incorrect tangent point and tool compensation dilemma

[Paul_NextMedicalDesign]

Hello,

I need to make a part with a small flange with two 25 deg chamfers on the sides.  Because of tight tolerances, I want to cut both chamfers with the same tool insert, a 35 deg neutral tool.  I am having difficulties specifying the insert's tool compensation correctly in the tool library, and this has a direct impact on my g-code path and part dims.  The insert has a .008 tip radius, and there is a .008 radius fillet at the bottom of the flange that I marked in the jpeg with a red R.  I made the model sharp so I can get the g-code to post "correctly" with a sharp corner, so that when the tool with the radius cuts, the radius will be on size.  I also made my tool insert with zero radius to try this work-around.  I think this problem and work-around ideas would not be necessary of I could select "tip tangent" in the tool compensation area.  But you will see in the other jpeg, where fusion misinterprets this insert and puts the tangent point at the insert width instead of where the tool cuts.  I am not a tool compensation expert, but as I toggle through the options, I don't see a solution jumping out at me.  Right I am making a zero radius tool and also manually programming my g-code to get this to work reasonably well.  Suggestions greatly appreciated.

PAul

[zwelsh91]

Two things stand out here:

1: You should be using a tool that is defined with the same geometry as the one you are physically using in the machine. That meaning add the .008 rad to the tool definition.

My suggestion would be to spend a little more time defining your tool in the tool  library.

2: With a properly defined tool the software will naturally generate the toolpath that you are looking for.

Here is a tool that I have in my library that was created years ago that is defined correctly:

(Note: This tool is used with CCW spindle rotation)

[Paul_NextMedicalDesign]

Hi Zak,

Thanks, and I agree with you 100%.  But Fusion will not allow me to define my tool correctly, hence I am using a zero rad tool as a work-around. 

If anyone is using a neutral tool (see jpeg) and can define it correctly with tip tangent, please jump in.

Paul

[zwelsh91]

I beg to differ. Here is a quick and dirty setup of a neutral 35º diamond tool with the compensation point in the correct location with a .008 corner rad:

[HughesTooling]

@Paul_NextMedicalDesign When I've done jobs like this I've set the tool up like @zwelsh91 shows in Fusion. On the machine I've touched off at the leading corner of the tip but instead of setting it to zero I set to +half the width of the tip so zero is the centreline of the tip.

Touched off where the arrow is.

[Paul_NextMedicalDesign]

Hi Zak,

You might be calling me a liar here....I looked again at the tool library and I want to say there is probably a bug....one might say a "minor" bug that might not come up often.  It seems that since I chose the option "no holder" under the holder tab, under style, it creates this situation (bug?) that throws the tangent point off the insert like I showed in the original .jpeg.  Your response spurred me to try replicate your tool, and I discovered this weird behavior.  So, this might be the solution I'm looking for...I just need to add the tool holder and hocus pocus, the cutting point looks to be correct ...I'll do a G-code test and report back.

As a side note, I typically do not use a "holder" in my tool libary because there are times when the holders don't match the tool I have (for example, small boring bar tools with no inserts) which can cause other issues.

Thanks,

Paul

[Paul_NextMedicalDesign]

Hi Mark,

Thanks for the tip.

PAul

[seth.madore]

---

@Paul_NextMedicalDesign wrote:

As a side note, I typically do not use a "holder" in my tool libary because there are times when the holders don't match the tool I have (for example, small boring bar tools with no inserts) which can cause other issues.

Thanks,

Paul

---

Running without the holder should only be done as an exception, not the rule