Bottoming out a collet nut

[Gasawdust]

Was reading RC Newcomb’s post about worn out collets (very informative responses….thank you) and started thinking about how to avoid “bottoming out” thus damaging your material, carving, and/or the collet and nut.
Maybe there is something already in Aspire or the controlling software that will indicate limits on the combinations of the x,y,and z cutting parameters and I’m not aware of it. If not might this be a place for a “gadget” ?
Just brainstorming.
Tom

[adze_cnc]

By "bottoming out" I expect you are not talking about inserting a bit so far into the collet that its blunt end comes into contact with whatever type of cone the collet is mounted in (which can eventually cause it to walk out of the collet).* I expect that you are talking about impacting the material with the collet/collet nut.

RhinoCAM for Rhino3D has the ability to enter the length the bit projects from the collet. It then uses that you avoid crashing the machine into the material. The problems with that are:

• every time you load the bit into the collet you need to update the value in RhinoCAM
• if you forget to do that RhinoCAM can generate code that can impact the material

Managing those lengths become so tiresome that you'll just put one long value in an revert to trusting yourself.

"Am I cutting through a 1.5 inch piece of material? Yup, then I need to make sure my bit projects greater than that."

"Am I cutting with a 1/8" end mill that has only 1/2" depth because it flares to a 1/4" shank? Then I can't cut through that 3/4" piece of HDPE"

A software solution can only tell you that you can't use the cutter. Sometimes you need to be creative to cut what you want so that you can use a cutter. At the top of the attached image is a step. That step is there to allow the collet nut to go below the level of the material so that the cutter (which was too short) could get to the bottom of this model's side.
 

 
Would it be good to modify the software/create a gadget to manage tool lengths? Maybe. But I still measure to make sure that the cutter can cut to its required depth. I have only rubbed against materials a few times when I tried to squeeze out that last 1/100th of an inch and found that the material was thicker in the middle than at the edges.
 
 
* Regarding bottoming out a collet. I once accidentally did that with a palm router. No one was more surprised than I was when, after a few cuts, the bit shot towards the floor and tried to embed itself into my steel-capped boots.

[Gasawdust]

“RhinoCAM for Rhino3D has the ability to enter the length the bit projects from the collet. It then uses that you avoid crashing the machine into the material. The problems with that are:
- every time you load the bit into the collet you need to update the value in RhinoCAM
- if you forget to do that RhinoCAM can generate code that can impact the material”

I don’t know nor own Rhino products but have invested quite a bit in Vectric to satisfy my hobbyist itch.

I posted in Vcarve but the issue , IMO, is equally if not more important to Aspire 3d use. There have been several times that I have bumped into the side of the model with the collet nut when carving a lower section (-z) of the model. I know there are precautions I can take by using a longer bit but sometimes it’s dang nigh impossible to predict it.

We specify bit sizes and the software warns us (and in some cases stops us) from using the bit selection when it won’t fit into an area we wish to carve. This being the case I don’t see the concept of specifying a collet nut size being much different. Yes, we would have to measure the length of the protruding bit but that, again IMO, is a relative easy process if that ensures we won’t ruin a carving.



I can’t be the only one that runs into this issue and if RhinoCAM for Rhino3d can predict this I’m sure the Vectric folks can solve this for us.

[Rcnewcomb]

I've used other CAM software that will do collet collision detection. It does require the user to enter additional parameters: the free length, cutting length, and the collet diameter. That adds further complexity to the tool database which makes the learning curve steeper for beginners.

I've submitted a feature request to include collet collision detection in a future release. If enough people request then Vectric would likely add it at some point.

[Leo]

I have also used crash detection but usually on more expensive software, MUCH, more expensive.

When putting a cutter in the spindle you can use a tool like this one :
https://www.amazon.com/iGaging-Double-S ... C83&sr=8-5
To measure and ensure that the cutter is sticking out of the collet far enough.

When I was programming in the industry I had set up sheets for the machinists to use. Where applicable I listed the "stick out" length. The machinist would use a square to set the length. It's quick and easy.

Having the machine stop and warn you about an impending crash is at a different level. Maybe Gary Campbell or one of the Lua craftspeople can devise a way to do it.

[Gasawdust]

That’s encouraging news.
We have other features that are toggled on/off depending on your circumstances and needs.
Thanks for the responses.
Tom

[SteveNelson46]

I have also used crash detection but usually on more expensive software, MUCH, more expensive.

When putting a cutter in the spindle you can use a tool like this one :
https://www.amazon.com/iGaging-Double-S ... C83&sr=8-5
To measure and ensure that the cutter is sticking out of the collet far enough.

When I was programming in the industry I had set up sheets for the machinists to use. Where applicable I listed the "stick out" length. The machinist would use a square to set the length. It's quick and easy.

Having the machine stop and warn you about an impending crash is at a different level. Maybe Gary Campbell or one of the Lua craftspeople can devise a way to do it.

Leo,
That's exactly what I use. I'm revisiting the butterfly box that llwood posted a couple of years ago and the shank on my bowl and tray bit is just barley long enough. It did take one "oops" though.

[cncroi]

I second the "need" to have CCD added to the tool database, or alternatively as a stop-gap, adding the ability to max the depth of clearance in the 3D roughing and 3D finishing carving options... the first would be more robust but second might do the trick for most people. It's easy enough to then have multiple tools, with different specs that WOULD clear to do the deeper work by adding rest machining.

[cncroi]

With 4 tools on my old CS40 on the tool changer, managing this was relatively easy, I've now upgraded to a dual-table C42-207 Thermwood with 19 tool changer so now this is actually a real concern as now I can optimize production further and keeping track of all the heights isn't something easily managed with vectric... crossing my fingers for April release of something like this.

[TReischl]

Some food for thought.

Is a software solution really the best way to go?

Most metric end mills are made to standard overall lengths. Maybe not accurate to within a gnat's backside, but pretty darn good.

Howzabout a mechanical solution? A collet nut that allows a bit to be bottomed out? Then one could have a simple database that says something like 6mm end mills stick out approx 50mm when inserted fully. One could still touch off the tool to get required accuracy, but the software would have the info it needed without a miserable exercise in maintaining how far things stick out, or having to tell it every time, etc, like is being discussed above.

I am thinking the conical nature of router spindles is the issue. Not sure what they do on real spindles since I do not have one. I am willing to bet if that conical shape was filled up by something that presented a spherical surface to the bit, the walking out of router bits would cease to be an issue. I think that cone shape causes the tool to seat at angle which results in the collet not being fully closed.

It would be easy enough to machine up a matching cone on a small lathe, give the end that touches the router bit a slightly spherical shape. Then pop it in with some thread lock. Heck, one could drop a small ball bearing in the spindle with a bit of thread lock on it.

It is my opinion that it has become common place to try to fix all things via software solutions. In a case like this we end up with a miserable solution that is hard to maintain by the average user when a simple mechanical solution is possible.

[TReischl]

With 4 tools on my old CS40 on the tool changer, managing this was relatively easy, I've now upgraded to a dual-table C42-207 Thermwood with 19 tool changer so now this is actually a real concern as now I can optimize production further and keeping track of all the heights isn't something easily managed with vectric... crossing my fingers for April release of something like this.

Face it, managing a 16 tool holder and all the tool lengths is not a walk in the park with any software. Early in my last life I programmed a Monarch VMC 150 vertical mill with a 40 tool changer. It was like the operator spent half his time keeping tool lengths set correctly and documented accurately.

[sharkcutup]

' Bottoming out a collet nut '

Not a problem here!

Paying Attention to the Details is always a good recommendation when planning/designing a Project. Checking, Measuring and Double Checking Everything is Truly KEY to a Successful Project!

Sharkcutup

[Gasawdust]

I was the OP and posted below is the original issue causing the discussion. I think we steered the intent of the discussion in a different direction.

“I posted in Vcarve but the issue , IMO, is equally if not more important to Aspire 3d use. There have been several times that I have bumped into the side of the model with the collet nut when carving a lower section (-z) of the model. I know there are precautions I can take by using a longer bit but sometimes it’s dang nigh impossible to predict it.”

Tom

[cncroi]

Bumping the side of a model or trying to go deeper without hitting anything else in a carving is the same thing in my book - and the solution would be the same as well. The longest bit I have in my system is 6" long 1/2" diameter roughing bit and even with that, I have to watch things with some projects I take-on.

To get around this for the time being, I'm going to have to slice-up models and glue them back together, absolutely not ideal but finding LONG bits just isn't easy, even if they are custom, many manufacturers of bits just don't want to make them for you as they are so prone to breaking.

Regardless, would be nice to have a way of letting vectric know the bit length isn't infinite as it assumes it to be now.

Jon

[Tailmaker]

I was the OP and posted below is the original issue causing the discussion. I think we steered the intent of the discussion in a different direction.

“I posted in Vcarve but the issue , IMO, is equally if not more important to Aspire 3d use. There have been several times that I have bumped into the side of the model with the collet nut when carving a lower section (-z) of the model. I know there are precautions I can take by using a longer bit but sometimes it’s dang nigh impossible to predict it.”

Tom

You could define a form tool, that includes the collet shape (and bit length). It is only a partial solution as (while it prevents a collision) it will also prevent the bit reaching the low areas if the collet gets in the way and it will give you no warning. But maybe you can recognize the problem looking at the simulation. Admittedly I have never tried that.