So I thought I had this figured out...
Anyway, I have a situation, can't be too specific as to what it is, but anyway, picture three plates welded together on the periphery kinda suspended in space. Not the most ideal fixturing situation, but overall it hasn't been all that bad for this operation.
I have a 120mm bore, which comes to me as roughly a 108-110mm bore. Plates are 30mm, 30mm, 25mm, and the exit is milled flat. The parts first came in flame cut, there were gaps between the plates and it was a bear with the boring tools we were using. Now, the gaps are much better, the bores are premachined before they weld them together, but the location moves around a lot, so the tool has to be able to handle a pretty deep cut on one side.
Test Scenario #1
Rough Bore with Twin Rougher to 114.5mm Dia
Semi-Finish with Tri Rougher to 119.3mm Dia (800sfm .008"IPT/ .024" IPR) (-5 degree lead)
Overall this setup was very successful, though adds a tool I don't think I need and every thing holds up well. Chip control is great, insert life is really good.
Test Scenario #2
Rough Bore Tri-Rougher Setup in a Step Cut Configuration (800 SFM .008" IPR)
Insert #1 110mm Dia + .8mm Axial (-5 degree lead)
Insert #2 114.5mm Dia +.4mm Axial (-5 degree lead)
Insert #3 119.3mm Dia 0 for Axial Reference (-5 degree lead)
I get awesome chip control with this setup, and I save a tool change and 3 head indexes which saves me about 3.5 minutes of bs non cutting time. Problem is, now I am having trouble keeping an edge on Insert #2 and #3. I don't have enough parts on it to believe that I have a wear problem, esp since I didn't have it before with an almost identical cutting condition, Insert #3 so far has not had an interrupted cut scenario yet, #2 will occasionally but for the most part will just have a varied doc, the inboard insert (#1) has had no failures yet, as has ran between 30-40 parts with a doc up to and so far not exceeding 4mm but no less than(at least for half of the cut) 1.5mm. I have now tested Kennametal CNMG432MN KCP25 and KCP40(tougher grade). I get the below failure with both grades by about 4 parts, not sure which one it failed on, the third or the fourth, but certainly by the fourth... If I run it two parts more the chip will weld in the bore and stall the tool, at which point at least two inserts are then broken. Where do you think I should go from here? Adjusting the depths of cut is painful and expensive as this is special tool, but I can take some liberties with some aspects of the setup, to find out what works. I just have a hard time believing it is the doc as it is very consistent.
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Done Puking on the Page. What am I missing from my description of the problem? I would be glad to write some more later if someone can help me identify the areas lacking information.
Husker
Anyway, I have a situation, can't be too specific as to what it is, but anyway, picture three plates welded together on the periphery kinda suspended in space. Not the most ideal fixturing situation, but overall it hasn't been all that bad for this operation.
I have a 120mm bore, which comes to me as roughly a 108-110mm bore. Plates are 30mm, 30mm, 25mm, and the exit is milled flat. The parts first came in flame cut, there were gaps between the plates and it was a bear with the boring tools we were using. Now, the gaps are much better, the bores are premachined before they weld them together, but the location moves around a lot, so the tool has to be able to handle a pretty deep cut on one side.
Test Scenario #1
Rough Bore with Twin Rougher to 114.5mm Dia
Semi-Finish with Tri Rougher to 119.3mm Dia (800sfm .008"IPT/ .024" IPR) (-5 degree lead)
Overall this setup was very successful, though adds a tool I don't think I need and every thing holds up well. Chip control is great, insert life is really good.
Test Scenario #2
Rough Bore Tri-Rougher Setup in a Step Cut Configuration (800 SFM .008" IPR)
Insert #1 110mm Dia + .8mm Axial (-5 degree lead)
Insert #2 114.5mm Dia +.4mm Axial (-5 degree lead)
Insert #3 119.3mm Dia 0 for Axial Reference (-5 degree lead)
I get awesome chip control with this setup, and I save a tool change and 3 head indexes which saves me about 3.5 minutes of bs non cutting time. Problem is, now I am having trouble keeping an edge on Insert #2 and #3. I don't have enough parts on it to believe that I have a wear problem, esp since I didn't have it before with an almost identical cutting condition, Insert #3 so far has not had an interrupted cut scenario yet, #2 will occasionally but for the most part will just have a varied doc, the inboard insert (#1) has had no failures yet, as has ran between 30-40 parts with a doc up to and so far not exceeding 4mm but no less than(at least for half of the cut) 1.5mm. I have now tested Kennametal CNMG432MN KCP25 and KCP40(tougher grade). I get the below failure with both grades by about 4 parts, not sure which one it failed on, the third or the fourth, but certainly by the fourth... If I run it two parts more the chip will weld in the bore and stall the tool, at which point at least two inserts are then broken. Where do you think I should go from here? Adjusting the depths of cut is painful and expensive as this is special tool, but I can take some liberties with some aspects of the setup, to find out what works. I just have a hard time believing it is the doc as it is very consistent.
Done Puking on the Page. What am I missing from my description of the problem? I would be glad to write some more later if someone can help me identify the areas lacking information.
Husker