#490

Hello, All,

I have been considering a conversion of my mini-mill to CNC.? I don't do any commercial machining, only my own projects, many of which are tools and accessories for other machine tools.? Do you think a mini-mill CNC conversion is worthwhile, and what would you do with it???

I also realized that I am not fully aware of what the finished CNC mill consists of, or HOW you use it.? For example, when wishing to do a simple machining operation, I know there is an electronic control box that is used; no more cranking the handles.? But how do you get your CNC-machined part to, well, machine?? Let's say I draw up a 3D model.? I know how to do that because it's necessary for my 3D printer.? But if I now want to machine this part, what do I do?? I think?that there is some kind of CAM (Computer Aided Manufacturing) program in which I define which end mills and such to use, and then define "tool paths" of where the tools will actually move, but I am not sure.? Is the CAM program completely independent from the CAD system?? Or must they be related?? Can I draw a 3D part with Fusion 360, for example, and then use a separate CAM program to specify the end mills and define the tool paths?

Any enlightenment would be appreciated.
--
Regards,

Charlie
New Jersey, USA

MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.

Bruce J

#491

开云体育

On Dec 9, 2019, at 5:47 AM, CLevinski <clevinski@...> wrote:

Hello, All,

I have been considering a conversion of my mini-mill to CNC.? I don't do any commercial machining, only my own projects, many of which are tools and accessories for other machine tools.? Do you think a mini-mill CNC conversion is worthwhile, and what would you do with it???

I also realized that I am not fully aware of what the finished CNC mill consists of, or HOW you use it.? For example, when wishing to do a simple machining operation, I know there is an electronic control box that is used; no more cranking the handles.? But how do you get your CNC-machined part to, well, machine?? Let's say I draw up a 3D model.? I know how to do that because it's necessary for my 3D printer.? But if I now want to machine this part, what do I do?? I think?that there is some kind of CAM (Computer Aided Manufacturing) program in which I define which end mills and such to use, and then define "tool paths" of where the tools will actually move, but I am not sure.? Is the CAM program completely independent from the CAD system?? Or must they be related?? Can I draw a 3D part with Fusion 360, for example, and then use a separate CAM program to specify the end mills and define the tool paths?

You pretty much have it nailed. CAD for design, CAM to actually tell the mill what to do. Fusion 360 has a CAM component built in.

Here is a listing of free and OSS software for CAM/CNC I found?

And another:

I do know LinuxCNC is well supported.

Any enlightenment would be appreciated.
--
Regards,

Charlie
New Jersey, USA

MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.

--?

Bruce Johnson

"Wherever you go, there you are." B. Banzai, PhD

#494

开云体育

Hi Bruce,

I've been doing a similar project for the last 10 years or so.? It started with adding Power Feed to the knee since the cast hand crank didn't fit very well and it was a pain to move the knee up and down.? So I mounted a stepper motor on it with a 3:1 belt drive and used a spare Electronic Lead Screw to serve as the motion control.

?

The next bit of automation was using my Lathe ELS to drive my rotary stepper motor to simplify making a much of parts with holes in the same spot for the mill CNC conversion.? Each jog distance was the mount to turn the motor.

?

Finally a few years ago I made it far enough to move the Y axis and the Z axis.? In this case I used a BeagleBone Black with MachineKit (LinuxCNC for the BBB) to test the motion.

?

And then I was distracted by this really good deal on a harmonic drive and the STMBL AC Servo drive kits for an A axis for the CNC project.? Still haven't created the casting to hold the motor nor made a face plate for it.? But it does turn.? For testing purposes it's once again being driven by my ELS.

?

Finally last spring the X axis was motorized and this video shows it running the roadrunner g-code with Mach3 on a WIN-XP system.

?

In the process of hunting down a spindle motor I ran across the Bergerda company in China.? With really good support I managed to swap the X axis with an AC servo and test the smaller of the two I bought on the X axis.

?

Since then I've built a cart to hold all the power supplies and motor drives.? Spindle changeover not yet complete.? For now back to the two DC Brushed drives and a PC that dual boots into either LinuxCNC or WIN-XP for Mach3.? The cheaper route to go is with a Mesa 7i92H Ethernet to Parallel port.? Only a lit bit more money buys an Ethernet Smooth Stepper for MACH3/4.? My conversion isn't finished yet.? I'll post some pictures and perhaps a video later this week.

?

For software I use AlibreCAD/CAM.? What I'm finding is that the wizards that come with MACH3 are very handy.? I've yet to import the equivalent tools into LinuxCNC.? I've also not yet moved over my touch plate code from my MACH3/USB Smooth Stepper installation. ?Again, there is some sort of graphical add on for LinuxCNC that can do this but also not done yet.

?

At the G-Code level the programming is the same.? It takes only a little bit of practice to type a few commands to set up power feed on any axis to mill something.? Many of the LinuxCNC people have become adept at writing their own small G-Code programs to say face a surface for that matter mill a step or groove in multiple passes.

?

Where the CNC really shines though is doing what you can't do with two separately powered axis.? That's to follow a curve.? To mill out a slot.? So that's the biggest reason for adding CNC to your mill.? So although these could have been milled by hand, and probably even faster it was an exercise in using CAD/CAM and the CNC conversion.

?

And even then there's a place for 3D printing since I didn't have any material in aluminum of the right size to machine the second part of the Z axis home/limit switch.

?

John Dammeyer

?

"ELS! Nothing else works as well for your Lathe"

Automation Artisans Inc.

www dot autoartisans dot com

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of Bruce J
Sent: December-09-19 7:42 AM
To: [email protected]
Subject: Re: [digitalhobbyist] Hobbyist CNC - is it worth it? #CNC #CAD

?

On Dec 9, 2019, at 5:47 AM, CLevinski <clevinski@...> wrote:

?

Hello, All,

I have been considering a conversion of my mini-mill to CNC.? I don't do any commercial machining, only my own projects, many of which are tools and accessories for other machine tools.? Do you think a mini-mill CNC conversion is worthwhile, and what would you do with it???

I also realized that I am not fully aware of what the finished CNC mill consists of, or HOW you use it.? For example, when wishing to do a simple machining operation, I know there is an electronic control box that is used; no more cranking the handles.? But how do you get your CNC-machined part to, well, machine?? Let's say I draw up a 3D model.? I know how to do that because it's necessary for my 3D printer.? But if I now want to machine this part, what do I do?? I think?that there is some kind of CAM (Computer Aided Manufacturing) program in which I define which end mills and such to use, and then define "tool paths" of where the tools will actually move, but I am not sure.? Is the CAM program completely independent from the CAD system?? Or must they be related?? Can I draw a 3D part with Fusion 360, for example, and then use a separate CAM program to specify the end mills and define the tool paths?

?

You pretty much have it nailed. CAD for design, CAM to actually tell the mill what to do. Fusion 360 has a CAM component built in.

?

Here is a listing of free and OSS software for CAM/CNC I found?

?

And another:

?

I do know LinuxCNC is well supported.

?

Any enlightenment would be appreciated.
--
Regards,

Charlie
New Jersey, USA

MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.

?

--?

Bruce Johnson

?

"Wherever you go, there you are." B. Banzai, PhD

?

#500

Many thanks, Bruce...?

Sounds like the CAM component must be compatible with the CAD element...
--
Regards,

Charlie
New Jersey, USA

MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.

#501

John,

Many thanks for the examples, explanations and links!? It seems to me that "following the curve" and such otherwise extremely difficult tasks are the biggest benefit.
--
Regards,

Charlie
New Jersey, USA

MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.

#504

开云体育

Hi Charlie,

?

One thing I might mention.? Almost from day 1 I've had a Shumatech DRO-350 and scales on the quill and X/Y axis. ?With a touch probe it's easy to find the center of a hole.?? Same with ensuring that an edge is parallel.? The Shumatech can even do hole patterns etc.? Guiding me to each new XY position before I bring the quill down to drill or mill.??

?

So series of holes that start with the initial center drill, then tap drill, then clearance hole and finally counter bore where the tool is only changed once per set of holes is dirt simple with the Shumatech DRO. Not nearly as easy with scales and counting turns.? And even easier with CNC where you just program in the X,Y positions and still manually move the quill.?? Otherwise you have to have the tool # and length of each tool calibrated so the automatic drilling works properly.?

?

If you haven't had a DRO then the CNC will be a wonderful addition.? If you have the DRO, then not as much depending on what you do.

?

John

?

Show quoted text

From: [email protected] [mailto:[email protected]] On Behalf Of CLevinski
Sent: December-09-19 7:17 PM
To: [email protected]
Subject: Re: [digitalhobbyist] Hobbyist CNC - is it worth it? #CNC #CAD

?

John,

Many thanks for the examples, explanations and links!? It seems to me that "following the curve" and such otherwise extremely difficult tasks are the biggest benefit.
--
Regards,

Charlie
New Jersey, USA

MURPHY'S CONSTANT:?Matter will be damaged in direct proportion to its value.

#505

Hi Charlie.
Thanks for the post as I am sure many forum members are thinking the same as "is CNC mill conversion worth it." ?
So iIf I may throw in my 10 cents worth.then here i go.
My Weiss mill was first modified for a power feed on the X axis only, then due to physical restraints I fitted a power feed to the Z axis.I must mention here that both of these conversions were very doable and the Weiss mill with the solid Z column IE
a positive feed screw was almost a given. I understand alot of hobbyist own a Sieg type mill with a rack and pinion?
type Z axis movement. but not to worry, Richard UK has done an excellent job on a full CNC mill with this type of head and
fitted a ball lead screw powered by a stepper. So it?s all doable, and i am sure he will assist if you ask as he says ?"just yell out".
Richard was the instigator for me to go the "full Monty" to convert my mill to CNC incl a 4th axis.
As i already had a stepper indexing head ( again using a Nema motor) the A 4th axis was a no brainier.
So this left only the Y axis, again not difficult, a stepper motor slung under the X axis table mounted on the side of the mill bed and drives the Y axis via a belt.and pulleys.
After much shopping around i decided on the purchase of a CNC control box, i opted for the DDCS v 2.1?
and basically built a control unit to power everything up from there.
I will gladly send photos as and when.
The choice of controller I admit had a few teething problems but the support from the suppliers engineering staff has been?
amazing and having there own web site and Facebook, I receive regularly new updates that can be easily installed.
by a USB stick.They have now introduced a v 3.1, but all the upgrades are suitable for V 2.1 and v 3.1.
So back to charlies is it worth it question.
IMHO YES.
Of course there are those that still prefer the manual use of a mill, nothing wrong in that, but i have a different outlook
on my hobby, why work hard when you can work smart.
The first job I did on my mill after CNC conversion was to cut scrolls on some new soft jaws, , not impossible manually
but very tricky to do.
Very rarely do i use the mill manually, only for a quickie fix it type job.
I have attached a video of milling in some finger grooves on a knob, again easy to do manually with a dividing head
but the grooves actually "roll around" the circumference, that?s difficult if approached manually.
If members need any help then i am also available.

John Lindo

--
John

MOV05830.AVI

Richard

#506

I CNC'd my Seig X2 because I could! Just about all of my projects seem
to be about making or enhancing tools, actually very little in the way
of making anything else!
The Seig is simple to CNC in my mind. For X I just mounted a stepper on
the end of the screw? on the left end. Y took a little more thought. I
did not like the idea of the stepper on the end of the screw so I
installed a timing belt drive with the stepper mounted back and under
the machine. For Z I created a "spinning nut" with a fixed ball screw
mounted to the head. It all works well.
Control is via Linux CNC. Since the original build I have added a
pendant control (thanks John) and changed the X axis to a ball screw.
I am using Cambam to generate my G code (2.5D not full 3D). Drawings via
Solidedge (2D), Mastercam 8.1 (3D) or Solid????? (3D).
Having CNC capability has enabled me to do things I cannot do on my
other mill. However it was primarily an exercise in making things!
I have recently assisted a friend in uprating his Boxford CNC mill. We
used HSS 2Nm Servo Steppers and the results look great at the moment.
Feed rates now up to 2500mm/min and acceleration at 250mm/s/s. I may
discuss these units further at a later date.
Richard

Show quoted text

On 09/12/2019 12:47, CLevinski wrote:
Hello, All,

I have been considering a conversion of my mini-mill to CNC.? I don't
do any commercial machining, only my own projects, many of which are
tools and accessories for other machine tools. *Do you think a
mini-mill CNC conversion is worthwhile, and what would you do with it?*

I also realized that I am not fully aware of what the finished CNC
mill consists of, or HOW you use it.? For example, when wishing to do
a simple machining operation, I know there is an electronic control
box that is used; no more cranking the handles.? But how do you get
your CNC-machined part to, well, machine?? Let's say I draw up a 3D
model.? I know how to do that because it's necessary for my 3D
printer.? But if I now want to machine this part, what do I do?? I
*think*?that there is some kind of CAM (Computer Aided Manufacturing)
program in which I define which end mills and such to use, and then
define "tool paths" of where the tools will actually move, but I am
not sure.? Is the CAM program completely independent from the CAD
system?? Or must they be related?? Can I draw a 3D part with Fusion
360, for example, and then use a separate CAM program to specify the
end mills and define the tool paths?

Any enlightenment would be appreciated.
--
Regards,

Charlie
New Jersey, USA

/*MURPHY'S CONSTANT: Matter will be damaged in direct proportion to
its value.*/

#508

Hi Richard,
I have recently assisted a friend in uprating his Boxford CNC mill. We
used HSS 2Nm Servo Steppers and the results look great at the moment.
Feed rates now up to 2500mm/min and acceleration at 250mm/s/s. I may
discuss these units further at a later date.
Richard
Interesting about the servo steppers.  I'm using DC Brushed Servos (or the Bergerda AC Servo) with a 3000 RPM constant torque rating of 1.6Nm and 3:1 reduction on the X axis.  The Y has 4:1 because it's got to carry that extra weight from rotating X axis assembly.  Peak Torque on the KL34-180-90 is 8Nm.

Anyway, with LinuxCNC and the MESA 7i92H allow me to move the X axis at 150 IPM (3810mm/min) and the Y at 120 IPM (3048mm/min) and they are incredibly quiet.

What sort of reduction did you use (if any)?  What's the max RPM of the motors you used?

John Dammeyer

Richard

#526

The Boxford mill is quite small about 200mm X and 150mm Y IIRC.
Reduction was about 2:1 Motors will run at 3000rpm not sure of the
torque at that speed.
I will get some firmer numbers in a few days.
Richard

Show quoted text

On 10/12/2019 09:32, John Dammeyer wrote:
Hi Richard,
I have recently assisted a friend in uprating his Boxford CNC mill. We
used HSS 2Nm Servo Steppers and the results look great at the moment.
Feed rates now up to 2500mm/min and acceleration at 250mm/s/s. I may
discuss these units further at a later date.
Richard
Interesting about the servo steppers.  I'm using DC Brushed Servos (or the Bergerda AC Servo) with a 3000 RPM constant torque rating of 1.6Nm and 3:1 reduction on the X axis.  The Y has 4:1 because it's got to carry that extra weight from rotating X axis assembly.  Peak Torque on the KL34-180-90 is 8Nm.

Anyway, with LinuxCNC and the MESA 7i92H allow me to move the X axis at 150 IPM (3810mm/min) and the Y at 120 IPM (3048mm/min) and they are incredibly quiet.

What sort of reduction did you use (if any)?  What's the max RPM of the motors you used?

John Dammeyer