Re: Horizontal vs. vertical mill

On 11 Nov 2005 06:12:29 GMT, D Murphy <spamto154@xxxxxxxxxxx> wrote:

>Will <Will@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote in
>news:jbv6n1l03ltq7jd43ba142np7s425av09m@xxxxxxx:
>
>> I was talking to someone who works at a shop that only uses horizontal
>> machining centers with a fourth axis ( tombstone rotates ) for
>> production. They are pallet fed with a robot system.
>>
>> Are these really better than verticals? He says the chips fall away
>> from the cutting area, is there any other advantage.
>
>It depends on the part and the machining required. In general horizontals
>allow you to get at more side of the part than a vertical can. A two
>pallet horizontal is good for high production as one pallet can be
>loaded/unloaded while the other is being machined. Two pallet machines
>are often constructed in such a way that they can easily accomodate
>hydraulic fixturing. Hydraulic fixturing is one way of automatically
>loading and unloading the fixtures with a robot.
>
>A multiple pallet machine is ideal for small lot sizes. If the work
>requires frequent changeovers you can't beat a horizontal with an APC and
>a multi pallet que. All of the required fixtures and tools remain in the
>machine at all times. To go from part "A" to part "B" you simply put work
>in pallet "B" and the machine will read the pallet number and pull up the
>right program and run the pallet. Total changeover time is the pallet
>change time. It's not at all unusual for these machines to have a 95% or
>better uptime (in cycle cutting parts). A standard VMC rarely achieves
>40% when measured over time.
>
>The problem with a multi pallet horizontal is the initial cost. They are
>quite a bit more than a standard VMC. Few companies bother to look beyond
>the initial cost to see what the long term costs of a VMC really are.
>They aren't very productive and there usually needs to be an employee
>standing in front of each one. Changeovers take forever. Here is an
>example of an 11 pallet horizontal. Changeover time is around nine
>seconds. http://tinyurl.com/8bcwa
>
>>
>> I think they are Hitachi's. He claims they cost over a million each.
>> Sounds too high to me.
>
>Sounds high to me for anything Hitachi made, but if that includes say 120
>tools and a dozen fixtures, along with some automation and a turnkey,
>maybe you could get there. I could see an extremely large horizontal with
>a large pallet pool getting up around a million tooled up and ready to
>go. The machine in the link for example would run from the low 300's up
>to the low to mid 400's depending on options and number of axes. Then you
>have to tool it up on top of that. That machine is smallish for a
>horizontal.

Dan, ( and all of the others that responded)

Thanks for the for the response(s).
Never having used or even seen a horizontal, I had no idea they were
that much more efficient.



Will
.