Try making your holes .78mm larger . I’ve found that the router bits aren’t always the size they’re supposed to be. You should be able to use the same material you’ve been working with… assuming you’re lining it up in exactly the same position.
Actual size MFT Top.crv (3.6 MB)
That doesn’t make sense. What did you change the diameter to?
When you jog 100mm , how far, exactly does the machine travel?
See post 15 for how far it moves in jog.
I saw that post. 92mm? 111mm? And then setting “it” to 201 gets the “closest”.
My intent is to teach how to set $$ values for steps per mm workout relying on a black box software solution.
To help set the correct value, an exact measurement needs to be known.
Those were the correct values. That’s why it doesn’t make sense. Every time I run the calibration it travels a new distance based on the previous distance that is input. The 201 is the X value that I’ve put in manually. That is the only value that travels 100mm.
The bit I was using was slightly under .25. So I set the bit diameter to the actual bit diameter. It did not make a difference. It should have though. If the longmill thinks a circle requires x amount of travel for a bit .25 in diameter, then it shouldn’t make a hole large enough, if the bit is actually smaller than it’s supposed to be. But when I updated the bit size (it should have recalculated the tool path), int made no difference in the size of the circle. That seems to me like the machine is misunderstanding the circle size.
So that part is fixed? It travels exactly 100mm?
Did you recalculate? The machine doesn’t think or understand. It’ll just move as it’s told. Your hole size was off by 0.65mm or 0.8mm, but you only changed your endmill diameter by 0.05mm. That won’t make much difference.
When doing things that need dimensional accuracy like this, you need to make sure you’re machine is well tuned but then you’ll still need to run a test. Otherwise you do what machinists do and sneak up on that final value… It’s a lot easier to make a hole slightly larger than it is to make it smaller.
@cmorrowk When you change the bit size, you need to recalculate the toolpath. VCarve does not do it automatically.
I know. And I did. And nothing changed.
@cmorrowk Sorry. I misunderstood your previous statement where you said that, after changing the bit size, “it should have recalculated the tool path”.
Yes, I understand that I have to tell it to recalculate the tool path, which I did. Apparently I just need to spend a day tuning the machine and make sure everything is doing what it’s supposed to do. I just figured that the steps in a stepper motor moved at a given value and the software understood that. But I guess there’s a little more dialing in that I need to do. I’ve only had the longmill for a little over a month and I’ve made several small projects. I’ve been trying to learn inlays which have been a little tricky but I really wanted to make something I could use in my shop. And this particular project has really helped me to learn the software and workflow. But it’s also teaching me that there’s still much to learn in terms of getting it to create exactly what I have in mind.
@cmorrowk There IS a lot to learn, for sure. As you have seen, there are experienced LM owners here ready and willing to help. It can be tough, though, if it’s a hardware issue as we cannot see your setup. Software issues are much easier.
FWIW, rather than dwelling on this one file, create another one, similar but perhaps smaller and run it. If the issue persists, at least you have some commonality. If the issue goes away, that, too, tells you something. In cases like yours, it’s important to use the same parameters in the new file as in the “bad” one. Same feed and speeds particularly since this seems to be a hardware issue. I would create a file with one cut out square. It’s easier to measure squares than circles - at least for me. Just a thought.
Good idea. I’ll do that. Thanks for your help.
Did you ever get to the bottom of this? I’m experiencing the same issue.
Yes. Ultimately I started over. I rechecked all my nuts and bolts and found that there were several that I neglected to tighten down during my initial setup. After making sure everything was tight, I recalibrated and it all worked fine. I have since built a new stand for it, moved it and everything is still dialed in nicely. No problems since.