Gantry Upgrade to C-Beam

To make the wiring easier I found a few different shield kits that add screw terminals.
And even cheep some pre-assembled knock offs.

I also found these wing versions. But I like the shield style better. I think the wings could be more prone to flexing under any weight/pull from the wires.

I got the new bolts to replace the pulley set screws.
One side swapped out easily.
Unfortunately the other side I did too good a job the last time I re-seated them. When I tried to remove then the alien holes striped out. :frowning:

I guess if that they are that tight they don’t need to be replaced yet?

I re-did the previous carve and the machine seemed to be carving much better. I am not sure if it was the new set screws, making sure the gantry was parallel (this might have been the issue before as I have gotten out of the habit of re-setting it every time I power up the machine), or the adjusted cut settings made the critical difference.

Thanks I will give that a try.

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I got the basic wiring done and tested it out the new controllers with one of the new motors. All the axis are working properly. :slight_smile:
Those new motors are strong!

It took me a bit to get chillipeppr to talk to the controller, but it was a simple configuration issue. once I got the settings correct it worked fine. It took me a bit to realize you could only change the communication setting when disconnected from the controller. After that it was just a mater of selecting “grbl” from the drop down menu.

I am really going to miss TinyG’s work coordinates though. They remain in memory, even when turned off, so if a print went bad I could just re-home and start over as it would remember the work zero. Also being able to home individual axis was nice too.

The next step will be to install the new motors and connect the new controller. I got some larger cable chain, the kind that opens for easier cable running. So if I am feeling ambitious, I can re-do all the wiring.

After a bit more research I found a chip that will covert the 3.3v output to a strong enough 5v output to drive the controllers and relays.
So if I want to stay with the TinyG, I can get a Arduino Due, (or knockoff as I think it has been discontinued) Load G2Core on it, and make my own shield to adapt the pin out voltages.

I may wind up doing this, especially if I ever add a 4th axis.
But for now I will stick with GRBL.

There’s a way to do this in GRBL (probably the same way TinyG does it). You have to use the G5X coordinate system and it’s saved to EEPROM. From https://github.com/gnea/grbl/wiki/Grbl-v1.1-Commands:

“G-code parameters store the coordinate offset values for G54-G59 work coordinates, G28/G30 pre-defined positions, G92 coordinate offset, tool length offsets, and probing (not officially, but we added here anyway). Most of these parameters are directly written to EEPROM anytime they are changed and are persistent. Meaning that they will remain the same, regardless of power-down, until they are explicitly changed. The non-persistent parameters, which will are not retained when reset or power-cycled, are G92, G43.1 tool length offsets, and the G38.2 probing data.”

I’ve not used it but I don’t see any reason why you couldn’t use it as standard practice. EEPROM write cycles should be relatively high.

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Did you need to load a config to the uno? Or what was the set up process? I understand the wiring. Just trying to figure the technical side.

Yeah you need to load the TinyG code into it. G2Core is what it is called now. (It is GRBL’s big brother. It works the same, just with a lot more configurable variables and more info available to be relayed back to the host computer if requested.)
From what I can tell the TinyG controller is basically an uno with a gshiled built in.

GRBL supports G10 L20 Px (x=1~6 for WCS 54~59) which is persistent. G92 is not.

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If you use bCNC as your sender, it has buttons for the work offsets G54-G59. The offsets all seem to be persistent through power cycling.

Update: I installed the new motors. It was pretty easy for the most part, except for the one pulley with the striped out set screws. :frowning:

I messed with it. Tried packing it with foil, bigger Allen wrenches. No joy.
I drilled it out with a smaller bit, that let me slip it off the old motor.
Using a tiny flat head screwdriver I was able to get one of the set screws out.
But the other wouldn’t budge. I drilled it again with a larger bit and while doing so the drill spun it free. :slight_smile:
I may replace it later anyway, in case the treads are messed up and it doesn’t hold properly, but at least I have something so I can finish setup and testing.

After I got it the new motors all installed I powered it up using the TinyG. Even with the lower current output of the tinyG these motors are a lot stronger. Pulling on the Y gantry as hard as I could I was barely able to make it slip. at full power I think the belt would slip before the motor does.

Next step will be to wire in the new controllers for testing and calibration.

You can drill it out and tap it one size larger. Hold the pulley in vice grips while doing so. THey are easy to tap and the larger set screw is helpful.

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Update: I got the router relay working and ran the wiring for the homing switches. I still need to hook them up.

I updated to the newer version of GRBL and re-set all my variables. Now I just need to calibrate my steps (I probably won’t need to adjust my setting much, if at all.)

If all goes well I will carve some MDF signs this week. :slight_smile:

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I got carving last night. I had nothing but problems :confused:
My axis step calibrations were WAY off. It took me a bit to re-calibrate them.

I updated GRBL to 1.1 - and the chilipeppr interface for it is buggy.

First you have to use a different build as the GRBL version of chilipeppr won’t work (took a bit of Google research to figure that out)

Second, there is a bug so chilipeppr displays in Inches when in in metric mode and vice versa.
Manually re-setting $13=0 fixes it. But you have to do it every time.

Third, the chilipeppr pause button doesn’t work. Manually sending a “!” does.
I do plan on wiring up actual buttons (Pause, Resume, Reset) - I already have the switches I just need to design the panel.

Finally, GRBL is so much more clunky compared to tinyG. I am going to go over my settings, but with GRBL the carve slowed down to a painfully slow rate as it cut a particular curve. It was done as a series of straight segments (dozens?) and it was start/stop, start/stop, for each one. Rather than moving through them at a constant speed.
I am going to go over my settings a bit more to see if there is a parameter that will fix this. But UGH.
If someone would just port TinyG to some 5v hardware I would switch and not look back.
I don’t know if it is worth the hassle of making my own 5v to 3.2v interface or just living with it until can afford to switch to Mach4 and a Ethernet board.

Reference:
I have been trying to figure out how to manual set the machine home position in GRBL
Short answer, you don’t.
I got used to TinyG letting you set it by using a G28.3 command (via a button in chilipeppr). This is not supported in GRBL

I am trying to adjust my workflow to have the X and Y zero point persist between cut operations as the only coordinate reset button on the GRBL chilipeppr is G92.
The way I did it for last nights cut, was to line up the bit and hit the reset button on the Arduino.
I guess I will get homing working and try manually using the G10 L20 command.
But that seems clunky.
If I am going to have to do a bunch of manual commands I may go back to UGS. Then I can at least set up macros.
Although I do really like having chilipeppr text me when a job is done.

Before resorting to a java gui, try something in python. bCNC is ligher, faster and more feature rich (plugins and macros and shortcuts, oh my).

From the GRBL wiki:

An advanced fully featured g-code sender for GRBL. bCNC is a cross platform program (Windows, Linux, Mac) written in python with minimal external dependencies. The sender is robust and fast able to work nicely with old or slow hardware like Rasperry PI (As it was validated by the GRBL mainter on heavy testing).

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+1 for bCNC!

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and also like to mention that Bcnc also has an auto level function that most senders do not have. very handy when working on fine detailed engraving on metal.

No. I didn’t realize you had one! I will have to book mark that.

Yeah it turns out my $11=0.000 - whoops! No wonder it was so slow!
I set it back to the default of $11=0.010 :wink:

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