My mate found time to finish off 90% of the dividing head ( YAY ). I rushed it home with the PC and controller box, attached a power plug that i had been putting off until i had a reason to. Then proceeded to install a copy of ECM running on Ubuntu 10.04 from a liveCD image to a USB key then onto the 4Gb CF card. the motherboard seems to be a little slow booting up so i may sink another $50 into the build and buy a 8GB sata SSD and liberate the processor..
Once I had the OS and EMC installed I Proceeded to attempt to configure EMC. this turned out to be in total a 2 day ordeal. first the problems were getting the LiveCD image to actually boot, just had to find a magical usb key and the right settings in the bios and standing on one foot with one eye closed :).
I purchased the Stepper interface quite a while ago and the exact user manual for my board so i started looking on ebay, i couldn't find the exact seller with the same unit. I did find several that looked the same, but when i downloaded the data sheets for them the pin maps just didn't line up properly, the 5 axis data sheet had the right title and said it was for the 5 axis model but the pin table only showed 4 axis, another had only 3 axis, then finally i found one that had all five axis labeled..
I ran the stepconf program to configure the stepper drivers as per the data sheet, but weird stuff happened, so then i looked at my cable that i have made to go between the par port and the stepper driver, turns out that this was rather wrong, so i turned the ends around about 5 times until i finally got the right orientation so pin 1 is connected to pin 1 and so on. i tested the results and yet another fail, not sure where the problem was i started testing, i grabbed a LED and jammed it in the end of the cable, then clicked on things in the gui and all the pins matched their functions. So then i figured i should probably check the pin functions on the stepper board.. this was a little difficult, i had to first work out which pins would make a led light up then try and work out what that led meant, in the end i managed to get each Axis spinning in both directions when commanded to, some of the axis were being difficult but got there in the end.
At this point in time i have all the Axis responding to the GUI buttons, i have calibrated the XYZ Axis' according to the numbers, leadscrews have 16TPI = 1.558mm/Revolution, 200 steps per rev on the steppers, 1:1 drive ratio and 2:1 microsteps. this results in 251.9steps/mm. for the Dividing head it has 200 steps per rev, 1:3 ratio, and 16:1 microsteps, resulting in 26.7 steps per degree, this should be fine enough for what i want to play with. I should be able to cut some gears and worms, but first on the list is a triple hyena bolt. Arcol from the reprap forums has designed a really nice drive bolt that grips the plastic really well and doesn't clog up, i have asked in the past if he could make me a custom one that has three sets of teeth but at the time it wasn't worth his time as he gets his bolts that he sells made in a workshop by real machinists if anyone is wondering what sort of bolt they should use see Arcol's blog.
Before i have even bolted all the bits on to the mill i already want to program it... I want to write some gcode that will cut my bolt :) there are a few parameters that i will have to get from the Mill itself for the code to be complete but i will write it anyway, have i mentioned before i am an impatient and impulsive sort of person...
next post some Gcode to cut a Drive bolt..