Machsupport Forum
Mach Discussion => General Mach Discussion => Topic started by: walr74 on December 03, 2017, 05:48:11 PM
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In short, for the past 7 years I've been running an CNC dedicated old Windows XP computer with mach 3 with no anti-virus, no anti malware, no internet connections. I have always had intermittent problems with loosing steps. I have changed driver boards, I've increased the size of my motors to more then double original, I've rewired it a couple times, changed the LPT cable, but would still loose steps at random times.
My last few projects have been between 300,000 and 400,000 lines of code (8-10 hours of cut time), so fairly large files. After ruining about $200 in wood and unknown number of hours from these lost steps, I decided to try upgrading to a USB breakout board and individual motor drivers. It didn't change, on my current project the first attempt lost steps around line 90,000 (about 2-1/2 hours in), the second attempt lost some at 20,000 (only 30 mins into program), a third attempt lost some around line 177,000 (about 5 hours of cut time), the forth attempt ran the whole program (8-3/4 hours) without any program issues.
Now I'm trying to repeat this project with no luck, again it started randomly loosing steps. Because I now have a USB board, I tried hooking up my laptop (running windows 7, Celeron Dual-Core 1.90 GHz 4.00 GB RAM on a 32 bit operating system) to see if it was the old computer is having some type of glitch that was interrupting the steps even thou the USB board was suppose to eliminate that. The laptop jogs everything perfectly, full speed, nice and smooth, but when I tried to run this program, it jogged from home to its starting point flawlessly, but then it started cutting. It was pulsating the stepper motors. Very noticeable on a slight z axis incline, the Y axis motor speeds up, then slows down, then speed up then slows down. These "pulses" and the uneven speeds of all the axis is taking the program almost twice as long to run. So I thought maybe my laptop just wasn't quite big enough, fast enough or plain not capable of running the CNC.
So, I grabbed my one office computers (windows 10) and temporarily hooked that one up, turned off everything that didn't need to be running and it does the same exact thing as my laptop. This computer is an Intel Core i7-2600 @ 3.40GHz with 8GB of RAM with a 64 bit processor, custom built, usually runs 3 screens and ANY multiple programs at the same time including AutoCad and 3D software while being on the internet. Way bigger and faster then I should ever need to run this CNC, but it won't run it efficiently. I've checked and double checked all my setting, I've tried changing as many settings that I know of to try to solve this problem with no luck.
ANY suggestion are welcome!!!
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What USB board do you have?
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SainSmart 4 Axis Mach3 USB CNC Motion Controller Card Interface Breakout Board with 3 SainSmart TB6600 CNC Micro-Stepping Stepper Motor Driver 4.5A
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I'm not familiar with that card, and have really not heard of an issue like that with a motion controller.
Here's what I'd recommend.
Use Mach3 3.043.062
Make sure you have the latest plugin for your board.
Try turning off the toolpath display.
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I'm willing to try anything at this point thank you, The CNC is hooked back up on the old XP computer right now, I'm at 200,000 lines and good so far. That's the frustrating part, it is completely random with the XP computer, but the new computer won't run it smoothly, again that doesn't make any sense to me, why would an old computer work fine (other then loosing steps) but neither new ones work with the new technology breakout boards and drivers?????
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My best suggestion would be to get a motion controller that is well known. I would recommend a UC100 motion controller. I have setup several of them and I personally own and use 2 ESS and 3 UC products. I prefer the UC line.
I would then go with a new cheap windows 7, 8 10 computer and a clean fresh install and setup the machine again from scratch. As Ger21 said, the .062 version seems to be the best one.
http://www.machsupport.com/forum/index.php/topic,36095.0.html
That is how I would approach what you are dealing with right now.
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If you are going to switch motion controllers, I'd get a UC400ETH.
It seems like any low cost made in china controllers are a roll of the dice.
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For the newer computers, I'd recommend the following, since Windows computers are intended for dedicated real time services:
1 Remove (uninstall) One Drive.
2 Change MACH3 short cut start up to run in ABoveNormal priority
DETAILS:
cmd.exe /c start "MACH3" /AboveNormal "C:\Mach3\Mach3.exe" /p CNC_Router
Where CNC_Router should be replaced with your actual profile name.
3 Disable unused network protocols on the ethernet port, leaving only TCP/IPv4, if using ESS.
4 PC and Screen set to NEVER go into sleep mode.
5 Turn off "Shared Experiences" and "Share across devices".
6 Disable Cortana using the Local Group Policy editor.
7 Turn off Windows Update service. This will require PERIODIC PC MAINTENANCE for updates.
This can apparently cause some difficulty in installing .NET Framework 3.5, etc, so may need to turn on for service, and then turn off again.
To turn Windows Update back on for an update, or turn off again:
A. Open "Administrative Tools" in Control Panel
B. Double Click "Services." Admin permission required here.
C. Click Name column to reverse the entries.
D. Find Windows Update Service and right click, and select Properties.
E. On the General tab, next to start up, insure Automatic is select to start it (Disable, otherwise).
F. If starting Windows Update, click "Start" if it's not already running.
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Hi,
I've been having a similar problem, from what I've read here, my problem could lay with the breakout board, where can i pick up a cheap but decent one? my current one is a Chinese Parallel one, no idea what the brand is, all i know is its Chinese
Thanks,
Alex
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Hi,
a parallel port breakout board is really only a buffer/amplifier and a place to hook up wires, it doesn't really do anything. Its not impossible
that a poorly designed breakout board could make Mach go screwy but its much more likely that its Machs parallel port driver, that is to say
the software driver running at kernel level on your CPU almost in defiance of Windows that's screwy.
If you want a good board I suggest one from the experienced players and an external motion controller not a parallel port breakout board at all.
https://warp9td.com/ (https://warp9td.com/)
https://www.pmdx.com/ (https://www.pmdx.com/)
https://www.poscope.com/ (https://www.poscope.com/)
https://www.cncdrive.com/ (https://www.cncdrive.com/)
http://www.vitalsystem.com/portal/index.php (http://www.vitalsystem.com/portal/index.php)
http://en.cs-lab.eu/ (http://en.cs-lab.eu/)
http://www.galilmc.com/ (http://www.galilmc.com/)
Don't buy cheap Chinese knock-offs, they abound on EBay, buy direct or from the manufacturers nominated distributor. If you try to buy cheap elsewhere you
will come to grief.
Note that all of these manufacturers have either USB or Ethernet boards or both, and all have Mach4 plugins in addition to Mach3, some more developed than
others, but Mach4 ready none-the-less.
With any of these external motion controllers you will be able to use any Windows OS including 64 bit so the choice of PCs to run Mach just became huge
and even more importantly they run Mach a lot smoother and way way WAY less faults than a parallel port.
A lot of Mach users depend on a parallel port and vigourously defend its use, I used to do the same until I bought an Ethernet Smooth Stepper, now I wouldn't
go back to a parallel port if you paid me!
Craig
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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
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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.
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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.
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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
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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.
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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
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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
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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
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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
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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
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For Lexan and cast acrylic the optimal settings are very non-intuitive. Has to do with putting the heat into the chip and not the tool, so it won't mark the part.
I had to "fix" a larger more expensive part once. The 3M stuff you get for cleaning up car headlights can do amazing things for fixing and polishing scratches on lexan and cast acrylic.
I don't do much aluminum on CNC at this time.
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I have been involved in electrical and somewhat in electronics since 1962 and also air craft electrical. 100% on crimped connections and extra flexible wire. One other thing, they do make stepper motors that have feedback like servo motor encoders. I looking into it at one time and they were not much more expensive than regular steppers. I will try to post a link if I can find the source.