Thursday, February 27, 2020

Heidenhain Millplus IT and Tilting the coordinate system in autodesk Fusion 360 CAM with G7

Tilting the coordinate system in Autodesk Fusion 360 CAM with use of G7
Heidenhain iTNC530 should be on the same principle as Cycle 19

In the CAM-system, when you are about to tilt the work plane for 4-5 axis machining, you need to use the right tool-coordinate system to make this work.
I use this rule to tilt the coordinate system:

(Right-hand rule for axis orientation and direction. (R. Hewitt,

The G7-code in this machine has 3 axis to tilt around  A5, B5 and C5 as X, Y and Z axis, in that order and that make A5 to mill on the Yside, B5 to mill on the Xside and C5 as Zside (damn that's weird..)

(From the millplus IT Ver 5.20 manual)

As mentioned in an earlier post about tilting  the sides have different coordinate systems.
In this case, we will use A5=90, A5=-90 for the Y sides, B5=90 and B5=-90 for the X sides to cover all the sides

All the facts of the CAM in fusion:
Use the pen-shaped button on the upper left.
Find setup1 and setup1 again and the 4 drilling operations but you will not see the tool coordinate system, only the tiny marking for the tool position, Download and use your Fusion 360-program to check this out
We have now a totally 5 coordinate system to juggle with, nice

The CNC-code:

N1001 (1001)
N10 (T1  D=10 CR=0 TAPER=118deg - drill)
N11 G90
N12 G94
N13 G17
N14 G71
N15 G99 X-10 Y-10 Z-61 I72 J72 K71
N16 G98 X0 Y0 Z-51 I52 J52 K51
N17 G74 Z0 L1
N18 (Drill1)
N19 T1 M6
N20 S5000 M3
N21 G54
N22 G7 A5=0. B5=-90. C5=0. L1=1
N23 M8
N24 G0 X-17.351 Y26.224
N25 G0 Z15
N26 G17
N27 G0
N28 G0 Z5
N29 G81 Z-5 Y5 B1 F1000
N30 G79 X-17.351 Y26.224 Z-1
N31 G0 Z15
N32 G74 Z0 L1
N33 (Drill2)
N34 G7 A5=90. B5=0. C5=0. L1=1
N35 G0 X25.112 Y-14.595
N36 G0 Z15
N37 G0
N38 G0 Z5
N39 G81 Z-5 Y5 B1 F1000
N40 G79 X25.112 Y-14.595 Z-1
N41 G0 Z15
N42 G74 Z0 L1
N43 (Drill3)
N44 G7 A5=0. B5=90. C5=0. L1=1
N45 G0 X17.687 Y24.823
N46 G0 Z67
N47 G0
N48 G0 Z57
N49 G81 Z-5 Y5 B1 F1000
N50 G79 X17.687 Y24.823 Z51
N51 G0 Z67
N52 G74 Z0 L1
N53 (Drill4)
N54 G7 A5=-90. B5=0. C5=0. L1=1
N55 G0 X24.699 Y18.413
N56 G0 Z67
N57 G0
N58 G0 Z57
N59 G81 Z-5 Y5 B1 F1000
N60 G79 X24.699 Y18.413 Z51
N61 G0 Z67
N62 M9
N63 G74 Z0 L1
N64 G7 L1=1
N65 M30
(my G74 needs to be Z-10 to work)

Every G7 has one active value if you'd choose the correct coordinate system when Fusion 360 posts the code.

This video shows how your choice should be done. Take note of how the coordinate arrows are placed on the tool

Back to the CNC-code then. I did a test of the code, it works the way I like it to work. There may be a lot of other ways to do this, I'm not an expert at all, I'm a noob on this, just started.

We will check the video out, I didn't use a proper workpiece ant tool for this, just something as a reference. The height depends of the lack of proper fixture for this type of machining in my DMG DMU80T.
Often, I do not use an edge finder and a bottle of windows cleaner when I'm milling, trust me on that :)

This was not a completely linear description of the solution, but some input on how to do it.
I needed to get this on paper for my own sake, hope anyone else can learn from it.
Comment below if something is wrong, smart, stupid or anything...