LR3 Klipper Build - Anyone interested & willing to help?

Hello everyone,

Finally got my LR3 hardware and table setup with few modifications, i’m using klipper and managed to make the XYZ axis, endstops working for now. With spindle and vacuum triggered by SKR Pro using SSR relay.

300 cm x 160 cm foldable table (mdf epoxy resin coated) with full sheet spoil board.

Spindle & Vacuum on off trigger by SKR Board via klipper using SSR Relay

I haven’t tried milling anything yet, and am trying to figure out to the last part to add XYZ Probe and created a simple 3d printed XYZ probe plate coated with alum sheet. Wired it to and it works, i just cant figure out how to get the XYZ probing to work with klipper.

I’m following the guide from Are You Ready to Learn to Write GCode for Your Touch Plates? - YouTube and adjusting the gcode to klipper, the problem is that klipper does not support many CNC gcodes and i’m using the config macros i found from https://github.com/vladbabii/klippy-cnc. The only problem is that it seems that it has been coded long time ago and seems like is no longer maintained. (Especially the G38.2 gcode)

I saw some videos of people successfully using klipper in MPCNC, and it will be great if anyone experienced can share how i can get these working.

Now in case you wonder why i use klipper as opposed to marlin, i’m quite new to 3d printing and had only started one year ago, and started learning it in klipper so more familiar with it. I’m running 2 printer simultaneously with 1 Pi 3B, and trying to run LR3 using the same PI. (In case you wonder if it works, long cable pulled from next room, it worked but i think its not enough to run 3 machine at the same time)

I have few questions if anyone can help:

  1. For the Z axis, the endstop is at the top. I’m abit confused as i’m used to 3d printing. I got z height of say 70 mm. Should the top endstop be 0 or 70mm? Because i’m trying to figure how it works when we have gcode run thought it and afraid may make the mistake and ruin my gantry.
  • a) If it’s 0 at the top, and 70 mm bottom, does that mean when we mill, it goes say from 0 to 10 mm progressively down?
  • b) If it’s 70 at top, and 0 bottom (i setup like this now), does that mean when it mills, it goes say from 70 to 60 progressively down? Which one is correct a/b?
    Because in 3d printing, i got both setup, Z stop at bottom=0 (cartesian) or Z stop at top=0 (corexy). But milling is opposite of 3d printing as it mills from top, meanwhile 3d printing layers from bottom. sorry for these questions, i havent started in marlin and cant understand how it works.
  1. Please correct me if my understanding is wrong. For spindle, I have 48v rated spindle, and SKR Pro can only go for 24v. I can setup PWM directly to the spindle, but it can only go for max 24v? I cannot seem to find a way / device to trigger 48v using 24v pwm, so i resorted to simple analog switch using SSR, and using dimmer to control the spindle speed manually. Is there any device that is able to switch from 24v pwm to somehow control the 48v spindle speed using the SKR pro? Or only GRBL able to do that?

  2. My last option is to go for Marlin and the pre built V1 firmware. (that means an LCD that i havent bought, and learn Marlin), but i really hope i can find someone that has got Klipper running that can help before i give up on it. Here are a few things i may need to solve:

  • a) What are the CnC gcodes that probably need to be added to klipper https://github.com/vladbabii/klippy-cnc has a lot and i tried adding that but that seems like a lot (about 50 of them)
  • b) Amongst those, to get the XYZ probe i need G38.2, but it does not seem to work and it links to other macros from the klippy-cnc (i don’t understand the coding inside the G38.2.cfg, only understand basic gcode macros and configuring the firmware configs)
  1. Lastly, for the current V1 Marlin firmware, can we use the XYZ Probing? As i read so far its mostly Z probe. If anyone has done it and can share some guidelines / tutorials that will be great.

Sorry for the long post, i guess this is my important last hardware / software aspect i need to solve / decide on, before moving on to probably learning the cam software. I hope anyone experienced can share their experience before i discover deadends. Thanks you everyone :slight_smile:

2 Likes

I have never used klipper, but I want to follow along to see what the solutions are.

1 Like
  1. In Marlin, we have lower Z go down. The homing operation goes up on the LR. Marlin thinks the top is Z=200mm (which is wrong). But that is ok, because we force Z=0 later with a Zprobe, or manually with G92 Z0. I usually want Z=0 to be the top of the workpiece, but other people like it to be the top of the spoil board. You can decide for yourself, but make sure your CAM knows what you want.

b) My setup is zero at the top of the workpiece. If I am cutting 12 mm stock, I cut to -12.5 or so.

  1. This depends on your spindle. Some spindles can accept a 5V pwm signal as control. There are level shifter circuits (and it would be a good idea to get an optoisolated one) if your spindle can’t. Be aware that the skr 24V fans and heaters don’t switch the 24V side, they switch the ground side. But you can use any 5V pin with a level shifter. Do your own research though. I don’t know your spindle.

  2. I haven’t used Klipper for CNC. But I can say we don’t use most of those. A lot of those are to make it more like grbl. Most gcode is easy to read. It has some setup, it has a bazzilion G1 commands, maybe some special code for bit changes in there, and some finishing commands. You can look at the gcode in the test crown for example, or do some of the estlcam basics and see what that ends up as.

G38.2 is tricky. Because we use that in Marlin for the low rider. In our Marlin setup, that probes down, until the Z touch plate closes the probe endstop. Then backs off 5mm (IIRC). You can combine that with G92 Z5.5 to set the Z height to the top of the workpiece. You can spend as much time as you want working on macros. They are a fun part of klipper, IMO.

You don’t need any of that though. You can cut right away with G92 to force the Z to be zero while the bit is touching the surface.

You also don’t need the screen to run marlin. My current setup is octoprint and an skr running marlin.

  1. Nope. Only XYZ homing and Z probing. XY probing isn’t that useful, because you still have to align the workpiece, or probe multiple points on an edge to adjust for twist.

An easy workaround is to use the CNC to cut some dowel holes in your spoilboard and then use the dowels to align the workpiece. It will be square and a known distance from the endstops.

2 Likes

Thanks Ryan. A lot of people may find it harder than Marlin, i guess because they are used to Marlin. I find klipper easy to use, as i have a fresh start. Kinda like how it is monitoring my prints with timelapses wirelessly thru phone.

And the best experience i had was that i turned my 10 year old crappy printer that was using Marlin that i gave up on, and manage to run it on klipper almost as good as my new coreXY Ender 6 only running on ramps mega.

Its cool that so far i only find V1Engineering using Marlin for CNC, and thats what actually got me started as its not too far from my basic understanding of 3d printing. When i read about it first time, i gotta build one for sure. If it was GRBL or Mach3, i think i would have passed.

Hopefully there may be addition to people who may use klipper on MPCNC or LR3 who can share as i saw some people who have done it.

2 Likes

Thank you so much Jeff for the clarification. That clarifies most of the things i have problem with.

  1. So it shouldnt really matter i guess, i can easily switch it. Will test it out.

  2. Ahh ok. I think my spindle are the basic cheap ones so shouldnt have that. But cool, will find out what are level shifter circuits.

  3. Oh cool, so not really needed. Am not trying to make it like GRBL. Just probably some useful Gcodes i may need.

  4. Z probe should be easy, not much different as using BLTouch etc. I dont use Octoprint as i think it may be heavy load on the PI after reading. So im using both FluiidPi and Mainsail in the same machine that i can switch whichever interface i like, to control as many device as i can. I had to figure that out the hard way as not much tutorial but work like a charm running 2 prints on budget.

Cool, thanks for letting me know, i just saw that XY probing looks cool and never tried yet so may proceed without that.

Thanks a lot for the ideas and clarification. I guess i should start without the G38.2 on manual for now to test how it goes. G38.2 is something cool that probably saves a bit of time for me to setup initially (like… after using BLTouch, never again im going manual levelling)

Thank you for the answers. If anyone interested in the configs to test do let me know. In the mean time, im gona try manually and hopefully have some other who can help with the G38.2.

2 Likes

There is some weird thing where the klipper fans (not really core klipper, mainsail and fluidpi fans) attack octoprint. But it isn’t slow or a heavy load at all. I run octoprint with my klipper and it is super reliable. It is a shame that they attack octoprint. They can do a lot more working together.

2 Likes

Oh i see. Octo have many useful plugins but i didn’t get to try them cause started on Fluidd and Mainsail. Not a hardcore fan myself, just reading and deciding on what to use early on. May want to try Octo later.

How do you setup octo and skr running Marlin at the same time btw? The firmware is Marlin right? Then what do you use Octo for if klipper not installed?

Is the G38.2 prebuilt into Marlin or you programmed into it?

Octoprint sorry of replace the screen. It holds the gcode files. It has controls to jog the machine. You can send clans and read responses on the terminal/console. You can set up macros.

Jamie made a cnc gcode preview plugin to make the gcode preview work for cnc gcode.

Marlin still does the heavy lifting. Klipper alone (the mcu and host code combined) is similar to marlin.

Octoprint and marlin are separate projects. I have one octoprint on my klipper printer and one on Marlin. They aren’t coupled like klipper and mainsail are.

It is built into the marlin firmware. We had to turn it on. The firmware at MarlinBuilder releases has it enabled (on the DualLR, at least)