View Full Version : Is a new PC needed?

08-04-2021, 04:19 PM
I have been happily cutting away using UCCNC with no issues. But my cuts have not been too taxing. My max time taken has been a couple of hours.

I’m now doing a bit more..... a lot more in fact. Probably not efficiently either! Basically I’ve got a predicted 72 hour cut with a 0.25mm tapered ball nose endmill with an 8% step over. Project is 800x450mm so I can only imagine the G Code running into many millions of lines!

UCCNC is properly crippled. Took over an hour to load the file, now for the last couple of hours is almost un-navigatable as any mouse click causes it to not respond for a few minutes. Basically beyond the limit of usability. As is the rest of the PC while it’s dealing with this.

The PC running it is on windows 7 64bit but is fairly low specced, 4GB ram, intel core 2 duo E7400 2.8GHz. But that seems to be well above the stated necessary specs quoted for UCCNC.

Am I asking too much? Will a better specced PC be the answer? Like what? I have an i7 overclocked with decent GPU and 16gb ram inside the house, but I’d rather keep it there! What does UCCNC need most? RAM, CPU, GPU?

Thoughts appreciated.

08-04-2021, 10:03 PM
Have you killed all processes not needed to run the machine?I also suggest you disconnect it from any network and disable virus protection for a while.If it isn't able to receive data-it shouldn't pick up viruses.You do seem keen to have a new machine,but you are only using this to send Gcode to your machine and not really scratching the surface of the capabilities it has.

I may be wrong about your project,but it must be very detailed to require a tiny stepover of a very small cutter over the entire surface.Could you not use machining boundaries to limit this kind of machining to those areas that absolutely need it?What software is being used to create the Gcode?Just for information my largest ever program had 188 million lines of code and the controller had a single core of less than IGHz speed and 64Mb RAM.

08-04-2021, 10:14 PM
I would start with buying a 2TB SSD and more RAM. But... 72 hours non-stop cutting... that's a long time and requires just about everything to be perfectly reliable, so maybe a new PC is well motivated. Nevertheless, you'll need a lot of RAM and I personally never going to buy any other HD than SSD. I remember when I bought my first one it was like day and night... A new computer, run significantly faster.

But... I would ask CNCdrive support for advice on such large file. I don't know if it has any limits.

08-04-2021, 10:42 PM
What's the size of the file?

GCode for UCCNC is just an ASCII enocded text file - it's a pretty shit way of storing data efficiently, but it does the job for most applications.

Notice when you load a file UCCNC shows you the entire toolpath immediately and shows you each line in the scroll box. That implies it's probably loading the file into memory and also creating a load more associated bits of memory to display it to you in a nice format (each one of those toolpath lines on the diagram for example needs some associated variables). This is great from a user experience point of view, but pretty limiting when wanting to handle large files - when you watch a movie for example, the program will buffer a small amount at a time rather than pull multiple GB into RAM. Let's guestimate that UCCNC uses 4x the file size in RAM when you load it up.

Now how much of your 4GB is free after Windows and UCCNC is loaded? Maybe 2GB? So any file over 500Mb is going to cause problems.

As A Camera says, more RAM will probably help you out here, and an SSD will make the loading of the file quicker.

08-04-2021, 11:29 PM
You've had the best advice already. Based on my own experience with video editting on a W7 machine, having only 4GB of RAM is not enough, Windows is already using most of it. Doubling up to 8GB will make a world of difference and make it seem like a new machine anyway. Whether you have to discard the existing RAM or just add an extra 4GB will depend on having available slots on the motherboard.

I haven't upgraded any of our computers for a while but when I did the research a few years back it was recommended NOT to spend money on the fastest, cutest looking, most expensive RAM available unless you have top components throughout the machine and are doing the most demanding tasks like editting Lord of the Rings or gaming. What is currently seen as vanilla memory from a repuatble maker like Kingston or Corsair is fine.

I'm interested to see how you get on as my own AXBB-E is due to arrive on Monday and I plan to run UCCNC on this laptop which is a bit long in the tooth and has only 4GB of RAM itself, plus a solid state HD (made a big difference fiiting that) and Windows 10.


09-04-2021, 12:03 AM
Thanks all for the advice. Kind of limited in upgrading the PC. One of those very small form factor jobbies that can’t take more than 4GB ram.

Tomorrow I’m going to shift my home pc out to my workshop and hook that up. That will certainly answer my question if it is the PC that’s the issue. Although it too is a few years old it has some decent grunt and chomps through HD and 4K video editing like butter.

09-04-2021, 12:56 PM
All sorted. Had to wheel out the big gun for this - a core2 duo with 4gb ram doesn’t cut the mustard.... new cnc pc is needed. 29796

09-04-2021, 01:24 PM
Before you go too far it might be a useful exercise to go through all the parameters you have set for the machine.I seriously doubt you will be achieving rapids of 3000mm/second.I don't think I have yet met a machine that rapid.There could be something in the mix that isn't helping.

09-04-2021, 03:10 PM
Yes. I spotted that. Just an error in setting the time calc. Machine is set for 3000mm/min.

10-04-2021, 12:20 AM
Good that it was 'just' the PC and not an AXBB-E/UCCNC limitation.


10-04-2021, 07:24 PM
Sure was the PC. After an hour of loading and then 4 hours of not responding I bailed. My decent pc did the whole calculation in 20 seconds.

I do however think I’ve gone far too small on the tool. A 0.25mm ball nose end mill with an 8% step over is daft. No wonder I’m 32 hours in, 3.5m lines of g code and half way through :beaten:

10-04-2021, 08:12 PM
Yes. I spotted that. Just an error in setting the time calc. Machine is set for 3000mm/min.

No, the machine's Rapid velocity is set at 10,000mm/min, in testing it reached over double this but we throttle it back to keep things sensible. 23,000mm/min is a little scary for new users on a small machine.:hororr:

11-04-2021, 09:11 AM
I remember you saying Dean. What I meant by machine is set at 3000mm/min is what I’ve set the feed rate for this particular cut. Lord knows why, just seemed a good number :indecisiveness::indecisiveness:

11-04-2021, 09:30 AM
I remember you saying Dean. What I meant by machine is set at 3000mm/min is what I’ve set the feed rate for this particular cut. Lord knows why, just seemed a good number :indecisiveness::indecisiveness:

Ah, we are talking apples and pears then.!

To be honest with 3D work if you set a high feed rate you will rarely achieve that feed rate, esp in the Z-axis, because the moves are so short so it doesn't have time to accelerate to the set feed rate before the next move comes along. If you watch the Actual feed DRO and you'll see how high it gets compared to the commanded feed rate.

So in actual fact, if doing mostly 3D work then you would tune the motors differently so they are biased to have a higher acceleration with a lower velocity, this way the machine accelerates faster between moves, and a higher feed rate is reached before the next move comes along. The best way to do this is to have a separate profile set up with the motors tuned for higher acceleration and call it 3D work.
The time saving can be quite dramatic because if you are shaving off just fractions of a second per move then multiply this by millions of moves and you can easily turn this into hours in saved time. The only downside to setting a high acceleration is that if go too high the machine can become very jerky or if overdone even cause missed steps (but in your case because you have closed-loop motors this won't happen, well it could but would cause an error so won't get very far.!) . . . Like everything there is a limit or price to pay.!

21-04-2022, 09:43 PM
I wouldn't go for a new PC, although this might help with the speed. However, what I would do instead is update your Windows. You have to keep your software up to date. You should also run a disk cleanup, and you can do it either manually or get some sort of software that can do it for you quicker. You could also defragment your hard drive, even though it might be challenging to do it yourself. But I reckon the guys from Salvagedata (https://www.salvagedata.com/raid-data-recovery/) could help. I've used their services to recover some lost data, and they did a perfect job.