Hi, I got the unit completely built. Now, I have a few questions about inputting the file into the Interface. Can you write your own G-code program and input it into Interface? How do you do that? What I will be doing is mounting the 'linear rail' on the table of my CNC mill, set '0' and allow the mill to do its drilling operation. When the mill has completed its program, I will command the 'linear rail' to advance a set distance, thusly advancing the part to another start point, then the mill will do its drilling operation again and I will repeat till the job is done. You are probably wondering why? Well the part to be drilled is 36" long and the mill only has a 15" feed. Joe
I have looked at the video and still would like to see an example of the self written G code. Say to command the unit to move 6.0". The one I use for my CNC mill would be Move X6.00 . Another question- can you mount two nut plates on a rail,to move together. Also can you mount another 'limit switch' on the rail for the 'end of travel'. Thanks, Joe Casalino
The Blackbox runs GRBL firmware. GRBL supports the simplest subset of Gcodes, documented in the wiki (you should read that whole wiki, knowledge is power!) Those codes that is does support are done so in the same way that LinuxCNC does, as documented here and here. With that knowledge... we know that movement can be absolute or incremental we know that many of the things one can set are modal - once set they stay set until changed. Many things are set to defaults when the BB boots. We know that we have a Machine Coordinate System (MCS) and 6 Work Coordinate Systems (WCS) MCS is set by homing, if you don't have a limit switch you have to fake the home - search these forum resources if you need to do that. If I understand your use case correctly you will need to make multiple relative moves of the same length. This is what I would do: Switch on and home Mount the workpiece Jog to initial position and set WCS zero(1) Possibly finetune that zero by probing Load the code Code: G17 G90 G20 ; make sure of some modal settings G91 G1 X6 F120 ; move X by 6" positive relative to current position at 120 inches per minute, should take about 5 seconds G90 ; back to absolute mode, this is the default and is the safest repeat Do the main drilling Run the above code on the Interface gotozero can be used to return to the start point for the next workpiece if and only if there is a good fixture in place that ensures that the new workpiece is positioned with sufficient accuracy. Always check the zero! (1) GRBL does store the offsets, so, given and accurate fixture this setting will persist through power cycles. This means that if it is correctly set, all that might be required is a 'gotozeroX' to return the machine to the correct start position. I would always check that this is correct before drilling, the few seconds it takes to compare the position to a gauge is much cheaper than an incorrectly drilled piece of material. I would use a printed checklist to make this process is followed correctly if I am not using this machine personally. It works for airplane pilots, it works for machine tools.
David- thanks for the full instructions and coding. The rail will be used to position the part under the head. Since the part is 36" long and the CNC Mill table has 17" stroke. The rail will be used to precisely move the part to the next starting position. Joe
