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Hourly cost for small CNC mill?

Conrad Hoffman

Diamond
Joined
May 10, 2009
Location
Canandaigua, NY, USA
We have a manual shop but are looking at some internal jobs that have to be CNC. Small aluminum parts with close tolerances on (probably) a small Haas. Let's assume the machine just appears in the shop and the cost of the machine isn't a factor. Can anybody give me an approximate cost per hour to run parts? I assume it includes programming and other support, coolant, maintenance, all the stuff that one would end up paying for during the year. If my part takes 20 minutes to run, what sort of baseline cost will I have trouble getting below? Cutting tools and stock not included. :)
 
We have a manual shop but are looking at some internal jobs that have to be CNC. Small aluminum parts with close tolerances on (probably) a small Haas. Let's assume the machine just appears in the shop and the cost of the machine isn't a factor. Can anybody give me an approximate cost per hour to run parts? I assume it includes programming and other support, coolant, maintenance, all the stuff that one would end up paying for during the year. If my part takes 20 minutes to run, what sort of baseline cost will I have trouble getting below? Cutting tools and stock not included. :)

IME with a 5 YO small CNC mill, per year costs:

coolant: ~$500
maintenance: $20 for auto-lube grease + $5 for battery change, unless I do something dumb and break something
programming: impossible to answer without seeing your parts, but for a data point, I estimate I spend 100-300 hours/year doing programming

Do you have enough air? You might need a larger compressor.

Regards.

Mike
 
I don't know how to think about labor, how much machine-tending, vs. how much other stuff a person could do while parts are running. It almost seems like fast running parts make the operator less efficient because they don't have enough time to break away to do something else and just end up loading and unloading parts and stock and then wasting the time in-between. I suppose at that point people look at getting more machines! We have two compressors feeding the system (for redundancy) so air shouldn't be a problem unless other uses in the factory drop the pressure too much.
 
Operator removes burrs between cycles. A lot depends on cycle time. I have a 120 second part. Operator unloads part, loads new part, green button. Operator presses a few bearings in and if he is quick he has 10 seconds or more to goof off before next cycle.
 
Hourly cost is a hard question to answer because it depends....

But, I can say that no matter what it costs I don't think you'll ever regret buying a CNC.

^^^^^This.
Do it. We can recommend medications to get you through it. Because you will need some muscle relaxers to prevent you from kicking your own arse bloody when you see what productivity you have been missing.
PUSH THE GREEN BUTTON! Let the force be with you.
 
It’s going to be super dependent on your parts. I assume initially it’ll be the same parts as your making now. For me it seems that for many simple parts the first one is about as time consuming for manual as cnc so similar cost. It’s the second one that’s just a button push and beyond that I don’t even want to think about manual milling anymore.

Also repeat work is nice since theoretically your programming is done. I still always seem to be tweaking them.

Regarding the timing it’s up to you how you spent the time. It’s true if the operator is doing two things at once maybe sometimes the cnc mill will sit a little between parts. If that’s a problem then just prioritize the cnc job over the other.
 
One local company, many years ago, decided the manual shop rate was $25/hr. After moving to primarily CNC they decided the new shop rate was $90/hr. I don't know what all went into that calculation but I'm sure it included the cost, maintenance, programming, etc of the new machinery.
 
IME with a 5 YO small CNC mill, per year costs:

coolant: ~$500
maintenance: $20 for auto-lube grease + $5 for battery change, unless I do something dumb and break something
programming: impossible to answer without seeing your parts, but for a data point, I estimate I spend 100-300 hours/year doing programming

Do you have enough air? You might need a larger compressor.

Regards.

Mike

Curious, what do you do that only requires 100-300 hours of programming per YEAR? I program full time (2000 hours/year) at my job. Technically, not *all* programming, that includes ordering material, tools, designing fixtures, troubleshooting programs, but anywho, most of my work is making new programs...??
 
I don't know how to think about labor, how much machine-tending, vs. how much other stuff a person could do while parts are running. It almost seems like fast running parts make the operator less efficient because they don't have enough time to break away to do something else and just end up loading and unloading parts and stock and then wasting the time in-between. ...

For a while after I got my first CNC, I tended the machine. Dropped what I was doing, ran across the shop to change parts, rotate fixtures, etc. Anything to keep that mill producing non-stop. My POV being " machine time is expensive and I need to keep it producing".

But after thinking about it a bit, the most valuable thing in the shop is my time. If second ops can't occupy me at the CNC, I do other things elsewhere and break to keep the machine(s) going when it's convenient for me.

YMMV
 
Curious, what do you do that only requires 100-300 hours of programming per YEAR? I program full time (2000 hours/year) at my job. Technically, not *all* programming, that includes ordering material, tools, designing fixtures,ss, troubleshooting programs, but anywho, most of my work is making new programs...??

Repeat jobs, multi-day production runs, etc. That was pre-Boeing troubles and pre-COVID though. In 2020 it was probably more like 600 hrs, lots of Xometry1-off's.

Also I'm a 1-man shop, so I have to do all the procurement, cleaning, shipping, paperwork, etc.

Regards.

Mike
 
Might help to break down the charges. Lets say you have a job that takes 100 hours on a manual machine. So it would cost you one employee 100 hours plus 100 hours of machine run time. How much are you charging for manual machine hours separate from the guy running it now?

On a cnc with the same job it requires 100 hours of machine time but only 20 hours of an employee's time. This isn't figuring consumables.(very rough example)

This might not help at all but just a different approach. Most places I've been at just bundles employees time, consumables, ect into a specific machine type whether waterjet, mill, lathe, laser and the rest. Few places I've been at just charge the highest they can get away with until they lose bids and the rest comes out in the wash. No number crunching just a good sense of their customers and company along with a very good ability to blame others.
 
We mostly do prototypes and fixtures on the manual machines, plus some "emergency" jobs to keep production going. No matter how I look at this, it appears cheaper to vend parts out rather than get a machine. Overhead is too high and volume is too low to make it pay. I'd also have to deal with whoever is doing the anodizing. It would give me control over some quality issues that others seem to have trouble with, but even considering the cost of those issues, I can't see beating the price our venders charge.
 
Startup/sustaining costs for a new NC machine in a small shop would be difficult to justify for mainly prototype stuff, one-offs and production tools. Model/tooling shops in large aircraft plants usually have approx. one programmer per NC machine. The machine operator is running the current "part" at the machine while the programmer's working on the next one. Then the next one, and the next one, and the next one.....

I was involved in one extreme example where one large machine required two crews of one programmer and two operators. One crew running their large "part" while the other crew probed/prepped/programmed the next article. This also required two complete sets of tooling. Aircraft mfrs can afford this due to what they can charge for the final product.
 
We have a manual shop but are looking at some internal jobs that have to be CNC. Small aluminum parts with close tolerances on (probably) a small Haas. Let's assume the machine just appears in the shop and the cost of the machine isn't a factor. Can anybody give me an approximate cost per hour to run parts? I assume it includes programming and other support, coolant, maintenance, all the stuff that one would end up paying for during the year. If my part takes 20 minutes to run, what sort of baseline cost will I have trouble getting below? Cutting tools and stock not included. :)

For internal jobs, i.e., jobs that are inhouse projects, I use a factor of a dollar a minute - or $60/hr. I factor this in when I have to make a fixture or supporting hardware for a customer's quote. It's something that's frequently overlooked when quoting.
 
In the US or the EU the typical "cost" of a CNC machine, internal burdened cost, aka all costs factored in, tends to run around 40€ / hr.

This means that if one runs a machine at 41$/hr one makes about 1$ gross contribution margin, incremental.

The cost includes the burdened avg. cost of an average minimum level operator,
shop floor cost (rental, heat/air/permits/taxes/whatever, overhead in bookkeeping and billing),
breakage, maintenance, tooling, setup,
ancillary tooling like parts cleaning,
wash, polish, tumbler, debur, metrology, packaging, shipping, etc.
Cost of material stock, racking, handling, stackers etc.

The incremental marginal cost may be much lower, sometimes, but it is a false premise that Your work and situation will permit that in any significant degree.

This means You can potentially, in theory, run a night-time shift, yourself, at 5$/hr "machinery+power" costs, after lights-out, while paying yourself no salary and or benefits, from the work You do.

False:
IF You could do all the work Yourself You would need no staff, bookkeepers, cleaners, maintenance etc. and still keep working 2 shifts producing parts 16 hours per day.
AND simultaneously selling, marketing and keeping up with clients.

In reality, You need to figure the costs of an experienced-skilled independent operator into the mix for night-time aka second shift, plus parts wear & tear.
+ CNC, tooling, ancillaries, etc.
Tends to run near the 40$ / hr figure, often higher.

A really skilled CNC operator night-time, will get 25$++ per hour.
If they don´t, they walk, sooner or later.
If they are not really-skilled they will make parts with errors or errors-with-machines, You will then wish You had paid the extra hourly salary for.

Reality check.
A really good automated system can drive the cost down to 5-10$ / hr.
Flextronics is a good example.
500k workers, 20.000+ robodrills, 51 ops for an iphone for 8$ total billed.
Maybe 30 minutes processing time for 51 ops.
16$ / hr with 15% margin.

With (nearly) free land, free loans, 1B$ / plant to set up, no hazmat fees, no taxes, no permits, no real accounts/taxes costs.
600$ / month workers.
Free shipping, nearly.

YOU are NOT flextronics, and You most likely cannot get endless workers for 600$ / month.
 
Let's assume the machine just appears in the shop and the cost of the machine isn't a factor. Can anybody give me an approximate cost per hour to run parts?

Aluminum?

Far and away the dominant cost in this scenario is labor. One month of payroll for a decently-paid operator costs more than all the consumables and power combined for the entire year. This doesn't even include programming.

Let's say you do factor in the cost of the machine. Even then, the dominant cost is still labor.
 
We mostly do prototypes and fixtures on the manual machines, plus some "emergency" jobs to keep production going. No matter how I look at this, it appears cheaper to vend parts out rather than get a machine. Overhead is too high and volume is too low to make it pay. I'd also have to deal with whoever is doing the anodizing. It would give me control over some quality issues that others seem to have trouble with, but even considering the cost of those issues, I can't see beating the price our venders charge.

I think you may be right. If you already have working relationships that allow you to do what you need and most of your work is one of.
 
Actually, I'm looking at batches of small aluminum parts up to Q=1000 and it still doesn't make sense to do it in-house! Any moderate sized shop will be running way more than that, and will beat me on efficiencies of scale for all the support stuff.
 
On can do spreadsheets into the way beyond.
I think most end up about a dollar a minute. Go down to 30 per hour and up to 90.
If an employee making the parts on manuals and now looking at cnc someone is already getting paid.
If outsource and one has employees will that payroll cost get cut out of the balance sheet?
Here is where many who outsource based on a "shop rate" make a big mistake.
In the end it is the final P&L.
If all was outsourced how much of a add on to keep the company floating?
If all done inside how much does that change the shop rate needed? What is the incremental cost if all the floor space, SGA. rent, taxes paid for?
What is left .... labor and bennies along with a small tooling and power usage per hour.
It is not simple.

If this cnc machine can run 20 hours per week and you are decent at it is likely best to bring inside.
Bob
 








 
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