Counterbore Questions

Here's the place for discussion related to CAM/CNC and the development of the Path module.
micksulley
Posts: 33
Joined: Fri May 11, 2018 9:28 am

Counterbore Questions

Postby micksulley » Wed Jul 11, 2018 8:18 pm

OS: Linux Mint 18.3 Sylvia
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.13959 (Git) AppImage
Build type: None
Branch: master
Hash: 2f18182b6dff87f8857787c854e39ca4d441f993
Python version: 2.7.6
Qt version: 4.8.6
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/UnitedKingdom (en_GB)

I have a design, attached, with a few counterbored holes. Just tried the gcode on my CNC and it raises a few questions, which may well be my lack of understanding -
1) I specified the hole diameter as 6mm (3mm bit) but is has cut at just over 5mm.
2) I specified the counterbore depth as 1mm, but it has cut at 0mm, i.e. not cut at all, just skimmed the surface. Looking at the operation properties it does show a Final Depth as 0.00mm, so I can adjust this, but I don't understand why it is not -1.00 as specified in the Hole properties.
3) If it had cut the counterbore it would only have cut the outer ring. My counterbore is 18mm dia, tool 3mm and it would have just cut the outer 3mm, leaving 12mm in the centre not cut. Is this how it is supposed to work?

Thanks
Mick
Attachments
test1.fcstd
(39.06 KiB) Downloaded 2 times
herbk
Posts: 912
Joined: Mon Nov 03, 2014 3:45 pm
Location: Windsbach, Bavarya (Germany)

Re: Counterbore Questions

Postby herbk » Wed Jul 11, 2018 9:05 pm

Hi,
you use the wrong operation for that... "Profile" makes allways only one "round", - it cuts a profile like the name says. ;)
Use Pocket OP instead and it removes all material in the holes.

For the wrong diameters, check your tool settings. At the file you postet there ps only the defoult tooll, not a 3mm as you write at your post and also the depth is at 0 for the counterbore, not at -1.

Here i used "Pocket" and to your placement fitting values for the dephts:
Attachments
test1_herbk.fcstd
(42.04 KiB) Downloaded 1 time
test1.jpg
test1.jpg (106.43 KiB) Viewed 107 times
Gruß Herbert
micksulley
Posts: 33
Joined: Fri May 11, 2018 9:28 am

Re: Counterbore Questions

Postby micksulley » Wed Jul 11, 2018 10:35 pm

Thanks for the reply Herbert, I have tried your code and it works, however I cannot get mine to work. The first problem is that I have Op Final Depth set to 0.00mm and you have -1.00mm. In your file I can change all of the Op Values, but in mine they are all grey and cannot be changed. Do you know why I cannot change those values in mine and how to fix it?
The other problem is that it looks like you selected each hole individually to create the operations. This design is an example, what I am trying to create will have around 200 holes, so I was hoping there would be a way to do that. Using the profile operation I just select the top or bottom surface and it picks up all of the holes. I cannot see a way to do that with pocket.

Mick
chrisb
Posts: 9045
Joined: Tue Mar 17, 2015 9:14 am

Re: Counterbore Questions

Postby chrisb » Wed Jul 11, 2018 11:09 pm

micksulley wrote:
Wed Jul 11, 2018 10:35 pm
In your file I can change all of the Op Values, but in mine they are all grey and cannot be changed. Do you know why I cannot change those values in mine and how to fix it?
These values are Expressions, which you have to discard before setting a fixed value or you click on the blue f(x) symbol and change the expression, e.g. by setting a fixed value.

The other problem is that it looks like you selected each hole individually to create the operations. This design is an example, what I am trying to create will have around 200 holes, so I was hoping there would be a way to do that. Using the profile operation I just select the top or bottom surface and it picks up all of the holes. I cannot see a way to do that with pocket.
There are several possible solutions:
- You take a mill which has a diameter bigger than half of the counterbore's diameter. Then you can take the profile operation
- if the holes have equal distance you can use PathArray to repeat a path
- you drill the hole first and the counterbore later, then the diameter of the mill has to cover only the stripe around the hole
micksulley
Posts: 33
Joined: Fri May 11, 2018 9:28 am

Re: Counterbore Questions

Postby micksulley » Thu Jul 12, 2018 8:49 am

Thanks for your help. Path Array is a gem that I had not discovered, just tried it and it is brilliant :D
chrisb
Posts: 9045
Joined: Tue Mar 17, 2015 9:14 am

Re: Counterbore Questions

Postby chrisb » Thu Jul 12, 2018 9:17 am

micksulley wrote:
Thu Jul 12, 2018 8:49 am
Thanks for your help. Path Array is a gem that I had not discovered, just tried it and it is brilliant :D
Glad to hear you could solve your problem.