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ammaratef45
27-07-2016, 01:47 AM
Dear All,
I'm going to make CNC machine prototype - I need it to be closed frame because that will be easier in the control design because I'm going to use servo motors instead of stepper motors
So I need closed frame design that i can build and apply the control I will design on it
Any help is welcome, I mainly need small mechanical closed frame design

Thanks everybody

routercnc
27-07-2016, 04:07 PM
Dear All,
I'm going to make CNC machine prototype - I need it to be closed frame because that will be easier in the control design because I'm going to use servo motors instead of stepper motors
So I need closed frame design that i can build and apply the control I will design on it
Any help is welcome, I mainly need small mechanical closed frame design

Thanks everybody

What do you mean by closed frame ? Is it like a commercial machining centre with an enclosure

Also steppers are very capable - do you need servos?

ammaratef45
28-07-2016, 01:15 AM
What do you mean by closed frame ? Is it like a commercial machining centre with an enclosure

Also steppers are very capable - do you need servos?

I need servo cause i want to test control theories - it is graduation project
I need design ready and tried cause my major is not mechanical engineering and i need this task (mechanical body) to be easy
And finally closed frame word is not my own description
I got it from book >> this is the chapter described that part https://drive.google.com/open?id=0B1El2XHLhbSCU1hYX1hTbUZfeVE

(https://drive.google.com/open?id=0B1El2XHLhbSCU1hYX1hTbUZfeVE)Any clarification will be helpful
I really thank you for your reply

routercnc
28-07-2016, 07:52 AM
OK. So a 'closed frame' is a 'fixed gantry' and an 'open frame' is like a conventional milling machine.

Good example of a 'closed frame' here, first picture in post#1
http://www.mycncuk.com/threads/9616-Thor-or-should-that-be-Zeus

But there are not many fixed gantry machines on this forum, most are another type with a moving gantry to cut bigger pieces. But have a look through the build logs:
http://www.mycncuk.com/forums/253-DIY-Router-Build-Logs

ammaratef45
29-07-2016, 12:18 AM
OK. So a 'closed frame' is a 'fixed gantry' and an 'open frame' is like a conventional milling machine.

Good example of a 'closed frame' here, first picture in post#1
http://www.mycncuk.com/threads/9616-Thor-or-should-that-be-Zeus

But there are not many fixed gantry machines on this forum, most are another type with a moving gantry to cut bigger pieces. But have a look through the build logs:
http://www.mycncuk.com/forums/253-DIY-Router-Build-Logs

Sorry I'm confused here, But i think the gantry is moving in the picture provided in the link! isn't it?

routercnc
29-07-2016, 07:58 AM
Hi,

The gantry is the large fixed frame connected to the bed, in the shape of an arch. It does not move.
The X axis carriage moves the Z spindle plate left to right on this fixed gantry.
The Z axis spindle plate moves the spindle up and down
On the bed the Y axis plate moves the workpiece left to right.
Hope that helps.

18939

Here is diesel's [closed frame / fixed gantry] machine:
http://www.mycncuk.com/threads/8510-fixed-gantry-router-mill-up-for-grabs?highlight=fixed+gantry

Here is Wals' [open frame / mill style] machine:
http://www.mycncuk.com/threads/7001-How-much-deflection-to-expect?highlight=fixed+gantry
(If you are going for max performance then use profile linear rails (Hiwin etc.) not supported rail.

Boyan Silyavski
29-07-2016, 01:19 PM
The way i see it your best bet is to make a simple fixed gantry machine from aluminium extrusions like the one at the picture bellow

18940


And maybe make it more miniature and enclose it like that:

18941


So at the end you finish with a benchtop CNC.


My advice is thought to use at least round supported rails /SBR, TBR..20 size/ , even better, Hiwin 20 / much more expensive and better/ and 0.8kw water cooled spindle. Use also 3nm nema 23 motors and Am 822 drives, PSU for motors non regulated at 70VDC



I mean when you will be spending money make a real machine that will later have some value. Otherwise go ultra cheap all in one board with drives, 24v motors, PC ATC power supply , nema 17 motors. A micro CNC, similar to 3d printers. The middle way between what i am suggesting, is to spend your money for nothing.

ammaratef45
30-07-2016, 01:05 AM
Hi,

The gantry is the large fixed frame connected to the bed, in the shape of an arch. It does not move.
The X axis carriage moves the Z spindle plate left to right on this fixed gantry.
The Z axis spindle plate moves the spindle up and down
On the bed the Y axis plate moves the workpiece left to right.
Hope that helps.

18939

Here is diesel's [closed frame / fixed gantry] machine:
http://www.mycncuk.com/threads/8510-fixed-gantry-router-mill-up-for-grabs?highlight=fixed+gantry

Here is Wals' [open frame / mill style] machine:
http://www.mycncuk.com/threads/7001-How-much-deflection-to-expect?highlight=fixed+gantry
(If you are going for max performance then use profile linear rails (Hiwin etc.) not supported rail.

That is awesome clarification .. Thanks very much

ammaratef45
30-07-2016, 01:08 AM
The way i see it your best bet is to make a simple fixed gantry machine from aluminium extrusions like the one at the picture bellow

18940


And maybe make it more miniature and enclose it like that:

18941


So at the end you finish with a benchtop CNC.


My advice is thought to use at least round supported rails /SBR, TBR..20 size/ , even better, Hiwin 20 / much more expensive and better/ and 0.8kw water cooled spindle. Use also 3nm nema 23 motors and Am 822 drives, PSU for motors non regulated at 70VDC



I mean when you will be spending money make a real machine that will later have some value. Otherwise go ultra cheap all in one board with drives, 24v motors, PC ATC power supply , nema 17 motors. A micro CNC, similar to 3d printers. The middle way between what i am suggesting, is to spend your money for nothing.

Thank you very much .. can I find CAD file for design like you posted?

Boyan Silyavski
30-07-2016, 09:32 AM
Thank you very much .. can I find CAD file for design like you posted?

GRABCAD (https://grabcad.com/library?page=2&time=all_time&sort=recent&query=cnc%20machine) is an excellent place to search for something.


18950