Hi everybody, I'm often have this trouble (see photos belowe); Kossel,

3D Printing
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Hi everybody, I’m often have this trouble (see photos belowe); Kossel, wantai motors 2.5 A, stepper driver A4988 with little dissipator set to 1.7 A; Arduino Mega + Ramps1.4, fan always running over stepper drivers, nozzle 0.4, layer 0.3, PLA 1.75… it seems about loosing steps, or what? thanks everybody

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Are you saying your steppers want 2.5A but you’re not able to source that current? That could account for missing steps. I have some monster Sanyo Denki steppers I’d like to use in a large CNC/printer, 3A, have been wondering what options I have with RAMPS1.4

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I read A4988 can supply up to 2.0 A, but it’s better to set them to a more secure 1.7 A, I don’t know if I’m right, I’m searching a solution…

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A4988’s are only built and rated for like 1.5A as far as I’m aware. Why in heck do your stepper motors want 2.5A anyways?! Generally regarded as some of the most powerful motors we use, the Kysan 1124090s only need 1.5A per phase. Likely what’s happening is you’re overheating the drivers. Turn them down to 1.2A.

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@Mark_MARKSE_Emery you can use other drivers and simply configure them to work with the ramps board. The Toshiba tb6560 is a good choice very good for high currents while also working with low ones. They’re cheap and also provide microatepping at max 1/16

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Deltas should be quite efficient. Are your drivers heating up? I hope that although the motors may be rated to 2.5 A, they are pulling a lot less on a Kossel-mini.

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Check that things are moving smoothly, and not too fast. I wish I recalled where we set acceleration limits on Marlin. Even if things are not too fast, if acceleration is set too high you can skip steps. Oh… although I know you are working on a Kossel Mini, what kind of printer is making this part? If it is a cartesian… ignore everything I said about efficiency. Make sure everything moves freely without binding. We had this happen on the makerspace cartesian when one of the gantry axes was sticky. New linear bearings fixed the problem.

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It is interesting that the error was symmetric. A sticky spot seems likely.