UM3 engraved text problem - help me :-)

[Deviant 0]

Hi to all,

 

Recently I have a problem with engraved text on models, engraving is 1 mm deep and it is on a vertical wall of the model. Tried to play with acceleration and jerk setting but without sucsess... some techinalities:

 

Layer height: 0.2

Speed: 60

3 walls

Line 0.4 (tried with 0.5 too)

Acceleration: 3000, 4000, 5000, 5500

Jerk: 10, 15, 20, 25, 40, 50

Temperature: 195, 200, 205, 210, 220

Flow: 95, 100, 105, 110

 

Picture of the problem attached. Settings are multiple because I tried all of them in different combinations without sucsess... please help if someone can.

 

Oh yeah, cleaned the core a couple of times.

 

[Deviant 0]

Can someone pleeeease approve my content? I have to print some adapters for respirators and it is awful... 

[SandervG 1,521]

Hello, your content has been approved almost immediately but you just didn't get a reply yet. Have you tried default acceleration and jerk, and just lower your printing speed to ~40mm/s? 

[Deviant 0]

yes I have tried that also, was printing from 40 to 80 mm/s... I prepared another one now with deafult settings in Cura and with speed of 40 mm/s, layer height 0.2, first layer 0.25, line width 0.35, everything else is default. Right now I'm printing 5 adapters and it will take another 6 hours... then 2 and a half hours for the new one with these settings. Sorry for asking again for approval, but I really want to help guys fighting Corona and got a little bit nervous... Thank you for reaching to me!

[geert_2 557]

I would suggest: cut out a small part of this model with some text for testing purposes only, so you don't waste time and material doing the whole thing.

 

Try printing at 25mm/s, cool (but without underextrusion), and in thin layers (0.08mm...0.12mm). See what that gives?

 

3D-printing is always searching for a balance between quality and speed, but often they don't go together. So you will have to chose your priorities...

 

In my experience (with UM2) such text on the sides always comes out poor, due to ringing effects and widening in corners when slowing down. And you never get sharp corners anyway.

 

Text on top of flat surfaces comes out *much* better. So if you could move the text to the flat horizontal plate halfway (if that doesn't get covered later on), this might be an option?

 

Photos:

 

Text on top of model: these characters are ca. 7mm high. Orange PLA. Left: smoothed with acetone. Center: heat-treated with hot air gun in attempt to smooth (this damaged the model, so don't do this). Right: untreated, as printed. Printed at defaults for PLA: 50mm/s, 210°C, flow 100%.

 

 

Printing speed and layer thickness tests: Top row printed at 50mm/s, bottom row at 10mm/s. Nozzle 0.4mm. Material is transparent PET. Model is 20mm x 10mm x 10mm. Watermark text (hollows) is 3.5mm caps height. Layer-thickness from left to right: 0.4mm, 0.3mm, 0.2mm, 0.1mm, 0.06mm.

 

 

So the only way to get good quality, is by printing slow and in thin layers. And then reduce temperature to prevent overheating, leaking, or decomposing of the material in the nozzle.

 

[Deviant 0]

Thank you for the advice! I'll try the speeds...

 

And yes I have noticed that with UM3 you basically cannot get nice 90 degrees corners. It is almost impossible! I have tried different speeds and acceleration / jerk values with no sucsess.

 

The reason I asked for the text is that now there is 5-10 printers printing the same model. Few Prusa MK3, one Prusa Mini, couple "no name" brands etc. All of them get the engraved text or logo just fine, some of them are looking perfect! I would say at first glance - it is the speed that matters! BUT, my sliced model is printing 1:43, if I tweak everything, top time is 1:08. With 1.43 you saw the results, with 1:08 you cannot recognize it...  Someone would say, ok, but their print is probably longer (let's say 2.5 hours), but it is not. Their prints are 1:20 and looking great 😞

 

The only thing I'm thinking about is maybe the print core got damaged somehow... I'm starting to try things that look impossible at first look 🙂

 

As soon as my current print finishes, I'll try what SandervG suggested and I'll post the results. Afterwards, I'll lower the speed to 30-40 and do the model with 0.15 layer...

[Framar 38]

One think you can do to mitigate the longer printing time is to create a modifier that covers the text portion and set a lower printing speed for that portion (ex: 60mm/s for the walls and 20mm/s for the text area).

[Deviant 0]

Framar, can I be so free to ask you to tell me how ti use modifiers? I have never done that... I appreciate if you have time to explain it to me...

 

Thanks in advance!

 

EDIT: no need to explain 🙂 found it and I know what you are talking about, but it didn't cross my mind... thank you for help!

Edited April 16, 2020 by Deviant

[Deviant 0]

Nope... thought I knew what I'm doing, but I can't find a way to make different speeds for different parts of the model... I can thought that adaptive layer is doing that, but I think it is only for the layer height change...

 

Help 🙂 because it seems that low speed really helps with the text...

[Framar 38]

Hello Deviant, 

 

Here's the steps that should help you.

 

1. Create and positionned the modifier.
2. Select the modifier and use "per model settings" and enable print speed.
3. Set a lower speed to be applied
4. Slice.