G-code problem - M204

[ryaneb85]

Hello all from sunny Singapore!

I've had my M2 all but a week now and as its my first 3D printer, I'm facing a very steep learning curve. Nevertheless, I am getting there slowly with the help of some online profiles that I have found on this forum.

One problem that seems to be unique to myself (based on google results!) is what my M2 is doing when using the M204 command. In theory this should be increasing the default retraction acceleration, but what it seems to be doing for me is lifting the nozzle approximately 10-20mm away from the print bed, meaning that all layers fall out of the nozzle as opposed to being squished down. As soon as I remove this line of code from the script, the world is put to rights once again. Drop it back in, and the nozzle lifts 10-20mm once again.

Has anybody else experienced this? The script line I am using is as follows:

M204 T10000 ; increase default retraction acceleration

Thanks in advance,

Ryan

[Tim]

M204 T10000 ; increase default retraction acceleration

Nothing in the Marlin firmware code suggests that it should do anything except set the filament acceleration. However, there is a comment in the code about also setting minimum segment time to prevent buffer underruns; I have no idea if that could cause weird behavior, though, if M204 is in the middle of the gcode. What code is around that statement?

[ryaneb85]

Thanks for the reply, Tim. Here is the g-code around M204:

M204 T10000 ; increase default retraction acceleration
M201 X1200 Y800 Z500 ; reduce maximum acceleration to reduce ringing
G28 ; home all axes
G1 Y50 Z0.3 F9600 ; move forward to avoid binder clips
G1 X205 Z5 ; move off platform
G1 Z0.4 ; position nozzle
G92 E0 ; zero extruder
G1 E25 F225 ; purge nozzle
G92 E0 ; zero extruder
G1 X190 Z0.1 E1.0 F1200 ; slow wipe
G1 X180 Z0.25 ; lift

However, after more trial and error I discovered there was in fact no fault with the M204 command, but it was with the line:

G1 X205 Z5 ; move off platform

The Z lift was previously set to 10, and it seemed that the next command line started before the Z would finish lifting (or bed lowering in reality), therefore the stepper motors would give a nasty grinding sound as the stepper motor was slamming in to reverse. Lowering the value from Z10 to Z5 seems to have done the trick as it now takes half the time to finish lifting.

One thing that I puzzled by though is why the next command line would start before the current one has finished. Any ideas?

[3dPrintingMD]

I'm going to take a wild guess here.

You have a very new M2, and are using profiles you found online, perhaps RSilvers.

Ask me how I know....

[SouthSideofdaSky]

M204 T10000 ; increase default retraction acceleration
M201 X1200 Y800 Z500 ; reduce maximum acceleration to reduce ringing
G28 ; home all axes
G1 Y50 Z0.3 F9600 ; move forward to avoid binder clips
G1 X205 Z5 ; move off platform
G1 Z0.4 ; position nozzle
G92 E0 ; zero extruder
G1 E25 F225 ; purge nozzle
G92 E0 ; zero extruder
G1 X190 Z0.1 E1.0 F1200 ; slow wipe
G1 X180 Z0.25 ; lift

That looks like a convoluted version of the default startup g-code in Simplify3D. As you noted, the Z was previously set to 10 (which is what mine is set at). But also, I don't have the M204 line in my startup g-code at all. Are you intentionally putting it there for a reason in the hopes of accomplishing something or is it just copied and pasted in from somewhere?

I have some speculative thoughts on the reasons behind why that line might be causing the problem you're seeing. But to cut to the point, my two cents is that if you're just starting, there's no reason you should need to mess with the default retraction acceleration. I have been printing for almost a year and a half and I've never once changed it. So I think you'd be safe just deleting that line. I'd defer to any of the more experienced people here though.

[ryaneb85]

3dPrintingMD - exactly right. New M2, fully assembled and using RSilvers profiles off Thingiverse. I'm glad to hear I'm not alone on this.

South side - yes, it's basically the default simplify3D start code with a few extra lines added. It is part of the highly recommended RSilver PLA profile, which seems to be producing amazing results for others. I'm trying to print pretty small, intricate items and am pushing for as much quality as possible, hence I am trying to replicate where others have succeeded (why reinvent the wheel, right?).

What I am trying to mostly achieve is eliminate the zits when starting new layers, so the default retraction rate must been having some kind of positive affects as his demo prints looked flawless. Now, what increasing the default retraction acceleration does that adjusting the retraction rate in simplify3d doesn't, I am not too sure.

[3dPrintingMD]

Yeah, can't use those profiles on a V4.

I'm not really smart enough to know why it doesn't work. There must be something in the profile, that is different from the standard V4 profile, probably has to do with the new Z motor.

[Jules]

Ryan, here's what you need to do if you just got an M2:

Read the How To: Guide to Getting Started at the top of the Getting Started section. It will save you days of frustration.

And assuming you have Simplify 3D, give the settings below a try for PLA:

You will need to change the settings highlighted in yellow to match the settings that you determined were correct based on your calibrations, from the Getting Started Guide.

Other spots that need to match are highlighted in pink (for the starting zits).

[3dPrintingMD]

Running these settings tonight on a 4 hour print. I'll let you know how it does. Looks very good so far.

I think one of the issues I was having with print quality is on the Other tab for the X/Y movement, mine was super high, like 9000. I think the stock profile is even higher. I want to say something in the order of 18000.

[Jules]

Running these settings tonight on a 4 hour print. I'll let you know how it does. Looks very good so far.

I think one of the issues I was having with print quality is on the Other tab for the X/Y movement, mine was super high, like 9000. I think the stock profile is even higher. I want to say something in the order of 18000.

Good! Hope it turns out okay....