Stainless Steel nozzle  

Re: Stainless Steel nozzle

Hi Alfonso,
i am also still a noob but how much do you rised the temperature?
And maybe you have to do a PID tunig for the Hotend.
br,
Bastian

Re: Stainless Steel nozzle

Sorry for my ignorance but why antibacterial PLA and a SS nozzle?

if you try regular PLA with the nozzle does it work? Does it even pass the calibration test print or even that doesn't stick?

Try cleaning the bed with acetone

Re: Stainless Steel nozzle

Hi again.

Thanks Bastian for the tip about the PID tuning. I'll look into it, but first I'll wait a bit if someone that has used one of these nozzles shares a experience 😉
I've gradually increased the extruder temperature from 195ºC (high end of the specs of the filament, that prints great with the brass nozzle) to 220ºC in 5ºC increments for each test.

Erick, the pieces I'm printing are going to be used by children, making exercises with the tongue and jaw, so we must guarantee to the parents that we are using top quality materials for the parts, that meaning using at least FDA approved filament, even better if it is also antibacterial. And about the steel nozzle, it's because brass hass a small percentage of lead, and even most people consider (and i must agree) that using PLA or PET the exposure to lead from nozzle wearing is negligible, again we must guarantee to the parents the best procedures we can offer. Plus, it is a cheap measure that gives a big added value for us. We also sterilize the pieces with the same procedure as any other instrument in the clinic.
The same happens with regular BP Premium PLA as I stated in the OP. The problem is not the first layer. That is perfectly stuck to the bed (I clean the bed with IPA before PLA and with glass cleaner before PETG). It's the rest of the layers that have a problem.

So, is anyone already using this nozzle?

Re: Stainless Steel nozzle

You won't have to do a PID tune for different nozzles; the actual temperature of the nozzle is not what is being measured. You may have to increase the temp by 5 or 10 degrees, depending on results.

You will have to adjust the Live Z to get a good first layer and your first layer height must not be less than 0.15mm.

Acetone can be used to refresh the bed adhesion as opposed to IPA which simply cleans the bed.

Peter

Re: Stainless Steel nozzle

I am, by no means, an expert. But I was reading up yesterday on alternate nozzles, and watched quite a few YouTube discussions. It sounds like the stainless steel ones, because they have lower thermal conductivity, need to both be hotter, and printed more slowly with, than the brass ones.

Given 210 is a "normal" PLA temperature, 220 may not have been hot enough, and it may still be printing too quickly for the plastic to melt completely.

Have you tried slowing down the print?

Re: Stainless Steel nozzle

Hi Alfonso,
I think also you should rise the temperature a bit more. This is from the Prusa PLA shop description:
Proudly made in Czech Republic.

PLA advantages

Printing of large parts is much easier with almost no warping
No chemical odors are produced during printing
PLA disadvantages

Parts start to loose mechanical strength at temperatures over 60 °C
Printing information

190 °C - 220 °C printing temperature 1)
40 °C - 60 °C heated bed temperature but only for bigger parts
Notes

3 mm filament is actually manufactured with diameter of 2.85 mm +- 0.05 mm as is common standard.

1.75 mm filament is manufactured with precision of +- 0.05 mm

We reserve the right to ship weights +/- 5% due to packaging variations.

1) Or up to 250 °C for all stainless steel Prusa Nozzle MKII

See the last sentence.

br,
Bastian

Re: Stainless Steel nozzle

Have you tried slowing down the print?

Yes I have. Last test was at 220º at 15mm/s

Thanks Bastian, missed that line (as I am printing with another PLA). Probably on the weekend I'll change the nozzle again for testing with a higher temperature then.

I'll be back 🙄

Re: Stainless Steel nozzle

Hi again all. Just a heads up with the results of the tests

I went ahead and printed another (2, in fact) temperature tower increasing the base temperatures, and it started to look and feel good at 235º temperature, but the stringing is a hell in this material. However, it's a nice filament for it's funcionality, specially in case you dont need tiny details that are affected by stringing. For me it's 195º with brass, 235º with stainless steel. From 235º on the layer adhesion is nice.

You can see the last temperature tower here:

Cheers

Dote

Re: Stainless Steel nozzle

Hi Alfonso,
maybe try to increse the retraction a little bit to get rid of the stringing.
br,
Bastian

Re: Stainless Steel nozzle

Hi again Bastian. That tower was printed with 2mm retraction. With the normal brass nozzle I did some tests increasing the retraction to even 10mm, and the resulting print of the 3d Benchy was great, but after that I red that retracting 1.5mm or more can clog the nozzle. After the benchy, in fact, I forced some extruding (some cm of filament) to unclog it because it was starting to look not so good.

For the pieces i'm using it, even the default 0.8mm retraction give only very little stringing, so it's ok.

Compromises!!!

Re: Stainless Steel nozzle

Hehe jep okay I know what you mean.

Re: Stainless Steel nozzle

I just ordered some SS nozzles as well as a silicone sock. Has anyone noticed if the sock reduces the need to increase temps? It's gonna be a pain to do a temp tower on ever filament again.

Is the increased temp do to the SS cooling off faster? The temp is maintained above the nozzle so not sure what causes the need for the increased temp unless the SS holds a colder temp and cools off the filament as it passes through.

Re: Stainless Steel nozzle

Is the increased temp do to the SS cooling off faster? The temp is maintained above the nozzle so not sure what causes the need for the increased temp unless the SS holds a colder temp and cools off the filament as it passes through.

Stainless steel does not conduct heat nearly as well as brass, so in order to get the same temperature on the inside of the nozzle while it's melting filament, you have to have a higher temperature outside the nozzle. And the thermistor measures temperature in the heat block, which is outside the nozzle.

-Ticc

Re: Stainless Steel nozzle

Hi Bastian, thanks for your suggestion

In some tests I have increased the retraction greatly, and I must admit that going up to 7mm retraction the 3dbenchy printed wonderfully, but I think we all agree that 7mm can lead to other type of problems (like clogging) even tho I luckily didn't experience any while printing the benchy.

Regards