I have been using my awesome mpcnc lately to build a bartop arcade for my father. It’s probably the most work I have asked of my machine as I have since building it only cut a few signs and lasered, but not much time lately.
I was having issues with chatter or run out or deflection or whatever its called while working acrylic and found that the legs of the machine where not very rigid leading to a lot of movement. The belts had also loosened over time or maybe the zipties. And finally some bolts on rollers and middle parts that effect z tubes. So I tightened the belts a bit but not too much, gave the bolts a small tighten but in no way tight, added gussets between the table legs in the front which made it rock solid. I took care not to alter the positions of the legs as to keep the geometry of the machine the same. I then tried to cut the same piece with 100 times better results, I still have to go slow to avoid chatter which is tough in arcylic where you need to go fast to prevent melting. I use a 300w spindle with speed control so I am able to turn the speed down to help but too low of a spindle speed has its own chatter issues. In the end piece looks great except I notice my sacrificial bed which was leveled long ago must not be because one side of the pocketing is 1.7mm deep, the other only 1mm!
SO, I get ready to run bed leveling gcode I made, I’m jogging the machine around as I have a 100 times before and one motor stops for a split second on the y axis! I check things out, all seems normal. I jog back and forth and it does it more, randomly, and the other side of the same axis as well! then a swear they sometimes go in opposite directions!
Mind you these are long ago proven wired correctly with all connections very secure and if possible soldered and shrinkwraped. I don’t use the quick connect screw down terminals on the rollers and the connections to my driver boards is secure and more over unchanged in all this time, no strain etc.
I should also say that during my build I already owned a usb controller board, 2.5amp driver boards and control software from buildyourcnc.com, they are very nice and purpose built so you would assume better than ramps setups.
I checked everything I can think of. I loosened all the bolts back just to be sure, I turned up the power on the driver board which seemed to help but not completely and the board and motor got too hot. I can’t see anything that would cause the motor to act like this, the belts still not too tight, wiring good.
Too say I’m sad would have to be an understatement. I originally bought a mydiycnc.com kit which was a total pos. I spent hours and $2k trying to get it to work (also why I had the premium electronics) before I found the mpcnc project. I was in love. the parts printed issue free which was a sign from god since my reprap is a pos too lol. I built a 4’x3’ machine on a sturdy table and all the issues that made ruined my hobby where no more! aside from the expected flex ( which I now wonder if gussets wouldn’t have solved) and limitations of a diy machine I was in heaven. My custom spindle mount has led lighting and line laser targeting, a dust collector, laser mount spot and wire plug. it’s perfect. I’m hoping someone has an idea or some insight I’m yet to think of
Thanks in advance for any help,