aluminum/magnesium protypes cycle times

[PaceToolmaker]

Our shop used to do orders of maybe 25 or less protypes at a time but lately we have been doing orders of over a 100 on 3 different parts at a time.Cycle times werent as big a factor as they are now.Most of these are fairly complex and we cut them either on Makino S64 or some older Fadals.Typical run times average 3-5 hours per part.I am looking to reduce these cycle times but have not had much time to be experimenting with these expensive parts.Typically when ruffing we will pocket or area clearance with 1/2 em .200 depth of cut at 100 ipm.I am looking for some kind of high speed milling charts or so that would recommend depth of cut,stepover,ipm etc.Typical cutters are 3 flute high speed ems.I've been wanting to look at the highfeed machining opton in mastercam to run our Fadals faster but workload doesn't allow for a lot of experimenting,just trying to keep the spindles turning and getting the job done at the moment.Appreciate any advice.Been reading some of the forums here about dynamic milling and seen some videos on youtube.Just wondering what the other prototype guys are doing here.

[PaceToolmaker]

I should add that most these parts are all drafted with a lot of bosses and ribs and everything has to be picked out down to .030 rads with cutters hanging way out.Use 2d pocket for most the ruffing then highspeed waterline for sidewalls and horizontal mach for the flats.

[Quickmike]

If you can use flat cutters with a corner rad.(bullnose) to cut down to a .03 rad wherever possible. Then maybe go back with a .062 ball using restmill and then a leftover. Not sure if this will work without seeing the part but this how I approach a lot of our parts. It works good for parts that have some 2d with fillets and some 3d areas.

[Josh T™]

Can you post pics or upload a file to the FTP site? That would give us a better understanding of your needs.

 

Thanks,

Josh

[chris m]

What kind of spindle RPM do you have available? HSS and HSCO cutting tools suck for material removal rate when compared to even basic solid carbide; hi-performance tools tailored for you materials will be an even bigger jump in performance. That being said, if you don't have the spindle RPM to properly run the tools, they don't give you what they could.

 

BTW, [25] pieces ain't a prototype in my book; we run [1] and [2] piece lots all of the time

[PaceToolmaker]

We have a makino s56 with hsk 20,000 rpm spindle.We do use carbide tialn cutters and bullnose etc.I will run some bullnose cutters at 15,000 rpm 150 ipm when finishing but typically when ruffing mostly will 2d pocket and create my own boundarys and ruff with 1/2 flat about .200 stepdown and 50% stepover at about 90 ipm say at 5 grand.The 3d ruff and 2d highspeed seem to take so long compared to regular 2d pocket toolpaths.I'm just thinking generally that this is too slow and have not tried dynamic milling yet.Im not really having a problem with anything,just looking to improve cycle times and wondering how other mag/alum protypers go about ruffing their parts.Ive heard some parameters that seem ridiculous and havent had the gonads to try them myself yet mainly cuz i havent got the time to be experimenting with such tight deadlines all the time.Im interested in this dynamic milling and wondering how hard you can push the cutters with this in regards to depth of cut,stepover,and feed rates.

For example say you were going to ruff an 8 x 4 inch pocket 2 inches deep with a 1/2' 3 flute flat em with some bosses and ribs etc.Makino S56 20,000 rpm spindle,and you were 2d pocket with ramp entry,what depth of cut,step over,rpm,ipm would you use?

[jeff]

For aluminum, I never use coated carbide, I stick with the bright finish.

Have a look at the Blizzard endmills from OSG.

They have both flat bottom and bullnose.

Reccomended speeds and feeds start at about 7600 RPM and 199 IPM feed for 6061 and 7075 aluminum.

If you need longer endmills than the Blizzards, Hanita has a Javelin endmill that is longer.

HTH

[Jayson Kramer]

I to would like to see the a picture of the shape as it can help.I use allot of the HSM for this stuff and go any were from 100 to 500 imp, going a 100imp these days for roughing in Alum seems slow.

Allot of the 3flt tools from OSG and Hanita have high SFM. The HSM works well for allot of this.

[chris m]

Dataflute, OSG, and Hanita all have some pretty sick tools for this type of application. I'm thinking 10K RPM minimum and at least 100IPM with any good tool. TiAlN is a terrible coating for aluminum, IMO; bright or TiN for me