Hi,

is there any way i can improve my situation without buying new hardware? im not able to get any new bits for a while but i also need to fix the problem im having.
its a rubbish dilemma really. its even more of a pain that i dont know the brand of the motors, drivers for the motors or the breakout board. i know the model of the motor drivers that's all that ive been told about that part of the setup. i know all the stuff about the PC and what im putting into mach3 its just whats happening between the PC and the Cutter.
it just loses steps and kind of shifts position and the part that ive been machining for however long, be it an hour or 6 hours is ruined, its even more painful when its the finishing pass in the last 1000 lines of code.

sorry for the constant relay of problems

Thanks,
Alex

This is a difficult problem without knowledge of brand and documentation.

However, take a look at some FAQ around setting up one brand of ESS board.  As you read through this, you can see how the plugin configuration can have a big effect on the operation of this rather dynamic system, such as particular frequencies and settings that enable it to run smoothly on one hand, and to avoid loosing information on the other.

https://warp9td.com/index.php/faq/faq-mach3#PinsTwoThroughNine

While this particular information may not apply directly to your hardware, it will give you an idea.  You may go to the plugins menu and configuation menu and see what is there for your hardware, as a first step.   

If you can deduce the brand or mfg, you can then look online for documentation.

Hope this helps.

it just loses steps and kind of shifts position and the part that ive been machining for however long, be it an hour or 6 hours is ruined, its even more painful when its the finishing pass in the last 1000 lines of code.

Hi Alex,

Could you perhaps post a picture of what is happening to the work when it goes wrong ?

Tweakie.

Hi,

This is the least extreme one that i haven't thrown yet, but I've tried illustrating where it's gone wrong but it will go through the program without fault for so long then either the X or Y axis will lose position, it's like the entire tool path is shifting and at random times anywhere after 1 hour of machining, I've not seen it do it before an hour. In some cases its shifted 4mm out, the most extreme case it was on a finishing pass around the outside of the part, this is at full depth of about 26mm taking off about 0.1mm to clean the tool marks from the stepdowns and it shifted 10mm out on the X axis and dove into the work too soon.

It's out by about 0.2mm here


Thanks,
Alex

Hi Alex,

I think 10mm out of position represents too many lost steps if they were just random so my best (and wild) guess is that you have a motor driver overheating and perhaps partially shutting down.

Perhaps check the temp. of the driver chips and temporarily fit a cooling fan to see if this makes any difference.

hi,

All my motor drivers have heatsinks and fans attached, although i haven't thought to check them yet, they are kind of bunched in their housing so it could be the ambient temp rising around causing the cooling to have no effect.

if its not that i'm thinking to rewire everything, re-shield and then if all that fails i'll be chief coffee maker till i earn enough points for a smoothstepper like Craig suggested

thanks,
Alex

I agree with Tweakie - this does not seem like small numbers of lost steps.

On my own machine, now 5 years into it's life, in year 2 after heavy use the wires to the motors started to work harden from the movement and develop intermittent breaks.  Was rare and infrequent at first.

I rewired all the moving wire chases.  I used commmercial / industrial wire meant to use on CNCs to replace the ordinary wire that the builder (a friend of mine) used.  I've had no issues since.  I should say that flexible wire was very expensive, but probably worth it.

Curt

Hi,

If its any help, before i shielded my cables the motors would occasionally slow suddenly and make an awful grinding noise.
but after shielding my cables and fiddling with the debounce setting it stopped

thanks,
Alex

Alex,
If you do decide to re-wire, I'd offer the following thoughts:

1) Use real CNC wire.  It is a flat cable intended for bending, with multi-conductors lying in a plane (e.g. parallel to each other).  Each conductor is made up of very fine wire strands for flexibility.  The jacket is clear and flexible (a urethane ??).
2) Wire connections are NOT soldered.  The wire will fatigue and break at solder joints.  I know from building an airplane, that all aircraft use crimped connections and not soldered for this reason.  I believe the special CNC wire has associated crimp connectors.
3) CNC wire is NOT shielded.  It needs to be flexible.  If you have those folding chain link style wire channels, make sure that they have as little extra stuff in them as possible.  The fuller they are, the shorter the wire life. 
4) If you have a shielding problem, get to the source of it.  My system only has a ferrite on the RS-485 from computer to VFD to eliminate noise spikes.  The electronics is in metal cabinet below the CNC working bed.

It's been a few years since I re-wired.

BTW - I've cut a lot of cast acrylic on my machine and have made some beautiful parts.  Part of the magic of a good cut is the speeds and feeds.  I can look up some data on that if you'd like.

Curt

Hi,

I think ive hit the sweet spot for a good finish on the sides and radii, i just need a facemill thats wider than the top so i can minimise toolmarks that are running parallel to the part, the tops not bumpy, its just visual. i've dabbled a little into tumble finishing but i have to keep costs down so im limited there too. although if you know the best statistics for Aluminium i wouldn't turn down any advice you have.

Many thanks,
Alex