I recently completed the build of a Big Ox/TinyG CNC. I set up the system using the great resources here: http://www.openbuilds.com/resources/how-to-setup-configure-an-ox-cnc-controlled-by-a-tinyg-v8.146/
I am having difficulties with the “smoothness” of operation. This shows up in two areas.
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When using the keyboard arrow keys to jog the machine, the x and y axis both exhibit a “stutter” when holding an arrow key down for a fast traverse. Since the z axis is so short, it doesn’t appear to be an issue. The stutter with the arrow keys seems identical the the stutter I get when running gcode with curves.
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When running g-code files that have curves being cut, the stutter becomes very pronounced. Here is a video: https://www.dropbox.com/sc/turs0xpi74i3k62/AACLdmaZm4uTwk-f8ewrCcAXa
The tighter the curve, the more severe the stutter and the slower the axis move. The axis movement actually stops and then restarts on very tight curves, also like it has run out of instructions (even with lots of buffering from Chilipeppr) Straight line cuts seem smooth.
I am running the system with a fairly new i7core Windows 10 laptop with all the latest drivers and upgrades. The laptop has 12gig of memory so performance of that aspect of the system should be fine… I have the latest firmware loaded in the TinyG. I am using the latest version of the JSON server. I have checked and rechecked connections and configurations. My homing setup works well and is reliable.
Beyond this, I have tried numerous things to address the stutter issue. I have tried running with no spindle mounted to reduce the weight to see if that made any difference… It didn’t; I have removed the Y-axis belts and monitored the steppers - the problem remains; I have gone into Chilipeppr and set the buffer to preload the TinyG with little change to the issue; I have reloaded the firmware; I have gone through the configuration file and reduced the values of $xjm, $yjm, and have tried reducing the cut speed… all with little effect…
I have ordered some shielded cable to re-wire each stepper, since I read somewhere that this can sometimes chase the gremlins away… Beyond that, I am at a loss.
Any ideas would be greatly appreciated.
My guess is there is some sort of clearance issue between parts when doing tight curves.
The confusion comes in with the arrow key movement. This is straight line and the same stutter occurs…
I’m not seeing this with nearly the same config tinyg included. Sure u have enough current for the motors? PSU big enough
Are your extension motor leads for your steppers soldered or are they connected with the crimp style connectors?
What are your trim pots set at on your tinyg it kinda looks like thermal overload
https://youtu.be/ERzIdQIwik0 at about the 9 minute mark he starts to show over and under current
@Alex_Krause The leads are crimped and soldered. I tinned the ends before crimping and then applied solder, so the connections are quite good.
The trim pots were tweaked using the Synthetos’ document. The video link you provided looks like a better/more accurate means of getting the current dialed in. I will have a go with that next.
@Glenn_West I am using the PSU supplied with the Big Ox kit I purchased from SWM3D so I am assuming there is plenty of current(the PSU runs quite cool as well so I don’t suspect overloading). As to the stepper current adjustment, I am going to try the method in the video link that A.K. provided.
Your test with the Y axis belts released pretty much says available current is not the issue, it takes very little torque to spin the bare stepper. Also, your machined pattern is correct, as I understand it. If you had current starving, you would lose position, due to skipped moves.
A quick experiment - go back to https://github.com/chilipeppr/serial-port-json-server#binaries-for-download and download SPJS ver 1.88 and see if the issue persists. Perhaps before doing that, open the Win Task Manager and watch the CPU usage for the SPJS process while running your Gcode, pay particular attention to the stuttering curves.
Of course, make sure you kill the currently running SPJS before starting the 1.88 process.
I am a little suspicious of your Gcode being a contributor, given that you have said that the Chilipeppr Logo ran without incident. Here a a long (21 minutes) file I know works, https://www.dropbox.com/s/5eoh0crfbo83sf3/ShapeOko_Calibration_Pattern_01b_cjm2_complete_2.nc?dl=0
Gode would not, of course, explain your stutter-while-jogging.
As a web guy, I have to ask, what browser are you using? Chilipeppr is a very intensive application. Try using Chrome if you’re using IE or Firefox.
I agree with Jace, CP is pretty demanding of the browser. I usually use Chrome, and have had good results with Firefox recently. IE? Never touch the stuff…
@Hugh_Griffin that’s an interesting one!
Forgive me if you posted elsewhere but what are your jerk settings?
[xjm] x jerk maximum 5000 mm/min^3 * 1 million
[xjh] x jerk homing 10000 mm/min^3 * 1 million
[yjm] y jerk maximum 5000 mm/min^3 * 1 million
[yjh] y jerk homing 10000 mm/min^3 * 1 million
[zjm] z jerk maximum 50 mm/min^3 * 1 million
[zjh] z jerk homing 1000 mm/min^3 * 1 million
[ajm] a jerk maximum 5760 deg/min^3 * 1 million
[ajh] a jerk homing 11520 deg/min^3 * 1 million
[bjm] b jerk maximum 20 deg/min^3 * 1 million
[cjm] c jerk maximum 20 deg/min^3 * 1 million
There goes that idea.
Can you manually create a gcode file by hand to do something like a circle or oval and ensure that its not your CAM.
I have been playing around with a couple files that seem to be running ok. I am still a bit confused by the keyboard arrow key movement. If someone else could weigh in on if their machines will jog smoothly with the keyboard arrow key held down…
Mine did the last time I tried (a while ago). My settings were G21 (mm mode) and move=1 (=1 mm)
What settings are you using?