Morph between two curves - RON, HELP! :-)

[Bob W.]

I have some geometry that resembles a test tube (cylindrical walls with spherical bottom) with grooves on the inside and I am machining the inside geometry.  I have got the morph between curves to work when there are two curves but how would I get that to machine all the way down to the bottom with one toolpath?  I tried chaining the upper curve and a point for the bottom and it didn't work, needs two curves.  Right now I am using two different toolpaths to get this done though i would like to get it done in one.  This is for the posts on a knee mold for investment casting.

[BCW]

Try a .010 dia circle at the same spot you would have tried the point.

[crazy^millman]

Bob, remember the chains do not have to be part of the model. You can use 2 chains off the model. Think of Blend, but with Multi-Axis Control. I did a Triangle the other day and showed 2 ways to go about it with Morph Between 2 Curves. Top and bottom of triangle had pinched toolpaths toward the small side and spread out toolpaths toward the big side. I took the bottom chanin and place it to the upper limits of the triangle. Now I got a very nice almost parallel toolpath through the whole shape that used the 2 chains as the fitting shape to make the toolpaths from. Try the same thing here. Make 2 chains to cover what you want and then try driving the whole shape using the 2 chains that are like the toolpath you are wanting. The chains can even be longer than the shape.

 

Don't forget Collision control and using tilt to keep the tool in the cut, but have it tilt where it needs in tight areas. Don't use the flutes, but use the defined holder(Most important part of the this toolpaths ti to use 100% defined holders and tools) We have done this on $250K parts and got the holders and heads within .01 and not hit or crashed.

 

FYI Ben and Murlin are very versed in this toolpath also.

[Bob W.]

Try a .010 dia circle at the same spot you would have tried the point.

I tried that and it fell apart when it got closer to the smaller chain.  It was late and I just wanted to get the machine off and running so I didn't spend too much time on it.  I'll see what I can do on the next part.  I have four more of these to make.

[Bob W.]

Bob, remember the chains do not have to be part of the model. You can use 2 chains off the model. Think of Blend, but with Multi-Axis Control. I did a Triangle the other day and showed 2 ways to go about it with Morph Between 2 Curves. Top and bottom of triangle had pinched toolpaths toward the small side and spread out toolpaths toward the big side. I took the bottom chanin and place it to the upper limits of the triangle. Now I got a very nice almost parallel toolpath through the whole shape that used the 2 chains as the fitting shape to make the toolpaths from. Try the same thing here. Make 2 chains to cover what you want and then try driving the whole shape using the 2 chains that are like the toolpath you are wanting. The chains can even be longer than the shape.

 

Don't forget Collision control and using tilt to keep the tool in the cut, but have it tilt where it needs in tight areas. Don't use the flutes, but use the defined holder(Most important part of the this toolpaths ti to use 100% defined holders and tools) We have done this on $250K parts and got the holders and heads within .01 and not hit or crashed.

 

FYI Ben and Murlin are very versed in this toolpath also.

Thanks for the response.  I'll play around with the curves on the next part to see if I can get it done in one.  I am controlling the tool axis from curve from start to finish so the tool angle stays pretty consistent as it goes down into the hole.  This is with a .015" 3 degree tapered ball mill in a 50,000 rpm air spindle.  I wish i was better at 5-axis, it is pretty cool what can be done with it.  The company I make these tools for swore these features would need to be made with a sinker EDM but the 5-axis kills it.

[crazy^millman]

Yes you can do some pretty amazing things with 5 axis, but just really need to get out of your comfort zone sometimes. Being Left Handed I always see it different than most, because the majority of the population is right handed. Funny I put Zero on the Left corner and people put it on the right and swear up and down I am stupid for putting it on the left because it is not their way. I don't care where I put zero and the same with 5 Axis if I can get to it with a tool I can machine it. Now quality and run time are where the rubber meets the road, but you tell me it must be this or it must be that and quality is the driving factor then if I have to draw the chains to put the tool where I need and draw all the axis control lines I will figure out a way to machine it if possible.