What's new
What's new

Milling Slot in 1/2 Steel Block

Fite13

Plastic
Joined
Jan 2, 2020
Location
Rockwall
I just bought a HAAS VF-4SS. I am VERY new to machining. I am trying to mill a .750" wide slot into a 2.500" wide x 2.250" long x .500" thick steel bar. The slot goes all the way through the .500" and 1.375" into the 2.250" side.

I have tried to use a 1/2" roughing end mill to start it and then finish it with a 1/2" 4fl end mill. I keep breaking both.

Any feedback or tips at all will be appreciated.
 
What are your feeds/speeds, DOC, is tool coated, running coolant? The more info you can give about what's going on, the more likely people can help you.
 
what rpm and feed are you running? depth of cut ? type of steel ? if I were to play it safe I'd be at around 1000 rpm or less on a 4 flute, about . 1 to .15 depth of cut. .75 (3/4) inch a min with flood. if you had some decent software you could do a interpreting cut with a smaller endmill like .25 and about 2200 rpm and .1 deep .02 side cut at about 22. Inches per minute. but start off with what works for you. and get some software when you can afford it.
 
You have quite the machine to be asking that kind of question.


Two hands here to help...

On the first hand- use a smaller endmill to start if your looking to finish the slot at .500. 1/2" mill will wind up going oversize as it will deflect and push some as you step down...more so if you do not. Which leads me to are you stepping down or trying to take in one or two shots? Normally you want to be less then 1/2 the tool diameter in depth of cut "DOC". But since your burying the tool in a full cut it would need to be less deep. I'd run a 3/8 or 7/16 endmill, spin about 300SFM at 10-12IPM leaving .01 on sidewalls with 3/16" cuts aprox for carbide.

Going corn cobb rougher...bring speed way down.

So I'd step and rough down to depth then a fresh EM to take a finished pass.




The second hand is telling me to ask what your doing now. A half inch endmill is not the easiest tool to break. Is the part moving on you? Are you trying to take in one shot?...or two?

Don't get discouraged...what your looking to do is pretty easy...but you need to remember tools do not like being buried...and I have a feeling that is what your doing. Enmill stays cool by slicing material off in the small area of contact, then tossing it away...along with the heat of the cut held in the chip.
Burying the tool has more tool engaged in the work so more friction.
The chip is larger, means more heat in the chip to be transferred to the tool and the worst part...the chip has a tough time being ejected in the small open area so chips are not taken away, heat stays AND the chip often goes around a second time and now the tool is cutting the material along with cutting the chip too and that does not make the tool happy.
 
I am having trouble visualizing what is meant by, "The slot goes all the way through the .500" and 1.375" into the 2.250" side."
 
I am having trouble visualizing what is meant by, "The slot goes all the way through the .500" and 1.375" into the 2.250" side."

I'm picturing a U or C shaped piece as the final product. I'm wondering if the vice is collapsing the shape when it becomes unsupported, and pinching the EM or allowing the workpiece to move.
 
I am having trouble visualizing what is meant by, "The slot goes all the way through the .500" and 1.375" into the 2.250" side."

Slot going the full depth in a 1/2" thick piece of 2.250" wide material, total slot length is 1.375"?

My question to the OP:

Are you clamping this in a manner that tends to squeeze the slot against the cutter? That would sure as hell be likely to break cutters.

Edit: I just read the post above mine. Looks like I'm late to the party.
 
I would program it to cut the outside of the slot and just drop down like .05 per pass or about 3* angle ,, drill a 11/16 hole in the center and chips have a place to go .. I make a part with a slot like that in Alum and 90% of the wear is on the bottom of the cutter to after dropping all the way down I just drop a extra .1 and take a finish pass around ..
 
That’s a great machine to learn on!
30hp and 1400ipm rapids, what could possibly go wrong?


Sent from my iPhone using Tapatalk Pro
 
On the Technology side- you noted being new- Are you using a CAD/CAM package yet? The simulators can be a great learning tool as well for visualizing what the replies are suggesting too. with no preference- you can sample/use several big-names and learn to use them via youtube training. (names out there like Fusion 360, Inventor, SolidWorks, bob-cad, dolphin-cad, etc)
Good luck. It's about reading, learning, and trying at this point. Have fun doing it.
 
Nobody that buys a VF4ss would struggle with this task, pics or it’s BS


Sent from my iPhone using Tapatalk Pro
 
Nobody that buys a VF4ss would struggle with this task, pics or it’s BS


Sent from my iPhone using Tapatalk Pro

.
its like somebody buying a $30,000 car and saying they are crashing car trying to drive it. and they are asking on the internet how to drive the car
.
probably somebody trying to sell feed and speed software, tooling, or cnc training. of course saying thats how the best people do it. or to be one of the best. or need to buy to keep your job.
.
knew a company got sold on buying a $30,000 invar metal tape measure guaranteed to not expand or contract much with temperature changes. trouble is what you measure does change with temperature. over 50 foot distance it was considerable length change with temperature changes even when using a 10lb spring scale to stretch tape measure consistently. literally measure 3 times in the morning measurements repeating ok but measuring 3 times 8 hours later it was much different measurement cause of temperature change
.....its actually better to measure steel parts and concrete with a steel tape measure (much closer temp expansion coefficient than invar metal). after wasting $30,000 on salesman talk we learned what was true and what was salesman BS
 








 
Back
Top