Changing tool length or tool does not change the Gcode

[Cole64]

Hello,

I have a part that I am machining and I am trying a new tool which is 10mm shorter than the previous tool. In Fusion I have been editing my tool body length and have even selected some other custom tools with varying length but when I look at the gcode I can see that the Z depth does not change regardless of tool length that I use. Any suggestions?

I have a DIY CNC made with Smoothie.

Thanks

Colin

[Stuart-H]

Is not the TLO set up in the machine controller and is setup as part of the machine operation

F360 only knows about Z0 

AFAIK the tool lengths in F360 are shown in simulation so you can check if the selected tool length will get the job done without crashes

Stuart

[LibertyMachine]

The physical tool length will have no impact on the actual code.

For instance,lets look at your Z depths; that value is based on your WCS origin. You can have a tool that is 1mm long and another that is 50mm long, and the code will be the same. The only thing that the tool will really impact is the amount of material you can take off in a single depth pass (length of cut).

Does your DIY CNC control allow for work offsets? This is what allows you to use tools of varying lengths with the same code. What is the control and what post are you using?

[Cole64]

Ok I think i'm getting some of what you are telling me. So F360 tool length settings are only there so you can simulate and see if there are any collisions. So this leaves me with offsets and post processing, which I don't know much about at the moment and hence am not using. I can see on the tool library there is tab for post processing which is somewhat described in this post. What I am stuck with at the moment is to where and how I can use these references. Will need to investigate further, if anyone has knows of any references, i will be very grateful if you share them.

[LibertyMachine · Accepted solution]

In the modern CAM and CNC world, there are a couple things in particular that those new to the field would do very well in understanding. That is Work Offsets and Tool Offsets.

Work Offsets: On paper; write directions around your city block, from where you are standing. They make sense, don't they? Now, move 40 miles/km away. Do they make sense any more? Not so much, since they are relative to where you were standing when you wrote them down. So, you need to give another movement direction, a Work Offset, so to speak. That would be your G54 to G59 in CNC world (assuming a modern control). So, the part is programmed to itself, and then you tell the machine where the part is, much like the directions around the city block.

Same sort of idea for the Tool Offsets. Each tool is programmed to go to it's specific depth, whether that is a 10mm deep hole, or a 20mm deep profile contour pass. Then, using Tool Offsets in the machine control (the CNC, not Fusion) you can tell the control where the end of the tool is in relationship to it's home position. 

That's basically it, in a nutshell.

For wonderful bedside reading material, I'd recommend this guy: http://www.cnccookbook.com/

The guy has more information then you would ever need, but a lot of it is explained in such a manner that makes a lot of sense.

I'd also recommend the youtube videos by NY CNC, a job shop that uses Fusion, you will find good tidbits there as well https://www.youtube.com/user/saunixcomp

[Cole64]

Thanks for that great explanation gearsoup. I am totally picking up what you are putting down now. This explains why there is no machine setup in Fusion and also saves me the time in moving my part around to the location away from 0,0,0. I have bCNC on my computer which I control my smoothieboard driven machine from, but still haven't found where I can place or modify this offset file, however this is probably not something I may not l find on this forum.

[LibertyMachine]

Good, I'm glad I was able to provide some assistance!

For the bCNC question, would this link help? http://www.shapeoko.com/wiki/index.php/BCNC

[Cole64]

Well I'm off and running now, the video tutorial on the Shapeoko was just what I needed to help me understand how to setup my machine and work co-ordinates, it all makes so much sense now. Thanks again gearsoup!