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View Full Version : Need a 1.00" Carbide endmill for plastics...



MauserBob
04-13-2009, 09:31 AM
Hello all.

I'm looking for a 1 inch, 2-flute,straight-flute carbide endmill source...preferably an off-the-shelf grind as opposed to a custom. My shop mainly runs plastic jobs in sheet form that run from @ .060" to .250" max (depending on the job), and the tool will be milling the finish profile on the edges so it must have a good plastic-relief profile. We usually use 1.00" Putnam HSS tools that work just fine, but they don['t hold an edge very long so we wind up pulling the tool out several times a run for resharpening. This is a pain in the neck and a waste of time that we'd like to eliminate if possible.

What I need: Either a solid or a carbide-tipped version with @ 1/2" minimum flute length. A stainless shank brazed-on tip version would be cheaper, obviously, but beggars can't be choosy and since I've mostly struck out in my attempts to find such a critter I'll take what I can get.

What I don't need: Insert-style tooling (not sharp enough), 1.00" Garr endmills (far too much regrinding necessary to be useful), and spiral grinds. Most of our jobs use vacuum fixtures to hold the parts down which works great but vacuum can fail with tooling profiles that "lift" the parts so that is why I need straight flutes.

We can do some regrinding to suit our needs, but not too much because we don't want to spend more time on the grinder than at the machine. As far as price goes it's not much of a problem at this point because most of our jobs don't use tools this large; this one's only for a couple of jobs that we do that only run @ 6-10 times a year so we could justify spending a bit more on a given tool as long as it lasts longer than the Putnams that we have been using for years.

Thanks in advance.


Rob.

jerseyTom
07-19-2009, 04:42 PM
Any particular reason it needs to be 1" diameter for profiling, if the sheet is only 0.060 - 0.250?

What kind of plastic is it? I worked a fair amount with polycarbonate and ULTEM1000 pieces that ranged from 0.060" to 1" thick. We used 2-flute 45deg helix carbide tools that were generally designed for aluminum milling and they worked great. For sheet work I never used anything larger than a 0.250" EM, generally 0.125", and for the plate pieces never anything larger than 0.500"

Using the smaller endmill sizes let us run pretty good speed and feedrates without generating much cutting and lifting force. Worked just great with double-sided tape and normal clamps.

I had to cut thin polypropylene tubes once and used some single-flute tooling from Harvey. Worked great. They generally seem to have a lot of good soft and hard plastic cutting tools up to 3/4"

http://www.harveytool.com

Superman
07-19-2009, 07:04 PM
??? any reason why only 2 flute for a finishing cutter, you could go up to 6 flute, same RPM, but 3X the feedrate, tool would be stiffer as it has a thicker web

Try HSCo cutters from "Niagara (http://www.niagaracutter.com/)"

RICHARD ZASTROW
07-22-2009, 11:43 AM
Or maybe coated hss? Or right hand cut left hand helix to push workpiece down instead of lifting up?

Dick Z

MauserBob
07-30-2009, 01:45 PM
We need a 1 inch cutter because, without getting into tedious specifics, the jobs we use the 1 inch HSS tool on are rectangular with an ID stepping down to an OD, where the OD is over 700" wider than the ID overall...this creates an even step .350" + wide all around the part...this inevitably leaves the corner over .500" wide on the diagonal, which we cannot cleanup with one pass of a 1/2" tool. Therefore, we're stuck with using a 1 inch wide tool because the nature of the finish demands and the cycle times dictate that only one pass around the ID be used. We've been doing it this way for longer than the 7 years I've been here, and it works just fine. The problem is that the HSS tool does wear out quicker than we'd like which isn't a problem on day shift since I've got a full crew of seasoned tool-regrinders to take care of it...but my night shift crew is, well, not so much to put it kindly. I find that we lose a significant amount of cycle time due to the machine being down at night during this particular job and a couple of others with similar characteristics. The fact of the matter is that my night guys simply have not absorbed the easy step-by-step instructions for resharpening the HSS tools, and have often run the tools dull in the course of the night with the result that I often come in to parts with burrs and other finish defects. Why this is allowed to continue is neither here nor there for the sake of this discussion...suffice to say, we do not have the luxury of time (or $$$) to sharpen & set aside a stock of freshly ground 1 inch HSS tools for the night crew to change out...I'd rather have a fresh carbide tool in there that I know will last through the night. It's not a question of feeds & speeds...when the job comes up we run so many parts that the edge is simply worn out by the end of the night. Our shop uses 1/2" tooling on the vast majority of our jobs, including straight-flute, upcut, & downcut spiral tools from a number of different sources such as Robb-Jack, Atrax, Vortex, Onsrud, etc....but none of them make an off-the-shelf 1 inch carbide tool. Some will make us a custom (we've already looked into that) but the price is unholy...and the places we looked into won't stock those customs for us. An off-the-shelf tool really would be the best solution. Inserts don't work for us either because the nature of the materials that we machine and a couple other limiting factors make it necessary to machine everything dry, with chip clearance done with airblast only. Some of the stuff we do cannot be run wet for various reasons...and Iscar, Valenite, & Sandvik inserts don't have enough side relief to allow the finishes we're required to hold in dry-machining which means we need to regrind the side profile (and grind off the insert's tip radius as well) before we can use any inserts. For my money, it's a bigger pain in the neck to regrind a handful of inserts than it is to touch up an endmill, so this is why I'd really rather have an endmill than an insert tool.

HuFlungDung
07-30-2009, 03:28 PM
I have an old Kennametal straight 2 flute insert endmill that I used to hate but then I never milled plastic with it, either :D It may no longer be listed as a viable tool, but who knows.....?
body number: KIPR-0.8-AE24-0
insert number AEC2422

This one is 3/4" shank, but the body is .875" cutting diameter, and the inserts are about .875" long. These are just a flat top insert and the body is two piece and clamps both inserts in at once with a couple of cross screws. The inserts I have are uncoated and very sharp ground edge, no hone, with a small radius tip, with some end clearance, but definitely not a plunge capable tool. The inserts are double edged, so two indexings.

Some of the lettering is worn off the shank of mine, but it may say something to the effect of 4500 rpm max?

Perhaps you can find some Kennametal dealer who can look up some old stock.

Apart from that, why no option to stock enough sharpened tools and toolholders to last the night shift? How many tools are you running? :D