Re: [CAD_CAM_EDM_DRO] Defiance VTX-1 VMC?

Hi Pizzaface:
I own a Defiance VTX1.
I bought it in 1999.
It is an earlier model with the Bridgeport DX32 control, not the later
Creative Evolution control.
Here's my two cents' worth:
The basic machine construction is OK with these caveats:
- the head was not perpendicular to the table in either plane, and needed to
be refitted.
- the tee slots are not parallel to the x axiz motion
- the table is a hot rolled mild steel plate about 1 1/2" thick and has
curled 0.0007" in "X".
- the machine is lightly built with 5/8" ballscrews and teeny linear
bearings
- the spindle is very simple in design, more like a router than a heavy duty
mill, but it does 10K all day and has been totally trouble free.
- the pneumatic collet clamp mechanism needed to be rebuilt.
The machine controller is easy to learn and use, and has lots of nice
functions like macro programming and full variable programming.
It uses some goofy proprietary G codes that you'll need to learn.
The controller is notorious though, for its inability to handle acceleration
and deceleration properly on short linear moves at high feedrates.
This makes the machine hop around like a machine gun when you are doing
surfacing of convoluted shapes with lots of direction changes.
The result is poor finish and accuracy, and an inability to do high speed
machining of hardened steel without trashing a lot of cutters.
This is purely a DX32 controller problem, and Bridgeport was sued over this
defect in a class action suit some years ago.
Defiance later switched to the Creative Evolution control which was reported
to be excellent.
My machine came with no toolchanger, and although one was promised by
Defiance, I'm not sure if one was ever actually produced.

On to my use experience:
I bought the machine to do a contract I'd won for developing an insect
habitat for the space station.
I have milled literally mountains of Delrin on the machine, and, once its
defects were corrected, it performed like a champ.
It is lightly built, but I have nonetheless used it to mill hardened A2 at
62 Rockwell C; this with a 1/2" cutter milling a 2" deep pocket, and
although it didn't like it, it did it!!
I can take a cut of 0.050" in aircraft aluminum with a 4 flute 1/2" cutter
at 5000 RPM and 30"/min without problems.
I've milled lots of electrodes on the machine, all in Telco, and it handles
that very well too.
The precision of the machine is less than stellar...it ain't no 2 tenths
machine, but I can circular interpolate within 0.0005" if I keep the
feedrate down and the cut light.
I do a good bit of small routing of ABS housings for a local manufacturer,
and it's been brilliant in that role too, mostly because it's tiny enough to
be handy to get into while sitting in a nice comfortable chair.
It's biggest limitation is the lack of a toolchanger...production machining
without one is a losing proposition unless your parts typically can run
unattended for 20 minutes or more.
As a prototyping machine it's been excellent, again because it's little and
handy.
My machine has no coolant, and I don't want any because it's my plastics
machine.
Without coolant though, you can't expect to do any amount of production
machining in metals.
The way covers are Gortite; I've no idea how they'd stand up to coolant, but
I'd suspect no too good.
It's a good little mill, but don't expect to drill 3/4" holes in steel with
it; there ain't enough rigidity in the head to handle it.
That's it in a nutshell..hope it's of some use in your decision.
I'm not sorry I bought mine...I got a decent deal and I made back its cost
in the first two months I owned it.
I still use it daily even though I've got a Haas too.
If the machine's in good shape, and if you don't hope to hog out big pockets
in huge mold bases with it, it's worth owning.
Cheers

Marcus

----- Original Message -----
From: "pizzafacepizzaface" <boutakis@...>
To: <CAD_CAM_EDM_DRO@yahoogroups.com>
Sent: Thursday, April 15, 2004 1:37 AM
Subject: [CAD_CAM_EDM_DRO] Defiance VTX-1 VMC?


> Hi, does anyone have any experience on a Defiance VTX-1 VMC? I am
> looking at buying one of these puppies, and I was wondering how good
> it would be for aluminum and steel? How viable is it for small
> production runs?
>
> Thanks