Nearly crashed my denford triac machine and not sure what went wrong, help please?

Hi all,

I nearly crashed my machine and have no idea how. Perhaps one of you guys may have some idea what went wrong. I was cutting a circular pocket in the plastic as per the photo. The plastic is 50mm thick I had cut 25mm deep fine in a series of 7 passes, it went fine I then cut another 25mm deep zeroing the z 25mm below the top of the part that was fine but I had not got quite deep enough so I had another go on the 6 or 7 pass things went wrong real quick.
The only thing I can think is perhaps I touched my mouse or shuttle and it override the code if that is possible. The part was secure in vice so it did not work loose. I have tried the code again directly above the part 3 or 4 times I would think and all seems fine. Perhaps one of you guys will know where I most likely went wrong. It dived into the bottom right part of the job an tripped the machine which was very lucky

Thank for any help

Suesihttp://www.mycncuk.com/attachment.ph...id=15455&stc=1

are you using mach3 ?

Hi Blackrat,

Yes, I am using mach3.

Thanks

Suesi

Did you try sending it back to Zero after it happened.? This would tell you if it lost steps as it would go back to the wrong place. Which would be the most likely cause, if not then it's a little worrying because if G-code is fine it means Mach went Awol which shouldn't happpen.!

Thou to be honest I'd be more inclined to say it just lost position thru missed steps maybe due to heavy load with possibly too high feedrate? I'd take a guess and suggest you may have the motors slightly over tuned possibly.?
The fact it cut air fine doesn't mean your motor tuning is Ok. You could just be on the edge with motor tuning but not enough to stall motors but enough to loose steps when under a heavy load and/or too high feedrate.

Post the settings for your motor tuning and give spec of the machine and I'll take a look.

one thing i can think of is that you shifted Z0 25mm below the part and you did not change the quote of safe Z, where the rapids movements are.

Quote:

---

Originally Posted by gianluca_g

one thing i can think of is that you shifted Z0 25mm below the part and you did not change the quote of safe Z, where the rapids movements are.

---

No unfortunatly that wouldn't explain the shift to the side and also Safe Z is Machine coordinate position not Work coordinate. It has nothing to do with the parts your cutting other than it lifts the Z axis to a safe MACHINE coordinate position before rapid moves.

This will be either Mechanical slippage of a coupler or motors are over tuned and it's loosing steps/position while cutting.

Hi Jazz,

Cheers very much for your reply here mate as I am very keen to get to the bottom of things. Unfortunately, I did not return to Z zero my initial thought was to get up and out of the material. I will know next time to try and return to zero, not sure how I should have done that x zero, y zero was centre of the hole. It happened on my Denford Triac, it seemed to me like the plastic was being cut like butter as I had been taking it what I thought was real easy! I will get the following later: Motor spec, Motor tuning, Feed and cut rates and I may also take a video cutting above the job so you can hear the motors.

Many thanks

Suesi

http://www.mycncuk.com/attachment.ph...id=15456&stc=1http://www.mycncuk.com/attachment.ph...id=15457&stc=1http://www.mycncuk.com/attachment.ph...id=15458&stc=1
https://www.youtube.com/watch?v=EgFz...ature=youtu.be

Hi Jazz,
I am well out of my depth here perhaps you can get my head above water!
I have found out some info, as per the manual on the machine max federate is X,Y 2500mm/min with the Z being 1000mm /min.Is states feedrate override potentiometer 0 to 150% but I do not know what that means.
The guy that converted my machine has done many Triac’s and set the X & Y at 3000mm / min, Z axis at 2000mm/min I am asking him for the spec of the motors.
To cut out the rectangular shaped part in the vice with radiusedc orners I used a federate of 1900mm/min, s4000, cut depth 3.8mm per pass.
When it all went wrong the cutter was not cutting anything as it was working down progressively to the bottom of the hole that had already been cut inorder to just cut the last 1mm of the bottom left behind and break through it went wrong on the 2^nd to last pass so it did not reach the remaining 1mm to be cut.
I have attached photos of the motor tuning, video of the part being cut above job so motor can be heard, the spindle is a 1.1kw, DC, 1.5hp
The X,Y and Z ballscrews 16mm (5/8”) diameter x5mm (13/64”) pitch
Many thanks
Suesihttp://www.mycncuk.com/attachment.ph...id=15456&stc=1http://www.mycncuk.com/attachment.ph...id=15457&stc=1http://www.mycncuk.com/attachment.ph...id=15458&stc=1
https://www.youtube.com/watch?v=EgFzqQqScPU&feature=youtu.be

Ok well nothing looks wrong or excessively over tuned here. Thou I'm not a fan of micro stepping at 1000ms (1000/5mm pitch=200 steps per) as I find for some strange reason this setting can give more resonance which can affect motors than 800 or 1600. That said I'm pretty sure this won't be your problem.

What your problem is I'm not sure and without being at the machine it's difficult to diagnose.

First port of call is checking all mechanical coupler connections or pulleys etc connecting to motors and ballscrews.
Then check the machine returns exactly back to X0 Y0 in work coordinates. (Not Home position) Make a Ref mark or set a DTI before starting code and check it comes back to same mark when sent to G0 X0 Y0 using MDI or Goto Zero.

If it doesn't then your loosing steps for what ever reason. I was trying to take note when watching the video because at first I thought it was stepping over slightly when returning to start of each step down but the camera is shaky so hard to see. Looking again a few times I don't think it is. Plus if it is it's certainly not enough to cause that amount of steppover you had.

If it does return exactly to Ref mark then I'm afraid it may remain a mystery until it either repeats it again or you realise it was something you did by accident.!!
Possibly could be electrical noise affecting the Machine but again with so much error I don't think so.!

Sorry can't suggest anything else it could be.!

Thanks Jazz for that. I don't understand what you mean about the steps but that is due to my lack of knowledge! I will try and check what you suggest to check tomorrow and see if I can see any issues. Sorry for the shaky camera. If I cannot find anything and continue on with the job I will put a packer behind the plastic block to get the moving jaw of the vice further out of the way!

I wonder if I could have hit my shuttle with my hand or the mouse and if that did something. I seems odd that I have run the code many times since without issue. I am getting a little more familiar with mach3 I guess every one starts somewhere.

Thanks very much for now

Suesi

Hi gianluca_g,

Thank you for your msg and trying to help me I appreciate it. Your clock looks great.

Thanks

Suesi

Don't worry about not understanding the Steps thing as you don't need to understand to work the machine. All you need to check is that the machine returns to Zero. If it doesn't then we'll worry about teaching you all about Steps per etc.

Regards Knocking the Shuttle then I can't see that being the cause unless you accidentally caught it before pressing cycle start and set one or both the Axis DRO's so a number other than Zero was entered into the DRO's. Then the Zero location would be differant to where you thought it was.
This is the only explination I can think of because if you was already deep into the material and the DRO changed from Zero to say +/- 5 then the machine would travel side ways.

Try this in air to see what I mean. Zero the DRO for X & Y then type 10 directly into either DRO. Then type G0 X0 or Y0 depending on which you changed into MDI input line and you'll see it moves sideways for that axis.!!

I have seen that happen to me in 2 scenarios.
-while when machine is cutting i forget about that and cut something with the plasma cutter outside the room. I know right away that the machine misses a step, cause i have connected loudspeakers to the pc, cause when not cutting i am listening to music. So when it skips a step from inteference there is a "piu" sound in the garage

-i have one slippery, to say, collet for my 3mm bits. Some times i will not tighten it well, so the bit would dig and make something like that. but this machine is flimsy so i dont know if that could be your case

Quote:

---

Originally Posted by silyavski

I have seen that happen to me in 2 scenarios.
-while when machine is cutting i forget about that and cut something with the plasma cutter outside the room.

---

Get your self a Cslabs controller.!!!. . . . I can cut with Plasma, weld with TIG or Mig right next to my machine while it's cutting and it doesn't even flinch.!!

Quote:

---

Originally Posted by silyavski

-i have one slippery, to say, collet for my 3mm bits. Some times i will not tighten it well, so the bit would dig and make something like that. but this machine is flimsy so i dont know if that could be your case

---

That crossed my mind Boyan but Wouldn't explain the shift to right thou would it unless it stalled motors first then ploughed on thru. Only Suesi will know for sure if he watched it close enough.
Also the cutter would be stuck out further from collet which would be sign. As would it not going back to same height or back to zero in Z but he didn't check that I've already asked.!

Hi Jazz,
Thank you very much mate for the help and for offering to teach me about the steps if need be.
I didn't knock the Shuttle prior to the pressing cycle start, and I am sure the X and Y DRO's would have read zero. I guess I just got a little paranoid thinking perhaps I knocked it at the point when things went wrong. I will make the checks you suggested and then if nothing show I think carry on with great caution! The tips you have given me and the thought you have given my issue have provided some reassurance.
All the best
Suesi

Hi silyavski,

Many thanks for the reply here. I was not welding as don't know the first thing about welding. I have no speakers connected to my computer. I may have had a vacuum running but I doubt it as I was hardly intending to cut much the only other thing on would have been a Makita radio and dehumidifier.
I don't think tool slippage was an issue in this case but thank you for the thought. One of my jobs on the horizon mind is to make a part to hold my tool holders.

As for an update on what happened I was stood right in front of the mill it started to go south and before I got to hit the E Stop the electric supply tripped and I was in the dark.

All the best

Suesi

The fact that the breaker/fuse for the mill didn't blow before the entire workshop power went out would worry me more than the mill running off.
Do you know why the shop supply tripped out first?

- Nick

Hi magicniner,

Thank you for your msg. What you have said about why the shop supply has tripped out first has got me thinking for sure. I think it was because I have the shop supply plugged into a circuit breaker. Thanks for the thought Nick.

All the best

Suesi

Quote:

---

Originally Posted by suesi34e

As for an update on what happened I was stood right in front of the mill it started to go south and before I got to hit the E Stop the electric supply tripped and I was in the dark.

---

That's pretty big detail you left out there Suesi sue.!! If you don't give all the details then it makes helping very difficult.!

When the Machine went wrong did the Spindle jam.? Being a DC motor this is about the only thing that would possibly hit the breaker hard as the converter ramps up the amps to try and maintain speed. Steppers would just stall and trip the drive rather than mains elecy.

Still doesn't explain why it went Awol but would explain the trip.!

"Plugged in" or "Wired in"? And with what cable running to the shop?
If your machine can draw enough current to throw the breaker is it possible that you're getting mains voltage drop in your shop when the mill is running?
Ideally you should have a breaker on the wall which will trip before the mill can throw the supply breaker,

Regards,
Nick

Hi Nick,
Thank you for your msg. What I have is a two way socket in a shed in that has a plug in circuit breaker, from there I have approximately 70 meters of 1.5mm 3 core cable to a container where I have my machine plugged in just the normal 3 pin plug. I only have one machine in the container so I am not running lathes, saws or any other machines just the mill. I used the circuit breaker in hope it would help protect my mill.
Many thanks
Suesi

Hi Jazz,

I thought I would thank you for your help and let you know how I got on. I struggled to check the connections to the balls screws as there is a casting for the stepper in the way and I was not sure about taking things apart I don't understand. I set a dial gauge up (a 1" second-hand one made in China) setting the x and y to zero with the G0 moves you suggested for the x and y, the needle fell each time no further out than a thou graduation so I am assuming that is pretty good. Do you think that takes away the worry of perhaps loosing step and the coupler issue? The dial gauge is perhaps not perfect. I could attach a picture of the motor mounts if you thing I should investigate further.

Thanks ever so much you have helped me a lot.

Suesi