Need help from the experts to get drag knife working with F360

[thburn]

Hi,

I am new to CAM of F360 and need some help from the experts here.

I know currently F360 does not support drag knifes natively so I try to get some workaround to get my drag knife working with F360.
To keep it simple I want to test my 1st cut on some cardbboard (1mm thickness) with following contour:

  

In the upper left you can see the contour I want to cut with my drag knife. This contour can also be an inner part (cut out) of a 2nd contour.

To get the sharp corners the drag knife must move ahead the black contour, follow the red slope and come back on the black contour.

Now the important thing comes: if the drag knife enters the red slope it must be lifted up on Z-axis but still keep in contact with the cardboard!

This is shown with the green line and arrows. This is necessary because the red slope should not be cut through. It is just to guide the knife to the new angle. If the cardboard has a thickness of 1mm I think the knife should lift for 0,8mm to stay 0,2mm inside the cardboard to guide it. Here the steps the knife should do:

1. Move along the black contour until the end of the edge.

2. Lift the drag knife for 0,8mm (knife keeps 0.2mm inside cardboard)

3. Move the drag knife along the red slope to guide it to the new angle

4. Move the drag knife down and cut the next edge of the contour.

Since I am fairly new to CAM inside F360 I need some help what steps F360 can currently do.

Here some questions I have:

1. What CAM mode should I use? 2D, 2D contour, 3D, 3D contour?

2. How can I get the red slope? Is there currently any feature in F360 I can use or do I have to draw them by sketch?

3. How I can make the lift up / put down procedure at the start and end of the slope?

Thanks for any ideas from you...

[LibertyMachine]

Off the cuff, I'd like to toss out this idea:

Project the toolpath (found in 3D operations tab).

You would need to model the heights into your part, but that's one option. The other is Trace, but that does require a 3D sketch, which I have ZERO clue how to go about making. I've seen 3D sketches talked about, but have never had need to dabble in them. 

I guess the question is; is it worth it? Isn't there cheap (enough) software out there that offers drag knife support? I understand wanting to work with one software across the board, but I think there might be practical limitations to that approach

[thburn]

@LibertyMachine: thanks for reply. Yes I think it is worse it because I am a hobbyist and don't have so much money to buy anoter software just to solve this task.

I also do not need this very often. Here and then I need to cut some parts from cardboard or foamrubber and I think if there is a good workaround to make it working with current F360 then I will give it a try.

I am also not familiar with 3D sketch. Today I tried a littlebit working with 3D sektch but if I lift parts of my sketch along the Z-Axis then I cannot use any constraints anymore.

They only work with sketch parts which are located at Z = 0. But to cretae the slope I need some constraint of the slope to the contour to get the correct angle of the drag knife.

Currently I am digging around but don't know if 3D sketch and trace is the correct approach.

Any further suggestions are welcome...

[WhiteRoomSkis]

Will the new "cutting" tool paths for Laser, water jet or plasma work with a drag knife?

[Fueler]

This fellow has done some drag engraving with 360. Maybe a clue in there.

https://www.youtube.com/watch?v=J3Izcw2dQOo

[Anonymous]

The video linked above shows a spring-loaded engraving drag knife. I found this post because I want to program toolpaths for a spring-loaded vinyl cutting drag knife. The difference is that the vinyl cutting knives have a horizontal offset from the tool center to the blade tip. That offset is important because it enables you to lift the tip of the blade to a thousand from the top surface of the material and trace a semicircle with a radius equal to the blade tip offset. This swivels the blade so that the next line can be cut at a sharp angle from the current one.

It looks to me like F360 does not have the ability to create the toolpaths with the extra swivel codes for drag knives. Vectric Aspire does have a gadget that generates these tool paths automatically. It's also too expensive for hobbyists.

Hope this helps.

[WhiteRoomSkis]

Right. I'm looking for a way to use a Donek drag knife without purchasing another piece of software. There are some freeware programs out there but I have not tried using them yet.

Thank you

[Anonymous]

I have exactly the same goal. I have a brand new Donek D4 that I want to use for testing dieline projects before I have expensive dies made. Can you update this thread if you find a solution? I'll do the same.

[Anonymous]

If you keep your designed radii at or below 2.5mm (or close to it) you can use the "trace" toolpath... it works great for base cuts, a little "tricky" for die-cut/inserts, as you really need to make sure you're using the same cut paths (orders, etc...) for the A/B parts to fit together seamlessly, or at least meet high-end tolerances.  Like most things, you're going to have to just jump in and try it a bit, then you'll develop your own technique for bridging the gap between Fusion, and a dedicated drag knife package like the ones for sale through Donek (which, by the way I have and use, but still do most of my cuts through Fusion).

When selecting your contours for the trace paths, remember you can select individual portions at a time, rather than the entire contour, this will undoubtedly come in handy when trying to tackle the minor headache of cut direction, ordering.  If you watch the Donek video a bunch you'll start to get a feel for what you're up against... the direction of the blade matters a great deal, so you're going to want to "line-up" your cuts/paths so that the blade is already aligned properly for the next cut as it leaves the current cut.  You can get really close to perfect through fusion.  For my base cuts I usually need to make no blade direction adjustment.  For logo die-cuts/inserts I get as close as I can to acceptable, then draw a "key" detailing any adjustments I need to make on the table to the blade direction between cuts (using the table's pause button).

Hope this helps... 

[thburn]

Hi,

I would like to ask someone from F360 team to this issue:

Is there anything planned on the roadmap to support dragknifes (including corner correction)?

BTW:

The image I posted in the 1st post is wrong, here the correct one:

[Laurens-3DTechDraw]

Guy's,

Have you tried Keep Sharp Corners with loop in the 2D Contour?

http://help.autodesk.com/view/fusion360/ENU/?guid=GUID35587504-2FD9-4032-BA57-1F3BCDE9BC4A

That's what I know others are using for this kind of loop for drag knife. 

Might not be 100% what you want but should be pretty close.

[macmanpb]

Drag knife support has landed!

For all of us that are waiting to produce drag knife supported g-code, here it is.

We have produced an Add-On for Fusion360 that converts standard g-code into drag knife compatible g-code.

You can find it here: apps.autodesk.com

or here: https://www.pbmilltec.de/Produkte/DragKnife/

Hope you enjoy...

[macmanpb]

For all of us that are waiting to produce drag knife supported g-code, here it is.

We have produced an Add-On for Fusion360 that converts standard g-code into drag knife compatible g-code.

You can find it here: apps.autodesk.com

or here: https://www.pbmilltec.de/Produkte/DragKnife/

Hope you enjoy...