Which would be the best toolpath/toolpaths choice for this project

[Anonymous]

I have modelled these spokes for a gun carriage wheel, but I can not seem to find a toolpath that works well enough to make these. I am using a Stepcraft 840 with a Cress machine and a 1mm end mill. They are quite small, and it may be that they are not suitable for making on a cnc, so if anyone can advise me, I really would appreciate it. I need to make them in two sides which is the other problem I have with the toolpaths I have tried, none of the 3d toolpaths allow me to put tabs on the spokes so that they stay in the stock when I flip it over to mill the other side. 

[mathew.hutton]

Hi @Anonymous 

What if you were to create the tabs in the design workspace and then add the tabs as model geometry to the setup or toolpath? Then when you want to remove them on your setup 2 you can either delete them or create another setup without them? Regarding toolpath selection, adaptive is a good enough strategy to use but my concern would be that you are plunging into stock to machine the spokes. Doing these plunge moves with the 1mm endmill might break it, what material are you cutting? In an ideal world you'd want to turn these parts on a lathe but i'm guessing you don't have a lathe? 

Hope this helps

Mat

[Anonymous]

I do have a lathe, but I think these would be to small for me to turn by hand, also the ends of the spokes have a concave surface on the end that goes on the wheel hub, and convex on the wheel rim end. Fusion, CAD and CAM is all new to me so I am trying to muddle through as best I can learning from YouTube, but its not as clear cut as it seems especially for a beginner like me. The plunge you mentioned, how or where would I change it to a safer option. I will be making these from Wood, probably Ash.

[mathew.hutton]

Hi @Anonymous 

Oh i see, so for the lead in moves if it is going to be solid material, i'd suggest selecting 3D pocket as this will apply helical lead in moves and ensure the tool will not just plunge to depth. I think what you will probably need to do is model in the tabs for the spokes as well. I can have a go at doing this for you just so you get a better idea. Do you have access any other tools that are larger in diameter or do you just have the 1mm Endmill?

Mat

[mathew.hutton]

Hi @Anonymous 

Had a quick mess around to show you how i would approach programming this job. Have a look and let me know what you think. 

Hope this helps. 

Mat

[Anonymous]

Thanks Mat, I appreciate you looking at this. I have 3 mm endmills too, I didnt use them in the tool selection because I thought it would leave a ridged surface on the spokes, more than a 1mm endmill, like I said this is all new to me.

[Anonymous]

Hi Mat, that looks so much better than my way of thinking, The tabs are just what I need. If I were to change the tool to a 3mm, would that change the surface finish on the spokes compared to using a 1 mm. Do you mind if I steal you idea and use it to do a test run. I have attached the complete Gun Carriage so you have a better idea of what I a making. The gun barrel I will be able to turn on my lathe. 

[mathew.hutton · Accepted solution]

Hi @Anonymous 

Looks like a cool assembly! You can use a 3mm endmill to rough the material out so that wouldn't be a problem at all, you just need to change the tool in the pocket toolpath. this would be better because you'll be able to get the material out quicker than the 1mm endmill. I would suggest duplicating the pocket toolpath and selecting the 1mm endmill but using rest machining though as the 3mm endmill will leave a larger radius of material in the corners. With rest machining activated, it will only target the areas of the model that the 3mm has left excess stock. If you went straight into the ballnose finishing strategy without the rest machining with the 1mm endmill, the ballnose would probably plunge into segments of stock and could potentially break the tool. Other than that though you should be fine, just make sure you change all the feed and speed, stepover and stepdown parameters as i left most of these as default settings. Glad i could help and give you the ideas for machining the spokes.

Mat

[Anonymous · Accepted solution]

Thanks Mat for your help on this, Hopefully next week I can try out a test piece. 

All the best

Mike