03-13-2015, 07:22 PM
aRM,
Glad to be of help.
Now tell me more about your machine and the material condition so we can discuss the parameters for running the cutter. Is that a CNC controlled machine with servo or stepper motor driven ball screws? I sure hope so, for best tool performance.
For the steels you are face milling, you'll find good info for cutting speeds and feed rates within the Walter catalog. I'm only familiar with the US/Canada version of their website, but on that Walter website you can download the catalogs, which can be viewed with ease if your computer has Microsoft Silverlight loaded. It also can be viewed on the website, but is slower that way. They also have apps for smartphones and tablets which work well.
Do you program the machine or run by "hand"?
Using my version of the catalog I get cutting speeds in "surface feet per minute", you might use "meters per minute". I'll try to translate.
For a high end tool steel that's at 400Hb (Brinell hardness), which I think is what you were having trouble with, the cutting speed for grade WKP25S is 300 sfm, or 91.44 m/min. That's to be used for a 1:1 to a 1:2 width of cut to cutter diameter ratio. The cutting speed can be increased by 20% if the width of cut with the 50mm cutter is reduced below 10mm wide. At a cutting speed of 91.44 m/min, your spindle rpm for a 50mm cutter is 582 rpm. That should be at the bottom end of your machine's "high range" for spindle speed, so use the low range and have more torque available.
The insert grade and coating determines cutting speed, the insert edge prep, approach angle, entry angle and chipbreaker design all factor in feed rate per tooth. For cutting with the grade WKP25S and geometry (chipbreaker) D57 at full width of cut, the maximum depth of cut is .1574", or 4mm. I don't think you'll be able to exceed 2.5mm with a 2HP spindle. The book is recommending .012" (0.3mm) feed per tooth, times 3 inserts = .9mm per rev, time 582 rpm = 177.4 mm/min feed. I apologize, as I don't know what units your machine runs, so that would be about 20.9 in/min. feed. It sounds somewhat high, but that's what those inserts can handle. You should see significant increase in tool life over anything you've tried thus far.
The HP pull of the cut depends upon depth of cut and the insert geometry, we know it's a 45º approach angle. I would hope you have ball screw drives and can "climb" mill with the cutter. Using the Walter Machining Calculator and entering those parameters for 25mm wide cut, 45º approach angle, a 1,5mm depth of cut and that feed rate, it pulls a little over 2HP but you actually get enough torque to do it in low range.
As for buying tooling over there, I don't know how it works there but here it's best to buy through a distributor who is authorized by the manufacturer. The distributors get a discount that allows them to make a profit selling up to (and rarely, over) the suggested list price. If the manufacturer sells direct to the end user for a discount, they wouldn't have any distributors for long. It's always better to have multiple outlets for your goods, so more end users can have access to the products and support them.
Glad to be of help.
Now tell me more about your machine and the material condition so we can discuss the parameters for running the cutter. Is that a CNC controlled machine with servo or stepper motor driven ball screws? I sure hope so, for best tool performance.
For the steels you are face milling, you'll find good info for cutting speeds and feed rates within the Walter catalog. I'm only familiar with the US/Canada version of their website, but on that Walter website you can download the catalogs, which can be viewed with ease if your computer has Microsoft Silverlight loaded. It also can be viewed on the website, but is slower that way. They also have apps for smartphones and tablets which work well.
Do you program the machine or run by "hand"?
Using my version of the catalog I get cutting speeds in "surface feet per minute", you might use "meters per minute". I'll try to translate.
For a high end tool steel that's at 400Hb (Brinell hardness), which I think is what you were having trouble with, the cutting speed for grade WKP25S is 300 sfm, or 91.44 m/min. That's to be used for a 1:1 to a 1:2 width of cut to cutter diameter ratio. The cutting speed can be increased by 20% if the width of cut with the 50mm cutter is reduced below 10mm wide. At a cutting speed of 91.44 m/min, your spindle rpm for a 50mm cutter is 582 rpm. That should be at the bottom end of your machine's "high range" for spindle speed, so use the low range and have more torque available.
The insert grade and coating determines cutting speed, the insert edge prep, approach angle, entry angle and chipbreaker design all factor in feed rate per tooth. For cutting with the grade WKP25S and geometry (chipbreaker) D57 at full width of cut, the maximum depth of cut is .1574", or 4mm. I don't think you'll be able to exceed 2.5mm with a 2HP spindle. The book is recommending .012" (0.3mm) feed per tooth, times 3 inserts = .9mm per rev, time 582 rpm = 177.4 mm/min feed. I apologize, as I don't know what units your machine runs, so that would be about 20.9 in/min. feed. It sounds somewhat high, but that's what those inserts can handle. You should see significant increase in tool life over anything you've tried thus far.
The HP pull of the cut depends upon depth of cut and the insert geometry, we know it's a 45º approach angle. I would hope you have ball screw drives and can "climb" mill with the cutter. Using the Walter Machining Calculator and entering those parameters for 25mm wide cut, 45º approach angle, a 1,5mm depth of cut and that feed rate, it pulls a little over 2HP but you actually get enough torque to do it in low range.
As for buying tooling over there, I don't know how it works there but here it's best to buy through a distributor who is authorized by the manufacturer. The distributors get a discount that allows them to make a profit selling up to (and rarely, over) the suggested list price. If the manufacturer sells direct to the end user for a discount, they wouldn't have any distributors for long. It's always better to have multiple outlets for your goods, so more end users can have access to the products and support them.