gcode resetting my surface zero to Z-0.200"

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Mr.Chips
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Re: gcode resetting my surface zero to Z-0.200"

Post by Mr.Chips »

Here’s the other two attachments
Attachments
CA978F34-AB9C-4CF7-B347-1898EEF312AA.jpeg
48139F76-196F-497C-A2D3-56ACC07DFAE1.jpeg

GME
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Re: gcode resetting my surface zero to Z-0.200"

Post by GME »

Mr.Chips wrote:Ok I’ll have all the steppers connected.
When I first started running this CNC I obviously was under some misconceptions in how it operated and they are becoming clear.
Namely i was under the impression that in EDIT TOOL when you set the FEED RATE and PLUNGE RATE that dictated the X,Y and Z IPM that would be used.
MOTOR TUNING: I didn’t get any suggested starting point or recommendations. Even Marcus of Gecko said he couldn’t give any recommendations because it all depends on your machine. I did not realize that the MOTOR TUNING overrode settings made in the EDIT TOOL section.
So, all these years I have again been fat, dumb, and happy running all this time being lucky. Until something got old, or worn and brought this to the forefront. I so apologize for this loooooong journey, it possibly could have been shortened had you all known all the details of my machine up front.

I have configured the file WOMENS 2019 Z 2.TXT as the below screens show.

Please take a look at the motor tuning and let me know the settings I should be using befor I start running the next test.
I’ll be loading 5 files don’t think I can attach them all to this file, so I’ll put three here and two on another post.

I think I misspoke in my last post. I think I suggested you leave the steppers connected to the axes, if your machine could handle increased IPMs. I should have said that it would give a better test if all the steppers were left connected except Z. Since we are trying to isolate a electrical problem with Z (versus) a mechanical problem, The Z stepper should be removed from axis and run without a load. You already know that the stepper will buzz when connected to Z at lower speeds, so leaving it connected won't tell you anything new.

I guess it's safe to assume your screws can handle 200 IPM velocity since you have your Y axis set to 199.98 IPM. My suggested settings: Velocity = 200 and Acceleration = 30 for all three axes. Then, I would adjust your toolpath to run your files at 100 IPM. It may be interesting to adjust your acceleration up or down on X and Y for subsequent tests. I probably wouldn't to higher than 30 for Z, but it may make sense to try lower for subsequent tests - depending on what the higher acceleration discloses.

Gary

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Re: gcode resetting my surface zero to Z-0.200"

Post by Mr.Chips »

Thanks Gary, FYI email to Gecko and they say no problem having any stepper disconnect from driver.

Ok go to air cutting at your suggested settings, right after lunch.

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Re: gcode resetting my surface zero to Z-0.200"

Post by TReischl »

Those settings are a flat out mess. Why are X and Y so different in terms of acceleration? Why are all the velocities different?

Try setting X and Y velocity to something like 50 for openers. While you are at it, set Z to 50 too. Do not worry about whether these are too high or not. You are going to control them via the cnc program code.

Set all the accelerations to 20.

Then run the machine with a test program.

It is highly likely your Z accel will be significantly different from your X/Y accerations. 20 is not an outrageous setting for most machines but I have no idea how tight things are on your particular machine.

If Z axis fails, lower it by 5 and test again, wash rinse and repeat. IMHO once you are below about 10 in/sec/sec on accel you can be pretty darn sure you have some other problem.

The velocity settings are to control the upper end of programmed feed rates. That is all they do, they have nothing to do with acceleration so do not fiddle with them thinking that it will help. If you feel you need to lower feed rates do it via the cnc program.

Edit: Gary and I are telling you the same thing, I am just being a bit more conservative.
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Mr.Chips
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Re: gcode resetting my surface zero to Z-0.200"

Post by Mr.Chips »

Per Gary’s suggestion.
It will air cut straight moves ie X38Y29 and X0Y0 just fine, even using MDI and setting F250.

But even with the 100 IPM and air cutting the file it’s much too fast the moves ate too short and jerking looses steps everywhere.

I’ll try the more conservative approach.

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Re: gcode resetting my surface zero to Z-0.200"

Post by Mr.Chips »

TR, do you still want the EDIT TOOL FEED RATE at 100IPM? That seems too fast for all the short stroke cuts.

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Re: gcode resetting my surface zero to Z-0.200"

Post by Mr.Chips »

I’m still confused about the EDIT TOOL FEED RATE and the MOTOR TUNING Velocity. Please explain their interaction if there is one.

Acceleration, is just how fast it speeds up from a stand still.

thanks

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Re: gcode resetting my surface zero to Z-0.200"

Post by GME »

Rosette.jpg
Here is a picture of a 3d rosette I designed for a remodel of my house. It is 3-1/2" x 3-1/2". I ran both the roughing and finishing toolpaths at 125 IPM. The finishing toolpath was with a 1/8" ball nose. Lots of short, up and down moves. It cut out nice; no lost steps.

I'm concerned about the lost steps. Were all the steppers losing steps, or just certain ones? Which ones? What were the indicators of lost steps, i.e., describe the noise? Could be that 100 IPM is too fast for your machine. Or could it be that the power supply was acting up and causing the lost steps? Lost steps were what you were looking for, and if the power supply was messing up, it makes sense that could cause lost steps on any or all axes. No harm in slowing down the cut rate (your Edit Tool Feedrate). TR suggest 50 IPM. Try it. If things run okay, try 60 or 75 IPM and see what happens. You don't need to change motor turning (see below). Just change the speed in Edit Tool Feedrate.

High rpm router and slow cut speed are tough on tooling and can mess with cut quality.

Your question about "Edit Tool Feedrate" versus Motor Tuning Velocity. The velocity you set in motor tuning sets the upper limit for the speed of the axis. The feedrate you set in V-Carve in "Edit Tool Feedrate" tells the toolpath how fast you want to cut. So, let's say you edit your tool feedrate to 150IPM. You are telling V-Carve that you want your toolpath to cut at 150IPM. However, let's say your velocity is only set to 100IPM. What happens then? Despite your telling the program to run at 150IPM, Mach3 will limit the velocity to 100IPM - the speed limit you set in Motor Tuning Velocity. Of course, if the numbers were reversed (motor tuning velocity = 150 and V-Carve tool feedrate = 100 IPM), the program would run as expected. That's because the V-Carve feedrate is less than the motor tuning velocity speed limit. Make sense?

Gary

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Re: gcode resetting my surface zero to Z-0.200"

Post by Mr.Chips »

The only thing the volucity does is set the upper limit that you determine your cnc will cut. The number you edit tool is the actual max cutting speed for that file. Ok makes sense now.
I think one reason these characters have so many movements may be the fact that they start out as a JPG file and are converted to vectors.
The riser was cut by a series of circles rather than a side to side cut pattern right.

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Re: gcode resetting my surface zero to Z-0.200"

Post by GME »

Mr.Chips wrote:
The riser was cut by a series of circles rather than a side to side cut pattern right.
Nope. The rosette was cut from side to side (raster) from start to finish, in both the roughing and finishing toolpaths. Aspire does not have a way of cutting a 3d model in a circular pattern - at least not that I've found. One option is to cut in what Aspire calls an offset. Offset cuts from the center out in a square pattern.

I've never had problems cutting from vectors that came from a .JPG. The rosette started as a drawing I made of the cross section. I drew the cross section (1/2 of the cross section) and used a 2 rail sweep to make the circle.. I had plenty of nodes to tweak. As 3d goes, it's not particularly complicated. Being able to cut my own saved some bucks. For our master bedroom, sitting room and closet, I need 22 pieces 1.25" thick. You can't get them off the shelf.

I'm wondering if the power supply was acting up and causing lost steps. The idea was to push the machine a little to see what it would do. If incrementally backing off doesn't solve the issue, then it could well be a power supply issue.

Gary

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Re: gcode resetting my surface zero to Z-0.200"

Post by Mr.Chips »

Yea, I don’t know about that PS, seems to be stable, fan cycles on and off, will do some searching about testing PS, YT is usually pretty good but there are some that make a video and are completely wrong, but you can usually.

I made the side view of a horse, STL file using raster with 1/8” ball nose, again I was extreme in my stepover and it was so smooth it didn’t need to be sanded. Was only about 6” high so it didn’t take too long. Got a picture somewhere I’ll try and find it.

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Re: gcode resetting my surface zero to Z-0.200"

Post by TReischl »

GME wrote: Nope. The rosette was cut from side to side (raster) from start to finish, in both the roughing and finishing toolpaths. Aspire does not have a way of cutting a 3d model in a circular pattern - at least not that I've found. One option is to cut in what Aspire calls an offset. Offset cuts from the center out in a square pattern.
Gary
Ummm, nope. It will cut in a square pattern if the exterior boundary is a square/rectangle. If you design something like a clock face and then select offset it will cut in a circular pattern. Really odd shape boundaries will produce odd interior shapes until they can resolve themselves into following outer boundary.
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Re: gcode resetting my surface zero to Z-0.200"

Post by TReischl »

Mr.Chips wrote:TR, do you still want the EDIT TOOL FEED RATE at 100IPM? That seems too fast for all the short stroke cuts.
Here is the thing, if you have programmed the machine to cut at 100 IPM in the cnc program and it cannot achieve that feed rate due to short moves then it will not move that fast because it cannot accelerate long enough to get to programmed feed rate. For instance, when I am doing a finish pass on a 3d model I will usually program 250-300 IPM knowing full well that it will never achieve those feed rates on intricate detail. But it will go as fast as it can and on less detailed areas it will achieve that feed rate.

It may very well be that your machine with screws on X and Y will not be able to achieve high feed rates like the ones I mentioned above. I highly doubt it, my first machine was all screw driven and the most I could get out of it was about 125 IPM. I was limited by the Z axis screw because it was a two start and its limit was about 80 IPM. My new machine is rack and pinion on XY and a five start screw on the Z. I can now get 250 IPM on the Z axis and have the limit velocity set to that value.

Way, WAY back in my former life I started out as a machine designer. Designed large flat bed laser cutters for the steel rule die folks. Those machines were all screw driven back then. What I learned is that a screw has a bunch of bad things going for it. First off it has its own inertia, just the screw. Second when a screw exceeds a certain rpm it will start bending into an odd number of curves, 3,5,7 etc as it whips around. The screw can be preloaded to help minimize this problem but it will still occur given enough rpm's. That whipping not only causes vibration it also adds friction to the nut because the load is uneven. Ok, so what does this have to do with your machine? Your z axis is screw driven, not sure how many starts your screw has, but hopefully you selected a five start, not a two start or lord forbid a single thread. The more starts the less your motor has to work to get it up to feed rate.

Back to the short moves thing. If the short moves are at small angles to each other, like going around a circle the machine will be able to accelerate to programmed feed rate because it has something called "look ahead buffer" and "constant velocity". In mach 3 you should set your look ahead buffer to about 200. Constant velocity is one of those things that we all have an opinion about when it comes to setting the angle. Here is how mine are set on the General Config page of Mach3:
Capture.JPG
These work for me, might be a good place to start for you.

Here is the section on the General Config page for the Look Ahead:
Capture.JPG
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Re: gcode resetting my surface zero to Z-0.200"

Post by GME »

TReischl wrote:
GME wrote: Nope. The rosette was cut from side to side (raster) from start to finish, in both the roughing and finishing toolpaths. Aspire does not have a way of cutting a 3d model in a circular pattern - at least not that I've found. One option is to cut in what Aspire calls an offset. Offset cuts from the center out in a square pattern.
Gary
Ummm, nope. It will cut in a square pattern if the exterior boundary is a square/rectangle. If you design something like a clock face and then select offset it will cut in a circular pattern. Really odd shape boundaries will produce odd interior shapes until they can resolve themselves into following outer boundary.

Good to know, but I doubt that I would ever use it in my practical world. Were I to make a clock face, or some odd shape, I would start with a square or rectangle and cut out the shape. I would use tabs to hold. I don't use a vacuum table, and double faced tape/tape with CA glue is more trouble than the maple clamping elements and t-tracks I use. So, an offset toolpath would always cut out in a square pattern for me.

I'm sure folks with vacuum tables, and others will find the information useful, though. Thanks for sharing.

Gary

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Re: gcode resetting my surface zero to Z-0.200"

Post by mtylerfl »

What???

Aren’t you ever going to cut any YoYo’s, round dishes/plates/boxes or anything like that?

:D
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