Build Thread- I need a small benchtop CNC mill

[widgits]

I have been coming here for info and reading posts for quite some time now.
As yet I have not done anything other than buy the old school Jet round
ram baby mill.

But at work I now have the need to buy a baby CNC mill.
Currently I have a Fadal TRM, Hardinge HLV and a RF45 clone.
But the Fadal is always backed up with work and no more time is available.
I have been needing a live 4th axis for the Fadal, not an indexer, for cutting
true spirals.
I have the controller card, amplifier and MPG for this but the cost of the
4th axis itself is quite pricey.
Fadal wants $7800, Calmotion wants $6500.
Jesus, Me thinks thats a bit expensive for a 5C collet popper that has
a AC servo motor, worm drive gear set, resolver or encoder and a couple
of cables with Amp plugs.

So I have now been give a budget of $5500 to come up with something.
Aint it funny how the bossman always wants to save a buck.
I would rather buy or build a benchtop mill w/ 4th axis and have the
extra spindle when I need it.
But I'm not too sure if I can buy something off the shelf that has the
accuracy, high spindle speed and 4th axis for this price.

So now I ponder about modifying a baby mill to meet my requirements.
I wouldn't consider a round column machine for obvious reasons.
But I don't like the drag and speed of the old school dovetail ways.
The RF45 clone that I have is a nice little machine, but it only goes
to 3000 rpm.
I need much much higher for running .010" carbide cutters.
Everything we do is super tiny for micro surgical tools.

But it would be nice to have linear rails and blocks.
Although a bit pricey to do this, what is truly gained?
Will it enable me to high speed 3D multisurf profile a new prototype handle?
Very large program files are needed to carry out a task such as this.
I could see setting up a little machine like this and coming back tommorrow.
I dont want to worry about dovetail ways getting lubed correctly.

Currently we send all our handle out for SLA process.
Although reasonably priced the tolerances the hold are not too good.
And they always need many hours of hand work to smooth out and
make presentable to a board of directors.

Ball screws are a must in my opinion.
But ground screws can get expensive.
How about preloaded ball nuts to help remove backlash.
Tiny tools break easily.
Plink!!! Where'd it go?

Servos vs Steppers?
I prefer oversized servos w/ encoder loop feedback.
Especially for lifting a head.
Unless counter weights are attached to help reduce weight.
Me thinks that the AC servo's are a bit pricey per axis compared to
a DC system.

VFD (Variable Frequency Drive) for controlling the spindle speed?
Belt drive for the high RPM?
Mach 3 software for the large file sizes?
How large of a file can this software handle?
DNC if not?
4"-6" rotary table with a 5C collet nose mounted able to be mounted
horizontal and verticle?

Buy a baby mill and gut it just to put it in my Fadal and machine off the
dovetail ways, drill and tap for linear blocks and rails?
New ball screw brackets?
Does anyone know about the Z-Bot toolchanger that uses the
Tormach tooling?

Being a machinist with 35 yrs knowledge, something such as this doesn't
scare me.
I have in the past retrofitted 2 Bridgeport Boss 8 mills with a newer
Centroid controller.
Wasn't too bad, but it took me 3 days each.
Tracing out the 9 wires from the encoders too the most time.
Mounting the cards and doing the basic stuff was pretty easy.

If I was to jump into this it would be nice to get all the electronic parts from
a good source that has done all the homework for me.
Can I get a good correct schematic to wire this from?
Can I just buy the encoders prewired for a reasonable cost.

I only have $5500 to get the most machine I can.

Any more thoughts?

Thanks in advance.

Widgits

[SpeedsCustom]

I can so far only suggest this Mill for that price range. http://www.syilamerica.com/catalog/p...roducts_id=856 You will have some money left over to pick up some needed supplies.


-Jason

[widgits]

I have looked in that place already.
Up in Coos Bay Oregon?
And have called them 3 times.
Only to discover that I am talking to an answering service.
And I get no returns on my calls or E-Mails.

Geez.
In this economy ignoring someone with money to spend is not a good sign.
Besides if it's this bad just trying to buy a machine from them.
Whats it going to be like should I need parts or service?

Widgits

[Crevice Reamer]

At that budget, you can forget about servos.

I'm thinking either Smithy 622:

http://www.smithy.com/product_home.p...id=16&pid=1006

or Novakon NM-135:

http://www.novakon.net/3.html

CR.

[williams480]

Originally Posted by widgits I have looked in that place already. Up in Coos Bay Oregon? And have called them 3 times. Only to discover that I am talking to an answering service. And I get no returns on my calls or E-Mails. Geez. In this economy ignoring someone with money to spend is not a good sign. Besides if it's this bad just trying to buy a machine from them. Whats it going to be like should I need parts or service? Widgits

Ditto on that experience.
Even PM'ed Syil here on the Zone.
Nothing, Nada.


I'm looking hard @ Novakon they have responded to ALL of my inquiries within hours even on the weekends.
Even gave me residential shipping qoutes when I changed from one machine to another (NM135 & NM200)

Good Luck on your search.

[Crevice Reamer]

Novakon has 6K RPM spindle.

CR.

[williams480]

Originally Posted by Crevice Reamer Novakon has 6K RPM spindle. CR.

That's critical when machining aluminum with smaller tools, to maintain 1000sfm
with carbide.

[ihavenofish]

Originally Posted by Crevice Reamer Novakon has 6K RPM spindle. CR.

its a very nice machine too. id venture to say a bit more refined than the syil. has stainless way covers and some other nice things. for $500 extra they put in a really nice gecko 203 based controller and also include a full license of mach3 and bobcam 21 as well as the stand. they have rotary axis packages too from about $1000 (4" with tail).

all in all a good deal. it wont compare in performance to a fadal, but it should be accurate and solid for light duty work.