KristianSilva
Aluminum
- Joined
- Nov 26, 2016
Right,
Im working on a jb at the moment where I have a cast iron impeller with a 30mm bore +/- 0.01mm, Im wanting to program the part efficiently and not use necessary tools if need be as this is a production part.
So my intention to machine the bore was to use a 28mm u-drill, offset the u-drill to drill 29mm, then take the bore to size with 1 finish pass, however im cautious that leaving 1mm in the bore might make it tricky to hold the +/- 0.01mm tolerance. Do you think this is a no go?
Typically my colleagues would drill to 28mm and then rough the bore 29.7mm then take a finish pass, leaving little in the bore to help hold size.
However the problem with this is that the bore is 70mm long and because we use standard tooling in our factory this means that I would need to use an 20mm boring bar stuck out 75mm th a 0.8mm nose rad. This is where i have had issues occur before because taking such a small cut with 0.8mm rad, the material acts as a wedge between the part and boring bar and causes vibration.
What would you do?
And unfortunately I cannot purchase new tooling for this job.
Also, i am reluctant to put a smaller u-drill in and then to take a bigger cut with my rough boring bar as I am trying to cut time and the No tools.
Opinions please!
Im working on a jb at the moment where I have a cast iron impeller with a 30mm bore +/- 0.01mm, Im wanting to program the part efficiently and not use necessary tools if need be as this is a production part.
So my intention to machine the bore was to use a 28mm u-drill, offset the u-drill to drill 29mm, then take the bore to size with 1 finish pass, however im cautious that leaving 1mm in the bore might make it tricky to hold the +/- 0.01mm tolerance. Do you think this is a no go?
Typically my colleagues would drill to 28mm and then rough the bore 29.7mm then take a finish pass, leaving little in the bore to help hold size.
However the problem with this is that the bore is 70mm long and because we use standard tooling in our factory this means that I would need to use an 20mm boring bar stuck out 75mm th a 0.8mm nose rad. This is where i have had issues occur before because taking such a small cut with 0.8mm rad, the material acts as a wedge between the part and boring bar and causes vibration.
What would you do?
And unfortunately I cannot purchase new tooling for this job.
Also, i am reluctant to put a smaller u-drill in and then to take a bigger cut with my rough boring bar as I am trying to cut time and the No tools.
Opinions please!