Fix Backlash - CNCnutz Episode 222
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- Опубліковано 12 вер 2024
- For more information, the Macro's and other resources used in this video please visit:
www.cncnutz.co...
Following on from the last video I explore further the problem of backlash on our CNC machines and how we can use backlash compensation to fix it. Before we start we first need to now what Backlash is and what causes it.
Put simply backlash is the effective loss of steps when an axis changes direction. These steps are used to take up the slack in the system before it starts moving in the opposite direction. These steps are not translated into movement in the axis so it doesn't travel the full distance. Backlash is non cumulative so will not increase as the cut progresses.
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I hope you enjoy.
It’s almost 3am here... how did you know? 😜
You can rest easy now.
Cheers
Peter
Underrated Comment in an underrated video :) (I was expecting it to have way more views). It pains me to live in a world that doesn't care about backlash!!!! Great video and thanks for sharing your experience/knowledge!
@@R3N0T3 title must be modified
Very well done Peter, your macro saved me lots of hassle.
Thanks Zulfqar glad it helps.
Cheers
Peter
Sorry you may not had a lot of views yet on this video but for us who do watch, Thank you! Very good info and very much appreciated! Cheers
Thanks Shaun. It normally takes a couple of days for the views to get to what I would call the initial watched level. Given the different time zones and the fact I release it while most of my audience is still in bed. it takes a while.
cheers
Peter
Peter, Thanks for the great calibration videos. I just got around to doing the backlash. Before I started I noticed a very loose Y axis which I was able to fix quickly. (I wouldn't have found unless I was fiddling around... thanks) Next I did the x axis that looked great. The Y axis needed a bit of backlash and the Z was spot on. Love the videos and enjoy your humor. Keep them coming. Next stop- new pendant, ordered a few minutes ago (PS4 made by VistaCNC).
Thanks Dave.
Peter, Excellent. I have thought about the backlash but never knew how to start to measure it or fix. I'll be heading down to the shop in the morning. Thanks.
Dave
Good one Dave.
Thanks again for another great tutorial
Great video Peter. This is the best video I have seen on backlash to date. I might be a little biased, but Excellent Job.
+John Revill
Thanks John. I think your allowed to be bias. 😉
Cheers
Peter
Peter, THANKS! I had some lingering issues with my machine, and backlash never crossed my mind. Z and Y were perfect, but X was really sloppy.
Happy cuts to you!
Good one Rick. You will be away and laughing now.
Cheers
Peter
Many thanks - I had done this manually a couple of times but this makes it so much easier to replicate and confirm the results...
Thanks Neil
The macro certainly makes things easy. Hopefully ask tested good.
Cheers
Peter
Great job Peter! Heading to the shop now to give it a try.
Thanks Rusty.
The thing I dislike the most about digital indicators is whenever I need to use one the battery is usually dead. Thanks for the informative video and the Mach3 macro.
I know what you mean. Everything has a battery these days and they are all flat.
Cheers
Peter
CNCnutz (Peter Passuello) I have seen a lot of round and rectangular batteries as well 😀, not just flat 🤗
Thank you sooooooooo much; you saved many 1000's hours for people
Thanks Vivart
my back has some backlash when i bend the wrong direction. Good video man
Thanks Frankie.
That's a nice way of dealing with backlah.I wish that would be a macro for centroid .Great job.
I just uploaded a Gcode version of the Backlash test routine and added it to my writeup.
Follow the link under the video.
Cheers Peter
I added backlash compensation to my machine because I was getting a positional error while doing inlays. X and Y required a .013 (imperial) entry to the backlash compensation in the Mach3 machine. after restarting I got backlash down to .001 which was ok for me, but I then ran a test using a 10-degree engraving bit .0100 deep, and at each quadrant, the backlash compensation corrected the position and had a jagged movement to correct for the backlash. Backlash measurement only measures it in the axis understudy so a multi-axis move may be aggravated by the compensation. Further research in Mach 3 manual said that using this method should be the last step. it trying to correct for backlash if all other steps failed. I was hoping to correct my backlash in software but learned that must resolve why I have the physical or mechanical problem first. I think it is the nut that is the main culprit, and I am researching that now. Thanks for your series, I enjoy all the episodes you produce. --Ken
Thanks a lot! Brilliant video
That dial moved 3 micron! I'm a service engineer and wouldn't worry about anything less than 10 generally on a 250k machine so for the hobbyist I'd say anything less than 0.1mm is perfectly acceptable. You have too many factors (encoder accuracy, dial accuracy, motor accuracy, etc..) eventually there comes a point where your fighting against each one. So to chase less than 5 microns you would be there a long time and may never get anywhere because of those other factors!
In context the average human hair is 60 microns 0.060mm!
Great video by the way!
Pete, you are a genius.Thanks for sharing.
Thanks Manny
I can't really take credit for a file someone gave me and explaining a subject older than I am but thanks anyway.
Cheers
Peter
Good shit Peter I am going to give this a shot next week. hopefully, I can get the same results. the temp of the day can make a difference.
Thanks Daniel. Good thought about the temp especially on hot days and cold nights. I'll worry about that when NASA comes calling for my services. 😉
Cheers
Peter
don't you mean rock lab LOL
I have tested backlash on an 8degC morning and 35DegC Day and on my setup at least, I don't see a measurable difference in backlash.
Thanks for letting us know. We thankfully don't get that type of temperature here. 30 is about as high as it gets here and that's far too hot for me. Mind you below 20 is too cold.
Cheers
Peter
Thank you for another great video and your macro !!!
Thanks Stephen
That looked like a lot of macros in your Mach3 folder. Fancy doing a video on them and sharing any good ones 😀. Please 🙏. Cheers
All the Macrors you saw in my folder are the default ones that come with Mach3
Ihave absolutley no idea what most of the do but the ones with nimbers below 100 are the M codes used in Gcode. eg M6 for a tool change.
Cheers
Peter
Great video.
Thanks Robert
Excellent, Peter! Thank you!
Thanks Geert
Great tutorial! Thanks! Found you by my viewers' suggestion. :)
And thanks for the macros! I'm using UCCNC and need soon to make final adjustments to my BIG cnc machine I've built. You can check the videos from my channel if you like.
Great information Peter.....thanks
Thanks Grant
Hello, thank you for your script. I need community advice. I'm setting up the backslash in the settings, saving it. Then I'm doing Save Config. Then I'm restarting Mach3. I double-check, and there are no changes. No matter what value I enter in Backslash, there are no changes.
Hello Peter can you please tell me where you bought the rack and pinion drive .
Thanks much Peter... gonna try this on mine. I don't even have a hairless cat either!
Thanks Lyle. Neither did I until recently.
hello peter, thanks for the great video! i'm a mach3 user i'm getting crazy cause i'm not able to find any usb motion controller that support backlash compensation in mach3... do you have any suggestion? should i opt for an ethernet controller???
Good tutorial. Refreshing.
Cheers.
Thanks Pierre
this is a really nice video. is there a way to take this software and use it in the openbuilds software program? i use the blackbox and it dont have backlash option.
I just added a Gcode version of the backlash script that will work with any machine.
You can download it from my website. Follow the link under the video.
Cheers Peter
Good video.
Thanks John
Hey Peter, I've been having issues with my Gatton and zeroing. I did your backlash test and I have about 0.002 even tho I have backlash nuts. When I go to try and fix it in the mach3 backlash settings, it doesn't change anything....any ideas?
What does khz mean on cnc board?
Great video. I have a Shopbot Buddy PRS alpha that uses Shopbot 3 software. Is there a macro available for backlash testing that would work in my control software?
The macros I showed were custom written for UCCNC and Mach3 by John and myself. To the best of knowledge there is no similar macros but I am not familiar with shopbot software.
Cheers
Peter
So going from one direction to the other, does Mach 3 add additional steps to take up the backlash and not calculate them in position?
It adds the additional steps to make the distance travelled correct.
Cheers
Peter
How have you found that .001 indicator? Is it actually any more useful than the .01?
I only just bought it so other than the last 2 videos I haven't used it for anything else. Maybe in the future I will find other uses but not really sure if I will need the extra resolution.
Cheers
Peter
I understand how the system compensates on direct x,y or z movements, but if your moving diagonal or circular motion and reverse direction does it compensate by ratio/percentage of the backlash? Cheers
Yes it does. It doesn't matter what direction you move. Before an axis can change direction it has to take up the slack in the drive so the backlash figure is exactly the same wetere ou are moving straight or diagonal. there is no percentage.
Hi I am next door from Australia I have a program running right now can you please let me no how I can stop it and continue tomorrow I am using mach3 thanks👍
Hi trent
Watch this video on stopping and starting Mach3
ua-cam.com/video/x6gvNP2paCo/v-deo.html
The short answer is press the feed hold button and when the machine stops moving turn off the spindle. Do not turn off the machine.
Cheers
Peter
Great vid Peter...!
Thanks David
You're not fixing backlash here. The problem isn't only that it won't go back to where it was, but also that it's backdrivable the backlash length. E.g., maybe your z measurements show 0 backlash because your gantry is so heavy that it'll just backdrive itself down, but as soon as you start to actually cut something, that will push it up by the backlash amount. Or if you have some backlash compensation in x, but as soon as you put pressure on it it'll move by the backlash amount in the backdrivable direction. In these cases backlash compensation does nothing. So it basically only works if your router is so massive with so much friction that it will completely overwhelm the cutting forces.
BTW: Link to the digiDial is no longer valid.
Thanks. That's the problem with specific links to sellers.
No more “whip” this week? 😋
Whip free 😉
it's a very useful video, but it's on the wrong software. I'm sorry, but the "UCCNC" sales support consists of cheap marketers. It is difficult to understand how such a legless and lying sales and support team was put in front of such successful hardware and software.
Excellent, Peter! Thank you!
Thanks Mark