Unwanted Z component in G2 and G3 output

[Zoeper]

Hi All,

 

I am having a niggly problem with a post that started to post a Z component in some lines with G2 and G3. This happens even when i am doing only 2d contouring and the drawing (imported via DXF) is all on one plane. The Z component is only a minute 0.003mm or so, but it bombs out the CNC control.

I only have Arcs in XY enabled, but can not get rid of the problem. Is there a switch that i am missing in the post to correct this?

As a workaround, i am just deleting the Z-moves from the arc moves by hand, but sooner or later i might make that one typo that wrecks a cutter, part or machine.....

Any help or guidance towards the fix would be much apreciated.

 

 

MasterCamX3

 

X253.622 Y-40.479

Z1.

G1 Z-1.833 F100

G1 X242.339 Y-29.231 F600

G3 X233.22 Y-31.58 Z-1.83 I271.89 J-162.81

G3 X253.62 Y-40.47 I753.05 J1132.13

G1 X259.523 Y-40.714 Z-1.833

G1 X243.951 Y-25.19

G3 X243.35 Y-24.941 Z-1.83 I243.35 J-25.79

G3 X243.17 Y-24.96 I243.35 J-25.79

G3 X224.23 Y-30.31 I271.89 J-162.81

G3 X223.662 Y-31.11 I224.51 J-31.11

G3 X224.16 Y-31.88 I224.51 J-31.11

G3 X256.87 Y-46.2 I753.05 J1132.13

G3 X257.2 Y-46.266 I257.2 J-45.41

G3 X258.01 Y-45.69 I257.2 J-45.41

G2 X259.68 Y-41.69 I287.14 J-55.53

G3 X259.77 Y-41.31 I258.92 J-41.31

G3 X259.52 Y-40.71 I258.92 J-41.31

G1 X253.622 Y-40.479 Z-1.833

G1 Z-3.667 F100

G1 X242.339 Y-29.231 F600

[Guess_who]

Try to project all of your geometry to the same Z plane. The re-do the operation.

 

BTW - I don't think this is a post issue. MasterCam is probably doing exactly what it should do. You contour must not lie perfectly on the cutting plane.

[Zoeper]

Hi Ray,

 

Thank you for the reply. I have checked several times to confirm geometry is "flat". I managed to pin-point the condition that sets off this.

 

In the snippet of code posted, i was contouring to -5.3mm with a maximum step of 2mm. the 5.3 not being devisible by 2mm, mastercam steps down in 3 steps of 1.7667mm each. If i change the total depth to -5.4 with a maximum step of 1.8mm (5.4/1.8=3) then it posts clean code. This was not always a problem, but something must have changed to cause this. I think MC should handle this OK, but seems mine just cannot deal with it.

 

At least i have a workable workaround untill i can solve the problem for good....

 

P

[Guess_who]

Can you post a zip2go file.

 

What version MC are you running?

 

Maybe for some reason your 'Z' is be truncated on the G2, G3 lines to a 2 place decimal, but not on the linear moves.

[crazy^millman]

Sorry, but I have to agree with Ray here. Without a file have to think it is doing what it was told to do. You say you have checked so you tripled checked by grabbing all the geometry in question and projected it all the Z-1.833 and also made sure you are seeing 2D contour come up as your option in the contour toolpath? I seem to be the king of weird stuff with Mastercam, but that one is totally new for me.

[Zoeper]

I will be in there again on Monday and will do the zip then. If the toolpath was'nt on the XY plane, why would it post clean code when I alter the depth and step size only and using the same geometry? I would happily concede my mistake if i can find it, but i think Ray is correct in saying that between G1 and G2&3, one gets truncated and one not. Is there a switch in the program or post that would set this?

 

It was on MCX3

[A.MAHLER]

You have to adjust your tolerances in the Control DEF. Change the "NC precision( minimum step value)" Start at .0254mm and increase the value until the z value goes away.

[Zoeper]

Thank all for the input thus far. I will give A.Mahlers suggestion a go and report back as soon as I had a chance to test it.

 

Regards

P

[PcRobotic]

I don't think it's a post issue, I think it's more likely the way program issue.