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What angle drill point? Recommend 135 or 140. Why 6000 on one drill and 2000 on the other? Recommend 75 SFM for both. Recommend peck at 1/2D max. Less peck at more depth.
Just wondering if you more experienced members can make an recommendations:
303 Stainless, .089" dia hole, thru, 3.84" part length.
Current approach:
Main Spindle
#43 MA Ford 205 series drills, 1" deep, .002 ipr, 6000 rpm, .050 pecks.
#43 Gurhing 336 series parabolic, 1.85" deep, .0015 ipr, 2000 rpm, .050 pecks.
Sub Spindle
#43 MA Ford 205 series drills, 1" deep, .002 ipr, 6000 rpm, .050 pecks.
#43 Gurhing 336 series parabolic, 2.20" deep, .0015 ipr, 2000 rpm, .050 pecks.
Tolerances are .089"+.005/-.010. Some mismatch is allowed, but the go pin must slide entirely through the part. I can only reach about 2 inches deep on the main and 2.2 inches on the sub on my Citizen A20. No HPC on the machine... for now.
The process above worked well but would like to look for improvements in tool life and mismatch (the long cobalts look used up at 400 pieces and mismatch was increasing). Thinking Titex might have something that would work better?
Dan
What angle drill point? Recommend 135 or 140. Why 6000 on one drill and 2000 on the other? Recommend 75 SFM for both. Recommend peck at 1/2D max. Less peck at more depth.
http://www.kirkcon.com/
The shorter drills (MA Ford 205 series) are carbide, the longer are HSS/cobalt.
Both are 140º drill points.
Do you have high pressure coolant. I have done a lot of deep hole drilling using Mitsubishi carbide coolant through drills. They make drills as long as thirty times the diameter. Much much faster than conventional drills. With these drills there is no pecking you simply drill a starter hole then enter you starter hole with the long drill turn on high pressure feed to bottom of hole then retract.
You do have to have a min of 1000psi.
Would you or someone clarify what .050 pecks means? Are you withdrawing the drill .050 every so often? If so, how often? I am looking for the procedure. Thanks in advance.
JB
Alas, no HPC... it's on my list for the future though.
Yes, .050 pecks means full retract, in this case. I use my own drilling macro to do it, which gives me more flexibility.
OK, full retract. That must take you around 3 sec. per retract? (at least...)
So, if I'm drilling 2.50 inches, that is 50 retracts...or about 3 minutes....Have you timed the retract, re-entry cycle time?
I have had some broken drills, and I can see I am not pecking enough....may use G83 canned cycle to do multiple retracts...
What diameter are you drilling and what material?
From the bottom of a 2.5" hole, rapid out and back in, might be 3 sec, probably more like 2 on my machine with 32m/min rapids. I use a excel macro to estimate drilling cycle time, it's fairly accurite.
I like a little dwell at the bottom of the hole and a longer one outside the hole to get more oil on the drill. I don't like the G83 cycle for this reason.
I am drilling 303 ss, 1/8 dia., 20XD. Currently using a black sulfur oil with some motor oil added to it.
JB
3 seconds? Have you even worked on a machine? They will peck (that is, rapid retract and rapid back into the hole) faster than you can blink my friend...Originally Posted by jbrookes
My estimate is based on having a second pause on full retract...I have been hesitant to write code like this:
G0 z.3
G4 K100
G0 z1.95
What is the code ou you are writing? If retracts are this fast, why bother with coolant-through drills at all? mmmm?
At that depth and diameter I would suggest some good coolant first and foremost. I personally would gun drill the hole but obviously thats not possible without high pressure coolant. I also have no experience with that alloy. If you tried a worthy drill company I would call their tech support and get some good starter dimensions. You could always write a while-do loop and set a pretty good depth with large pecks to start and smaller pecks for the second half. don't overlook how long to pause outside of the hole to cool the drill tip off. i personally keep one flood line on the tip of the drill and one aimed at the end of the workpiece when pecking. i also generally pause my drill for one rotation at the bottom of the hole.
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