Need to boost print speed, where are the obvious places to start?

I want to boost my print speeds, even by a little bit.

I am using accels in the 700 range, way too low. I am going to boost those to 1200. They used to be at 3000 but the machine would shake like crazy. What affect does acceleration have on print time all else being equal? Is there an approximation one can make, by going up a certain accel, your print time will change by a certain amount?

Another thing, can someone please tell me where in configuration.h, I can find the non-print travel speed default? I am looking at my printers printing, and I really do feel that this value can be increased slightly.


Other then those two basic things, what else is there?

Thank you

If you can put up with the gory detail that ended up in the thread, this may be of help to you - Marlin Motion Related Configuration.h Settings for MakerFarm i3v. Maybe you don't have an i3v, but it'll still explain all the motion related settings in Marlin, and describe how I went through options in speeding up my printer.

outta here for the night. Good luck.

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Originally Posted by DBFIU

Another thing, can someone please tell me where in configuration.h, I can find the non-print travel speed default? I am looking at my printers printing, and I really do feel that this value can be increased slightly.

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The short answer to your question is that DEFAULT_MAX_FEEDRATE is what sets the upper limit for each axis, regardless of print vs travel. Look at it as a definition of what the hardware is capable of. In Marlin, there's ancillary speed settings for homing and manual moves, but the printer doesn't have settings specific to printing vs. travel moves. Those are defined by settings in the slicer, and conveyed to the printer as part of the gcode file. The printer just makes sure that what the slicer tells it to do is no more than the DEFAULT_MAX_FEEDRATE settings.

To be thorough, there are exceptions to this. Through the LCD, the user can set values that exceed DEFAULT_MAX_FEEDRATE firmware values. This can be handy for short term testing of higher limits than those defined in DEFAULT_MAX_FEEDRATE. Also, if EEPROM settings are enabled, Marlin is designed to ALWAYS use the settings last saved to EEPROM instead of anything you might try uploading in new firmware. The latter is a common gotcha that people run into. The way around that is to either disable EEPROM settings during testing new values, or after flashing new firmware, command the printer to do an M502 followed by an M500. The M502 will load the variable space with "factory default" settings from the new firmware, and the M500 will save the variable space data into EEPROM.

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Originally Posted by printbus

The short answer to your question is that DEFAULT_MAX_FEEDRATE is what sets the upper limit for each axis, regardless of print vs travel. Look at it as a definition of what the hardware is capable of. In Marlin, there's ancillary speed settings for homing and manual moves, but the printer doesn't have settings specific to printing vs. travel moves. Those are defined by settings in the slicer, and conveyed to the printer as part of the gcode file. The printer just makes sure that what the slicer tells it to do is no more than the DEFAULT_MAX_FEEDRATE settings.

To be thorough, there are exceptions to this. Through the LCD, the user can set values that exceed DEFAULT_MAX_FEEDRATE firmware values. This can be handy for short term testing of higher limits than those defined in DEFAULT_MAX_FEEDRATE. Also, if EEPROM settings are enabled, Marlin is designed to ALWAYS use the settings last saved to EEPROM instead of anything you might try uploading in new firmware. The latter is a common gotcha that people run into. The way around that is to either disable EEPROM settings during testing new values, or after flashing new firmware, command the printer to do an M502 followed by an M500. The M502 will load the variable space with "factory default" settings from the new firmware, and the M500 will save the variable space data into EEPROM.

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I was under the impression that in simplify3D that the non print motion settings were for calculations only and not going to be used. Do I have that wrong?

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Originally Posted by DBFIU

I was under the impression that in simplify3D that the non print motion settings were for calculations only and not going to be used. Do I have that wrong?

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That'd be news to me. AFAIK, slicers are always in charge. Running a small test print or using a gcode viewer to look at move speeds after changing the setting for them in S3D would prove it one way or the other.

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Originally Posted by printbus

That'd be news to me. AFAIK, slicers are always in charge. Running a small test print or using a gcode viewer to look at move speeds after changing the setting for them in S3D would prove it one way or the other.

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Unless you try to exceed the maximums set in the firmware in which case the firmware controls it by reducing the requested rate.

I see, nevermind I am stupid. It only uses the Z axis speed for a calculation. The XY speeds are true speeds that fall into G code.

Here is what I saw.

Attachment 6213

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Originally Posted by DBFIU

It only uses the Z axis speed for a calculation. The XY speeds are true speeds that fall into G code. Here is what I saw.

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Actually, I'm sure the same rules apply for Z and I think the S3D comment is confusing/misleading. For the gcode I've looked at, S3D tells the printer how fast to move in Z using this setting just like it does for X and Y. I think all the comment is trying to say is to set it to what your printer can do so that the print time estimate is more accurate. You could set it to 100mm/sec and S3D will use that in the gcode commands, but if the DEFAULT_MAX_FEEDRATE in your printer's MARLIN has Z set to 2.5, the printer will use 2.5 instead, increasing the print estimate error. As both Mjolinor and I have noted, the printer limit checks all speeds in move commands, and will only move as fast as the printer is configured to do.

So is my default max feedrate my maximum non-print move speed during a print? Right now mine are set at 500, thats kinda freakin high! Am I missing something here or are those units in mm/min? It does say mm/sec, after all this is maxmimum and wont go that fast until I tell it to...

#define DEFAULT_AXIS_STEPS_PER_UNIT {160.9,161.064,804.4,319.38102} // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {700,700,100,3000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.




Also I noticed during a print, there is like a 300-500ms delay easy, between retraction, pressurize extruder, lift and move to next location. How do I get rid of that delay or reduce it? It is totally unnecessary and accounts for probably a big chunk of print time.

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Originally Posted by DBFIU

1. So is my default max feedrate my maximum non-print move speed during a print? Right now mine are set at 500, thats kinda freakin high! 2. Am I missing something here or are those units in mm/min? It does say mm/sec, after all this is maxmimum and wont go that fast until I tell it to...

#define DEFAULT_AXIS_STEPS_PER_UNIT {160.9,161.064,804.4,319.38102} // default steps per unit for Ultimaker
#define DEFAULT_MAX_FEEDRATE {500, 500, 5, 25} // (mm/sec)
#define DEFAULT_MAX_ACCELERATION {700,700,100,3000} // X, Y, Z, E maximum start speed for accelerated moves. E default values are good for Skeinforge 40+, for older versions raise them a lot.

3.


4. Also I noticed during a print, there is like a 300-500ms delay easy, between retraction, pressurize extruder, lift and move to next location. How do I get rid of that delay or reduce it? It is totally unnecessary and accounts for probably a big chunk of print time.

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1. Again, yes, assuming you don't have EEPROM enabled and something different set there, and don't set a different limit using either a gcode command or the LCD (if you have one).

2. The values there are mm/sec. Yes, 500mm/sec is fast, but bear in mind there's acceleration involved. It could be the printer rarely actually reaches those rates if it is having to spend a lot of time accelerating and decelerating. This is where some the gcode snippets in the Marlin Motion Control Settings thread I referenced earlier can help - the non-printing code snippets make it easy to see how different setting values "feel" on the printer.

3. There's another important setting missing - DEFAULT_ACCELERATION. Unlike DEFAULT_MAX_ACCELERATION, there's only one value that is a composite to be applied across all axes. The acceleration value Marlin uses will be the LOWEST of the two. For example, if in your case DEFAULT_ACCELERATION is 100, the higher values in DEFAULT_MAX_ACCELERATION won't be applied.

4. Welcome to the trades involved in optimizing printing. Is this a cartesian printer with threaded rods used on the Z axis? I assume it is based on the comparatively slow feed rate on Z. Lifting the hot end on each retraction is going to be the big hit to your print time. You'll have to decide whether the print quality gained by doing the lift is more/less important than the additional time required to do them. Your other option is to increase the distance between retractions in order to reduce the number of retractions, but that's another trade...