Doubt about shutdown pc and mach3

[Lc1975]

Hello.

As i am a beginner and being the 1st time that i use my cnc for the first time to do a service in 3D using Mach3, I have a doubt ..
The work itself takes up 31 Horas be done..

I do not know if it's still lack of practice in which it could put it faster or actually takes that long...


(EndMill ball nose 3.2mm to make a dragon on a plate with 160mmx210mm)...


Can I stop the Mach3 and writhe in a paper the line where i click STOP and tomorrow reconnect everything and continue from there?


Question from a newbie ...
Beginning to learn
http://d1r5wj36adg1sk.cloudfront.net/images/smilies/smile.gif

[Master Splinter]

The best thing to do in your particular case would be to do a few simple test cuts to see how well your machine picks up from where it left off.

And then maybe consider using a few different end mills to remove stock faster, reserving the ball end mill (with lots of stepover, I presume) for final passes.

I'd only think about leaving it running for that length of time if I had plenty of hard limit switches that would shut it down if something unexpected happened.

[Lc1975]

Thanks..

But i tried doing:

I worte the line and cordinates in a paper today i tried to start everything and pufff...
Ruined 7h of work...
After that i went to check and in "Y" maked a difference of 3/10 of a millimeter i didn't notice that and then it cut a part of the body..

My difficulty was that appears a small box with coordinates to start from that point "X" was ok "Z" was ok too and then notice that "Y" maked a difference of 3/10 of a millimeter.. and i could not make the change in that...

Going to start all over again...

[Malibu]

For me, if it were a job that were to continue after a shutdown, I would put a reference mark in a known point in relation to the job (a hole or something) and use that to re-align/check the spindle on the next power up.
I would also shutdown between machine op's, not halfway through one.
To reduce machine time use several tool sizes and machine ops as suggested. Probably a roughing pass with a large bit and 50% stepover, a second pass with a smaller bit, then the finishing pass with the final bit with a small stepover value (5%, 10% - whatever gives the result you're looking for).

[Lc1975]

Thanks for the tips.
:)

I started with a roughing with Endmill 6mm, then another roughing 3.175mm and for finish 3D use a Ball Nose 3.2mm in a material that have: 170mmx240mm
45minutes for the 6mm (5 passages)
2Hours for the 3.175mm (4 passages)
And 33Hours to the 3D finish +/- (1 passage)

in total is 36 Hours...
:sad1:

In another place (cnczone) suggest to stop the work, write the offsets (x,y,z), home the machine, shutdown.. Then power up and re-home the machine, insert the offsets and start up the job..
Thats what i understood...

my doubt is how do i insert the offsets and tell the machine to go that offset...

This is all new for me..
Bit confused..

Find now the stepover to change...
My program is in Portuguese...
Changed that to 5% take now 8H to do the job...
Better now :)

[foobillious]

what feed rates, step overs and cut depths are you using? that seems quite slow for a small work piece.

My standard practice is pretty much as has been suggested above: stick a hole somewhere in the scrap (normally x10,y10) and use that to reference off for subsequent pieces. Its very handy if something goes a bit pear shaped, but not pear shaped enough to ruin your piece.

For high precision jobs you might want to look at making a jig like: https://www.youtube.com/watch?v=8OZNiOvetYY. The process is pretty similar - your initial tool path should drill a hole in the waste material, which you then put this into. Use the centre-finder plugin in mach3 and then reference off that.
*edit* apologies - that wasn't quite the video I was thinking of. The video I saw had a centre pin as well, so you just dropped it in the hole.

[pippin88]

Are you using home switches? You'll have no chance if not.

[Lc1975]

Hello
:)
Like i told i'm a beginner on this ..

I was now cheking the "stepover" and yes in the moment that i insert new tools and almost all tools i down the stepover between 0.01% to 0.3%.... :club:

Really a big mistake...

After see Malibu explanation i went to re-check that part and it was really that one of the problems of take 33H to finish the job...

Now after change that it's 5H to finish 3D it's less 28H... Put the stepover at 6% on this job..

I didn't stop the machine in the middlle of thwe work.. Prefer to wait until change tool make home shutdown and start from there today home again check tool again and start.. until now is ok..
I now that maybe in future i will test that in a middle of a job using yours explanations..

:)

Thanks for the tips with this we can always learn to do things better
:)

[Bob Willson]

Hello Lc1975

You don't say what speed you are running the machine at.

What is the distance per second that you have set to run at? About 1200 mm per minute would be OK for a 1mm round nose ball so long as you have previously used a larger tool to remove all but about 0.75mm of the stock.

I am presently cutting a job using a 1mm dia ball at 18000 rev per, and expect it to take me about 8 hours to do. However, the job is 900mm long by 90 wide. I am using a stepover of 5% and I am cutting hard wood.

Because the timber is so hard and the ball so small, I can only cut at about 1250mm per min. It may well be able to cut faster, but I only have the one 1mm cutter, so I don't want to take a chance on breaking it. If that wasn't a worry, then I would up the speed to about 3000 mm a minute and the revs to 24000.

[Malibu]

I am presently cutting a job using a 1mm dia ball at 18000 rev per, and expect it to take me about 8 hours to do. However, the job is 900mm long by 90 wide. I am using a stepover of 5% and I am cutting hard wood.

Because the timber is so hard and the ball so small, I can only cut at about 1250mm per min. It may well be able to cut faster, but I only have the one 1mm cutter, so I don't want to take a chance on breaking it. If that wasn't a worry, then I would up the speed to about 3000 mm a minute and the revs to 24000.

That sounds about the feeds and speeds I'd run mine at too Bob.
For something like a 1mm endmill in Ebony on a profile cut, I'd run at around 5mm/sec but for a pocket, I'd use 15mm/sec at 50% stepover, at most maybe a 2mm pass depth. For smaller stepover, I'd increase the speed up to 20mm/sec.

As an afterthought Lc1975, what is your Mach3 'Motion Mode' set to? If it's set to exact stop, it could increase the time taken over constant velocity because of accel/decel times.

[Bob Willson]

For something like a 1mm endmill in Ebony on a profile cut, I'd run at around 5mm/sec

Ebony? Wow, I'm impressed John. The largest piece of that I can afford is about the size of match stick. :D

[Malibu]

Ebony? Wow, I'm impressed John. The largest piece of that I can afford is about the size of match stick. :D

Ah yeah... I know what you mean!
Fortunately my customers send the ebony to me and I do the machining and/or inlaying then send it back :)

[Bob Willson]

And they are? Blunt axe heads with little runnels to let the blood flow away?

[Lc1975]

Hello.
Once more thanks to all :)

In steps and velocity i have to check that because i used this video:

https://www.youtube.com/watch?v=EVrqObwaAF4

to calibrate the steps per unit in mach3 (i use mm's) but after doing that the motors were very but really very slow...

The steps per unit i think that is around 156/157 no more then that.. and velocity around 80 i think i don't remember because i change that quick because it was really slow...
maybe a snail was faster to go once side to other of the table... :D

The accelaration is around 70 or 80

I change the velocity to 600 i think but i have to confirm that and i will put here.. even on 600 i think that is a bit slow... but if i put more the engines start to make a bit of noise...


Here a small video of my machine...

Please do not laugh.. It´s my first machine... :p

But works great!
Ands it is all aligned

:)


http://1drv.ms/1FI6pBU

Regards.

[Malibu]

And they are? Blunt axe heads with little runnels to let the blood flow away?

They're guitar tailstocks with the string slots cut in them... I just put them up as an example. :)

[Lc1975]

This is what i have in motor tunning:

Step per unit X: 157.5947368
Step per unit Y: The same above
Step per unit Z: 157

Velocity in mm's in all axis: 600
Acceleration in mm's in all: 70
G's: 0.0071383

[foobillious]

You can sanity check those numbers if you know what your leadscrew pitch is, and how many steps per revolution your motors are.

calculation is as follows

Steps per unit = steps per revolution / leadscrew pitch

[Bob Willson]

Try changing the velocity to about 4000 and the acceleration to about 300.
Give that a go and let us know how you do.

[Lc1975]

Thanks

I will give a try later..

Damn work dosen't let me go on this month...

Only at night i am in house and on that hours is complicated because of neighbors...

:~

[Lc1975]

Try the numbers you give me..

Working is ok. A bit hard when stops or start but works...
The only problem is when i use the keyboard to left or right the motors after maybe 2cm stops and then i have to repeat in the keyboard..
I think that is too much...
I used half of the values...
2000/150
Works fine until now even with keyboard...

Thanks for the tip

:)

[Bob Willson]

You shouldn't be getting any run on at all, nor should it only move a small distance before requiring a second keyboard press. So, try setting it to ' exact stop' to remove any run on and make sure that you have the program set for continuous jogging.

[Lc1975]

You shouldn't be getting any run on at all, nor should it only move a small distance before requiring a second keyboard press. So, try setting it to ' exact stop' to remove any run on and make sure that you have the program set for continuous jogging.


Sorry Bob but my translation and understanding is not that good...

When put that values the motors should not move with the keyboard??
Is that what correct?
Or i understand wrong?
The Program is to "continous run"

Sorry about this

[Bob Willson]

Hi LC1975

I think I may have misunderstood what you were trying to say.

If you were getting good results from a speed of 2000mm a min and acceleration of 150 then OK. But, that is quite a slow speed for what appears to be proper ballscrews on your machine. If you are getting too much noise or vibration at 4000 * 300 they also try at 3000 velocity by 200 acceleration. If the velocity seems to be OK at this speed then try upping the acceleration in increments of 25 until faults occur, then back off 100.

Just doing this should drop your cutting times if you are cutting at full speed (G0 F3000). (NB. I am not advising you run at this speed, just showing the code example)

[Lc1975]

Hi.
Vibration it dosen't make none..
Noise maybe a little it's the first time that i use this type of motors.. and for what i'm accustomed with low speeds in the moment is a bit louders, worms up a little (just a little bit) after a while, normal?
The rest i really like see the machine working..
:)
Very fast compared to other works...
I will try more configurations to see if i get a good work and stability of the motors...
Maybe i have to change the configurations of the DQ542MA..
i have to see that better...
Thanks for the help from all..
A bigger thanks for Bob Willson

But on this momenty my real problem i think that it's solved...
I now if i stop a work in "FEEDHOLD" of Mach3, i then right down the offsets (just to compare) and the line of the file in the moment, then i home the machine, shutdown the pc and machine, in the next day i just insert the line and start from there and in the software Mach3 appears a little box to me to confirm if is the correct coordinates to start the spindle in that location of the work piece, i press ok and the machine starts to work from the last point that i stop..
:)

This was a person from cnczone that tell me to try this.. nickname ger21.
And it works.

Regards

[Bob Willson]

If Ger21 said it, then it is so. He is VERY good at these things, So if I say one thing and Ger says different, then go with what Ger said. :)

It is normal for stepper motors to get quite hot - maybe even very hot - but should be no more than about 70oC.

[epineh]

Yes stepper motors get very hot, I found this out on my 3d printer with a plastic printed extruder, the motor got so hot it melted the extruder assembly and the 3d printed gears...another reason I like servos :D

Russell

[foobillious]

a lot of controllers include a low power idle function for the stepper motors. This can help to reduce heat build up. It certainly does with my machine.