Maintenance: VMC vs HMC

I'm interested in how a VMC would perform against an HMC in terms of maintenance: complexity, cost, frequence, etc.

To compare apples with apples both machines would have to perform the same tasks, have the same specs, heavy duty machining (Ti or St).

From my experience VMC's are simpler and require less maintenance. And if they do, it's usually easier and shorter. However, nobody has really done a thorough comparison within our company and I couldn't find much on the internet either.

Any good sources of information ?

Thx, Stan

Just note that any comparison you do has to be based off of spindle run hours, not off of base time. An HMC will typically have a considerable amount more spindle run hours above a given VMC when looking at base time.
IMHO, I don't think you will see a whole lot of difference. They are mechanical twins - in a basic sense.

Having been charged with maintenance on both our VMC & HMC I can honestly say they are quite similar just set on floor in different positions. lol Not sure why but so far the HMC has been a kinda needy & persnickety but it is a re-furbished unit and due to some matters I have no manuals on maintenance, wiring, mechanics or anything for that matter. But that just makes it all the more fun to fix her when she throws a seven. The VMC is a Lancer 2000 and has been a bitch from the get go, named her Jennifer after a totally crazy ex-girlfriend. Not sure if the machine is just old and fussy or has some fundamental design issues but she is always spitting alarms and doing some off the wall stuff.
Bottom line in my eyes there is really no comparison it is plums and mangos, depending on the operator and how hard the machine is pushed. Preventive maintenance is the key, I do a kinda pre-flight on them both every few days and it pays off, catch a lot of potential problems before they really gum up the works. One thing is though they like to run as machines do, if they are idle for a few days that is when things seem to go south, running machine is a happy machine.

All else equal, the frequency of maintenance is the same for VMCs and HMCs based on spindle hours. As Tony stated, HMCs rack up the spindle hours much more quickly, so they would likely require a higher frequency of maintenance from a calendar perspective.

I don't think VMCs are necessarily simpler than HMCs. Clearing out chips is certainly a bigger PITA on a VMC. Add a pallet changer and rotary 4th, and I think the HMC would be the simpler machine.

-Sol

Tony and Sol hit it on the spindle time part, so I would add that the basic HMC has a lot of items that are standard vs. most VMCs - you will most always find a spindle chiller, multiple coolant pumps, higher class ball screws and rails, core cooled ball screws, possibly a dual belt chip conveyor, 4th axis rotary gear mechanism and such on a HMC, but depending on the level of VMC, those items may not be present. What you will also most likely find is that the HMC will have very high quality components (that includes all the little things) whereas the VMC is generally "cheapened" up to be very cost competitive - the conveyor and coolant tank on our horizontal was probably close to $30k, don't see too many Mayfran Concept or Turbo Micorfine conveyors on a vertical. The HMC is usually destined for a more "production" life and is generally built to work in that environment.

In the long run, a horizontal will probably be less expensive to maintain than a vertical for a given job and equal number of hours just from the build and component quality, but I am thinking more on the lines of a "commodity" VMC, not a $300k Makino 30"x20" VMC.

Steve

How about:
Table Size 50.15"x30.11"
Table Load Capacity 4,410 lbs.
X-Axis Travel 40"
Y-Axis Travel 30"
Z-Axis Travel 30"
Tool Magazine Capacity 30 Position ATC

Vmc compared to an HMC???????

What are you trying to compare with those specs?? Looks like you are giving dimension on a decent sized vertical mill, but with a pallet size that large on a horizontal I would expect to see 60" of travel or more... At least in my limited experiences...