Thread: Doubt about shutdown pc and mach3

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.

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...

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).

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...


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

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.

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

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%....

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

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.

Originally Posted by Bob Willson

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.

Originally Posted by Malibu

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.

Originally Posted by Bob Willson

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

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

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

Hello.
Once more thanks to all

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


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...

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...

But works great!
Ands it is all aligned



http://1drv.ms/1FI6pBU

Regards.

Originally Posted by Bob Willson

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.