planetary gear motor mounting

Hi,

im just looking for a 2nd extruder setup and wanted to test out direct (mk8) extruder with a planetary gear 5:1 motor, however the mounting holes are different.
drilling new holes in the extruder mounting plate cant be done and motor with a square flange are so rare the cost 100$ more. is there any smart workaround for this?

There are a ton of extruder designs on thingiverse and youmagine. Did you need something special?

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sungod3k
Hi,

im just looking for a 2nd extruder setup and wanted to test out direct (mk8) extruder with a planetary gear 5:1 motor, however the mounting holes are different.
drilling new holes in the extruder mounting plate cant be done and motor with a square flange are so rare the cost 100$ more. is there any smart workaround for this?

Well I found one that cost $5 more than the standard See Flanged Geared Stepper $34 they also do an adapter to extend a std motor as in there Bulldog XL Extruder

Doug

Bot gearboxes have an 8mm output shaft and that doesn't match the MK8 hobbed drivegear.
IMHO for 1.75mm filament a geared extruder is almost useless. I can strip and jam my filament with a weak 0.4A MK8 direct drive, why would I need even more torque?

BTW, according the datasheet the planetary gear is only suitable for 4Nm momentary and 2Nm continuous load. Not worth the extra weight and mounting hassle.
-Olaf

Stripping and jamming is not caused by high torque. It is caused by low pinch wheel tension. If the filament isn't pressed hard against the drive gear, its teeth don't dig in deeply and the filament can slip easily. If the filament meets any resistance from the hot-end (such as when printing very thin layers), it stops moving. That's when the drive gear carves a divot in the filament and loses grip completely.

High drive torque allows you to keep the pinch wheel tension very high, and keeps the motor turning and the filament moving even with that heavy loading.

I have a BullDog XL that I use for 1.75mm filament and it has literally never stripped the filament or jammed since I installed it on my printer in January. The pinch wheel tension is so high that I can barely release it with my hand when I want to change filament. After my recent bed flatness/level tests I put the extruder back on the machine and didn't adjust the zero level. With the first attempted print the nozzle was against the bed and the extruder couldn't squirt out any plastic. The extruder motor started missing steps, but it never stripped the filament. That's exactly how you want it to behave.

The BulDog XL has a 600 mA NEMA-14 motor.

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Ultra MegaMax Dominator 3D printer: [drmrehorst.blogspot.com]

I'm using a geared stepper and the MK8 hobbed gear with 8mm bore from Tridprinting. It has never stripped or stopped feeding the filament. It's also a Bowden setup, so there is no weight penalty.