Differences

This shows you the differences between two versions of the page.

--- openbuilds_cnc_machine_2018 [2019/05/01 21:05] – [Electronics] tell
+++ openbuilds_cnc_machine_2018 [2021/08/02 22:37] (current) – [Electronics] tell
@@ Line 5: / Line 5: @@
 Based on the C-Beam Machine kit from Openbuilds.com: https://openbuildspartstore.com/openbuilds-c-beam-machine/
+{{ cbeam-openbuilds.jpg?200 }}
 Steve and Jeff assembled it following the video on https://www.youtube.com/watch?v=HVR8pABCHXI
@@ Line 21: / Line 23: @@
 The interface board also has inputs that can be connected to limit and emergency-stop switches.
-There is no schematic that I've found for the interface board, but the signals are connected as follows, according to silkscreen text on the board:
+The interface uses the [[CNC Parallel Port Mapping | parallel "printer" port signals]] to control the stepper motors.
-^ DB25 connector pin      ^ PC Parallel Printer Port Signal      ^ CNC control function         ^
+The interface board is cabled to the parallel printer port on a PC.  The parallel port must either be on the motherboard or on a PCI expansion card; USB control is not possible (see the linuxCNC documentation).
-| 1                       |    C0                     |   unused     |
-| 2                       |    D0                     |   X step     |
-| 3                       |    D1                     |   X Direction  |
-| 4                       |    D2                     |   Y Step       |
-| 5                       |    D3                     |   Y Direction  |
-| 6                       |    D4                     |   Z Step      |
-| 7                       |    D5                     |   X Direction  (unused)    |
-| 8                       |    D6                     |   A Step      (unused)  |
-| 9                       |    D7                     |   A Direction   (unused)    |
-| 10                      |    S6                     |   E-stop     |
-| 11                      |    S7                     |   unused?      |
-| 12                      |    S5                     |   (X axis limit)      |
-| 13                      |    S4                     |   (Y axis limit)     |
-| 14                      |    C1                     |   Common motion enable  |
-| 15                      |    S3                     |   (Z axis limit)      |
-| 16                      |    C2                     |   B Step      |
-| 17                      |    C3                     |   B direction or Spindle Enable      |
-The interface board is cabled to the parallel printer port on a PC.  The parallel port must either be on the motherboard or on a PCI expansion card; USB control is not possible (see the linuxCNC documentation).
+====== First Motion ======
-If curious, more parallel port information is at https://en.wikipedia.org/wiki/Parallel_port
+The machine first moved its motors in June 2019: https://www.youtube.com/watch?v=QzRUWVw7nxc
+(This is from the motor test function in the linuxcnc setup program, which moves one motor back and forth at high speed.  The test is OK if the motion is smooth and repeatable)
 ====== Control Software ======
@@ Line 55: / Line 42: @@
 LinuxCNC's job is to take a file containing G-Code instructions, and feed them to the stepper motors to move the cutting tool along the paths specified by the G-code.
-====== CAM Software ======
+====== Simulate before cutting ======
+Before running a g-code program on a real machine to actually turn metal into shavings,
+we can simulate that program to make sure that it does what we want.
+[[https://camotics.org/|CAMotics]] is a nice, free g-code simulator that installs easily on windows and recent linux.
+====== CAM Software ======
 To be determined.
 Simple G-code can be written by hand. https://en.wikipedia.org/wiki/G-code
+There are simple g-code generator python scripts at https://github.com/LinuxCNC/simple-gcode-generators
+The output of these is easy to understand, and will be some of our first trials.
+But to really make parts, we need a true Computer Aided Manufacturing (CAM) tool, that takes a 3-d model from CAD and turns it into the long sequence of cutter moves described by g-code.
 We can get a free/student version of MasterCAM with a voucher code from FIRST