Need some basic help with CAM toolpaths on simple U-Channel part

[hatch789]

Hello Guys,

I have been working in CAD for a few years. Some SolidWorks but mostly OnShape. I recently got a small business license for F360 because I wanted to try it out. I was especially curious about the built in CAM. I have a 2.5D Tree 200R in my shop with full X&Y CNC controls but manual Z. So for my first task I was trying to do something in need for a Real Life project. I exported a piece from OnShape in STEP format and imported into F360. That worked fine. Then I tried the CAM toolpaths and that's where I got stuck.

If someone would be willing to do a 15 minute TEAMVIEWER or something with me I am sure this is a simple thing for experienced users. I just have some basic questions and problems.

Yes we could probably try to do it all in the forum here but that'll take a long time so if you have a few minutes I'd be grateful.

[LibertyMachine · Accepted solution]

I could be available for a call, but not anytime soon. I'm in the shop, so machines are running. And them I'm out tonight with my son and the Boy Scouts....

Adaptive can be restricted a couple easy ways:

1) heights. Set your "bottom height" to the top of the surface where the bores are. It won't go any lower than that

2) "Rest Machining - From Prior Operations". This is an option in the 3D toolpaths (for the most part) where it will "look" at what is leftover and machine what is there. Results may vary depending on "Stock to Leave", Tolerance and a couple other factors.

Looking at your part, I'd not suggest Adaptive as the best solution for your part. It seems that 2D Contour with multiple depths of cut would work just as well. Select the inside bottom edge. If it gives you trouble and wants to select a whole lot of contour, just depress the ALT key and make your selection

[hatch789]

Hi Seth,

OK that makes sense I'll try 2D contour milling. I'll try what you say. So is there a way I can tell it I want to center my machine tool (in this case on a dot I made) and once I have that [homed??] on the dot I would then want to begin. Everything would be based off of that HOME position. Maybe I mean a START position? Not sure of the term.

But if I do each piece in this same way they will all be identical from that center point so slight variations to each end won't matter much at all. 

[LibertyMachine]

What do you mean by "make a dot", and how do you propose locating the channel each time in your machine?

[hatch789]

These parts are going to be for my Vertical Axis Wind Turbine design. I need 10 total and they will nest together. The part here was the top and I have to CAM up the bottom pieces then. The holes are identical in each but the grooves are different between the top and bottom to allow them to nest at a specific angle of offset.

So I was just going to put a simple dot with a Sharpie marker at the center point between each of the ends (X axis) and then my my Y axis will be controlled by the vice jaws. So long as I have a close to accurate dot or scratch locating center (left to right) I should be fine.

The milling will then take place based on this central starting point for each piece and allow them to be accurate in relation to one another based off of the center point.

If you want to see what I'm working on search YouTube for "Harmony VAWT" and view my playlist with latest updates.

[LibertyMachine]

Ok then, I understand. So what you would want to do is go into sketch mode and create a sketch on the floor of the channel. Sketch a circle of any size (you can use a point as well) at center. You can find center one easy way:

Sketch a line from top left of the part to bottom right. The midpoint will be the center.

In setting up your WCS, just select this point.

Sending you a PM

[hatch789]

I have everything working in Fusion 360 simulation but when I import it into LinuxCNC it's complaining about "Radius to end of arc differs from radius to start". So I'll try to fiddle with this some more. Also you spoke of doing a start point in F360 but to what end? Do I need that as my HOME? I am sort of struggling with how to home this piece now in my LinuxCNC. But I'm getting closer.

Thank you for the help so far.

[LibertyMachine]

Just to make sure; you are using the Linux post processor, correct? And is this an EMC or EMC2? Post Processors are available for both HERE

The goal of sketching a point on the part is to provide for a spot to select for establishing your WCS. If you want XYZ zero set to that Sharpie point, you need some way of defining that in your Fusion CAM Setup

[hatch789]

Hi Seth,

Thank you for the help thusfar. You got me past the parts I was stuck on, believe it or not. Yes I was using the LinuxCNC post processor that's built into Fusion so that part appears to be fine.

I just watched my machine run through the toolpath 4x ...well above my table mind you; and it seems to work quite well for the first few run-throughs with actual table movements. I will go ahead and take your advice on the start point for my WCS and tying that into the sharpie dot.

Now I need to work on some simple things like a PAUSE built in so I can adjust Z before a rapid move. Also the table moves all the way back to 0,0 when it's finally finished even though I tried using both "Touch Off" and also "Tool Touch Off" ...neither of which stopped the odd behavior at the end.

All in all I've come leaps and bounds from where I was last week just trying to figure out just what CAM software even did. -So again, thank you! Here's a video for you!