Why Your Next VMC Should Be A HMC


As a Supervisor and an Operator you are tasked to be more efficient, reduce your workload, and improve and insure quality. As an Owner or Manager your concerns and questions could be slightly different, such as:“How do I increase my throughput?” “How do we separate ourselves from our competition?” and more importantly,“How do we reduce our overall operating costs?” I think these are all good questions but, the first thing you need to ask yourself is “Does this make good business sense?”

With horizontal machining centers traditionally being more expensive than vertical machining centers, how can an investment be justified? Well before we go any further, let’s puts some facts on the table. Here is an industrial fact:

  • Utilization is measured by spindle run time.
  • On average, a VMC has a spindle run time of 25%
  • HMC utilization is routinely 85%

American Machinist & University of Michigan Surveys

I have even seen HMC machines up near the 95-96% range, when tooled up and planned properly. So what we have just learned is it would take three VMC’s to have the same throughput as one HMC.

For a general six-sided part you would have to perform six operations in a VMC. Six operations in a VMC also equals six set-ups, thus handling the part six times. (I am sure you can see where I am going with this.) On an HMC, that same part could be done in two operations. You would only handle the part twice, not to mention there would be no down time between operations because the second operation would be loaded while the spindle was cutting on the first pallet. Can you say efficiency? Wow! I apologize if I seem a little excited, but I can’t help but see the Benjamins falling from the sky!

You probably already knew this, but many HMC purchases in the past have been based on longer running jobs. So why is an HMC the right machine for much of your general work? And how do I get to 85% efficiency when I run general job shop parts? The answer is - set yourself up to be successful:

  • Find commonalities with your families of parts.
  • Use versatile tombstones with dowel pins and tapped holes.
  • Know where your fixturing is so you can tell the machine where your parts are.
  • Use probing to find your parts.
  • Utilize your tool magazine by standardizing tooling.
  • Plan the process before it gets to the machine and eliminate downtime at the machine during set-ups.

Lower operating costs just makes good business sense.

Increase your efficiency, reduce your operating costs, and grow your business without having to add additional labor. America’s manufacturing future needs us to be all of these things, and I for one want to see your company grow. If you have any thoughts or questions please feel free to contact a Hartwig Application Engineer. We are here for our customers.

Summarized Advantages - HMC vs. VMC

Spindle Utilization

Fewer machines required

Remember 25% vs 85%?

Shorter Throughput Times

Increased shop throughput

Less in process work

Set-up Time Reduction

Efficiency / less downtime

Set-ups internal to machining cycle

Chip Evacuation

Better tool Life

Higher quality finish in parts

Reduced Operator Attendance Time

Reduced direct labor $ COSTS $

Put your labor to better use, like inspection or other equipment

If we don’t do something different, how can we expect different (better) results?