Hello all,
i am having problems with this boring opeartion mainly that i can't reliably hold the 20H7 tolerance(mm), sometimes loosing 0.01mm from the 1st hole to the 2nd.
The main problem it that the entrance surface is angled at 30deg. and the cross hole causing vibations.
Currently i am ramping to 19.8mm then using a boring bar with a 0.2mm radius at 850rpm and 76 mm/min (0.09mm per rev). Thinking of leaving more stock for the boring bar and incresing the feed.
The second problem i have is when i am deep drilling a 5mm hole (125mm deep) the drill is going off centre.
Drilling a pilot 5mm pilot hole 20mm deep then deep drilling with a carbide parabolic drill at 1800rpm and 110 mm/min feed(0.06mm per rev). I know i should increse the feed but the thru coolant isn't clearing chips and you can see them while the drill is retracting.
Material: X20Cr13 - 420 Stainless
Any suggestions? Thanks!
i am having problems with this boring opeartion mainly that i can't reliably hold the 20H7 tolerance(mm), sometimes loosing 0.01mm from the 1st hole to the 2nd.
The main problem it that the entrance surface is angled at 30deg. and the cross hole causing vibations.
Currently i am ramping to 19.8mm then using a boring bar with a 0.2mm radius at 850rpm and 76 mm/min (0.09mm per rev). Thinking of leaving more stock for the boring bar and incresing the feed.
The second problem i have is when i am deep drilling a 5mm hole (125mm deep) the drill is going off centre.
Drilling a pilot 5mm pilot hole 20mm deep then deep drilling with a carbide parabolic drill at 1800rpm and 110 mm/min feed(0.06mm per rev). I know i should increse the feed but the thru coolant isn't clearing chips and you can see them while the drill is retracting.
Material: X20Cr13 - 420 Stainless
Any suggestions? Thanks!