Each layer external shell starts out rough.

MindFuLL · 2016-09-23T00:18:27.000Z

What is your x/y jerk setting? Might try lowering to 15 or 10.

MindFuLL · 2016-09-23T00:22:53.000Z

Yeah, the common wisdom seems to be that you should keep your layer height at 80% or less of nozzle diameter. I personally never go above 50%, even on infill, for reasons above.

wirlybird · 2016-09-23T00:50:25.000Z

Ok so whrere do I find that?! I’m on S3D.

MindFuLL · 2016-09-23T01:00:18.000Z

It’s a setting that is stored on the board itself. If your board uses EEPROM(and has it enabled) it’s as simple as sending a few gcode commands. If not you would have to re-flash the firmware. Which firmware does your machine use?

wirlybird · 2016-09-23T01:15:30.000Z

This one is a FFCP 2016 with sailfish 7.8

MindFuLL · 2016-09-23T01:40:47.000Z

I mostly use Marlin and have zero sailfish experience but it looks like the gcode is the same. “M501” will return all the current settings stored on the EEPROM.

FIRST THING you should do is take a screen shot of these setting so you have them as a back up/reference.

You should see the lines:

Advanced variables: S=Min feedrate (mm/s), T=Min travel feedrate (mm/s), B=minimum segment time (ms), X=maximum XY jerk (mm/s), Z=maximum Z jerk (mm/s), E=maximum E jerk (mm/s)
M205 S0.00 T0.00 B20000 X20.00 Z0.40 E5.00

In the example above, the jerk is 20. To change it to 15 you would send “M205 X15” and then “M500” to save the changes. If you do not send “M500” after entering any setting, it will not be stored. You should then send another “M501” to verify the changes were made and are correct(a decimal in the wrong place can be a disaster). The jerk settings are kind of subtle unless you make extreme changes(don’t do this). If 10 or 15 doesn’t fix anything don’t try going lower. Regardless, you just got access to some stuff you didn’t know was there. Enjoy.

wirlybird · 2016-09-23T11:59:58.000Z

Thanks, I’ll check this out and I need to research this setting since I don’t know what it is for or what it does.

How about acceleration settings? I don’t need this thing lightning fast but smooth and steady with out using the “granny” gear!!

More to learn!!

wirlybird · 2016-09-23T13:29:47.000Z

I was just looking at stuff and reading up and I think I can change this stuff via Replicator G. I did use that to fix a lighting issue and change a couple other minor things on the advice of FFCP support.

Does this seem right? I can post a screen shot this evening of what I am seeing.

Thanks for the help guys!

Perry_1 · 2016-09-23T13:34:12.000Z

You have to be careful comparing certain M commands that work in marlin that do not work in Sailfish, and vice versa.

So with marlin, you can easily recompile the firmware, and there are a few GUI ways to do this.

Sailfish, which I personally like, some of the slicer software allows you to do change parameters.

Sailfish has accelleration built into its firmware, and messing with the firmware settings messes with some complicated formulas that provide excellent prints from Sailfish.

The simple 1D kinematic equation for distance including jerk is:
s = vi*t + (1/2)*ai*(t^2) + (1/6)*j*(t^3)

where s = distance traveled, vi = initial velocity, ai = initial acceleration, j = jerk (i.e. rate of change of acceleration), and t = time

You can change “jerk” settings with sailfish. The key is that this is often a choice of last resort, because it can be difficult to change back to defaults without reflashing the software.

S3d does not have jerk setttings, and I recommend getting dialed in with S3d, but if you really want to know all there is to do, and expand your control, you can mess with firmware settings. Jerk is explained in the sailfish manual at "4.3.2 Maximum Speed Changes " under firmware settings. In effect, it will do the same thing though-slow down your printing.

wirlybird · 2016-09-24T13:12:50.000Z

Thanks. I guess I better leave it alone. It just seems odd I can’t print this small barrel faster than 1000mm/min. The one large enough to hold pens and pencils will take over four hours to print!

I am going to draw one myself to see if it is any better.

It has been a good learning experience.

MindFuLL · 2016-09-24T14:52:17.000Z

Jerk (not the actual physics term, which is the second derivative of velocity) has to do with how fast an axis makes a direction change. It should only affect your overall speed unless you make significant changes but small changes could have a big impact on the type of issues you are dealing with. Don’t mess with it if you are not comfortable.
-Jesse

wirlybird · 2016-09-24T15:17:55.000Z

Thanks, I am comfortable with it, plenty of experience with BIOS’s and firmware (computers) but don’t want to go making changes if it is not really a good idea or hard yo undo!!

I think Perry indicated a re-flash my be needed to undo. If it is simply running the flashprint and doing the firmware upgrade again then no problem!

I am going to post a pic from RepG of the acceleration page and see what you guys think and advise!

I see a button for “fine print” and it seem to change only the first two items “max acceleration” settings down to 2000.

I would be ok with going in the direction of “fine print” settings as long as it doesn’t bring the overall speed to a crawl!!
RepG Acc.png

wirlybird · 2016-09-24T16:04:14.000Z

Thanks, I really do appreciate all of the help and advice. I have found that I am able to offer simple advice now to those who are newer at this than I am because guys like you guys take the time to help me understand this whole process better and improve my knowledge and prints.

MindFuLL · 2016-09-24T16:09:00.000Z

Looks like “max speed change” is the equivalent of “jerk” on marlin but I would defer to @perry_1 on this because he has more experience with the specific firmware/software you are using.

MindFuLL · 2016-09-24T16:15:16.000Z

For the most part, forums like this and endless tinkering got me to where I am. I’ve tried to offer as much info as I could on this thread specifically because of your previous contributions in the forum. Happy to help someone who helps!
-Jesse

MindFuLL · 2016-09-24T17:08:12.000Z

BTW, those option are the EEPROM I was talking about. Your software just has a nice interface for you to change them. Does “RepG” display the gcode that is being sent to the machine? If so you should notice that when you change those settings it’s actually just sending the gcode that I listed above. Sorry if that caused confusion.

wirlybird · 2016-09-24T17:19:01.000Z

No confusion. I was thinking it would be easier for me to make the changes using the RepG interface.

I think it does display the G-Code but I didn’t look at it.

Perry_1 · 2016-09-24T19:55:53.000Z

Yes, Rep G has one function anymore. To change/update firmware.

When I spoke of having to reflash, I spoke mostly of the once you get all the settings all mucked up, you might have to reflash.

…

Acceleration in sailfish, is explained here http://www.sailfishfirmware.com/doc/sailfish.pdf section 4.3.

If you haven’t already, this is a great manual on the firmware, and explains a lot. Good bedtime reading.

wirlybird · 2016-09-24T22:24:58.000Z

Thanks, I have been reading up on this.

I made the changes below, the top two were applied when I selected “fine quality” I also changed the other two in the red box from 15 to 10. This hasn’t had much effect if any but it has not hurt speed.

After watching this more the bed does drop pretty hard at the layer change. Do you think this could be contributing to the ringing? It is at that point in the print.

Would I want to slow the bed a bit to smooth the layer change? From 10 to 5 or to 0?

I am going to try but wanted your opinion on this.

Thanks. I think this is about as much as I can do before making a new model to try.

wirlybird · 2016-09-28T17:41:14.000Z

Follow up: I went ahead and changed the X and Y max speed change from 15 to 10 and the X from 10 to 0. I haven’t tried 5 on the X-Y since I got the impression that may be to low. If you guys think it would be ok then I could and see.

The changes do seem to really smooth out the printer without a noticeable speed sacrifice. It didn’t seem to do anything major for the ringing issue but may have helped a bit. A print at 2000mm/min is pretty good.

One thing I haven’t tried yet to see if it helps is printing more shell layers. I am at 2 and maybe it doesn’t like that. I am not sure of the actual wall thickness since it is just an STL. However when I made my own sample I gave it a wall thickness divisible by the nozzle width I have set (.4) and that didn’t make any difference. Anyway, I’ve learned a bunch more so thanks again!!