Closed Frame Machine Design

[routercnc]

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-...d-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]

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-...d-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]

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.



Here is diesel's [closed frame / fixed gantry] machine:
http://www.mycncuk.com/threads/8510-...t=fixed+gantry

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

[Boyan Silyavski]

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




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




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]

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




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




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]

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

GRABCAD is an excellent place to search for something.

[ammaratef45]

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.



Here is diesel's [closed frame / fixed gantry] machine:
http://www.mycncuk.com/threads/8510-...t=fixed+gantry

Here is Wals' [open frame / mill style] machine:
http://www.mycncuk.com/threads/7001-...t=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