4 axis programming question

[bkstout]

i just recieved a job that requires me to cut a pocket in a tube on a 4th axis indexer as well as put a radius around the pocket to take away all the sharp edges on the outside of the tube anyone got any tips before i start playing and creating a lot of scrap waste this is going to invove the indexer to rotate while cutting the pkt as well any suggestions are greatly appreciated

[HuFlungDung]

Sounds like an application for a 4th axis wrap. Do you have any kind of cadcam software with a 4th axis wrap capability? While it is possible to program it by hand, you might as well use whatever software you've got, if it can help.

Is this a 'cut through' pocket or a pocket with a curved bottom?

[bkstout]

this is a through pkt and i use bobcad and excalibur x-mill have not seen the 4th axis wrap option any tips on using these options if they are available or any other tips are greayly appreciated

[HuFlungDung]

Maybe post a question on the Bobcad forums, either here or over at Bobcad. I know there is a 4th axis wrap 'convertor' in the ncsetup in Bobcad. I never actually got around to using it back when I had Bobcad.

It basically converts your Y axis values into rotary axis moves. All it does is basically convert axis moves in that axis to the letter name 'A', and then scales the Y linear movements by 57.296° (which is 1 radian, if you are interested )

For example, if a 2" diameter workpiece is mounted in the indexer, it has a circumference of 2*Pi = 6.2831
So take that value and scale it up by 57.296, you get 360 degrees, or one full rotation of the indexer.

4th axis wrap is a technique of laying out the surface of your part as if it were a flat map. Draw a rectangular box with the X side equal to the length of your part, and the Y side of the box will be as long as the circumference of your part. Lay out the other surface features of your part as a form of 2d construction within this box. You'll have to figure out where zero is going to be on your part, and map the other features relative to that.

Then, you'll have to make a toolpath as per usual in Bobcad, turn on the 4th axis conversion thingy in nc setup and flail away with a toolpath.

In case you are interested, OneCNC's 4th axis is very easy to use, much more than Bobcad was (in version 18 where I left off). But the principles of 4th axis wrap are the same. I recently did some 4th axis pocketing, using wrap in OneCNC. It was easy....easy in the sense that I could try and see several different scenarios until I got something that looked correct, making several complete programs without a lot of painstaking work. OneCNC has some nice options in their 4th axis setup for degree/min output, or if you set up your controller (like a Haas) and tell it what diameter A is working on, regular linear feedrates will be interpreted properly by the controller without any fuss on your part. Expensive touch to buy this software for just one job, though I thought you might like to know in case this job is worth big bucks.