Archive for October, 2013
I’m building another Prusa i3 to be done as a group printer build weekend in a similar way to the http://botbuilder.net/ one that happened recently. To try to reduce costs I figured I’d try the SainSmart RAMPS bundle which at $80 is about $40 cheaper than the other sources I considered. http://www.sainsmart.com/starter-kit/3d-printer-parts/sainsmart-mega2560-a4988-ramps-1-4-3d-printer-kit-for-arduino-reprap.html
The pieces arrived in a couple weeks in bags in a plastic box. Unfortunately nothing protected the pins of the stepper drivers and RAMPS board so a few pins were bent. None of the pins were bent bad enough they couldn’t be bent back.
I installed the stepper drivers in the RAMPS board making sure they were correctly oriented, twice, because I didn’t initially notice that the micro-stepping jumpers were not included. That’s okay for this one because I have a bunch of those I can use.
When first powered on the Arduino Compatible Mega 2560 released its magic smoke. That’s not supposed to happen. (I know that it can happen if the stepper driver boards are installed the wrong way around, but I am certain they were not installed wrong)
On further inspection, the current adjustment on all 5 of the stepper driver boards spins freely. These stepper drivers probably don’t even work.
The RAMPS board was tested with a stepper driver borrowed from another printer, and a working Arduino Mega 2560, and seemed to behave fine. I ordered new stepper drivers from Maker Farm where they shipped with the pins protected in foam via first class mail and arrived before the weekend.
So, yesterday I was able to try with another Arduino and the new stepper drivers. Motors moved, bed gets up to temperature, fan gets up to speed, but I wasn’t getting any heat out of the hot end. The hot end heater appeared to be working, but a meter wasn’t showing any voltage on the heater output. We fixed this by replacing the MOSFET.
I also bought their makerbot-style endstops and MK2 heated bed which work as expected.
The heated bed was not shipped well and has a gouge on one edge and is not flat, but didn’t destroy anything.
I will not be buying any further printer parts from SainSmart. I don’t mind spending $40 more to get the micro stepping jumpers, heat sinks, and electronics that actually work.