Aluminium profile CNC

[Clive S]

my ballscrew isn't very straight. Could it be a problem when everything's bolted down?
Is it a correct way to adjust the space between ballscrew and plate?
Attachment 23755

Thanks

Yes, in English it is called shimming you could use tin foil or you can buy shim of various thickness

[JAZZCNC]

I just find time to update my design and change several thing. I hope I take into account every advice.
If you see anything wrong please let me know. Thanks.

Attachment 23728
Attachment 23729
Attachment 23730

Ok well straight away I see Chicken and Egg problem.! How do you access the linear bearing bolts under the gantry.? If fasten the plate to bearings first then how do you bolt profile to the plate.? Also how do access bearing bolts when squaring setting up etc.?

A much better way is to have 2 plates. One that fastens to the linear bearings which also incorporates the X-axis ball nut mounting plate. Then another bolted to the gantry which then bolts into the bearing plate.
This method makes it a lot easier to setup and square the gantry etc. Also can remove the gantry in one piece if ever need to move the machine and not loose setup.

These pictures show what I mean although it's set up for R&P.

[MikeyC38]

Great post Jazz - there are some things we miss out on in our original designs like how to mount the stepper motor cable chain? or how to adjust the spindle position for tramming? - both mistakes I made in my design and build!

[BriceO]

Yes, in English it is called shimming you could use tin foil or you can buy shim of various thickness

Nice, I will take a look at it.

Ok well straight away I see Chicken and Egg problem.! How do you access the linear bearing bolts under the gantry.? If fasten the plate to bearings first then how do you bolt profile to the plate.? Also how do access bearing bolts when squaring setting up etc.?

A much better way is to have 2 plates. One that fastens to the linear bearings which also incorporates the X-axis ball nut mounting plate. Then another bolted to the gantry which then bolts into the bearing plate.
This method makes it a lot easier to setup and square the gantry etc. Also can remove the gantry in one piece if ever need to move the machine and not loose setup.

These pictures show what I mean although it's set up for R&P.

I didn't see that to be honest. Good point, I'll add a plate, thanks you JAZZ :)

Great post Jazz - there are some things we miss out on in our original designs like how to mount the stepper motor cable chain? or how to adjust the spindle position for tramming? - both mistakes I made in my design and build!

I'll add it too, thanks :)

[BriceO]

I would like to have your opinion guys. I'm want to be sure to understand this: What's the difference between having high side plate like my first design and the newest one? In my point of view, the sideways movement are less important if you have short side plate. Will it be stiffer? And will vibration be a problem ?

[JAZZCNC]

I would like to have your opinion guys. I'm want to be sure to understand this: What's the difference between having high side plate like my first design and the newest one? In my point of view, the sideways movement are less important if you have short side plate. Will it be stiffer? And will vibration be a problem ?

It's late here in UK and I can't be messing around looking back thru 60+ posts to see your design so I'll answer this using my experience of building all types.

Sitting The gantry directly on the bearings using high sides does give much stiffer machine. This leads to less vibration at the tool giving better surface finishes and less tool wear.
However, this is only really needed if cutting mostly harder material like Aluminium/Brass or very hardwoods. If just cutting a general mixture of all materials but mostly woods then gantry with side plates isn't a problem provided the gantry is strong and the plates of suitable thickness and securely braced to bearings.
There are advantages to the machine using gantry sides if mostly used for wood or sheet materials because of easier material loading and access etc.

I have built machines which use both types and in real-world use, both will cut aluminum fine. However, the High side machines can be run little more aggressive in harder materials due to being that little bit stiffer.
You have to decide whats more important to you, higher Stiffness or better accessibility and little easier to build.

[BriceO]

It's late here in UK and I can't be messing around looking back thru 60+ posts to see your design so I'll answer this using my experience of building all types.

Sitting The gantry directly on the bearings using high sides does give much stiffer machine. This leads to less vibration at the tool giving better surface finishes and less tool wear.
However, this is only really needed if cutting mostly harder material like Aluminium/Brass or very hardwoods. If just cutting a general mixture of all materials but mostly woods then gantry with side plates isn't a problem provided the gantry is strong and the plates of suitable thickness and securely braced to bearings.
There are advantages to the machine using gantry sides if mostly used for wood or sheet materials because of easier material loading and access etc.

I have built machines which use both types and in real-world use, both will cut aluminum fine. However, the High side machines can be run little more aggressive in harder materials due to being that little bit stiffer.
You have to decide whats more important to you, higher Stiffness or better accessibility and little easier to build.

I will go for the gantry with side plates so, it will certainly be cheaper too, thanks a lot. I'm working on my design and I'm thinking about adding a 40x120 extrusion under the gantry as you do. In my case will it add some benefits from your point of view?

[BriceO]

Update on the design.

I try to add a profile on the bottom of the X axis. Now, I have to move the gantry a 40mm higher. The Z clearance will 170mm maximum.

I have some work to do with the Z,Y axis.

There is many good ideas in your design JAZZ, I steal some of them. Is it possible? :-)

[JAZZCNC]

[QUOTE=BriceO;100624]There is many good ideas in your design JAZZ, I steal some of them. Is it possible? :-)

No problem take what ever you like and if want to know anything just ask.

[BriceO]

Hi,

Some update of the design. I've lower the extrusion side, add an extrusion on the bottom of the x axis, moto mount and the side plates.
As usual if anything seems to be wrong don't hesitate to comment :)

The ballscrew of the X axis is now higher to screw it directyl to the bearing plate. Thanks Jazz!
I don't add it but the cable chain will be on top of the 120X40 extrusion.


The Y axis motor mount plate:

To mount the ballscrew, I will use a separate plate. I think it will be easier to adjust if necessary.





If you see anything, please let me know :) Thanks