Run Your Second Job
Let's see what we have done:
- Unit assembled?
- Electronics connected?
- Software installed?
- First job run?
If you've met all three of those criteria, then you're ready to run your next job!
This is the fun one, because now you actually get to make a thing. You can really ShapeOko for the first time!
- Open up GcodeSender (Windows) or Universal-G-Code-Sender (Mac / Linux / Windows).
- Select the correct com port from the dropdown menu on the left. Mine is COM17, yours is probably COM3 or COM4. If you plugged in your arduino after launching gcode sender, just hit the refresh circles next to the dropdown menu. That will rescan for new hardware.
- When you've connected to your arduino you'll see something like this: $ dump settings. GREAT! That means we're talking to the arduino.
- you might have to toggle the /n/r /n options at the top.
- Go ahead and type '$' into the input box. This will dump GRBLs current settings to the screen.
- Assuming you have set 8x Microstepping on the X&Y axis and full step on the Z Axis:
Your settings should look like this...
Grbl 0.8a '$' to dump current settings $0 = 43.74 (steps/mm x) $1 = 43.74 (steps/mm y) $2 = 320.00 (steps/mm z) $3 = 30 (microseconds step pulse) $4 = 500.00 (mm/min default feed rate) $5 = 500.00 (mm/min default seek rate) $6 = 0.10 (mm/arc segment) $7 = 28 (step port invert mask. binary = 00011100) $8 = 25.00 (acceleration in mm/sec^2) $9 = 0.05 (cornering junction deviation in mm)
If something isn't set correctly, you can set it by typing the value you want (e.g. $0=87.49). Settings are stored in EEPROM and will be retained when the Arduino is turned off.
- Move the z axis to the middle of the work area we'll call this 0,0,0
- Now, if you're ready, turn the power on to your Power Supply. You should hear a very satisfying "click" and "whooooosh" noise as your steppers engage. Great! We have power.
- Type X10 into the input box and press enter. If everything goes well, your X axis (left and right) will travel 10mm to the right! Whooohooo! Hello World.
- Type X0 into the input box and press enter. Your X axis should move to the left to return to it's starting point.
- Do the same thing for the Y and Z axis. The Y axis needs to move to the back for positive values and to the front for negative values. For the Z axis, positive is up and negative is down.
- If your axes move the wrong way, you need to play around with the inversion bit setting of your Grbl (Setting $7)
- Spend some time playing around with your machine.
Helpful G-code instructions
- F = feed (this is your speed). So something like F1100 would be 1100mm/minute. F100 would be 100mm of travel per minute. If you do not specify an F setting grbl will either use the last one entered, or if you do a G0 it will resort back to your default seek speed.
- Example: F100 Z-10 (move the z-axis down 10mm)
- G20 = inch mode (if you enter G20, then all units after will be interpreted as inches. Be careful when switching back and forth. It's easy to overrun the axis. If you feel like you might hit an edge, just press the reset button on the stepper shield! That will stop the machine and prevent any further movement until the next command is entered.
- G0 - this tells your machine to go as fast as it can (default seek speed) to whatever coordinates you're entering.
- Example: G0 X100 Y100 Z-25 (move the X and Y axis 100mm in the positive direction, and the Z axis 25mm in the negative direction (down)
Drawing in the air
Got the hang of it? If you think you're ready, let's draw some stuff, in the air.
(Here is the sample file we'll be working with: Hello World ShapeOko)
- Browse for the sample file using the browse button on the right hand side. Find the file and open it.
- Move your machine to the center of the work area
- Be sure your z axis is at least an inch above the table.
- Press the reset button on the stepper shield (this will essentially home the machine - 0,0,0)
- Take a deep breath
- Click "Print"!
You'll see GCodeSender start streaming the text file line by line to the arduino. Once the arduino received a command, it will start interpreting the gcode into step and direction pulses to be sent to the pololu drivers. The pololu drivers will in turn move the stepper motors in the correct direction and speed.
Sit back and enjoy. Try to listen to the machine and get used to what it sounds like under regular conditions with no load. The more you're in tune with how the machine sounds and acts, the better you'll be at troubleshooting and figuring out how to solve problems. This job should take about 2 minutes to run. notice how in between "letters" the z-axis comes up a certain height, then "rapids" to the next location before going down. That rapid is also refered to as your "Seek Speed", it's one of the variables defined when configuring grbl. If it's too fast, you risk loosing steps and/or stalling the motor completely. Seek should be quick, but doesn't have to be blazing fast.
Drawing on paper
Now that the "air job" has finished. Let's move on to Phase 2: A ballpoint pen (or sharpie marker).
- Use a piece of duct tape (or any tape really) to tape a ball point pen or sharpie marker to the z-axis extrusion. make sure the pen's point is below the bottom of the extrusion.
- After our pen is mounted, go ahead and slowly move the z-axis down until the pen is barely touching the paper. It should be right in the middle.
- Once you're satisfied with the pen's height, press the reset button to home the machine.
- Take a deep breath.
- Press the print button.
Sit back and watch as the machine draws out the gcode. This should sound and "feel" a lot like the "air job" we ran earlier. There's really no forces involved here other than gravity and friction, so things should run pretty smooth. The gcode was generated with an F of 60ipm. (G20 F60). That's pretty fast, a little faster than we would run if we were actually cutting something.