Need Help!- Best Method for Milling V-Grooves

[Monotoba]

Hi All,

My father has asked me to write him a program for generating g-code to produce v-grooves. His groves will sometimes have a flat bottom and I realize that I cannot mill the bottom any narrower than the tool diameter.

My issue has been how do I minimize the stair step I get from my current algorithm. Currently I am basically milling a pocket in n-steps. Where n-step = the total depth / the cut depth per pass. With each step I shrink the box based on the slope of the sides and the number of total steps to final depth.

My background is programming and not machining. I have a VB working example but would like to know if there is a better approach to minimize the stair stepping that occurs in my algorithm.

Thanks for any input and ideas.

[Delw]

either a slitting saw cut for the shape or a endmill specially grounf, you can also buy endmills alread ground from Harvey tool,

the other way is to suface the slot if you ahve the right cam software its very easy to do, limit your step overs to no more than .001 and you will get a 63 or better finish.
If you dont have a decent cam software Regular cad sofwate will work, draw your v groove then offset it, then break the line in many places and you have your points, its tricky but it works

[Shane123]

a place i used to work at had an old horizontal mill with an insertable barrel for doing these grooves, worked awesome for that application. for single grooves, we use an indexable chamfer mill, and just run it down. if it needs a sharper bottom point, use a ground carbide chamfer tool to clean it up after the indexable.

[jharvey407]

Based on your description it sounds like you are cutting progressively deeper pockets with verticle sides.

Perhaps the way to eliminate the stair steps is to plunge the bit at an angle using a tool path that interpolates between the top of the pocket to a norrower bottom of the pocket to create the angled sides.

[Monotoba]

Yes my technique is to simply create progressively deeper pockets. For the plunge method to work I'd have to do one plug, move up and over and then plunge again. Then a scallop would be formed from the round bit.

I realize that the there are special tools for making v-groove. What he wants to do is create these grooves without the need for a dedicated tool.

Not being a machinist myself (my specialty is SE/EE), I do not completely understand the indexing tool mentioned. However I am wondering if a v-shaped mill could be used to finish cut the sloping sides and final depth after roughing with my current method. If so, then I would expect that a mill with and angle matching that of the groove sides would be needed.

Any other ideas would be helpful.

Thanks again for all your input.

[Delw]

with out a print and dims the sky is the limit on what you can or cant do, Theres a 1000 ways to skin a cat.
have your dad have someone who knows machineing and program along with tooling to make him a program it should cost that much to do it,

either that or buy a cad cam system, your a programmer so I assume you have one.
using a full depth/ width cut tool can cause chatter depending on the machine, material and size of the v groove.
I think you will get more accurate info if you gave more accurate info

[jharvey407]

Originally Posted by Monotoba Yes my technique is to simply create progressively deeper pockets. For the plunge method to work I'd have to do one plug, move up and over and then plunge again. Then a scallop would be formed from the round bit.

I'm not sure if I really understand what you are trying to do. Here is a video of my machine cutting the curved interior of a wire way I made for a flat screen install.

It should be easy enough to use the same method for a V shaped channel.

YouTube - ‪MOV07696‬‏

[Monotoba]

Hi All, thanks for the input. What I am doing is writing a app that gives him a set of code generators (similar to the wizards in Mach2/3). The applet will allow him to enter dimensions for various tasks and generate ISO formatted gcode.

The app includes the v-groove applet which allows him to enter the grooves top width, bottom width, depth, length and location. My algorithm works, I was just wondering if there was a better method.

You may ask why I don't just use a CAD/CAM program. The main reason being that my father is not as study as he used to be and machining is a hobby for him. He has trouble using a mouse and I don't want to have to draw everything out for him each time he needs something. He would have to wait until I was around and then wait for me to complete it. So by providing him a set of generators he can generate the code needed for some of his more common tasks, and can continue to be productive. And, I don't need to constantly produce the code through CAD/CAM software for him.

The wizard currently produces the v-groove code (using the pocket down method. I would like to try the plunge method as well. I suspect that like the pocket down method the progression must be in very small steps or scalloping along the [x/y] axis can occur. Just as my method stair stepping can occur along the z/x or z/y plane.). Other applets provide rectangle and round pockets. Round pockets with round islands, rectangle pockets with rectangle islands and radial and rectangular drill patterns. I will be adding to this list to allow him to produce spoked flywheels. He mainly builds small gas and steam engines. He has been hand coding but even has some trouble typing anymore. So this project's goal is to simply make things easier for him (and me).

Thanks again for all your help.