Spiral hole drilling

[shoeshine]

Ok I know I've read this before here somewhere but I can't find it.

I would like to cut some 3/16" holes with a 1/8" bit. How does one set up a spiral hole drilling routine? Pocketing path with ramping? How do you know what values to enter in the ramping dialogue?

Has anyone used this for high(er) accuracy holes? accurate enough to tap threads into afterward? (working in brass and aluminum) or am I just better marking my drill points on the bot and use a drill bit afterward?

Thanks for any info.
Chris

[scottbot]

Chris,
I use a profile path with a large ramp value to drill holes all the time.
I've never really bothered to do the math to figure out the to correct ramping value.
I just take a guess but err on the big side. The Bot will stop when it reaches the correct depth.

I don't use it for holes that require a high degree of accuracy (although it might work fine) I use this technique because it's much quicker to drill holes this way.

Scott

[tmerrill]

Chris,

If you are using Partworks/VCP/Aspire use the Profile-Inside toolpath and select Spiral Ramping. With Spiral Ramping the bit will smoothly ramp from top to bottom with the depth of each revolution equal to what you have set for pass depth.

Attached picture shows the toolpath for drilling 1" thick material with pass depth set to 0.125".

I have never used it in metal but use this frequently in wood and it is accurate.

Tim

[curtiss]

I would think somewhere you can find some 3/16 diameter bits that will fit a 1/8 inch collet.

Can you drill some pilot holes with a 1/8 inch bit and then enlarge them ?

[shoeshine]

Thanks all,

Scott, damn I knew it was in there somewhere. Thanks

Yeah I already mark my holes via vBit to drill. I'ts more of a time saving measure. Every unit (3-10 units a day) requires 30 tapped holes. Right now I mark on the bot, drill on the press, tap by hand. I was hoping to eliminate a step.

Chris

[oddcoach]

you could buy a collet for the size bit you need
http://www1.mscdirect.com/CGI/NNPDFF?PMPAGE=1576&PARTPG=N2DRVSH&PMT4NO=86609162&PMITEM=09689084&PMCTLG=00&PMT4TP=*LTIP