CNC Vcarve tool library

Space Teams CNC
1

Is there any way to lock Vcarve’s default tool library to prevent user changes from propagating into it? Because every time I have to change a tool for a toolpath at the shop, there are a huge array of variations, and you can grab an innocuous looking tool and get caught by absurd settings.

I broke a bit yesterday using a generic looking ‘softwood 1/4” end mill’ profile because its feed rate was set to 6 inches per second (360 inches per minute). I will absolutely concede that this is my fault for not checking every single parameter, especially since I’ve come across this exact problem before. But why was that tool setting in the library? What maniac is cutting at 360 inches per second with a 1/4” bit?! I wouldn’t try to cut marshmallow with that combination. Needless to say my bit snapped like a toothpick at that rate even though I was only cutting 1/4” deep into pine.

I don’t know if there’s anything we can do about it — it sounds like a problem with Vcarve — but it bears looking into.

Addendum: This will still be an issue with the new CNC; but we’ll be starting with a new VCarve install, which seems the best time to address this.

2

Use your own settings. Unfortunately I don’t think it is possible to lock it down. I can imagine a way to automatically re-image the computer occasionally to an image with the correct settings, but not sure how feasible that is as regular maintenance. Education (and rules) is probably more effective. You can also set up your files at home and I believe it should not change your setting if you just go to the space to export G-Code.

3

This is something I stress heavily in my class. Like the lasers, the stock profiles are likely to change drastically.
There are a couple of solutions.

  1. You can bring a laptop to the space and use that to create and adjust your files. This of course means transferring them to the licensed shop edition and saving g codes from there.

  2. Secondly, you can create your tool database at home and save it on the thumb drive you bring to the space. VCarve does allow you to import tool databases. You could import yours from the flash drive and use it accordingly. Even if you didnt remove it when you left, the usb file would remain un changed. Re load it the next use, and your settings should always be correct.

  3. last option, and not recommended, buy a full version of VCarve and you can bypass the shop computer all together.

Option 2 is the best IMO. You can also use this option to save the databases off the popular bit manufacturers.

As you stated, in the end it is on ourselves to verify the settings. It is easy to over look that step, and sucks when it causes the issue you had.

Hopefully this info helps.

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I will look into the library import. I almost always start my files at home, so I only run into this when modifying them or doing something quick. In this case, I wrote a small file to create a jig for my main job, and I was careless in my haste. It’s all too easy to miss the “in/sec” vs “in/min”. But the proliferation of junk tool profiles is crazy.

There is certainly a computer based solution of some kind. I wonder if Vcarve would work if you set all those files to be read-only in the OS?

5

What kind of feeds and speeds are you using? 360ipm seems high to me, but not THAT high. I’ve been able to run 300ipm with a 1/4" bit

edit: to clarify, I only really ever cut at 50% of the diameter of the bit. But assuming 18000 rpm (cause that’s what our spindle uses), a 2 flute cutter at 360 ipm is exactly a 0.01" chipload, which as I understand is fairly normal for soft woods. Could be mistaken, but that’s what I’m seeing online.

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I may be responsible for some crazy feed rates. If I’m using a 1/2" bit on MDF I may go above 300 ipm. Usually I’m cutting plywood with a 1/4" bit, 250-300 ipm feed, and 18k rpm speed. That speed may be shortening the life of my bits but the machine handles it well.

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I’m glad I have gotten in the habit of asking myself if I might be wrong and looking things up before responding online. Because I was about to respond “0.01? You obviously dropped a zero there.” (leaving the “you idiot” implied :wink:), but it appears maybe I added one, though I’ll have to check my notes. I’m pretty sure that my CNC instructor gave some example settings that ended up with a chipload of 0.0011 in/tooth, a tenth of what you suggested. Though that was for a 1/8" bit, and I’ve now learned that different chip loads are considered appropriate for different bit diameters, which makes sense but I don’t think was mentioned (or I missed it).

Online, I do indeed see recommended chip loads around 0.01 in/tooth for 1/4" bits (and 0.005 in/tooth for 1/8" bits). I don’t know though. First, I do drop the spindle speed a bit for 1/4" bits, to about 15K, which does seem in line with recommendations I see. That raises the chip load for a given feed rate. I upped my feed rate to 180 in/min for some cuts yesterday, a chip load of 0.006 in/tooth, and that wasn’t crazy but sure seems about as fast as I’d like. And I was getting some spindle wobble, leaving a slightly irregular surface, when cutting in Y at that rate (but not in X).

But 360 in/min seems too fast. I wondered for a second if I’d mispositioned something and it was still tramming (which is 720 in/min), but jogs are always made above the piece height, and the cut depths I was seeing – briefly! – were about right, both horizontally and vertically.

One factor in this is that I was using an extra-long bit (1.5" cutting length), which definitely requires you to drop the chip load / feed rate. But even at regular length, I think I’ll stick to 180 in/min or lower.

So 360 in/min may not be as “Oh my god, that’s insane.” as I thought, but I also don’t think it should be a default setting.

In any event, my original point about the tool library is still relevant, because I had to pick this tool profile out of about ten variations because the library has become so cluttered. I’d still prefer to lock it down, or at least make the program ask “Are you sure you want to put this tool/setting in the original library?”; I think most people don’t realize that they are polluting a shared space when they do.

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8

I just set the library and default toolpath settings files to read-only on my Vcarve install at home. We’ll see if that causes issues.

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My better bits are Vortex bits. I carry this sheet around as reference.

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10

FWIW, I agree that it’s probably unnecessary to use 360 at any point, that’s pretty speedy and even if it could work it’s just risking a lot and it’s harder to stop the machine if something goes awry. I used to cut at very low feed rates (30-80ipm) and it works alright but leaves worse finishes and wears our your bits much faster, not to mention being super slow. 150-200 seems like a good medium.

Also, it’s worth mentioning that I’m 95% sure that our current CNC spindle is not variable speed. It just constantly spins at 18000 rpm no matter what you put in vcarve. But that info will be irrelevant very soon as I’m sure the Laguna will be variable speed.

Toolstoday has a good chart for their Amana bits and it seems to corroborate what you found. for their 1/4" bits they recommend 180ipm for wood/plywood and 215ipm for mdf/laminate

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Of course the current CNC is variable speed, and it readily accepts the settings you put in VCarve. You can absolutely see and hear the difference between 18k, 15k, and 12k. I’ve even dialed it down manually to just 3600 rpm, 20% of max. (You can do that, as well as start and stop the spindle, using the pendant or in LinuxCNC.) I used that speed in order to use the edge finder to set more accurate zeroes. (That’s actually a bit fast for the edge finder; 10% might be better.)

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That was the exact table I came across online.

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Fair enough, I haven’t done those tests. The reason I mentioned that is due to this slide in the CNC class notes from 5-5-2020, which are linked in the wiki. Perhaps it is outdated or I misunderstood what it was saying. That’s very good to know haha, thanks for the info. Glad I specified I was only 95% sure :slight_smile:

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14

Sorry to derail your thread! I agree that during the switchover to the new CNC we should try to standardize the tool library. Perhaps we can use the Amana .tool file that they provide on toolstoday and which contains a plethora of standard bits and the recommended feeds/speeds for those? CNC Software Vectric and Fusion 360 Tool File Database | ToolsToday

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I don’t know why those class notes say that. Odd.

But I will note that the settings that slide recommends give you a chip load of only 0.0028 inches/tooth, a bit below the recommendations of the chart above even for a 1/8” bit in the hardest materials. Interesting.

16

Importing is a bit messy in VCarve, it just adds more and more tools into a pool on that machine’s hard drive, without a good way to clean it back again. I believe it can overwrite other tools, too. I don’t know of a way to just point to a tool library on your flash drive, it must be merged with the library on the machine first, a persistent change to the machine.

The best answer might be to have a “tool master” decide for you what bit parameters should be and otherwise write-protect the tool table directory at the file level so no one can ever import a tool, but there’s a wide range of bits and materials and cutting styles out there.

17

Yeah, I was experimenting with importing and discovered this.

I believe that a locked master library doesn’t prevent people from setting the tool parameters in their personal file. I think you just have to select the tool with the default parameters, then edit them, rather than setting your own parameters when selecting the tool. As far as I can tell, the former doesn’t propagate back into the library, but the latter sometimes does. But I’m not completely certain; I’ve been experimenting.