View Full Version : Titanium Machining


vadimvc
02-20-2008, 01:37 PM
Hi, I'm a freshman in college looking for some help as to figure out the proper way to machine a 5x3x.875 piece of titanium. I have a Haas VF-4 to work with but can't seem to find a proper cutter as well as feed/speed. I'm trying to find as cheap a cutter as possible. I've been recommended by a friend to use the following: http://www.use-enco.com/CGI/INSRIT?PMAKA=308-0545&PMPXNO=12428069&PARTPG=INLMK32

with a feed of .25IPM and a speed of 200 RPM with a .3" DOC (for a slotting operation.)

I would be ok with this but as of right now I'm calculating this will be about 30 hours of run time which is a bit much for me. So I wanted to ask if anyone else had any suggestions for a cutter/feed/speed for approximately the same price.

In case anyone is wondering this is for a combat robotics (Battlebots) project.

Thanks in advance
--Vadim

bugzpulverizer
02-20-2008, 03:17 PM
I have milled plenty of titanium on HAAS VF-2's, and what I found out is you need really sharp cutters, high chip load(low speed high feed), and you can never let your tool rub the metal (tool will generate heat, and break down before you can hit e-stop.) That .25 ipm seems real low. Might be about to rough out slot with a high speed rougher, and then finish with the carbide. I used to hog 1/2" DOC full width, with a high speed 1.0" roughing e-mill. (250 rpm at 4. ipm. Hope this helps.

cam1
02-20-2008, 08:12 PM
Hi:
Why Titanium?

regards

vadimvc
02-20-2008, 10:30 PM
same reason everyone else uses it, low weight for high strength

LeftCoastCNC
02-21-2008, 12:11 AM
I have had excellent result in various materials with Niagara's Stabilizer endmills. The Stabilizer HT is designed for difficult to machine materials.

http://www.niagaracutter.com/solidcarbide/elite/stabilizer/stabilizer.pdf

From Niagara's website
For slotting with a 1/2" endmill in Ti, they recommend a starting S&F of 2100 RPM and 12.6 IPM.

The cutter is a little over twice the cost of the cheapo you were looking at but money well spend IMO.

Good Luck!

cam1
02-22-2008, 07:10 PM
Keep it simple, why go with unobtanium, high priced materials, when 6061 or 7075 Al will do the job, with ordinary cutters. I've worked in an Aerospace test and eval. shop for 15yrs, and rarely see a requirement for Titanium. It's usually the grads or newbies that specify this material, with little regard for tooling costs etc.

regards

LeftCoastCNC
02-22-2008, 09:56 PM
I taught manufacturing engineering at a university and some of the best learning experiences for students were those projects they were passionate about getting completed, no matter how impractical. After spending lots of money on material and breaking expensive tooling, they learn how important a practical design is. Hopefully this lesson is learned before becoming an "engineer" and all of the head aches of the poor design are seen first hand...

holbieone
02-22-2008, 09:59 PM
Hi, I'm a freshman in college looking for some help as to figure out the proper way to machine a 5x3x.875 piece of titanium. I have a Haas VF-4 to work with but can't seem to find a proper cutter as well as feed/speed. I'm trying to find as cheap a cutter as possible. I've been recommended by a friend to use the following: http://www.use-enco.com/CGI/INSRIT?PMAKA=308-0545&PMPXNO=12428069&PARTPG=INLMK32

with a feed of .25IPM and a speed of 200 RPM with a .3" DOC (for a slotting operation.)

I would be ok with this but as of right now I'm calculating this will be about 30 hours of run time which is a bit much for me. So I wanted to ask if anyone else had any suggestions for a cutter/feed/speed for approximately the same price.

In case anyone is wondering this is for a combat robotics (Battlebots) project.

Thanks in advance
--Vadim

3 flute dataflute carbide end mill with a .03 cr

1250 rpm 30 ipm

vadimvc
02-23-2008, 01:51 AM
Well I tried to make my last response general but I'll go into specifics about the reason behind titanium. It is for a weapon for a one pound robot. I need the weapon to be as large as possible but still be able to survive hits. Aluminum doesn't fall into this category as a piece of aluminum would just get immediately destroyed. Titanium will do the job, as will steel however steel is far heavier meaning the weapon must be significantly smaller. I found a nice chunk of Grade 5 Titanium on ebay for cheap and so now I'm trying to work on the next step of the process on how to actually cut it. Thanks for all the suggestions, I'll hopefully pick something out soon.

stevehuckss396
02-23-2008, 07:28 AM
Well I tried to make my last response general but I'll go into specifics about the reason behind titanium. It is for a weapon for a one pound robot. I need the weapon to be as large as possible but still be able to survive hits. Aluminum doesn't fall into this category as a piece of aluminum would just get immediately destroyed. Titanium will do the job, as will steel however steel is far heavier meaning the weapon must be significantly smaller. I found a nice chunk of Grade 5 Titanium on ebay for cheap and so now I'm trying to work on the next step of the process on how to actually cut it. Thanks for all the suggestions, I'll hopefully pick something out soon.


You dont owe me an explanation. If you want to make something out of titanium, than that is what you want to use. I made a tool for a few people at work that cannot be purchased in stores. All were aluminum except one guy requested brass. Well brass worked great and looked great. Now there is no way I was going to let his be cooler than mine so I made one for myself in of course, titanium. Did it NEED to be titanium? No. Sometimes it's not about the bare minimum needed for production. For people like me, this is a hobby and there are reasons not considered by "production" guys like COOL FACTOR. The tool i made is the only one there is, the only one there ever will be, and i have already turned down enough money for it to cover the cost of all the expensive tools plus.

I'm not a machinest so all i can offer is this.

Solid carbide endmills and drill bits at low speed and take a good bite. Dont be afraid to feed some material to the cutter. When i tapped a hole i used a new HSS 2 flute tap and alot of tap magic. Cutting was easier than i thought it would be.

cam1
02-23-2008, 07:43 AM
Hi:
Valid argument LeftCoast, I guess I tend to look at things from a commercial perspective now. I agree, perhaps smoke a few tools, no harm done.
When I'm approached by colleagues that require components, the "why" that material question is appropriate and relevant to ask. For the hobby world, it may not always apply.

cheers

antichip
02-23-2008, 08:17 AM
HI GUYS,

I don't have alot of posts here, but I machine Ti on an almost daily basis all day long. I love this stuff. It finishes so nice. We use solid carbide endmills at work with some pretty good speeds and feed as it was said earlier to keep the cutters from wiping the part instead of cutting it. All the parts I make at work are aerospace/ millitary and optics systems. My friend is in the process of designing and constructing a Ti R/c monster truck. I also do Ti rings and smoking pipes out of it in my home shop. All of this being said AL-6 stainless is a VERY hard material, just saying as a weapons force is directly related to it's mass and speed, maybee Ti weighted for a more forcefull strike. ok later guys have fun, Oh and remember to take a propane toarch to the Ti to give it some awsome colors.

cncswiss1
02-23-2008, 01:35 PM
I cut Ti every day in my job making medical implants.. and it is not that bad. use ample coolant (striaght oil or really thick water based ) and use carbide tooling, for milling start at about 135 sfm (drilling at 75 sfm) and in the 1/4 TO 1/2 endmill range try .001 to .005 per flute feedrate for starters.. adjust according to the sound, if in doubt feed harder.. quality carbide endmills are a must, SGS,mitsubishi,iscar,greenfield,osg, etc.. TiAlN coating is ok for higher speed work (500 sfm high speed machining) just plain TiN coating is fine for finishing.. some folks say coating is bad and it makes the edge duller, and i agree partially, i avopid CVD coatings and dtick with the PVD (vapor deposit) coatings, most everytihing nowdays is CVD anyway. get a 1/2 SGS Z carb spin it 1000 RPM and try to break it with heavy feed.. grade 5 is a very soft Ti as far as Ti goes, it may not make the best bashing instrument and will be ahrder to machine than other grades (very gummy) you will see some chip welding if the coolant flush is not good.

if you can get some Ti 6Al4V it will be a better blunt force tool, and a heck of a lot easier to machine.

oh yea Ti flexes a lot you will need multiple spring passes for a fine finish and better tolerance holding. to that end it likes to eat taps, drill a little bigger than stated in the book (+10-15%) for any given tap size and you will have better luck.

apologies for any grammer errors international keyboards are funky to a redneck.¿

APP
02-25-2008, 12:45 PM
Grade 5 is 6al4v, or grade 23. The only difference is grade 23 has less oxygen.


I think you will be better off making your weapon out of steel.