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Author Topic: Rectangular pocket vs cutter diameter  (Read 5808 times)

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Rectangular pocket vs cutter diameter
« on: February 20, 2014, 01:03:54 PM »
Hello all,

I've tried cutting a 1/2" rectangular pocket with a 1/4" end mill and I get a notice about width must be twice the size of tool diameter. Why is that and is there any way around it in Mill Wizard?

Re: Rectangular pocket vs cutter diameter
« Reply #1 on: February 20, 2014, 03:24:19 PM »
No, it is that way by design. You cannot cut a clean pocket if the tool is exactly twice the pocket, At least not with the toolpath I use.

Either ask for a .501 pocket, or tell it the mill is .249
« Last Edit: February 20, 2014, 05:51:23 PM by Ron Ginger »
Re: Rectangular pocket vs cutter diameter
« Reply #2 on: February 21, 2014, 02:12:23 PM »
Is it just me ? or, does something look funny here ?
Half inch pocket ... with a quarter inch cutter ? ? seems like that should work just fine.

"You cannot cut a clean pocket if the tool is exactly twice the pocket"  This part makes sense though. (quite difficult to do though).

Not sure,
Russ
Re: Rectangular pocket vs cutter diameter
« Reply #3 on: February 21, 2014, 03:47:08 PM »
Actually the issue is the circular ramp in which we set to be a ramp of radius equal to tool diameter. I am not really sure how we arrived at that number, but Brian picked it and it works cleanly. I suppose the code could check to see if a plunge cut is requested then allow the smaaller pocket.
Re: Rectangular pocket vs cutter diameter
« Reply #4 on: February 21, 2014, 04:19:28 PM »
Hi Ron,
 
In this case, maybe switch to a zig-zag plunge, then straight to cutting with a small (cutter * .25)  horizontal lead-in .. 
Thanks,
Russ
Re: Rectangular pocket vs cutter diameter
« Reply #5 on: February 21, 2014, 05:17:11 PM »
Thanks for the input guys. I tried changing the dimensions slightly, but it did not work. Even went to .600 and did not work. I am using a 15 deg. ramp in. I will try a straight plunge when I get a chance and get back to you. I might add that you guys are the greatest with taking your time to help us newbies.
Re: Rectangular pocket vs cutter diameter
« Reply #6 on: February 21, 2014, 05:24:15 PM »
Rev 1.0.11 works fine here.
What ver. are you using ?
Care to post your .job file ? Maybe you are not entering something correctly ?

Just a hunch,
Russ
Re: Rectangular pocket vs cutter diameter
« Reply #7 on: February 21, 2014, 05:33:23 PM »
The real issue here is that inside corners smaller than the tool are likely to chatter badly in the corner as the tool suddenly increases.  So I always try to design using a  radius about 0.010" larger than a standard tool so the clean up pass sweeps smoothly through the corner.  When I had to deal with on size radii I used to head to the tool room for an under size regrind. They were always sharp because no one else wanted to use them, and the tool guy really liked that I preferred them.
Re: Rectangular pocket vs cutter diameter
« Reply #8 on: February 21, 2014, 05:42:37 PM »
The real issue here is that inside corners smaller than the tool  ...........................

What exactly are you talking about ? Do you mead a .25" cutter creating a .125" radiussed corner ? If so, I get that.
A .25" cutter in a .5" wide slot is the same as a .25" cutter in a 5 mile wide slot. :)

Thanks Gary,
Russ :)
Re: Rectangular pocket vs cutter diameter
« Reply #9 on: February 21, 2014, 06:14:37 PM »
Russ,
Go get a 0.240 regrind and a put radii on your toolpath!  No chatter marks no programming problem.