[mikefalkner]

When using Mastercam’s “Lead In/Out” feature on Contour toolpath programming, it will leave a dent where it leads in and leads out. See attached photo of an example on a piece of scrap wood. Dent is between yellow arrows.

I have tried many, many settings under the “Lead In/Out” tab, and always this dent. Plunge rate is allows half the feed rate.

Have tried Perpendicular vs Tangent.
Changed Length % from 150, 100, 80,60, 40, and 20.
Changed Radius % from 150, 100, 80, 60, 40, and 20.
Changed Sweep from 150, 100, 80, 60, 40, and 20.
Checked Override rate from 100, 80, 60, and 40.

I can solve this problem with a work around for outside contours by modifying the geometry for a start/end point off the contour. But that is a lot of work when the Lead In/Out feature should eliminate this problem. However, I cannot modify an inside closed contour. Besides, there are many closed contours in our work pieces.

I have watched a basic Lead In/Out tutor at:
youtube.com/watch?v=GurqXngB7oE]mastercam

Nothing works. What am I doing wrong?

[Tony T]

can you post your file. I will take a look at it. If I get time over the holiday I could post it an run on my machine to see if I get the same thing.

[mikefalkner]

Thanks Tony,

Attached is the MCX-6 file in zip format. Hope you have version 6 or higher. If not, I have uploaded screen images of the key parameters for you can input the same parameters in your version.

Again, thanks for your offer to help.

Mike

[Tony T]

Hey Mike I downloaded and posted your file out went through the numbers and am not seeing anything obviously wrong. I'm wondering if it might be something in your setup or maybe machine following error. I will try to run it in some wood this weekend to double check the nc output.
Tony

[Robert M]

Another thing....tickle me.....what is your machine and set up !?

[Superman]

Another thing....tickle me.....what is your machine and set up !?

Also, I am not seeing "depth cuts"
- you are cutting 1/2" deep with a 1/4" cutter.... my calcs tell me it is a 2 flute cutter
.....is cutter new ?
.... HSS/CBD ?
....how much cutter stick out of tool in holder ?
.... Width of stock being cut ? (ie 50% of cutter width or less)

Does your finished part measure the same as the Mastercam drawing ( or close to it ) ?

Your 1st pic seems to indicate cutter flex

[hoffmannm]

file looks good to me as well. You could try to add .7 or whatever variation to the "overlap" option in the lead in/out, that will spread out the lead in/out.

I am leaning to the cause being something in real life though. How close in the EM to .25?

[mikefalkner]

SOLVED

Found my problem - several of them.

First, finally noticed that my bearings on my linear rail shaft has gotten some dust contamination in the bears, causing loss of precision. Then found my x-y axes slightly out of square. Both of these were not the direct cause of poor line up with lead in/out problem, but it certainly does not help! Noticed this when I was tring to cut matching circles -- but circles were not perfect.

Second, I was just brute forcing a dull HSS 1/4" compression bit at 1/2" cut depth at 100% cut width with stick out distance of 1" -- not a good idea. Started think about the issue with this brute force dumb method after reading Superman's comment (THANKS).

Conclusion: Take a couple of days and replace bears, completely re-align my cnc table, and learn about proper feed/speed settings and use of multiple cuts (rough and final). Sorry to had bothered the cnczone community with my elementary problem, but sometimes one just need to talk to someone else to get some ideas and direction -- even if you are stuck with such a simple and obvious problem. AGAIN, THANKS

Mike

[Robert M]

Glad you solve....or at least you found it and it got you evolved in this ( CNC-ing).
See....you should't feel dad or excuse to "bother"...this is part of...call it mission....of these groups / forums....is to help in any "best possible" way.....witch in your case, it got you going and help / motivated you to find your ...trouble !
Ooray !!....i see this as win /win !!
Perception....amazing hen !!
All the best in your learning curve