-)

Right after the print one can already see some issues here:
blobs (as I said, temp might be too high...) but also sometimes not sticking material -
seems to me as if the temperature of the material was not consistent during print?
(btw., bed was at 60°C, printer closed, room as well).
Why these strange strings? Why such an inconsistent printing?

As you can see here, somewhen in the middle of the print a serious offset of approx. 5mm happened on the Y-axis.
This is straight on the Y-axis so it certainly does not seem to be caused by the nozzles hitting the object -
in that case it would never have been so straigth, I assume?

I wonder whether this is caused by an electrical or a mechanical problem?
If so, what could be the root cause?

Regarding the BVOH:
Dissolving it in water works surprisingly quick in the beginning.
From the "packaged" object (first picture) to the "unpackaged" object it took roughly 30 minutes.
I did support the process by placing the object into an ultrasonic cleaner. Water @ approx. 38°C,
20 minutes runtime. The remaining material then could be washed off under the water tap.
Some material remains which requires a bit more efforts, e.g. to be brushed off.
Or just leave it in water for some hours, I guess.

Currently I have a second test print ongoing.
This time I manually changed the temp. to PLA@210°C, BVOH @200°C after starting the print at the higher temperatures as m.a. .
The idea is to get a good foundation (due to better sticking material) and then have more precision for the rest.
Let's see.
I am also very curious to see whether this strange offset happens again.

[Tinkerer]

Where you failing with PVA in adhesion to the buildtak? PVA will not stick to Buildtak. use a bare glass plate with a glue stick. https://www.amazon.com/Elmers-Disappearing-Purple-School-E562/dp/B00143SNPG/ref=pd_day0_229_6?_encoding=UTF8&psc=1&refRID=CKHYZMJX7D3G743F3ZNS

With PVA I have tried quite some combinations so far.
All failed:
glass plate and / or hardpaper plate with
- Scotch Blue Tape
- Scotch Blue Tape + PVP (Pritt, UHU)
- Packaging Tape (Tesa)
- Hairspray
- Hairspray + PVP (Pritt, UHU)
- carpet-fixing-tape (double sided duct tape)

I am trough with PVA. I hate it;-)

[Vicky@Raise3D]

Not sure BVOH, but 220C for PLA is too hot. If taking the not bonding well out, what temperature is perfect for BVOH to keep proper extrusion?
For not bonding well problem, how much vertical offset did you set for support and model? For PVA we will recommend 0 offset and several dense layer of support to provide better adhesion between support structure and the model.

For the shifting problem, it is not easy to judge whether it is electronic problem or mechanical problem from one test print.
If electronic problem, such as bad stepper driver, it will also happen at the same direction when you print high, single nozzle print.
If mechanical problem, you may feel stuck when moving the extruder around X&Y direction.
Or you cannot lock the extruder in that direction when motors enabled.
Or maybe the nozzle hitting problem, since it is a dual-extruder print. If the height of the two nozzles at the almost same height or even the right nozzle is lower than left, the right nozzle may hit the model and cause shift.

[Tinkerer]

Verbatim's BVOH is rated between 200-220°C.
The extrusion is fine so far.

For Raise3D's PLA the specs say 195-220°C...

Currently a test is running w. PLA@200°C and BVOH@205°C.
I also lowered the Bed to 50°C.

So far the print goes well.

But this object is not so complicated/does not have so very small details like the last one.
So adhesion is not that much of a problem here.

Unfortunately the wipe tower is "gone" already - it had a raised edge on the side which is pointed towards the model and got ripped off.
So the printer now "wipes" in the air. Seeing that answers one question - where do those strings com from?
Cause wiping "in the air" does not cut off the wipe-material. Instead, it is pulled to the printed object and sticks onto it.

I guess it makes sense to position the wipe tower a bit more far away from the object plus making it a bit bigger?

Regarding the shifting:
I have not seen that before nor after this test print.
Even at the moment the print goes fine and it's already way above the height of the shifted layer.

Regarding nozzle-hits:
Strange thing is, that the offset is looking so clean, isn't it? Perfectly onto the X-axis.

If that was caused by a nozzle hit, one should be able to see evidence on the surface just before the shifted layer that there was something sticking before it has been pushed to the side?
And why did printing resume more or less nicely on the shifted part?
To me that does not sum up...

I just remembered that I recently tried to print a vase.
(wavevase from https://www.thingiverse.com/thing:983438)

And that this print also failed and had some shifted layer as well
Just took it out of the plastic-waste and took a look.
The shift has taken place in a very similar height!
I did not recognize that earlier since the print was a complete disaster anyway.
There have certainly been some nozzle hits;-)

By the way, I can't find a good way to even slice this vase correctly.
In Cura it is either completely filled or does not have a bottom layer (so is open on top and on the bottom).
In IdeaMaker it has errors in the outline:

And you really see those in the print.
By the way - this is what you get in IdeaMaker when you slice the vase after scaling it to 50%:

...not the expected result, I'd say...

[Vicky@Raise3D]

For the wipe tower, If one layer PLA and another PVA layer, they may cannot bond with each other such well to build a tower together.
By the way, have you given WipeWall for a try?

For the shift problem, if next time you'd like to test again, I would recommend you to move the right hotend a little higher to avoid the affect from right nozzle.

For the dots in Preview bug, we will fix it soon. But on the printed out model, there will have no dots.

For the 50% scale, if you want to carry out a Vase Mode print, each layer should be a closed loop.

After scale the model to be 50%, the lower parts will be too thin to be a loop, but lots of single extrusion lines, because the width is around 0.4mm.

If you slice it with Cura, it will also be abnormal to be a normal Vase print.

[Tinkerer]

Thanks, Vicky.

I tried it in Cura as well.
Interestingly I did not get it to work with a bottom layer...

But now that we now that scaling this does not work as expected -
what are "we" going to do?

As for the Pokemon & the shift in the print (which also happened with the vase print before it totally got messed up):

This was certainly no nozzle hit!
If it was, the model would have been detached of the print bed.
(otherwise - why should the print be shifted?)

And usually you then have a mess of filament in the air (curled hair, so to say).
But the model was perfectly on the platform after the print.

As far as I am informed, this can happen that the stepper motor drivers behave erratically and cause this problem.

Vicky,
I have also learned that this is not really new to Raise3D...?

So I wonder why I am constantly told about nozzle hits...?

Makes me feel ... just a little bit...

[Vicky@Raise3D]

As the pictures I shared yesterday, if you want to print a model to be a Vase Mode, every layer of it needs to be a closed loop.
For this model, when it is 50% scale, lots of layers are too thin to be a closed loop. So it works strange under Vase Mode.

Move the not being used nozzle a little higher, if still have the same shifting problem and at the same direction, we will take consider the stepper driver or mechanic problem. So moving the right nozzle higher is just removing nozzle hitting from the list of possible. It's a test not a solution.

[Tinkerer]

As we say in german - a picture tells more than 1.000 words:

Btw. - right nozzle as far upwards as possible.
Note that the printer is still printing "into the air" here.

If you do not believe it - I made a video of it.
Unfortunately I can not upload it here.

[Vicky@Raise3D]

As we say in german - a picture tells more than 1.000 words:

IMG_3865.JPG

Btw. - right nozzle as far upwards as possible.
Note that the printer is still printing "into the air" here.

If you do not believe it - I made a video of it.
Unfortunately I can not upload it here.

Is that everytime's shifting is from left to right? Any time from forward to backward?

[walshlg]

you may be suffering from a head strike because of edge curl. You can get that on any filament, especially bad with PLA. i suggest insulating your hotends.

[Michael.P@Raise3D]

Tinkerer,

If the printer is shifting in one direction we would begin to suspect a mechanical fault or electrical fault. By moving the inactive print head away we have eliminated the nozzle contacting option. Please utilize the following attached document to check the gantry for any loose screws. Please also let us know if you encounter shifts in different directions as well.

[Tinkerer]

Ah. Forget it.

This printer will be returned to the dealer next week.

P.S.:
To answer the questions from the raise3d-people:

It did not happen everytime when I did a print.
It seemed not to be related to the printers temperature (happend or not happened w. PLA as well as other stuff).
It always happened in X-direction (left-right).

And to the guy who talked about headstrike:
The lower part of the model was still sticking to the build plattform very well.
And the printhead was "working" to the right of it.
The picture shows that quite clearly.
So I can absolutely not understand how you can talk about headstrikes here -
that simply does not make sense.

[Tinkerer]

Tinkerer,

If the printer is shifting in one direction we would begin to suspect a mechanical fault or electrical fault. By moving the inactive print head away we have eliminated the nozzle contacting option. Please utilize the following attached document to check the gantry for any loose screws. Please also let us know if you encounter shifts in different directions as well.

Hello Michael,

thank you for that document.
On of the pages of documentation that so many Raise3D customers are missing...
It would be more or less complete if it would contain detailed information about the
check/work to be done.
For example - how much should the screws be fastened?

[Vicky@Raise3D]

We didn't define torque force for tightening the screws on pulleys or position limit columns.
Just tighten the fixing screws with short end of hex wrench and make sure you can't move the pulley or position limit columns after tightening the screws.