[stumpxj]

Ok, question on my next post.

[stumpxj]

Ok, so I have been on a heck of a steep learning curve trying to get all this CNC stuff figured out, and have learned a lot -but now I need some help.

I have basically just gotten finished converting my BF-20L / G0704 milling machine to CNC. I just installed the ball screws, and motors/drivers/power supplies etc etc etc...

I have the motors/tables moving just fine, but need to tune everything in like it should be. First, here is what I am using:

Mach 3 software
BF20L mill
36volt power supply
Keling KL6050 drivers for all Axis (info HERE)
Keling KL23H284-35-4BR motors (more info HERE) I use these on the X and Y axis.

For the Z axis, I use a Keling KL34H280-45-8A motor. (more info HERE)

On all axis, they are direct connection to the ball screws, no reductions.

My ball screws came from this guy, they are the same as in this link.
3 anti ballscrews RM1605-450/1000/1000mm-C7 for CNC router | eBay


I have looked on the Keling website about how to tune in Mach 3, but I am not getting the correct numbers. Its simple math, only if you have the variables.

I KNOW the motors are 200 steps per rev. (this is the ONLY thing I am sure of)

I DONT know the step resolution of the motor driver. (is this 1/8 or 1/2??, not sure if those are the numbers I use, or something else. Most other things I see are whole numbers i.e. 5, 10, 20, etc., not fractions.)


I also DONT KNOW the thread pitch of my ball screws. I *think* they may be 5mm, but dont know for sure. It didnt say anywhere on the package or the sales ad what they are, but have read on here that they could be 5mm. The are the same as the other 1605 screws I have seen.


I am trying to make sure I have all of this stuff correct so I can configure my Mach 3 and tune my motors.

Also, do I set my Native units to MM or English? I often use both when machining, is one easier to use for set-up tuning purposes based on the info given above?


HELP ME! Thanks in advance. ~ James "Stump" (<more like 'stumped' right now...)

[hoss2006]

The driver will be either 1/2 or 1/8 microstepping depending on what you set switch 4 to.
If you set it to 1 then it's 1/2.
The screws are metric so technically 5.07 tpi so in this case the steps per would be
200 x 2 x 5.07 = 2028.

1/8 microstepping would be 8112 steps/per.

Set your native units to english (inches)in this case.
This is letting mach know how many steps are needed to move 1 inch, metric you would calculate how many steps
to move 1mm.
Hoss

[stumpxj]

Hoss thanks a TON for all the help you offer us new guys with this stuff, your videos and websites have been instrumental in getting the project into the final stages for me!

Thanks for the information, that is very helpful. One question, which would be 'better' 1/2 or 1/8 microstepping? Does it matter?

~ Stump

[hoss2006]

1/8 should run a little smoother and quieter.
Hoss

[corderopilot]

Hoss thanks a TON for all the help you offer us new guys with this stuff, your videos and websites have been instrumental in getting the project into the final stages for me!

Thanks for the information, that is very helpful. One question, which would be 'better' 1/2 or 1/8 microstepping? Does it matter?

~ Stump

X2!

[stumpxj]

Thanks again Hoss, I tried both set-ups/numbers you gave, and the 1/8 definitely runs quieter and smoother. I am going to run at 1/8 for now, and I set my velocity at 70 and accel at 25 for now. They seem like reasonable numbers.

Thanks a TON!

~ James

[Fastest1]

James, Welcome to the new challenges. There is plenty to learn. Hoss gave you the numbers so your accuracy should be close. You will need to use the calibration tool within Mach to get the exact distance traveled. Anyway I just wanted to point out 2 things I notice in your set up. First your velocity is set to 70, this will limit your rapids to 70ipm if you are inches. There is nothing wrong with this speed, it is slow to the professionals but it will allow you to break tools plenty quickly in the beginniing :-) Also in regards to microstepping values the 1/8th provides a much smoother and quieter operation but in theory could limit your maximum attainable speeds. Again this in theory, the speeds will be just fine while you learn the nuances of this new undertaking. Buy cheap end mills at first. Enjoy

[stumpxj]

James, Welcome to the new challenges. There is plenty to learn. Hoss gave you the numbers so your accuracy should be close. You will need to use the calibration tool within Mach to get the exact distance traveled. Anyway I just wanted to point out 2 things I notice in your set up. First your velocity is set to 70, this will limit your rapids to 70ipm if you are inches. There is nothing wrong with this speed, it is slow to the professionals but it will allow you to break tools plenty quickly in the beginniing :-) Also in regards to microstepping values the 1/8th provides a much smoother and quieter operation but in theory could limit your maximum attainable speeds. Again this in theory, the speeds will be just fine while you learn the nuances of this new undertaking. Buy cheap end mills at first. Enjoy

Good post, thanks for the info. Based on what I have read and seen, I realize the 70 ipm is very conservative (atleast on paper), and I am ok with that. I think, as you mentioned, my learning curve when learning to use the machine will be a bumpy road, and is part of the reason I set it very low. I suppose I could tune it higher, and then run at what ever conservative level I feel I need. After running this machine manually for several years before deciding to switch to CNC, I still think I will be light years ahead even at the lowest ipm settings, when it comes to machining time. Not to mention the vastly improved abilities of CNC over manual operation.

I keep thinking to myself how close I am to making chips with this thing, but I also have a fair amount of work to do before that happens, so I am probably closer than I was a few months ago, but still quite a ways to go. Then there is the learning curve of CAD/CAM/G-code, all of which I know virtually nothing about....but I have ambition, so it will all work out in the end.

Just out of curiosity, what maximum ipm numbers should I look for on this type of set-up when tuning? What would be a conservative setting for all three axis and what would be a 'hot rod' set-up for all three based on my equipment?

Thanks

[Fastest1]

Looking at Hoss' set up IIRC he runs in the 200ipm range at least during proof of operation runs. 70ipm is fast enough unless production was the goal. Even at 24ipm it can seem too fast when you needed to hit the Estop. I am impatient, knew nothing prior to getting in and tore up quite a bit of clamps and endmills and probably will continue to do so. I started on a Sherline so crashes werent damaging to the machine itself. I remember building my first controller (Hobby Cnc Pro kit), it passing all of its electrical tests was connected to the steppers and the computer correctly, Mach was configured well enough and I had no idea how to make the machine move. It took 2 days of continuous reading til somebody told me how to use the MDI line and what to put in it! Now I know a wee bit more and I mean a wee bit.

[hoss2006]

I can run 300 ipm with the same drivers but I'm running 570 oz/in 5 amp steppers not 355 oz/in 3.5 amps ones
and I'm also running at 48 volts not 36.
maybe 100 ipm would probably be the best you could get with your present setup, 70 will do you fine as long as you're not missing steps when running it.
Hoss