A tools length or total distance from the tip of the tool to the holder is a vital factor in the operations rigidity. Other factors like the machine itself, the toolholder, and even the pull stud retention pressure, all play a role in the overall rigidity of the system, but the tool length is often the factor that offers you the least options. For that reason, SwiftCARB cnc in Kent, Wa. believes that having choices are good. That’s why they have recently increased their offering of standard end mill flute lengths by 1500 lengths! That’s 10-15 lengths per diameter of tool in any given geometry of end mill available right in their catalog. By using an end mill that is shorter you save money on the tool, but more importantly the increased rigidity always equals longer tool life, higher achievable speeds, and a better finish.
Switcarb has 15 length options on their 1/2 inch 4 flute differential pitch/helix aluminum finisher alone.
How often are you stuck buying a tool that’s longer than you need?
Ask this question of any Machinist, Programmer, Engineer, or Purchasing agent and you’ll get a similar answer nearly every time: “always, every day, or every job” seem to be the common answers. End mill manufacturers have always offered the same 4 to 5 lengths of tool in any given diameter; generally a stub, regular, medium, long, and extralong, but with 10-15 lengths available from Swiftcarb, you are always able to get a tool right at the correct length, or at most within ½ times diameter of the actual needed length. For instance, one of the most common holes in the 5 length system is on a half inch end mill between 2 and 3-1/8 inch lengths of cut; so, if you needed say 2.100 LOC, you may be stuck with a 3-1/8, or 3-1/4 LOC tool. That’s over 2 times diameter more length than you need. With Swiftcarb’s selection of 5 flute finishers for steels and exotics, you will find 4 different flute lengths in between 2” and 3-1/4” in their catalog. “Being stuck with ½ times diameter of extra flute that you don’t need makes such an impact on productivity, that often it can be the difference between an application working or not”, says Steve Swift, president of Swiftcarb, “especially in the cases of exotics, stainless steels, and hard metals, we have seen cases where getting just a quarter inch shorter, takes a milling application from chattering and squealing, which is murder on a cutting tool, to a nice smooth hum. That’s why we did this!”
Rigidity = Productivity = Profits
Although putting hard numbers to the increases gained by getting more rigid can be difficult, because of the many other things that factor into the rigidity, Swiftcarb believes that each ½ times diameter can be worth up to 5% in aluminum, 10% in steels, and 10+ in exotics and hard metals, and these numbers can be even more dramatic on the smaller machines. So, in cases where you are are 1-1/2 to 2 times diameter shorter the gains can be 30-40% in speed, feeds, and tool life.“Everything about the operation gets better when the tool is the correct length”, says Swift, “and when you make parts faster, and of a higher quality, it drives higher profits on the shop floor. The biggest impact a machine shop can make to its bottom line is by reducing cycle times and being more productive, especially when you can get 40 hours of work done in 25 hours; now your overhead is cut in half on the job which greatly increases the profitability.”
Everyody gets it
The real beauty of this offering is its simplicity. Swiftcarb is currently manufacturing patented tools that can mill titanium at 450 SFPM and ramp in 1018 steel at 10 degrees, but there is a huge challenge in getting people to entertain these ideas because it is so far beyond what had previously been done. Swift says it can really take a lot of work to convey a new idea to a customer because they have been promised a lot before, and tool makers don’t always live up to their claims. “This is really simple though, everybody gets it”, says Swift, “machinists have always grabbed tools and cut them off to get the right length, we are just giving them the options that they have really always wanted or have tried to make for themselves.
Swiftcarb has made it a point this year to put in stock all of the old lengths and new lengths along with all of the standard radii and coatings as well, so that a customer can get exactly what they want right off of the shelf. Their philosophy seems pretty straight forward: make the tools people have always needed and asked for, and they will take advantage of it. Swift summarizes, “There’s no need to look anywhere else… we’ve got it!”