RE: [CAD_CAM_EDM_DRO] Mill recommendations needed for new CNC Project

Hi,

I'm in the process of converting an equivalent to a Grizzly G3616 mill.
It's also available as a G3617 which has a horizontal mill drive. The
G3617 also has a larger table in the X direction. Don't know why they
made the G3616 table smaller.

Anyway, the biggest drawback to this mill is that the X axis can also
rotate which is useful for the g3617 with horizontal mill but not so
handy for the one without. It adds a few inches of height which
restricts the maximum distance between the spindle and the table.

The other down side is that the quill rotation is prevented only by the
teeth on the rack and pinion part that raises and lowers the quill. On
mine, at the moment the DRO scale does that which is not a good idea; I
have the Shumatech DRO on all three axis. I will be adding a more
robust guide to fix this issue.

For the CNC part, I've done up drawings in Alibre for motor mounts. I'm
going to use Keiling DC Servos with HP UHU drives for the X and Y axis.
I'll use a stepper motor drive for the knee since speed isn't an issue
there. Eventually I'll add power down feed to the quill too. Don't know
yet if it will be a servo or stepper; haven't decided.

On the spindle front, I will be installing a 2HP 3-phase motor and VFD.
I have flood coolant (came with) that will also be MACH controlled.

Finally long term plan is to add a raising block between the column and
the head just large enough to also hold an R8 Spindle run with an HP UHU
servo and add the horizontal mill feature to this system.

Ball screws are also in its future.

John Dammeyer


Automation Artisans Inc.
http://www.autoartisans.com/ELS/
Ph. 1 250 544 4950

> -----Original Message-----
> From: CAD_CAM_EDM_DRO@yahoogroups.com
> [mailto:CAD_CAM_EDM_DRO@yahoogroups.com] On Behalf Of mayfieldtm
> Sent: Monday, June 30, 2008 1:07 PM
> To: CAD_CAM_EDM_DRO@yahoogroups.com
> Subject: [CAD_CAM_EDM_DRO] Mill recommendations needed for
> new CNC Project
>
>
> I'll be approaching my Boss on the possibility of putting together a
> small CNC Milling Station.
> Our need is quite specialized and it might be better suited if we
> build our own. I know a ready made commercial machine will be out of
> the question. All of our in-house CNC Machines are tied up in
> Production or tool making.
>
> So I'm asking you-all on your recommendations on a good new starter
> Mill that could be converted. Would like to keep the Mill price around
> and under $2500 (new). I'm figuring another $1500 for other parts.
>
> For my Home Shop, I converted a Grizzly (of the rong-fu type design).
> Although it's perfect for my hobby use, It would just not be tight or
> beefy enough for our application. And of course, you-all know about
> the round column problems.
>
> We often design Forming Dies (two dimension) for various types and
> thicknesses of spring steels.
> The results of bending a part, often, is not quite as expected
> (calculated) and will fall out of tolerance, so the Die needs to be
> reworked or remade. The second try is usually successful.
> Most of our Dies are EDM'ed by an outside source, and can be expensive
> and most importantly, time consuming.
> I believe I can justify the concept of a small in-house CNC for this
> purpose only. I would not expect nor want the Machine to be used in
> Production.
>
> My Maximum Milling Envelope would be: X=6" Y=3" Z=1".
> The Typical size of a Die is 3"w x 1.5"h x 0.25"thk. with a profile
> along the 3" dimension.
> Most of the time I would be using an 1/8" Mill in 0.125 - 0.25" thick
> material. Typically "O1" or "D2" tool steel. (Annealed of course)
> Probably use Servo Motors, speed is of no importance, so Step Motors
> might be OK.
> Dual Nut Ball screws mounted on Annular Bearings for Minimal Backlash.
> Will be using Gecko Drives, a Brute Force Power Supply, Computer
> Interface and a Computer running Mach3.
> I found that the most difficult part of converting the grizzly was the
> Z-axis, so the basic machine should be well suited for that.
> The converted machine will be CNC only with no manual operation.
>
> What did I forget?
>
> Thanks in advance for suggestions, support and???
>
> Tom M.
>
>
>
>
>
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