Controlling Material Left In The Center Of Small Holes

I bought a file from Etsy that might possibly become a wall hanging based on an old Japanese woodcut I’ve always liked called The Great Wave. If I solve a few issues it’ll be 4 layers of 5mm material. I was trying to cut the top layer which has a number of smallish odd shaped holes to allow seeing the color of the layer beneath. I’m using woodworking tape to hold the material down and thought I’d pressed it down enough so the centers of the holes would be held in place, but, in two attempts the center of a smaller hole has come loose and caused enough commotion to cause the belt to skip a few steps and I aborted the job. Of course my old pal Murphy wouldn’t allow that to happen too early in the run. So I’m asking, are there more reliable methods to keep this from happening?

Cut the hole as a pocket??

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how small of a hole are we talking?

I’m assuming the piece that’s getting stuck is larger than the size of the bit.

If the hole is small enough, it may just be a simple matter of using the endmill to drill a pilot hole in the middle of the hole so that cutting the edge removes everything. If the hole is larger than that, then I agree with Tim that I’d do a pocket on the smaller holes to remove everything.


Doh! Thanks guys, I hadn’t even considered switching to a pocket but it sounds like a plan. :+1:

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Reconsidering how to do this as I think I’ve made enough kindling already. Instead of worrying about there being enough tape under the bigger cut outs I can switch to holding tabs but the last time I tried that(may have also been the first)I got undercuts on either side of the tab like so:
Is there something avoidable that causes this?

And looking at pocketing strategies, they all seem to have islands. I only want to pocket the smaller cutouts but would really like to start in the middle and work outward so there’s nothing left to break off and cause problems during the final cut, just sawdust in the vacuum. Is there a way of doing this?

The over cuts on the tabs is commons and caused by a difference in flex during the plunge vs side cutting. Not sure what cam you are using, but in f360 there are ways to use lead ins for open contours which can eliminate the over cut near tabs. This can lead to a lot of work though as you have to do a separate operation between each tab.

Edit… the over cut may also be caused by plunging too fast where the bit is walking a lot. If this is the case you can try reducing your plunge rate for the tab operation and see if it helps.

Regarding the islands… in f360 you can break out each pocket separately to do them in order. With 3D pockets you can select geometry to contain each operation… or use 2d to select actual contours etc.

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Thanks, that I can understand. I’m using Estlcam for CAM and kinda almost getting comfortable with it at times and other times not so much.

I learned some CAD/CAM 20 years ago on a pricy commercial program, MasterCAM VIII Level I which cost ~ $5K back then (a friend had a shop). While I have no doubt a number of the free programs available today are at least as capable if not more so I have yet to find a more intuitive program to use. I may have had 15-20 minutes with a company rep but literally sat down and pretty much started doing what I wanted to do. When they forced V. X on my friend, while it may have been an upgrade for the full time user, for us basically using it at a hobby level, we quickly reverted to V. VIII. I’m still looking for something as intuitive to use today.

I came from solid works (v5 iirc) which is what my work used. I have the cd and license to use it, but when I started the mpcnc project I looked at more modern stuff. Estlcam just did not fit for me, and f360 felt familiar to me (college drafting taught me acad).

Btw… had some latent thoughts and edited my post above. Just wanted to make sure you saw the part about plunge walking. I honestly think this is more so the cause for most mpcnc rigs especially with smaller bits.

Yeah, it was a small diam. bit and a little walking doesn’t surprise me.

I stumbled around F360 a bit and while impressed with its capability it seems a bit complicated for my needs. My needs would likely be met my simple lines, arcs, shapes, tangents, etc. What I miss is having two intersecting lines and being able to choose the segments I want to keep and deleting the rest easily, Or forming a fillet or rounding a corner to my specified radius easily. I used to be able to do something like draw say a circle on one level, an ellipse on another, and with 2-3 clicks create a surface between them. And tho it wasn’t a full 3D version I could slice it into thin segments, mill it, and it sure made a 3D shape. Nothing I’ve looked at yet in the hobby area seem to do that, I thought maybe it’d all filter down after 20 years.

Paul, I am new to all of this and bought an F360 class on Udemy for $20.00. By lesson 4, we are doing all of the things you just mentioned.

“What I miss is having two intersecting lines and being able to choose the segments I want to keep and deleting the rest easily, Or forming a fillet or rounding a corner to my specified radius easily. I used to be able to do something like draw say a circle on one level, an ellipse on another, and with 2-3 clicks create a surface between them.”

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Appreciate the reply, Thanks! I’d fiddled a bit with 360 in the past and seemed to have an amazing ability to click in the wrong place and get myself completely off track. :roll_eyes: I’ll probably have to have another look although I have to confess I never really read through the changes they made recently about just what you can/cannot do with the free version. I’ll have to check out that class. Do they have classes for other programs? Of course I’d still like to find something that’s so intuitive, sitting down and using it is possible.

The only intuitive interface is the nipple, after that it’s all learned… 8^)

I would bet that even what you remember from Mastercam wasn’t intuituve when you first encountered it. I don’t see any of the CAD/CAM options as intuitive. Some are easier to pick up than others (tinkercad…), but limiting; while others are much more powerful, but inherently present a steeper learning curve. I think the thing to do is research the options, and try to determine which option seems most likely to meet your needs. Then devote some serious time and effort into learning the program.

Shortly after I got a 3d printer I started looking at the CAD options available. I’m a linux guy some my options were more limited, but taking the cloud based options into account there were still a number of choices.

I had essentially no CAD experience…I had used AutoCAD…a tiny bit…in the '80’s, so regardless of which route I chose I knew I would be starting from scratch. I opted to try FreeCAD. It runs on linux (as well as windows and mac), and is open source, which I strongly prefer. (The recent changes to Fusion are one good example of why I prefer open source). There are a number of multi-part youtube tutorials I watched to help me get going. Sadly I don’t pick up anything as quickly as I did 30+ years ago, so it took some time and effort, but I’ve gotten pretty good at the basics. I still have a lot to learn, and would certainly pay for a good course in more advaced usage, but I’m happy with my choice.

When I built my Lowrider I revisted the CAD/CAM options to see if I might want to try a different approach for the CNC, but decided to stick with FreeCAD. There doesn’t seem to be much in the way of tutorials for the CAM functionality, but there was just enough to get me up and running.

I don’t know, I don’t think my memory’s that far gone … yet. :scream:
If not intuitively, I know I picked it up really, really quickly for something I’d never seen before. I was basically a hobby user but we’d been in touch with someone using MC VIII virtually every day as a small business owner, even he said that when he ‘upgraded’ to MC X the learning curve was much steeper than with VIII. Logic would tell me that upgrading to a newer version of something you’ve been using, it should be a relatively easy transition, apparently not. Kinda like when some programs do an automatic ‘upgrade’ and become less user friendly, I have difficulty considering that an ‘upgrade’.

I completely agree with you when you say "I think the thing to do is research the options, and try to determine which option seems most likely to meet your needs. Then devote some serious time and effort into learning the program. " I guess the real problem may be I suffer from ‘Kid in the candy store’ Syndrome. Soooooooo many choices, which one to pick? :woozy_face:

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I spent a bunch of time trying different cad packages and I got frustrated a lot at first. Part of it was, I was blaming the UI for me not understanding how to use it. But some of it was just that I didn’t like to think the way the cad package was making me.

The first CAD I used was autocad (not fusion, some 2D thing from the 90s, using the license at my high school). I got pretty good at that for 2D drawings. I then tried sketch up in the 00s and that also made a lot of sense once you learned a bit of it.

I wasn’t happy with any of them until I tried librecad, but now that I use a “real” 3D cad package, I find librecad cumbersome. I think it’s ok to move around (as long as you aren’t buying all of these packages) and I think there are plenty of free choices that no one should have to pay to try any of them out.

Each package I tried, I did learn a little and I honestly think I could get along well enough to make something like a rambo electronics case in any of the packages I’ve tried in the past. For me personally, I am most comfortable in onshape, and least comfortable in fusion.

What I’d like to be able to do and am not sure it’s possible:

Something like F360 is amazing, I know if I wanted to spend a large amount of time, lots of practice, and likely a good part of my sanity, I could likely do a complete animation of a V-12 engine at work. But that’s no where in my projected needs. What I’d like to be able to do is take any icons on the UI that only pertain to doing something I don’t need and delete them just to eliminate some distractions and things I might try when I can’t figure something out.

And I’ll freely confess, while I’ve looked at a number of programs I haven’t felt enough interest in any yet to spend a lot of time studying. For some simple things I’ve made do with Tinkercad but definitely want something more capable. At the moment I’m working with a file obtained from Etsy and it’s been teaching me some things about Estlcam so I’m making some progress, tho in fits and starts it may be.

At times I’m my own worst enemy when I don’t pick something up asap.

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I think you’re doing fine.

I would point out a few things:

  1. The tool is just a tool. There is no reason fusion is any better than tinkercad. I think that is a false assumption. Anything you can finish in tinkercad is a project well done. I wouldn’t feel any pressure to use something that gatekeepers deem as “better” if you aren’t enjoying it. And if you ever do “grow out” of tinkercad and need something with more options, you will have stronger footing with your experience in tinkercad. They really all have something in common.
  2. The large array of icons can be intimidating, but there is a point when you can get a mental map of what is there and you don’t have to understand everything, you just need to know how to find what you need. It won’t really serve you to have more than one layout in the long run, because once you grow past the starting icons, you will have to remap everything with a new layout. My guess is that once you’ve used a third or half of the functions, you will have that map and be able to find them all a lot quicker.
  3. You don’t have to know everything all at once. If you learn one new button/tool with each project, and you are actually finishing projects, then you’re winning. It is a marathon and not a sprint.

Probably one of my biggest mistakes is not reminding myself of that more often, I get antsy. :roll_eyes: In school, although I could study things like history until I ‘got it’, I sometimes had problems studying something like math if I didn’t grasp a concept first time through, but I learned to work through it. Given ~9 months ago I never thought I’d have a CNC machine in the backroom I guess I’m pretty far ahead of where I thought I’d be. :grinning:

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I just cut the top layer of the piece I’m working on and ‘pocket’ was a good idea! Thanks to timonjkl for suggesting it . :+1:

I also learned I should be a little more judicious with what areas I pocket when working with a 1/16" bit, it was a looooooooong cut. :roll_eyes: Laser has entered my consciousness.

Now a question, the last operation was drilling a hole in each corner of a rectangle and the transit speed between hole locations slowed way down from the transit speed between the multiple areas I’d cut. Is there a setting in Estlcam for speed between hole locations that’s different than speed between pockets, parts, etc. that I missed?

Sounds like it is using the tool move speed not the movment between cuts speed G00 or G01. If there are just a few cuts do them separate and see if that helps.

I didn’t know there was a difference. Used the same tool for the entire job and the tool speed was the only speed I set. Is ‘tool move speed’ settable?

But I have another issue. I cut multiple pockets and holes, all thru cuts. In 3 pockets, cuts didn’t go thru as they should have while cuts on either side of them were fine. Near as I can tell there was no alien force field sucking the wood down in those 3 places. :roll_eyes: I’d just decided today I thought I could live with Estlcam and paid the license fee. I feel like I’m being punked. I’ll post a pic or two tomorrow, right now I feel like I’ve earned an adult beverage or three.