Machsupport Forum

Mach Discussion => General Mach Discussion => Topic started by: Shaggy on January 08, 2016, 07:11:46 AM

Title: Problem with round letters
Post by: Shaggy on January 08, 2016, 07:11:46 AM

Hi!

Im drawing in CorelDraw, than I create toolpath in ArtCAM which I use on MACH3.
Im using EndMill 2mm.

Mach 3 settings:

Velocity: 600
Acceleration: 140

My problem is that machine causes those weird errors on round letters like you can see on pictures.
Some of letters like ''D'' are perfectly shaped in the other hand there are lettery ''O'' and ''F'' with those errors.

I tryed changing velocity and acceleration  but problem stays the same.

Does anyone know how to solve this problem ?

Please help!

Thanks
Good letter:
(http://s14.postimg.org/l5843ay65/Dobro.jpg) (http://postimg.org/image/l5843ay65/)

Bad letters:
(http://s14.postimg.org/vpi1lw2nx/Lo_1.jpg) (http://postimg.org/image/vpi1lw2nx/)
(http://s14.postimg.org/ve0l94m7x/Lo_2.jpg) (http://postimg.org/image/ve0l94m7x/)

Title: Re: Problem with round letters
Post by: Davek0974 on January 08, 2016, 07:17:15 AM

Is there any backlash in either of the axes??

Title: Re: Problem with round letters
Post by: Shaggy on January 08, 2016, 07:56:02 AM

Quote from: Davek0974 on January 08, 2016, 07:17:15 AM

Is there any backlash in either of the axes??

Here, I uploaded a video of a working machine, so check it out.

https://youtu.be/zTNxxEgkmW4

Title: Re: Problem with round letters
Post by: Tweakie.CNC on January 08, 2016, 07:59:47 AM

There appears to be a lack of rigidity with your machine - perhaps tool flex, perhaps axis flex, perhaps backlash (as Dave has suggested).
Maybe more passes with shallower depth of cut, reducing the tool loading, would help.

Tweakie.

Title: Re: Problem with round letters
Post by: Shaggy on January 08, 2016, 08:11:06 AM

Quote from: Tweakie.CNC on January 08, 2016, 07:59:47 AM

There appears to be a lack of rigidity with your machine - perhaps tool flex, perhaps axis flex, perhaps backlash (as Dave has suggested).
Maybe more passes with shallower depth of cut, reducing the tool loading, would help.

Tweakie.

How to reduce tool loading ?
I dont think more passes with shallower deoth of cut would help, cause I tryed it already.

Title: Re: Problem with round letters
Post by: Davek0974 on January 08, 2016, 09:43:10 AM

To reduce tool loading, run at a lower speed on the X/Y
Or increase tool speed/rpm but only of course if the tool/material can take it

Title: Re: Problem with round letters
Post by: rcaffin on January 10, 2016, 04:42:06 AM

Quote

There appears to be a lack of rigidity with your machine - perhaps tool flex, perhaps axis flex, perhaps backlash

Yup, and possibly both flex and backlash.
You may have run into a limit of what your machine can handle.

Cheers
Roger

Title: Re: Problem with round letters
Post by: Davek0974 on January 10, 2016, 05:58:02 AM

What machine is this?

A plasma table?
Wood routing table?
Other?

It's not a milling machine thats for certain;)

Title: Re: Problem with round letters
Post by: ger21 on January 10, 2016, 07:31:49 AM

Try ramping in rather than plunging.

Title: Re: Problem with round letters
Post by: BR549 on January 10, 2016, 09:09:48 PM

Also varify that you are useing tools that are end cutting. There are those that are NOT.  Also try a tool that has a point or a ball end. That coul dhelp take out some of those forces that tend to push and pull your backlash or flex around.

Just a thought, (;-)TP