Hi there, I have a project that requires me to drill 15- 135" dia holes in the fixture's base. I have 34" long piece of Aluminum Angle iron that needs to have those holes spaced 60mm apart along its whole length. My CNC Mill's 'X' axis will traverse only 15". I plan to mount another CNC table on top of the machines table. I have done the 'drill so far, then slide the piece down' , reset the machine, and then locate the last hole and proceed from there, route. The auxiliary table will be CNC controlled so I can traverse that table to its end and then start using the machines controls to finish the job. I am looking for a CNC controller board to put in my computer and use it to drill those first holes. This will be only one axis and I will also need software to control its motion. What exists that I can get to connect from my PC to the stepper motor on the aux. table. Thanks, Joe
Just pass the piece through against a fence, using Tiling https://m.youtube.com/watch?v=nHH99VN4JuI Tiling is used all the time for pieces bigger than your work area
You can use a BlackBox which connects to the PC via USB. Connect a motor only to the X driver. Generate suitable Gcode to drive only the X as you need it. This is not what I would do though. I would attach a backing plate to the existing table and drill a hole in it 1 hole spacing to the left of the first hole in the part. Put a pin in this hole. Maybe also mill an alignment ledge into this fixture. This initial hole is X0 Y0 Generate Gcode that drills the other holes (to the right) using this hole as 0,0 move the part to the left and hook the last hole onto a pin in this initial hole. run the program again. repeat.... This way the only careful aligning you need to do is for the first run where you need to make sure the position for the first hole in the part is 60mm to the right of the pin. I would carefully make a spacer that goes between the pin and the end of the part. Toggle clamps will greatly assist in making this a fast easy process Horizontal Toggle Clamp Straight Base All Arm Types
That is interesting idea. I have thought of doing the same type of thing. One Question-Can the C beam X large linear activator be customized to use a specific lead screw? I found out that if I were to use a 5 turns= 1" ball lead screw and a specific stepping motor, I would be able to attach the 'X' axis feed off the machine on to motor. In so doing give the machine a longer 'X' axis with all the CNC controls.
yes of course you can. The combination of motors steps per rev, driver microstepping, leadscrew pitch, and any gearing between motor and leadscrew is boiled down to a single value, the steps per millimeter The controller uses this value to convert from 'move X 20mm' to 'move this many steps', all internal math. All you have to do is calibrate. Calibration can start with known values and then refine that theoretical value. So a LEAD machine has 200 step per rev motors, 8x microstepping, and 8mm per rev leadscrews. 200*8 (steps per rev) / 8 (distance per rev) = 200 steps per mm. You tell the controller that value. Then you calibrate because leadscrews are never spot on accurate because of the way they are made, ones we can afford are rolled, and that means the pitch is a little short or a little long. One can also start with no known values. You can set steps/mm to 1 and do the calibration process. By the 3rd iteration you will have a 'good enough' value for steps/mm. I did this with an old cable drive printer mechanism and it worked perfectly. I should make a video (-:
I have been thinking this project through and decided that I could use the C Beam X large just as it is to only move the piece into different position for the regular CNC to do its job. What would be the necessary parts to make the linear activator move? I saw an interface that would have everything that I need to do the movements. Do I need something else between that interface and the stepper motor? I would like a closed loop system. The part would be mounted on a fixture mounted on the linear activator. Thanks, Joe
Interface is just a "user interface". See docs.openbuilds.com and in particular docs.openbuilds.com/blackbox and docs.openbuilds.com/interface
