Printing using PLA-Pro - questions before buying a spool

[dsc]

I’ve recently got an M200 and so far only used Zortrax’s own ABS with very good results. I’ve tried some PLA the other day, namely PLA and PLA+ from rigid.ink, results where terrible but I’ve blamed this on the material settings in Z-Suite. Having done more research though I can see that using PLA, even Zortrax’s own PLA Pro isn’t a trivial task on the M200:

Tips for Printing with Z-PLA Pro - Zortrax

Can someone explain why the need for a brand new hot end just to print PLA? isn’t this the easiest material to print with? I’ve never seen any other manufacturers suggesting brand new hot ends for PLA prints, so I’m just trying to wrap my ahead around what makes the M200 different.

Using rigid’s PLA I’ve had no major issues with extraction, but I’ve taken the entire hot end apart and cleaned the nozzle properly before loading PLA (btw this hot end has been used for a long time with ABS). I’m now contemplating getting Micro Swiss hot end for all filament types, but I’m still not 100% the machine can handle PLA without issues.

Regards,
T.

[Marta]

Hey there!
We suggest to use a separate hotend, as the residues of materials with higher printing temperature (such as Z-ABS) can cause issues with extrusion, as Z-PLA Pro prints with much lower temperature.
You thoroughly cleaned your hotend before printing, that’s most likely prevent it from clogging.

[dsc]

Hi Marta,

Thanks for the reply, a few more questions:

• there seems to be three hot end versions from Zortrax V1/2/3, which one is the latest suitable for a bog standard M200?

• is the clogging happening in the nozzle as that’s the only part which is not PTFE lined?

• what symptoms normally point to extrusion issues? Missing steps on the extruder? Filament “balling up” on the nozzle?

Rgds,
T.

[Marta]

V1 Hotend was sold with first hardware versions of M200. V3 Hotend is dedicated for M200 Plus and M300 Plus 3D printers. For M200, you can use Hotend v2.

Clogging can happen both in PTFE tube and in nozzle.
Symptoms of extrusion issues are normally extruder clicking, paths missing on the model or visible artifacts, and generally quality deterioration.

[dsc]

Brand new hotend, brand new spool of PLA Pro, followed all tips for printing PLA from your website and here’s a rather abysmal result printing a very simple 10mm cube:

Printed using PLA Pro selected in Z-Suite, all default settings.

Any ideas how to improve this?

[Marta]

This model looks very overheated.
I suggest that you try to print it with 100% fan speed in Z-SUITE and let me know how it turns out.
Have you noticed some issues with other materials lately?

[dsc]

ABS prints very well so I doubt it’s a faulty temperature probe / heater as this would affect all materials. Still I’ve got the equipment to check both components if you have any instructions on what to test.

[Marta]

Let me know how the print turns out with 100% fan speed.

If the issue persists, I’ll provide you with instruction on how to check if heater&thermocouple works properly .

[dsc]

Here’s a comparison showing a 100% fan setting only (still using the Z-PLA Pro material profile in Z-Suite) and a completely custom material profile based on the built in ABS based material profile, with the temp changed to 210*C:

100% fan setting still looks horrible, the custom material profile is much better, but that’s not the reason why I got the M200, the idea was to not touch the settings at all…

[Marta]

To be honest, no one has reported issues with Z-PLA Pro profile settings. Do you use the newest Z-SUITE version? Let me do some tests and in the meantime check heater’s resistance and let me know the value.

[dsc]

Yes latest Z-Suite, it did an update yesterday before I did any prints (it was running the most up to date before than anyway). I’ll measure the resistance later on today.

I can post the 10mm test cube stl file to make testing easier if that helps.

[Marta]

Sure, that will be helpful.

[dsc]

I’ve check the resistance of the heater, it’s 18ohms, so different to the 15ohm result shown on the photo.

Also here’s the test cube:

10mm_cube.STL (17.7 KB)

[Marta]

Hi!
Thank you very much for the file.

Regarding measurement, was the printer’s extruder at room temperature? Please, repeat the measurement. If it’s still 18 ohms, then heater&thermocouple should be replaced. Correct resistance should be 15-16 ohms, higher values indicate overheating.

[dsc]

Yes it was at room temp, but I’ll double check today and report back.

[dsc]

Checked again, it was 17.8ohm, so higher than the suggested 15-16ohm.

Can you explain the whole concept of higher resistance leading to overheating? Surely the temperature is kept at a certain level (or within a range) using most likely a PID controller, so why would the resistance matter that much? It’s a closed control loop at the end of the day with a thermocouple measurement acting as feedback.

[Marta]

Resistance measurement is a way of checking whether the heater isn’t malfunctioning. As it is a PTC heater, resistance exceeding 16 Ohms means that it is overheating the hotend and material. If resistance is way below 15 Ohms, a user may experience problems with underheating.

[dsc]

I’ve ordered a replacement heater from a local reseller (Dream3d in the UK), but the resistance on it is 13.7ohm so it’s not right either.

@Marta have you tried printing that model that I’ve sent in Z-PLA Pro?

[Marta]

Hi, @dsc.

My colleague is taking care of your case.

As for the model, yes, I’ve printed. It’s definitely not as overheated despite printing with auto fan speed.