hi guys

wondering if you can help diagnose a problem iv had since day 1. Since im at a near stage of everything working now i thought i would try and tackle this to get print quailty up a lot.

while im printing circles or arcs my printer will stop and start stop and start to get the circlr down.

it does not go in one complete motion. if its going very very slow you can achully hear all the motors shutdown for like like 1 milli second

nothing to do with electronics i have had the same with a whole different setup of electroincs and stepper drivers.

when this happens i get blobbing as the hotend isnt moving quickenough acorss the print.

problem seems to be a bit better when i run marlin at 11520 serial speed instead of the standard speed.

iv check computer performance tab while priting and CPU is never over 5% and ram has loads free all the time

any ideas what i can try to solve this ?

Is there any buffer settings i can increase?

Which driver should i be using for my electronics ? (currently using FTDI i downloaded from the net for my ramp1.3)

Use an SDCARD adapter, all your printing will look better, especially if you print fast and have high speed acceleration settings in your firmware.
It's the only way I can get Marlin running at full speed on the mendelmax, Even 250k baud causes issues that the SDCARD interface sorts out.

It's really noticeable if you try to print a single walled stretchlet bracelet at high speed, the delays cause a poor print, use the adapter with Gcode on a decent SDCARD and it's sorted.

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[richrap.blogspot.com]

yes i was going to give my micro SD addon a try tommrow.

only printing at 60mm/sec is this classed as high speed?

If doing lots of tiny moves and reasonably fast acceleration settings in FW, yes.
If I use a netbook pc and 250k baud with max acceleration set to 6000 in Marlin and a perimeter speed of 35mm/sec then I get noticeable slow-down when printing stretchlet bracelets or similar objects with a lot of tiny perimeter moves. Use an SDCARD and I don't get the slowdown issues at twice that speed.

It does get better with a better PC, but using a SDCard adapter is much better all around.

If you have one, give it a try and compare results

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[richrap.blogspot.com]

I've got the same issue with my large printer. The second iteration of this machine is only a few hours old now, but the growling it does on curves is unsettling. I've got plenty of microstepping (32x) and it moves quickly, quietly and smoothly on traverses and non-curve print areas.
Will try out the SD card printing tonight when I get home. Very hopeful.

To tune my machine and have a 1:1 torso, I've been scaling up the Pink Panther Woman, pictured at 4X and 2X.
I did abort at about 7" high, when the filament jumped out of my hobbed gear for a few seconds leaving a weak layer. I've since grooved the idler bearing and hope that solves it.
The print envelop is currently limited by my glass size of 18x18x18 inches.

I've recently dropped Slic3r and started with Kisslicer, and the results improved. There are still plenty of stutters, and this SD card thing makes sense to try. Big thanks in advance Rich.

Dave

This SD card printing works wonders. Currently printing the link bracelet at 70mm/s with no grumbling.
I had to remove the comment in config.h, near the bottom, #define SDSUPPORT

Still can't mount the SD slot/card on a PC, but will just load the cards on the PC, then pop them into the Azteeg.

Dave