Steppers stalling.

All info relating to the Denford Novamill CNC Milling machines

Moderators: Martin, Steve, Mr Magoo

Post Reply
Madkite
Posts: 5
Joined: Mon 17 Aug , 2020 22:30 pm
Hardware/Software: Denford Novamill 3
Fusion 360 for cad/cam
Probably Mach3 but not built it yet.

Steppers stalling.

Post by Madkite » Sat 20 Mar , 2021 17:58 pm

So I got my novamil all coverted to mach3 for a while.

But I have been having trouble with the x and y. Especially the x.

For no good reason it will stall. Not when ploughing through stuff but just when doing a move.

I have decreased acceleration. Incread and decreased micro stepping. Same with amps. Usually it makes it worse. And I can't get over 1000mm a min or the motors stall.

Sooner or later it seems to stall whatever

I have now ordered some nema 23 motors as I think the x may be on the blink. They all meter out except the y thay somtimes read right on 1 phase. And sometimes it just wont settle on the meter.

When they are installed I will see as not had this unpredictable trouble with nema motors before. It's always been an obveouls overload or somthing.

When it's working I'm quite impressed. It will basically cut to the power limit of the motors. I'm sure it would do much more with more power. The frame is super strong.

Have taken 18mm deem at 0.5mm step over 800mm a min feed in aluminium. And that's about as much as the spindle motor can drive. It did that job without an problem. So it's not an overload issue.

Martin
CNC Guru
CNC Guru
Posts: 1897
Joined: Fri 24 Feb , 2006 17:09 pm
Location: Brighouse

Re: Steppers stalling.

Post by Martin » Sat 20 Mar , 2021 18:22 pm

It is only set to run at 1000mm per min in VR Milling so its about correct unless you have changed something.

Madkite
Posts: 5
Joined: Mon 17 Aug , 2020 22:30 pm
Hardware/Software: Denford Novamill 3
Fusion 360 for cad/cam
Probably Mach3 but not built it yet.

Re: Steppers stalling.

Post by Madkite » Sat 20 Mar , 2021 19:41 pm

That works out about right with the gearing to my other cnc in terms of motor rpm.

I assume it's like with a trasformer where the more you increase the frequency the less current you can pass. As it's a kind of ac motor I am gussing it's the same thing.

It's just it does it when there is no good reason to do so. If I didn't suspect he motor I would think it was trying to move with no acceleration suddenly.

And increasing the current doesn't seem to help. And decreasing the micro stepping made it worse.

It's a shame you can't get the big nema 23 motor in but it would hit the case at full travel.

Madkite
Posts: 5
Joined: Mon 17 Aug , 2020 22:30 pm
Hardware/Software: Denford Novamill 3
Fusion 360 for cad/cam
Probably Mach3 but not built it yet.

Re: Steppers stalling.

Post by Madkite » Thu 25 Mar , 2021 16:58 pm

So changed the motors for nema 23 off the rack cheep as chips motors.

Jobs not to bad. Just looking up the wiring to join.

My x and y were not the motors that have been listed on here before.

They were HY200 2220 0210 ACM8

These were 8 wire motors. They joined 2 sets to make it 4 wire. So it's dead simple to chage.

The new motors are higher current and it shows.

So with the old motors it would permanently stall in a sright move at about 1500+ mm a min. So 1000 is max speed.

These I got up to 2100+ mm a min before it would constant stall. So can easily do 1500 for rapid moves.

Just need to recalibrate the x and y and I will be ready for some real tests.

Did some air cut tests ramping up the feed to max to try and make it skip. Far faster than you could cut metal in it. Seem ok so time to make some chips next chance I get.

kapow
Posts: 1
Joined: Fri 07 Apr , 2023 8:51 am
Hardware/Software: Fusion 360 for CAD and CAM
Mach3 and Denford Novamill

Re: Steppers stalling.

Post by kapow » Fri 07 Apr , 2023 9:04 am

Hey Madkite,

I discovered your videos a few years ago when I got my Novamill. They've been a guiding light - whenever I run into a problem with it or questioning how hard to push it I find myself watching your videos to give me faith!

I've been running into the same problem you were encountering here (at 791mm/min feedrate). My X and Y steppers are occasionally stalling but Mach 3 registers a move nonetheless and throws the coordinates off accordingly. Often 1 hour into a program with an expensive piece of metal ruined and an afternoon wasted. The stall might only be a second long, but it will effectively skip a step that might otherwise have taken 10 seconds, so it looks like it is jumping ahead in the program.

I am planning to swap the steppers (original, I think) with Nema 23's as you have done. You said that it's dead easy... would you mind sharing the steps involved in this? I'm wondering whether you had to change the stepper drivers to new ones compatible with the Nema's. What other steps did you have to make to get it running so well?

Thanks,
Max

Post Reply