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Calculation of face milling cost

scott24898

Plastic
Joined
Sep 8, 2021
As an average, what is the best calculation of face milling? I have a 4"1/4 A36 plate that needs to be milled to 4". The plate is 24" x 5'1". I'm being told the cost is $500.00. Sounds very high. I would think with the proper cutter it would only take about 20 to 30 minutes to mill 1/4" off. Thought??
 
There is some missing info.

Is this just rough finish on just one side?
Flatness requirements?
Dressed corners?
Short deadline?

Let us know.
 
There is some missing info.

Is this just rough finish on just one side?
Flatness requirements?
Dressed corners?
Short deadline?

Let us know.

Agreed. Other missing information,
what heat treat does the A36 have?
Has it been machined already, or does it have mill scale on it?
What tolerances do you need held on the size?
How many?
How fast are they going to get it done?
 
I could do this job easy, but no way for 500 bucks... You have to pay for my taxes on the building, the overhead crane to lift the damm plate out of your old truck, pay to clamp it to my 125,000 machine. pay for the drug induced clean up boy to pack the chips out and the fee to haul off the garbage. You also have to pay for the wages of the machinist and the pay roll taxes. And then if I make any money the irs wants there cut too...then the book keepers wages, the cost of a 1k facing head and the inserts, the electricity bill, and the coolant cost and the wasted hour of hearing your life story why I am ripping you off charging so much for a simple job. I have a great idea go buy your own machine and do it yourself CHEAP, you should just pay the 500 bucks and concern your self with the fact that you have a go to guy that helps you ... my 2 cents worth ...Phil
 
As an average, what is the best calculation of face milling? I have a 4"1/4 A36 plate that needs to be milled to 4". The plate is 24" x 5'1". I'm being told the cost is $500.00. Sounds very high. I would think with the proper cutter it would only take about 20 to 30 minutes to mill 1/4" off. Thought??

Please show your math.
 
Wow...great replies. 20 to 30 minutes, seems a tad quick. The set up alone might take that long. That breakdown of the costs makes me cringe....I think you left off workers comp, healthcare, electricity, etc.etc.etc.
 
Sure if it was a regular customer or friend I would find it a bit expensive. But it depends on the tooling and time available.

But I would not even bother for a stranger coming in from nowhere for less than 1k. Not worth the potential hassle.
 
366 cubic inches of material. So a 10hp cut for 36 minutes. So it should cost $36.

Then of course, you need a machine, that is at least 61 x 24.. And not everybody has
that, so double the cost.. It should be $72.

Now I have to lift it??? Well shit, can't just pick it up like a tackle box.. So we
need a crane or a fork lift, and the floor space to get it to the machine. That's going
to take a while... So $172.

Now we have to figure out how to hold it.. Giant vises? Toe clamps? Another $100 to get it
held down.. So $272...

ETC.... ETC... Don't forget the tooling cost.. Shiny costs more than shitty..

Tolerances add cost, paperwork adds cost, there is always the "pain in ass" multiplier.

Your cost is not always tied to time and tooling, if nobody within 300 miles has a machine
that can do it, then they can charge whatever they want.. Its what the market will bear.
If you can ship 1700lbs 300 miles away and get it done for $250, would your total cost be
less.

I'd say $500 is a fair price.. That's some big heavy shit that requires some specialized
equipment.. Maybe not "specialized" but I would say only 1:20 shops even have a machine
big enough for it. I'd say only 1:50 would want to be bothered just facing off a chunk
of material.

From a shop.. I would say that is a fair price. If its from a material supplier that says
they can machine your blanks and are selling you a giant slab of steel, then I would say its
probably a bit high.. They should be set up for that.
 
IF we had a machine that size (We do not) it would be a no quote or if we did quote it at least $1500 to make it barely worth the hassle. Maybe a fab shop that does machining or a "hobby shop" would be a better choice.
 
so a 61" x 24" plate....... ya that isnt a small plate to machine off, sure, with no tolerances might still be 3-500 bucks it takes $1000 in tooling and at least a 150K machine to be that big plus paying a guy to do it. some of those large machines charge $250/hr and need to include setup time in the per hr cost, so 2 hrs start to finish is reasonable.
 
so a 61" x 24" plate....... ya that isnt a small plate to machine off, sure, with no tolerances might still be 3-500 bucks it takes $1000 in tooling and at least a 150K machine to be that big plus paying a guy to do it. some of those large machines charge $250/hr and need to include setup time in the per hr cost, so 2 hrs start to finish is reasonable.

And if it's a brun part, and the slag takes out a bunch-o inserts on that big facemill ?.....Cost of inserts, and operator time (while tying up the machine) to change them out.
 
As an average, what is the best calculation of face milling? I have a 4"1/4 A36 plate that needs to be milled to 4". The plate is 24" x 5'1". I'm being told the cost is $500.00. Sounds very high. I would think with the proper cutter it would only take about 20 to 30 minutes to mill 1/4" off. Thought??


I programmed it for my Hurco VMX & for a Haas (haaspower)
The program used a feedmill for removing 0.24" and the last 0.01" using a 3" face mill.
The calculated run time was between 1:57:00 - 2:28:00 for run time.

A 300 HP monster mill (think 300HP cut video link, below) would knock that out in very quickly; however, as stated above, the burden rate on that machine would put you over $500 before it was even setup. Figure $1500.00

Heavy Cutting on Machining Centre - YouTube

My $0.02

Doug

@ BobW
That ingersoll mill would rip off 366 cubic in roughly 1.2 minutes. LOL
 
I would think with the proper cutter it would only take about 20 to 30 minutes to mill 1/4" off.

Call up Titans of CNC over in Texas. He would take a Kennametal 30" face mill, 1,000 inches per minute. 20-30 seconds is more like it.
 
I programmed it for my Hurco VMX & for a Haas (haaspower)
The program used a feedmill for removing 0.24" and the last 0.01" using a 3" face mill.
The calculated run time was between 1:57:00 - 2:28:00 for run time.

A 300 HP monster mill (think 300HP cut video link, below) would knock that out in very quickly; however, as stated above, the burden rate on that machine would put you over $500 before it was even setup. Figure $1500.00

Heavy Cutting on Machining Centre - YouTube

My $0.02

Doug

@ BobW
That ingersoll mill would rip off 366 cubic in roughly 1.2 minutes. LOL

Cat 50 box way with 4" facemill would do that in 30 minutes, but it's still half a day screwing around setting it up and trying to get paid.

Assuming flat and parallel is wide open and we are only cutting one side.

Flipping a 1800lb part and resetting isnt trivial. The material handling on this one is way more than the part.

I would guess any shop that is capable of doing this has at least a 500 minimum charge. Heck if something really goes wrong, the replacement steel from Alro is around $4500 per their web pricing. It's not often I work for less than a steel plate costs to replace.
 
Agreed. Other missing information,
what heat treat does the A36 have?
Has it been machined already, or does it have mill scale on it?
What tolerances do you need held on the size?
How many?
How fast are they going to get it done?

Since OP hasnt come back:

A36 isnt heat treatable. The scale isnt a big deal, its only around .015 thick, just take at least a .030 cut and get under it. Tolerance is likely flat within .0015 per foot or less. Qty 1x. 1-2wk delivery.

Or at least thats what I see all the time.
 
@ BobW
That ingersoll mill would rip off 366 cubic in roughly 1.2 minutes. LOL

So it should cost less than $5.. Not $500. <--- Sarcasm.

A minute to put it on the machine, 1.2 minutes to machine, a minute to take it off.
3.2 minutes at $90 an hour. That's a $5 job all day everyday.. Any shop should be
happy to have that job.. Preferably paid in pennies and nickels, not even in rolls,
but in a used sandwich bag that has crumbs in it, and a mayonnaise smear.
 








 
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