Re: recommendation for machine

Was your quote from a CNC punch/fabricating shop or from a CNC machine
shop? If it was a machine shop, the prices could easily be 3X the
price from a punch/fab shop if you've got any appreciable quantity.

For low volume chassis fab work its still hard to beat a Wiedemann
RA41P turret punch. They'll carry about 20 tools in the turret, and
tooling is readily available in round, square, rectangles, slotting,
oblong, D's and double D's, etc. Max round capacity is just over 3"
thru 13ga mild steel. They're around in the used market, and often
available with tons of tooling, since most people who are getting rid
of them have moved to cnc punches and the tooling isnt interchangable.
They're a template type machine, and a stylus drops into a 1/4" hole
at the center point of each position where you want to punch, as
simple moving the clamped part and pulling a trigger. Not as fast as
a CNC turret punch to be sure, but can be bought for $4000 with
tooling as opposed to $400,000 plus tooling for the cnc variety. With
properly clearanced punches you can get far better results on parts
like this via punching as opposed to any type of routing or milling.
Copper sheet is particularly difficult to drill or mill and get a
clean edge, but no more difficult than any other metal for punching
operations. Once tooled and set up (not difficult) they can be run by
your average chimp with an hour's training.

--- In CAD_CAM_EDM_DRO@yahoogroups.com, "c123666" <c123666@c...> wrote:
>
> Hello,
>
> I am new to this group and not a machinist but an accountant who is a
> partner in a small venture to manufacture a limited production of
> rather expensive tube amplifiers. After pricing out having chassis
> built by a CNC shop we have decided to investigate acquiring our own
> equipment to get the job done.
>
> Our basic requirements are that we need to perform very accurate and
> clean drilling/punching/milling operations on a maximum sized 18" x
> 14" sheet metal (copper, aluminum, stainless steel) with a max
> thickness of 0.090".
>
> The maximum hole sizes we need to cleanly cut/drill/punch are 2.75".
>
> We would like to know if such a machine exists that can be had for not
> a small fortune that require a hangar for room!
>
> I"ve attached an Autocad file with samples of the drawings of the
> chassis if anyone is interested. All help is appreciated.
>
> Regards,
>
> Carl