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September 26, 2017, 20:41:48 pm


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Author Topic: 3-wing 3.2mm slot cutter for edges (vertical surface of hardwoods)  (Read 844 times)
Gordo
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« on: July 15, 2017, 20:32:08 pm »

After some trial/error I wonder what Mop should be used?   Also wondering if the 47.6 dia 3-wing x 1.6 or 3.2 width of cutter (6.36 arbor shank) is a problem?   I  ran (no load) at speed - seems solid wo vibration. 

My first go... simple test project: Walnut 50x50x50 (end grain is the top surface).  Wanting to route a 3.2 wide x3.2 depth slot around the 4 sides (vertical surface of the cube, say, at -10Z.  I'll set the depth increment "tender" to check quality of cut & machine attitudes…with fire extinguisher at hand!

Thanks,
Gordo
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dave benson
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« Reply #1 on: July 16, 2017, 04:22:43 am »

HI Gordo
I'm not exactly sure what what you were after, so I've made a file with what I think you were wanting to do.
Here's the cb file and a few shots of what it does.
I've used conservative speeds and feeds so you can always up to suit your machine.
Dave


* test square Capture.PNG (17.37 KB, 553x328 - viewed 32 times.)
* test square.cb (4.21 KB - downloaded 10 times.)

* testsquarecbCapture.PNG (145.48 KB, 1045x653 - viewed 26 times.)
« Last Edit: July 16, 2017, 04:25:48 am by dave benson » Logged
Gordo
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« Reply #2 on: July 16, 2017, 05:58:50 am »

Dave,

Thanks for your efforts - the complete .cb and resulting graphic of the cube.   Unfortunately that's not the problem I'm facing; I'm good with pocket mopping on the top surface of stock.

With a slot cutter mounted on a mandrel & chucked in the CNC, I want to route a continuous slot horizontally located at -10Z around the 4 vertical sides of the cube.  Other than the cutter moving, in the beginning, from 0 "Z" to -10 "Z", there is no other "Z" travel.  In case you're not familiar, a 47.6mm dia. 3-wing slot cutter is essentially a tiny 3-tooth saw blade; not able to cut material (pockets) in the top surface ( - "Z" travel).

Therefore several trips around the 4 sides, each trip increasing the depth of cut (only X & Y) till the slot is 3.2 deep.

I hope this better describes the project; and you can state the proper mop to use to define the tool movement around the four vertical sides of the stock.  If the stock was not a cube, the four vertical sides could be called edges.

Thanks again for your efforts; the fine files and examples.
Gordo     
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dave benson
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« Reply #3 on: July 16, 2017, 06:04:39 am »

HI Gordo
I now know what you mean, look here http://www.cambam.co.uk/forum/index.php?topic=6526.0 this will do the job.
edit fixed link
Good Luck
Dave
« Last Edit: July 16, 2017, 06:22:44 am by dave benson » Logged
kvom
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« Reply #4 on: July 16, 2017, 13:03:03 pm »

As a longtime CB user I find it's quite easy to cut slots like that using a regular profile MOP.

Define the tool as the diameter of the flutes.  You can use the border polyline and specify a negative roughing clearance for the amount of the slot depth.  Or else draw a polyline to match the depth needed.

To get multiple passes set the stepover to match the cut depth for each pass, and the cut width greater than the tool diameter by the slot depth minus one pass depth.

Set the target depth to position the cutter at the proper depth, with depth increment = 0.

Finally set tangent as the leadin and leadout with sufficient radius to clear the slot at the end.

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dave benson
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« Reply #5 on: July 16, 2017, 14:19:42 pm »

HI kvom
Just tried that and it worked well.
Dave


* groove around block Capture.PNG (23.51 KB, 773x381 - viewed 37 times.)
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Gordo
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« Reply #6 on: July 16, 2017, 23:54:01 pm »

Thanks, Gentlemen.

I'm just getting to it; I'll feedback after a trial run.  Good news, Kvom.  I purchased the the slot cutter, with the 3.2mm kerf hoping that CB could drive it, for horizontal carving. 

Dave, your "grooved block capture.png" shows some "Z" changes - various slot widths on the sides of the block. You must have had some "Z" settings differing from Kvom's info?

Many thanks for the help,
Gordo
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dave benson
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« Reply #7 on: July 17, 2017, 00:33:54 am »

Yes I was trying to get the tool down to position before entering the stock without having to use the leadin and leadout.
If you can post a pic of your slot when your finished. It would be interesting to see how it turned out.
Dave
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Gordo
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« Reply #8 on: July 17, 2017, 09:50:08 am »

Hello Kvom,
I worked through your notes: A question on this one:  "Finally set tangent as the leadin and leadout with sufficient radius to clear the slot at the end"   With the cutter radius of 23.8 and a slot depth of 3.2 and the stock is 48.8 x 48.8,  what would the "sufficient radius" be?  Radius measured from/to?   I set the center of the 47.6 dia cutter at X 0, Y 0.  The corner of the stock is X 23.8, Y 23.8

Also, is the tool profile "unspecified"?
I set the cut depth at .8  (4 passes) with cut feed at 100 to eliminate chatter and rough edges; probably too conservative?

Gordo
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dave benson
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« Reply #9 on: July 17, 2017, 10:43:49 am »

HI Gordo
Here is my file with tangent leadins and outs as per Kvoms instructions.
And a shot to see the toolpaths in camotics.
Hope this helps.
Dave


* my slotting file with tangent leadins and outs.PNG (23.82 KB, 832x383 - viewed 17 times.)
* slot test around block.cb (4.86 KB - downloaded 19 times.)
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kvom
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« Reply #10 on: July 17, 2017, 12:54:54 pm »

The actual radius isn't that important as long as it's large enough that the tool doesn't hit the work on the way down and back up.  The larger the radius the longer the tool cuts air at the start;  not important for a 1-off part.
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Gordo
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« Reply #11 on: July 18, 2017, 22:09:38 pm »

kvom,
The tool paths graphic shows only two passes, the first at .8 and the second at 3.2 (final slot depth).  With .8 as depth of cut for each pass -- .8 x 4 passes = 3.2   Shouldn't it show 4 passes?

I must be missing something in your notes:  "To get multiple passes set the stepover to match the cut depth for each pass, and the cut width greater than the tool diameter by the slot depth minus one pass depth."  Therefore I set 'stepover' at .8   and 'cut width'  at 50.   47.6 + 2.4  (3.2 -.Cool

BTW, the tool paths diagram shows the paths (blue & green) of the axis of the slot cutter.   My drawing has the cutter axis at 0,0 and the stock at 23.8,23.8   Is that OK ? 

G.
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Gordo
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« Reply #12 on: July 18, 2017, 22:27:22 pm »

kvom,
Upon opening the .nc and .cb files of this project, I'm getting  "An unhanded exception has occurred - Object reference not set to an instance of an object."    I must have a glitch in my settings.

G.
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kvom
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« Reply #13 on: July 18, 2017, 22:30:23 pm »

Post your CB file.  Always a requirement for help.
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Gordo
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« Reply #14 on: July 19, 2017, 03:13:25 am »

Post your CB file.  Always a requirement for help.

Slot in cherry.cb 

BTW I've changed the stock size "Z" from 50 to 38 & from walnut to cherry -  both from original specs….. the "Z" for CNC carriage clearance.  FYI in case you were wondering  Smiley
G.

* Slot in Cherry.cb (4.53 KB - downloaded 16 times.)
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