Re: [CAD_CAM_EDM_DRO] Digest Number 474

>Message: 7
> Date: Mon, 01 May 2000 19:59:27 -0000
> From: mnels@...
>Subject: Help: CNC mini-mill comparison
>
>I'm sure this has been discussed before, but I'd really appreciate
>any advice on a CNC mini-mill purchase. I primarily want the mill
>for machining plastics, PCB drilling/machining and some light metal
>machining. Some of the plastic work will be for semi-production use
>(so speed is important). The three obvious choices are:
>
>The MaxNC mills... probably the 10-2. It's the cheapest turn-key
>solution but I've not heard good things about the mill or the
>company. I've heard the spindle/motor mount has problems and the
>motor speed and CNC control electronics are very substandard. The
>rest of the mill looks pretty solid.

[I'd say get their new closed loop machine instead, if you can afford it.
The speed and accuracy are noticably better, and the spindle speed control
is done in the software instead of with a (somewhat flaky) potentiometer. I
remounted the motor on mine- it's not a big deal to do, if you're handy.
You can also get an inexpensive air turbine attachment for high-speed
milling.]

>
>A Sherline 5400 retrofit (probably Progressive Logic or do it
>myself). The wide variety of accessories for the Sherlines are great
>but the mill itself seems less rigid and durable than the others?
>Another downside is a low 2800 rpm max spindle speed. This mill also
>has only a 2.25" throat depth.

[Sherline makes a solid little mill. I'd rate it as more heavy-duty than
the MaxNC, but not as beefy as the Taig. While their motor is a bit slow,
you could probably boost it with pulleys if you needed to; Sherline
supplies a 1/2 hp DC motor, so you'd have plenty of torque.]

>
>The Taig Micromill. Using the MicroProto CNC package, it seems to be
>the fastest (30 in/min rated and they claim up to 60 in/min). It
>weighs over twice as much as the Sherline and is supposedly much more
>rigid. The CNC version has a max spindle speed of 8500 rpm which is
>better suited to our needs. It has a 3 5/8" throat which is a big
>improvement over the Sherline. It also has 1/2" leadscrews versus
>1/4" on the Sherline.

[I like the Taig CNC too. It is also possible to get them with bigger than
standard 200 oz/in motors (for a little more money.) The 60 in/min speed is
for rapid traverse, not cutting. They are now using a 1/5 hp spindle motor,
so it has more power than the 1/8 hp motor they were using before. And it
comes with the SuperCam software, for no additional charge.]

>
>Does anyone have anything to add to the above? Specifically, does
>anyone have anything bad to say about the Taig Micromill?
>
>Thanks!

[They have been having a problem getting delivery on their regular stepper
motors- the supplier has been jerking them around. So shipments have been
delayed quite a bit lately. This is supposed to get resolved in the next
week or so, and they should get back to a prompt shipping schedule, but
check before ordering.]

Andrew Werby
http://www.computersculpture.com

Andrew Werby - United Artworks
Sculpture, Jewelry, and Other Art Stuff
http://unitedartworks.com